I was bored today and started looking all though AF. Found this section, and thought I may as well ask. I found some electric superchargers on e-bay a while back. At the time, I figured I'd need 9 of them for my truck (3 in series, 3 of those in parallel) to get the flow I'd need and still have any pressure. I've heard that the electric ones work on small ricer engines, but what about a 350 small block chevy? Has anyone put the electric ones on a big engine? I know I'd need a second battery (optoma yellow top, shared with my winch) with an isolation switch to keep from burning up the alternator. I have the room under the hood to mount 9 of them. All I need to know is would they really do anything?

Thanks-
-Jason

See here:

http://www.automotiveforums.com/vbulletin/search.php?searchid=853816
[AF Search Engine]

I had already searched for past threads. I came to the same conclusion I did 2 years ago when I first heard of the electric superchargers. Now can anyone answer my question? Has anyone tried them on larger engines?

If you had really read the answers, you would have seen that they don't work, period. I don't care how many you have, you'll exceed the available amperage draw by tenfold before you gain even a single HP.

It would literally take about 15 hp worth of electric motors to create enough flow to create boost. At approximately 150 amps per HP at 12v, that equates to about 2250 amps. If you had a conductor about as big around as your leg, 30 alternators, and 30 batteries, you might create an extra 10 hp. Of course, at a cost of about 7 hp per 100 amps of power not including belt losses, that's a loss of over 150 hp just to drive the alternators. That doesn't include the packaging concerns or the added 500 lbs of alternators, belts, and wiring.

No matter how you slice it, it costs more power than it makes, or restricts the intake more than it boosts.

I did read the answers, and searched before I posted. There were positive and negative answers. They have about 1 PSI boost at 300-400 CFM. So, I would need several for my truck. If we can go back to my original question:

HAS ANYONE USED ELECTRIC "SUPERCHARGERS" ON A LARGER ENGINE? I just want it for a little boost through the mud pits or climbing a hill, It's not like I'm going to be driving down the street with them on.

If you can point me to a specific thread, rather than search results, that would be alright too. It is possible that neither my searches, nor Alastor187's search hit the page that would benefit me.

I don't see why you're getting upset. All they said was that they DO NOT work. Even if you are just using them for "the mudpits or climbing a hill. You'll get like 2 psi of boost, which will make no differnce, whatsoever. Using them on a larger engine would yield about the same results as on an import engine. NONE!
These people are trying to help you by telling you not to waste your time or money on superchargers that SUCK.

...I may have misunderstood your emotions, but caps usually mean you're yelling...

I didn't intend to "yell", just drawing attention to my original question. I suppose i could have bolded or underlined tho...

I don't know a lot about forced induction, but why wouldn't a couple PSI make a difference?

Actually, no matter how low the boost you add, you WILL get some advantage.

All normally aspirated engines operate under a vaccuum condition in the intake manifold.

All normally aspirated enginrs have a point at which "volumetric efficiency" becomes nil. Simply said, they can't suck in enough air, so as to overcome the inertia of the air itself, that they start to choke. Choke is actually a bad word, as the engine cannot drag enough air past the venturis, in a carbureted engine, to drag fuel in. So they lean out, instead, to the point that they die.

If you can boost the air by "even" 2 psi, you will raise the max at which the engine starves, again.

At 5000 RPM that 350 needs 500 CFM. When your manifold vaccuum rises too much, you are sucking less than the engine needs to burn the fuel. To add an electric centrifugal blower that can PASS over 500 CFM, not only as boost, WOULD boost volumetric efficiency, as would be demonstrated by those naysayers here who have had their intakes polished to reduce resistance to flow, such as Extrude Hone's process.

And, 9 in a row, is an exagerration. A centrifugal compressor, a blower in this case, doubles the pressure, per stage..

I'll have to get a measurement from some of the blowers in the garage. I know you can't hold your hand over the outlet, at least not easily.

I've built them, in a factory, large ones, that were capable of 10,000 PSI, and that is not a misprint. These were centrifugal compressors, for deepwell oil applications. Some damned dense air, when you got to the last few stages. No piston, nor gear,nor vane pump could handle the volume required.

Cheers,

George

And the blower, as such, should not have that big a current draw. Work it out on your shopvac.ANY free air you get is a bonus.

I have a few things for you to think about.
These "Electric Turbo/Superchargers" that you see on ebay all time? Do you know what they really are? Do you know what they really cost? They are fans... Most of them are bilge fans for boats. Bathroom vents... and they cost less then 20 bucks brand new. The qualifying term here is "FAN"... They are NOT compressors. They have no way of "compressing" ANY kind of intake charge. Look up fan and compressor in the dictionary. Most of these "fans" flow under 200CFM at full load with NO outlet restriction. Put them in an intake tract and all they do is restrict flow to the carb/injectors. A good running small block will outflow one of these things by the time it's transitioned off idle...
Do what you have to do but realize these things are being sold as automotive hardware which is a blatant misrepresentation of their intended use.
Do a google search for "bilge fan" or bilge vent". You will see the exact same pics of these fans that the sellers on ebay stole to put in their auctions. Bathroom fans do not make "superchargers".
Read this... Scroll down a bit and you'll find a pretty comprehensive article on these bilge fans...
http://www.dansdata.com/danletters105.htm
Mark

Sorry, I'll read the OP more thoroughly next time.

You're right, those would block airflow more than help.

If the OP wants some boost, he's gonna have to spend more than those 20 buck fans cost.

Cheers,

George

http://www.emotipad.com/newemoticons/Funny-Above.gif
PSST!! I got this pill. You put it in your gas tank and then fill it up with water. C'mon, 10 bucks!

I wasn't refering to the fan-in-a-tube that's all over e-bay now. The one I saw was actually a centrifugal blower. It was also a bit more than $20, been awhile so I don't remember what it cost. I have decided to wait till my engine wears out (it's gonna be a long time) and then put a real turbo or supercharger on the replacement engine.

I know the $10 pill doesn't work, I tried the top of the line $30 pill and it didn't even work. Maybe I used the wrong kind of water.

Thanks for the help... and the smart-ass comment.

The answer is VERY simple.
Back-pack type leaf blowers!!

Black and Decker has a 12 volt 12 amp model.
Look:http://eshop.msn.com/marketplace.aspx?pmpType=1&mpId=0&pcId=3012&catId=350&page=0

The gas powered kind blow really strong and can easily blow pebbles and stones off a parking lot. They develop huge volume and decent pressure, much more than an electric one.

Look: http://www.echo-usa.com/prods_list.asp?Category=POWERBLOWER

I have one in my garage. Lets see....I can bungee it to the roof of my car, and cut a hole in the hood for the hose......and I can even open the sunroof to pull-start it.
Who knows, I might win a race or two.

'Rat,

Alright, you found the answer. A B&D Leafblower will do the trick.

They ad them at MPH, 120 MPH, 150 MPH, etc.

Just wonder how many CFM. Pressure doesn't come into it, as if you can feed the intake enough air, it will take it.

Now, problem # 1, you have to start the engine with that obstruction in the intake.

Problem # 2, if the thing puts out more than the engine can handle, what do you do with the excess. As in, an engine that is 10:1 compression is that only with atmospheric pressure, not turbo, unless the turbo does not kick in till the engine starts to starve.

Now, you need to plumb the thing in so that it will give you boost, and not be an obstruction, and still be able to boost when you need it, so you have to engineer a wastegate, for one, and a "check valve" so it doesn't blow all the air back out of the naturally aspirated engine's intake.

What's next?

Cheers,

George

The answer is VERY simple.
Back-pack type leaf blowers!!

Black and Decker has a 12 volt 12 amp model.
Look:http://eshop.msn.com/marketplace.aspx?pmpType=1&mpId=0&pcId=3012&catId=350&page=0

The gas powered kind blow really strong and can easily blow pebbles and stones off a parking lot. They develop huge volume and decent pressure, much more than an electric one.

Look: http://www.echo-usa.com/prods_list.asp?Category=POWERBLOWER

I have one in my garage. Lets see....I can bungee it to the roof of my car, and cut a hole in the hood for the hose......and I can even open the sunroof to pull-start it.
Who knows, I might win a race or two.
A leaf blower is as the name implies, a blower, a blower doesn't compress the air. To get a power increase the air must be compressed (no ifs and buts), to compress the air the blower must feed air in a rate greater than the engine can consume. This will result in an increased pressure and and then a state of equilibrium where the mass flow over the compressor is equal with that over the engine. The problem with the leaf blower (those fitted with high power output gasoline engines) is that its blower isn't designed to increase pressure, it's just intended to increase airspeed and increasing the pressure does not only require quite some power, it also needs a carefully designed compressor.

12 volts and 12 amps is equal to 144 watts... I have more power than that in my electric R/C car.

I will however not say that it's totally impossible to get more power using leaf blowers. There are poeple that have build their own flow benchs using vacuum cleaner motors and fans, these only test on one cylinder and the pressure achieved with the fans are very low... still you need perhaps 10 motors to get the performance you need. So for a leaf blower to work you will need say 10 of those in a series increasing the pressure little by little while maintaing their flow. If you do that, then you probably can increase the power just a little on a small engine.

^Exactly. I have tested it with a shop-vac. I fitted a pressure gauge on it and closed off the end of the hose. It was close to 1psi of pressure. And this shop vac rated the speed of the blower at 170mph. So no it won't work.

And Saabjohan, I think he was joking.

All engines operate under a vacuum until the throttle blade is opened enough. On a NA engine that is. Do you honestly think you discovered a breakthrough in FI technology? I mean, I guess I shouldn't have spent $2500 on my turbocharger setup. And all the professional car builders should just go on Ebay sometime.

Well, maybe I shouldn't have thanked Twitch1 for his smart-ass comment, just keep getting more.

Well, maybe I shouldn't have thanked Twitch1 for his smart-ass comment, just keep getting more.
The reason you keep getting smart ass comments is because you aren't listening... THESE THINGS DON"T WORK!!!! (was I yelling?) Sorry...
This... http://www.electricsupercharger.com/ is the ONLY "legitimate" electric supercharger I know of...
Go to the site... Read their ad. Do you see where it says their unit MAY provide a 4 to 6% increase on motors up to 5.0 Litres? 5.0 Litres is around 300 Cubic Inches. Your "350" is bigger then that. Your 350 is may be putting out 190 HP. 6% of 190 is 11.4 HP which you MAY see but, more then likely won't, because your motor is too big for the supercharger and all it will do is restrict airflow.
This is all stuff I've learned by first hand experience, searching and reseaching on my own. I will recommend you do the same. If you have a problem with the answers you are getting then do the damn research yourself. (Now that I've done it all for you...) :rolleyes:
:banghead: :banghead: :banghead:

A leaf blower is as the name implies, a blower, a blower doesn't compress the air. To get a power increase the air must be compressed (no ifs and buts), to compress the air the blower must feed air in a rate greater than the engine can consume. This will result in an increased pressure and and then a state of equilibrium where the mass flow over the compressor is equal with that over the engine. The problem with the leaf blower (those fitted with high power output gasoline engines) is that its blower isn't designed to increase pressure, it's just intended to increase airspeed and increasing the pressure does not only require quite some power, it also needs a carefully designed compressor.

12 volts and 12 amps is equal to 144 watts... I have more power than that in my electric R/C car.

I will however not say that it's totally impossible to get more power using leaf blowers. There are poeple that have build their own flow benchs using vacuum cleaner motors and fans, these only test on one cylinder and the pressure achieved with the fans are very low... still you need perhaps 10 motors to get the performance you need. So for a leaf blower to work you will need say 10 of those in a series increasing the pressure little by little while maintaing their flow. If you do that, then you probably can increase the power just a little on a small engine.
Saab, I was joking. But thank you for your in - depth reply.
All these leaf blowers provide excellent flow, but when the column of air slows down past a certain point the impellers tend to cavitate and pressure falls, which, of course is the opposite effect than a real compressor. As you say, this is a function of the impeller design.

The old style GM turbos (60's Corvair and Jetfire) as well as the old McCollough centrifugal superchargers functioned at about 5 psi - which would be a reasonable goal for my project. I do intend to work with this concept and post any relevant results.

Yes, 12 amp at 12 volts is not much power. Still the concept of an electric compressor has some merit in certain applications.

Just because I was there, I looked at the "leaf blowers" at Sears.

400 CFM, average.

Ridiculous to think of putting a 2 cycle gas powered blower in line, BUT, any forced feed of air, regardless of the pressure, WILL give you an advantage.

If you are drawing 21 inches of vacuum, at 5000 RPM, and dying, feeding the intake 400 CFM, at a "1 pound" max, as above, gives you, still, 400 CFM of air that you didn't have.

That 350 draws 506+ cfm at 5000 RPM.

How, pray tell, can forcing even 1 additional pound of pressure not help, at 400 CFM? The reason that a turbo has 1.4 BAR of boost is to make up for the starvation when the engine is trying to suck more air than the intake will allow to pass, as the damned thing is a slave of inertia.

And, no, that leaf blower, or that shop vac, is not just a "fan", it actually does create a vacuum, and it will actually put out a pressure. When you shut off the intake of a vac, it does not whine in "agony", it howls with glee, as there is no air for it to move, so the impellor is freewheeling, totally unloaded.

This is entirely for argument, as I don't intend to attach a leaf blower to my Audi. However, I must admit, my 85 5000 Turbo had much more balls than my 90 100.

Cheers,

George

I'm sorry,I ignored SaabJohn's post.

An airpump can be either a simple air pump, or a vacuum pump, or a compressor. Depends on what you are doing with it.

You can have a propellor, or an impellor, or a vane type air mover.

All will make pressure, though to varying degrees. You might think ONLY a turbo design can move air as you need it. All other designs are useless. Nikola Tesla, around the turn of the 20th century designed a turbine that had absolutely smooth sides, no vanes, fins, nothing.

Just because I was there, I looked at the "leaf blowers" at Sears.

400 CFM, average.

Ridiculous to think of putting a 2 cycle gas powered blower in line, BUT, any forced feed of air, regardless of the pressure, WILL give you an advantage.

If you are drawing 21 inches of vacuum, at 5000 RPM, and dying, feeding the intake 400 CFM, at a "1 pound" max, as above, gives you, still, 400 CFM of air that you didn't have.

That 350 draws 506+ cfm at 5000 RPM.

How, pray tell, can forcing even 1 additional pound of pressure not help, at 400 CFM? The reason that a turbo has 1.4 BAR of boost is to make up for the starvation when the engine is trying to suck more air than the intake will allow to pass, as the damned thing is a slave of inertia.

And, no, that leaf blower, or that shop vac, is not just a "fan", it actually does create a vacuum, and it will actually put out a pressure. When you shut off the intake of a vac, it does not whine in "agony", it howls with glee, as there is no air for it to move, so the impellor is freewheeling, totally unloaded.

This is entirely for argument, as I don't intend to attach a leaf blower to my Audi. However, I must admit, my 85 5000 Turbo had much more balls than my 90 100.

Cheers,

George

I'm sorry,I ignored SaabJohn's post.

An airpump can be either a simple air pump, or a vacuum pump, or a compressor. Depends on what you are doing with it.

You can have a propellor, or an impellor, or a vane type air mover.

All will make pressure, though to varying degrees. You might think ONLY a turbo design can move air as you need it. All other designs are useless. Nikola Tesla, around the turn of the 19th century designed a turbine that had absolutely smooth sides, no vanes, fins, nothing.

Okay, for arguments sake, lets use your numbers as an example...
You say that the leaf blower puts out 400 cfm average. This will be at full speed with NO restriction at the outlet. What does it put out when you hook it up to an air intake? You can't tell us that because there are no numbers to back it up. The leaf blower is not designed to "work" with a restriction. It cannot compress the charge therefore output will go down because it can't flow freely.
You also say that a 350 draws 506 cfm at 5000 RPM. Think about this for a minute. If your leaf blower only puts out 400 CFM how is it going to supply 506CFM to a 350 motor running at 5000 RPM? In order for this "blower" to work as you describe, it will need to be running in a sealed system that allows NO outside air flow. How many CFM will the motor actually be getting? I guarantee it will be a lot less then it really needs to run efficiently.
There is nothing to substantiate that ANY of these fans will "improve" performance in an automotive application and any real testing has proven them to be only a restriction that hurts performance.
Mark

OK like I posted in the other eletric turbocharger thread.


ok peeps


A turbocharger DOES NOT INCREASE AIR FLOW BY BLOWING MORE AIR INTO YOUR SYSTEM. A turbocharger compresses the air charge and then feeds it to you engine. It's like taking all the air that is in the room your in right now and putting it into a beer bottle. Still the same ammount of air..... Just more compressed, Which means you have a more dense air charge.


Like this.

http://files.automotiveforums.com/gallery/watermark.php?file=/500/87736turbohowto1.jpg


Now a "eletric supercharger just twirls around and does nothing.


http://files.automotiveforums.com/gallery/watermark.php?file=/500/87736retardid1.jpg
In fact I garuntee that when you went WOT your engine would pump enough air to Drive the fan.

I feel visual learning is the most effectiveway to communicate :p

Astroracer,

One thing you have to realize, at 5000 RPM,that engine theoretically draws 500 CFM.

But it won't draw a full charge at high revs. Air has inertia. It's one of the reasons they developed turbos and superchargers.

Also why an engine develops max torque and max HP at less than max RPM. It's running out of air.

So, any extra air you can force into the throttle body, the better the performance.

I'm not condoning this entire idea, just saying that most anything except that heating duct fan in the picture will put more air there than you will get without, as long as it doesn't, at the same time, cause an obstruction.

Anytime you move air, even by waving your hand, you ARE compressing air. You are trying to force it into the space your hand is waving toward, but there is no restriction there so those molecules move so the pressure goes back to equilibrium, atmospheric pressure.

I just went to the garage and put a gauge, just held in the web of my thumb, over the shop vac outlet hose, not a tight seal. It also has a not new filter, so some restriction to flow.

It puts out 18 ounces, 32 inches H2O, 8 kilopascal. So, you see, it actually does compress air.

A turbocharger, with no restriction, such as an intake manifold, would also move a lot of air with not a very high rise in pressure. When you use it in a car, depending on the throttle position, you might get up to, what, 2 BAR?

You get the engine to 6000 RPM or more, you might be sucking more air than even the turbo can supply, the engine poops out.

Have to go back to the engineering site, check this stuff out. No idea of the volume an Audi turbo has.

Gotta go , now, but this is interesting.

Cheers,

George

Just because the leaf blower can flow 400cfm doesn't mean its gonna. All it will do is back up into the blower and the blower will discontinue flowing air. Put your hand over the end of one of those blowers. What happens? Air just stops coming out.

Put your hand over the end of the turbocharger. What happens? Your hand doesn't stay on it very long.

Nissan,

Do you know that for a fact, or are you surmising?

You are missing my point. The leaf blower is trying to move air, it simply can't "blow your hand off it", as you say, and I'm not too sure of that. I've never felt the need for one, so can't go out and check its output pressure.

However, it does indeed build pressure, with a 3 foot or so pipe and a flattened "nozzle" at the end. There is drag in the pipe, and a restriction of the pipe itself, not to mention that same nozzle. You can't move that volume of air, in that size pipe, without a rise in pressure

When you put your hand over the nozzle, you don't cause it to go to zero pressure, you simply get it to the max pressure that type of impellor, in that particular machine can maintain. Your hand isn't just resting on the nozzle, as if it were lying on a table, you are tensing against that particular pressure. And the pressure doesn't continue rising because, for this application, they did not need to design an efficient impeller, one that could force even more air into that closed tube.

Once you have equilibrium on the intake and discharge it just churns the air in the impeller itself, no air going out, so no air coming in.

Try it on your shop vac. Plug the discharge, then hold your hand over the intake. You will feel very little suction, if any.

And, I said above, that at the maximum boost range of your engine, so I've read elsewhere, on this forum, you may get up to 2 BAR of boost, 29 1/2 PSI

I'm not sure if the turbo guage is set at absolute or atmospheric, 2 BAR, I would assume atmospheric, and at idle, you would be at, perhaps, .7 BAR, the NA ideal of about 21inches of vacuum. So, at 1 BAR, you are at free flow, you can get all the air you need, and when you go faster, you get the turbo to produce as much air as the engine needs, with a positive pressure, as much as another BAR, another 14.7 PSI.

At some point, however, you are going to get to the point where your turbo, unless oversized, cannot deliver the air your engine needs, and "volumetric efficiency" falls off, the engine starts to gasp for air, and the power produced plateaus, you quit gaining speed because you are out of breath.

One advantage of this leafblower idea is that you would have all that instant response at the low end.

Ah, well, probably hit the sack, now.

Cheers,

George

If this whole electric super/turbo charger worked, dont you think more racers/drivers would actually be using them?

I never said it was a GOOD idea, just that it is not infeasible.

No, I think money is no object to a race team, but weight is.

A turbo big enough and a motor strong enough to give enough air to an 800 or 1000 HP engine would probably throw the whole car out of kilter, handling wise.

When they mount a Roots type blower, for instance, it's in the center of the engine, all the weight distributed on both front wheels.

They take a lot of horses to drive, too. Most, if not all, that I have seen pictures of, are driven by 2 inch or wider v-belts, although it's possible they are using variable speed pulleys.

The ones I have worked with, at various times over the past 40 years, have been driven by 4 or more 6L belts, or direct coupled, or on GM diesels, gear driven.

And, of course the air stops coming out when you put your hand firmly over the end of the hose, but the pressure in the hose doesn't go to zero, just as when you shut off the air hose from your shop air compressor, the pressure in the hose doesn't drop to zero. The impellor is still "compressing" the air in the hose, ie, not allowing it to just gasp back out through the now useless impellor, that is no longer moving air.

Now, I know, you're thinking "Aha, gotcha, there's a whole tank full of air still there, so of course there's still pressure."

But, do the same with a tankless compressor, and the hose is still charged, if there's a pressure switch, or a pop off valve, or if the motor even dies from overheat. The hose still has the system pressure.

Your leaf blower would, without a doubt, provide extra air to that motor till you got to a demand it could not keep up with.

I think that my NA Audi is 10:1 compression. My turbo Audi was either 8.2:1, or 8.3:1, or maybe even 8.8:1, as my book shows those ratios. They did not make those different ratios so that they would cover everybody"s bases, they did it because a NA engine gets air at atmospheric, and FIs are fed a "compressed" charge of air, ie, too much air for a 10:1 ratio, same as maybe 12 or 13 to 1, maybe more. The turbo force feeds it to bring it to about 10:1 equivalent

You try to compress that air, your compression pressure is going to skyrocket, cracked pistons, bent rods, not to mention, if it ran, you dont have the injectors to deliver enough fuel to make a rich enough mixture in the fuel-air charge, lean burn, hot as hell,there go the valves, piston crowns, head bolts probably stretch, bent rods, ad infinitum.

God, all these cans of worms, we're opening.

Long post, hope it's not too boring.

Cheers,

George

And just because I said you ARE compressing air.

Sure have tested it. They barely make 1psi. Turbines are high speed devices. Why is it that normal exhaust driven turbines spin in excess of 100,000rpm and even some these days surpassing 150,000rpm?

Tip speed, pure and simple.

The higher something spins, either the smaller it has to be in diameter, or the more exotic the alloy, and exotic alloys,to the point that they are using ceramics in some of the higher rotation devices.

The more exotic the alloy, the higher the manufacturing cost.

The higher the manufacturing cost, the higher the cost to you, the consumer.

The higher the cost to you, the consumer, the fewer the sales, so the price won't fall to where you can afford it.

Off topic, of course, but they are having a few problems with the polycarbonate DVDs, because they spin so fast at 16X, they burst into thousands of pieces, and that's at approaching 32,000 RPM!

What are you gonna do with a titanium impellor at 150,000 RPM?

Have you looked elsewhere? The housing is designed to contain the shrapnel!!!! They aren't sure they'll take the turns!

As to the Knight electric pulse device, it looks exactly like the vacuum drives on my dust collector in my woodshop, with an open frame DC motor installed.

1k deposit? What the hell does it cost, in the long run?

Cheers,

George

Well thank you for the belated tech lesson, but that is exactly the reason why a leaf blower will not work as a power adding device.

I believe your whole post was in regards to centrifugal force. Materials also have some to do with lag as the less mass and weight of the impeller, the less rotational inertia aka time it takes to reach speed.

NO, no, no.

I don't, really, know what you are trying to say. A leaf blower has such a heavy impellor that it takes too much time to spin up?

A turbo has the lag we are talking about. It takes time for the exhaust gases to get the turbine side to move.

An electric motor, if we are talking electric, goes to the next speed with an almost indiscernible lag. Try your 3 speed fan. Push the button or turn the switch, it almost instantly goes faster.

Look, I said, way back when, that this could be called silly.

BUT, I don't care what you say, any additional air WILL help.

Christ, go back to WWII, Buzz Bombs, V2s, Ram Jets, they fired off ,gained speed, going fast meant the air in front of the engine was being compessed, since the engine was going so fast the air in it couldn't push that air aside so that it had normal air pressure for combustion.

You want to argue for argument's sake, okey-dokey, I'll argue with you all day long.

You just wanna tell the OP he's an ass, you're wrong. Period. And an exclamation point to boot!

Cheers,

George

........if this works so great, do it then for yourself and show us a dynosheet..

Dyno sheet?

Hell, I'm an old man, not into all that modding, even if my NA Audi was low compression.

Have you guys been to the site with the electric super charger, read the specs, seen the warnings that low compression pistons would have to be installed?

Some of you guys are being realistic about this, a few are just trying to throw roadblocks in the way.

I still have not said it was a good idea, but it is not implausible.

I don't think the OP wants to go from 200 to 400 HP. He wants a little more efficiency at the complete range of RPMs.

Turbos, expensive, requiring much modification, electronics, etc., you are not gonna do it without a package designed for YOUR auto.

Electric suprcharger, Knight, etc, asks a 1000 bucks for a deposit, what's the whole shmear cost? And, it runs on caps.

When some of you write that a super, turbo-charger, doesn't move air, it "compresses" it, you're being silly. It compresses it only to the extent that it is providing enough air, in some cases, more, than the engine needs, to keep atmospheric at the throttle plates.

When an engine sucks too little air, it gasps. The less air going through the carb, or through/over the mass air flow sensor, the less fuel, so your engine poops out.

Fact of life. You're not gonna change it.

Add some air, get some gain.

Cheers,

George

Yep, but how much air does a leaf blower flow when its blocked off? Not much. Thats the difference with a turbocharger. It compresses air when its blocked off. It will still flow air when air backs up in the manifold(boost). As long as its sized properly for the amount of air that the engine can inhale, the turbo will continue to flow air. The leaf blower on the other hand, will poop out. Most don't flow enough to keep up anyways so your $100 powertrip ends early at about 2500rpm.

Lag is the time it takes for the engine to reach the RPM where enough air is moved throught he engine to spool the turbo. A lot fo things can cause this. Rotational inertia, turbine housing size, impeller design(turbine), manifold design(believe it or not, logs acutally spool sooner:) tubulars just make more power), downpipe/ehxaust size, intake tracting, engine tune, ect.

What I was saying, before you continued to tell me how turbocharger impellers work/are made/out of what, is that the impeller inside a leaf blower is very large supporting decent leaf moving flow at a low RPM. It isn't spinning fast enough to create any boost or move any air. It isn't designed to either. Not balanced properly, diffuser prolly isn't designed right, and neither is the housing. Compressor impellers rest less than approx. 1/16" from the compressor housing(saabjohan could chime in here as I've never measured/read this). Last time I looked at my blower, it was approx. an inch away from the housing. So, uh, this isn't gonna work without more work/money than it would cost to use an average turbo and be happy.

Turbos, expensive, requiring much modification, electronics, etc., you are not gonna do it without a package designed for YOUR auto.

This is very wrong. Many instances will not require any electronic tuning or buying a new ECU after turbocharging and running a basic setup. And putting togethor your own setup is more effecient and cheaper than buying a kit IMO...

I run 9.5:1 compression ratio(comes out to be 180psi compression) on my car. 6psi from a T04B Garrett turbocharger(about to be 9psi and prolly 13psi for dyno runs after a tuned ECU with 615cc injectors). Pump gas.

My kit is completely pieced together.

Most recent engine shot

http://nissaninfiniticlub.net/photopost/data/500/19378engine_overview3-med.jpg

and all the photos. You can kinda tell the most recent ones from the old.

http://nissaninfiniticlub.net/photopost/showgallery.php?cat=500&ppuser=19378

lol, I'm a young guy. Clocking in at a rather high 18 years old. But I rate people on what they know and nothing else. I won't even use expirience as a factor in an arguement.

i was hoping you would chime in on the not piecing togethor a kit comment :) thats what im doing..slowly

Nissan,

Do you refuse to understand what I am trying to say?

NO centrifugal pump, whether air or liquid, can build pressure when it reaches its max. I do not care whether it is a vac or a super duper Garrett Turbo. Unless it puts out more than any normal centrifugal air compressor can, or is multi stage, you are stuck.

A centrifugal pump on a firetruck will go to 100 PSI and churn. You will have 100 PSI available, but you have to open the nozzle to get any work out of it, ie, move water.

Take your turbo, disconnect from the intake, put your hand over the delivery end, the output, and you will most likely shut it down, unless you are a wump.

It will put out X PSI, and stop, keeping the pressure in the plenum at X PSI, because it is still trying to push air, and not allowing any air to get back past the impellor.

Are ye all daft? Can you not understand this? The pressure in the discharge does not fall to Zero because you stuck your mitt over the discharge. You had 2 or 3 or 167 PSI, it is still there. Take your hand off the discharge. It doesn't take time to build pressure up again, or volume.

Nissan, believe it or not, a 16th of an inch is unacceptible in turbos, or air compressors.

If you had said 2 thousandths of an inch clearance, I would have given you a little of the benefit of the doubt.

You obviously know little of air compressors.

You THINK you know much about air movers, but, again, anytime you move air, you are compressing it into either a reservoir, or a restriction, such as an air intake, or an air nozzle, with a trigger.

Lag is the time for the turbo to spool up to where it can feed the engine enough air to get boost, not for the engine to get to high enough RPM to SPOOL the TURBO. Where the hell you been, boy? Get your nomenclature right, at least.

Those who buy a kit that does not require any of the following:

"Many instances will not require any electronic tuning or buying a new ECU after turbocharging and running a basic setup. And putting togethor your own setup is more effecient and cheaper than buying a kit IMO"

are buying a pig in a poke.

Do as you will. No skin off my nose.

Cheers,

George

Better you should buy a 100 buck leafblower, IMO.

You're right, I don't know anything.

Lag is the time for the turbo to spool up to where it can feed the engine enough air to get boost, not for the engine to get to high enough RPM to SPOOL the TURBO. Where the hell you been, boy? Get your nomenclature right, at least.

So, uh, what do you consider what happens when you punch the gas in 5th gear at 2k and no boost, but when you hit 4k, you reach full boost? What do you call that RPM range between idle and 4K?

And you just explained why a leaf blower will not make any power on a car...

You're right, I shoud just pull all the shit off my car and accept that I know jack about cars. I have been reading on this stuff, listening to non-A hole people like Hypsi, Saabjohan, Formula, and the rest of the "decent" people on here for a little bit. But I should just accept it was all in vein because some douche comes on here and has a hard time trying to explain his point of view to someone about a subject with absolutely dick relevence as he knows it has no potenital to work in the first place.

Cheers...

BEtter you should stick to not modding cars.

Watch your tach, next time you punch it at 2k in 5th.

Since you're in overdrive, in most vehicles, you don't have the power to build RPMs quick enough to get the exhaust spinning the turbo fast to get much boost, although it is still building turns, and it is providing more air.

But you are also sucking that air in, so it doesn't show on your BAR guage.

Put it in 3rd at 2k and punch it, you'll raise the revs so fast that in a second or 3 you'll be at maximum boost, since you DO now have the muscle to spin your tires. RPM rises fast, exhaust rises even faster, turbo spins faster, so fast your wastegate opens.

Back in 5th at 80 MPH on the level, your guage will probably drop back down to about 1 BAR, since you're not working the engine hard, just cruising, even though it IS still pushing air, not compressing it, as per your definition.

I'm gonna stick to not modding cars.

Better than pictures, though, and yours are nice, how about some dyno sheets on your Nissan project. I doubt you have any "pre", but "after" stats should compare favourably with an un-modded engine to see if you have made much difference.

I didn't start the leaf blower chat, kiddo. I just added comments and figures on , them, and tried to educate you on the principle of moving and compressing air.

What's the name and model of your turbo? I'd like to see the spec sheet on it.

Cheers,

George

It runs at like 1-2psi all the way until I hit 3.5k and then its hold on.

1/4 times were with 5psi unintercooled with a stock coil that was going out. It sputtered like crazy toward the end of the track. I ran a 15.3@93mph. Sorry I don't have any dyno sheets. As I said before, I'm about to buy a Jim Wolf Tech ECU so I don't really see any point to spending $100 for a couple dyno runs right now plus I don't wanna spend the money right now.

Turbo model is a Garrett T04B .60ar S-Trim compressor/.69ar P-Trim turbine.

I know it has made a massive difference. Wheelspin is an issue up to 45mph whereas it wasn't really an issue at all before. I say its making at least 200whp and about the same torque.

Air/Fuels are 12.5:1 so its running decent. Timing is handled via MSD BTM with 3/8* of retard per psi starting at 3psi.

I'm only doing 6psi now. Mods include...

Revhard log manifold
Turbonetics evolution 35mm wastegate
Boostdesigns FMIC kit
greddy type S
IAP oil lines
Custom 3" Stainless downpipe fabricated by me
3" Apexi exhaust
K&N filter
ACT clutch
PLX M-300 wideband
Vortech 8:1 Fuel Management Unit
Walbro 255lph fuel pump
and some more I'm sure.

But the turbo won't even spool unless I'm at 3.5K and I push the pedal at least 50%. Obviously less if I'm at a higher RPM. I wanted exactly that because it drives so smooth this way. I never hit boost unless I want to. But when I do, it hits hard.

Thank you for being much more polite.:thumbsup:

i doubt you would be able to put your hand over your compressor outlet, if thats what your trying to say. That would mean you would have enough force to hold your exhaust from leaving your manifold, since that same force creates the inertia and power to move the compressor blade... yeah, sure....thats not what you were trying to say was it gmatov? And when i stick my hand over my leaf blower it dies out, if a weak guy like me can stop the pressure, i doubt it will be enough to sufficiently add power to your engine..

"Where the hell you been, boy?"

Nissan, if you are refering to the above, which is the only post I have made that I think could have pissed you off, it's an anachronistic question that an old guy would ask a young guy. Kinda like a "jag", if you understand that.

Good on you that it is working for you.

I have been to other sites stressing turbos that do not give the best results for aftermarket "add-ons".

Unfortunately, they promise the sun and stars, and are barely able to deliver the moon, and at a really, really, high cost, like 10 grand, plus.

"I ran a 15.3@93mph." Is this supposed to be a 1/4 in 15.3 seconds?

If that's so, performance has gone to hell. I used to run a '65 Merc Monterey convertible, all 4500 pounds of it, faster, with a 400 cid carbureted engine. 3 speed auto, to boot.

Cheers,

George

OK, try 2,
Hit n run,

15 PSI is not a lot of pressure. Would you agree to that? Even a wump, as you describe yourself, should be able to hold that pressure in the blowgun with your thumb. Now, if you should be talking about a 3 inch hose, go to pi, 3.14 x times radius squared force. Now we are talking holding back 50 pounds of force, so maybe your self acclaimed weakness comes into play.

Correction: Just did the calculation, at 15 psi exhaust pressure, with a 3 inch pipe, you have 106 pounds of effort pushing your hand off it.
When you hold your hand over your tail pipe, by no means are you holding back hundreds of psi. You have lots of VOLUME, which we have been speaking of, here, but very low pressure.
Edit: this is because of cooling and expansion in the exhaust system, the pressure at the exhaust manifold itself is several hundred PSI.


ie, if you had a hand 144 square inches in area, and a 1 pound (Edit:1 pound per square inch) force against it, you would be holding back 144 pounds of force, can you understand this?

Cheers,

George

Good grief. Can't we all just get along? This whole flow vs. pressure thing is like the HP vs torque debate over in the engineering forum.

I don't care if a leaf blower can provide 6,000,001 CFMs of air. If it doesn't make any pressure, it won't make any power. Engines ingest air at atmospheric pressure anyway. If the air coming from a blower is 1atm, I don't care how much it flows, it won't make any power. The whole point of forced induction (and I hope you more edumacated folks will correct me if I'm wrong) is that it pressurizes the air, so for the same CFMs of air the engine ingests, there is more "air" per CFM it takes.

Hold your hand 1" away from the nozzle of any leaf blower. Serious flow, right? Now seal your hand over the nozzle. The pressure stops. The problem is that the blower design just moves air; not compresses it.

Lag is the time for the turbo to spool up to where it can feed the engine enough air to get boost, not for the engine to get to high enough RPM to SPOOL the TURBO.

Exactly. I get so tired of people equating "lag" with the time it takes to achieve boost after mashing the pedal.

Curtis73,
Actually, engines do not ingest air at atmospheric pressure, they're always under a vacuum.

Air has weight and mass, therefore, inertia. You open the throttle, the pistons try to gulp X cubic inches of air right now, but inertia causes a vacuum, because the air has a resistance to flow, plus all the resistance of a filter, ductwork, bends in the same, etc.

1 pound of "boost", from any source, will help a little.

And, as for the leaf blower, or shop vac, they absolutely make pressure. You're confusing the air flow stopping when you put your hand over the wand with it not being much pressure. If it was actually NO pressure, then you could put a pice of paper over it with your hand, lift your hand, and the paper would keep it sealed. Just saying that sounds silly.

The impeller is not very efficient, nor the housing, way too much clearance, as well as not enough rotational speed. They're designed just well enough, and cheaply enough, for the job, picking up dirt.

I mentioned, a week ago, that my shop vac, with a dirty filter, produces 18 ounces of pressure, with the hose plugged except for the guage.

Turbos were originally designed to allow planes to fly where the air is too thin to allow an engine to run. They probably do pack a double gulp of air into the cylinders, but since the air is half as dense, equated to a gulp at sealevel. (Actually, probably more, in time, as the builders would want to brag about their super engines, as well as allowing smaller engines or bigger planes with the same engines.)

Ah, well, still interesting. And, I'm not fighting, I'm trying to make a point, but don't seem to be doing too well.

Cheers,

George

I don't care if a leaf blower can provide 6,000,001 CFMs of air. If it doesn't make any pressure, it won't make any power. Engines ingest air at atmospheric pressure anyway. If the air coming from a blower is 1atm, I don't care how much it flows, it won't make any power. The whole point of forced induction (and I hope you more edumacated folks will correct me if I'm wrong) is that it pressurizes the air, so for the same CFMs of air the engine ingests, there is more "air" per CFM it takes.

Hold your hand 1" away from the nozzle of any leaf blower. Serious flow, right? Now seal your hand over the nozzle. The pressure stops. The problem is that the blower design just moves air; not compresses it.

Word...

I just looked in Hugh Macinnes Turbochargers and I apologize, I did have lag confused.

The impeller is not very efficient, nor the housing, way too much clearance, as well as not enough rotational speed. They're designed just well enough, and cheaply enough, for the job, picking up dirt.

Didn't I say that earlier?

You are still not getting it.

You have a vacuum in the manifold. If you tapped the manifold at several points from the valves back to the air cleaner, you would see different levels of vacuum, because of inertia, the air closest to the valve, the vacuum source, here, will register the highest vacuum, those closer to the air cleaner, the lowest, because of the inertia.

Air has inertia, because it has mass and weight.

You cannot, NA, get a full charge of air, due to that inertia (valve overlap has an effect, too, but we'll ignore that, for now.).

If you force air, at 400 CFM, into the intake plenum, under 1 or 2 PSI, you WILL make up some portion of the air that the engine CANNOT get in NA state.

400 CF of air is approx. 28 pounds of air, by weight, not pressure. If it ingested it all, you could, theoretically, burn 2 more pounds of fuel.

Remember, some of the bolt on aftermarkets only offer 2 to 6 PSI boost, and in some instances that will partially go out through a waste gate or BOV.

Again, I don't condone a leaf blower rig, but this is theoretical, at least I thought it was.

Don't apologize for a mistaken thought. I'm sure you are learning something, from the others, if not me.

I made a mistake one time. I thought I was wrong about something or other, and found, later, that I was right, so, you see, I was wrong.

( That's a joke. I've been wrong on other things, too, I am not perfect.)

Cheers,

George

You are still not getting it.

You have a vacuum in the manifold. If you tapped the manifold at several points from the valves back to the air cleaner, you would see different levels of vacuum, because of inertia, the air closest to the valve, the vacuum source, here, will register the highest vacuum, those closer to the air cleaner, the lowest, because of the inertia.

Air has inertia, because it has mass and weight.

You cannot, NA, get a full charge of air, due to that inertia (valve overlap has an effect, too, but we'll ignore that, for now.).

If you force air, at 400 CFM, into the intake plenum, under 1 or 2 PSI, you WILL make up some portion of the air that the engine CANNOT get in NA state.

400 CF of air is approx. 28 pounds of air, by weight, not pressure. If it ingested it all, you could, theoretically, burn 2 more pounds of fuel.

Remember, some of the bolt on aftermarkets only offer 2 to 6 PSI boost, and in some instances that will partially go out through a waste gate or BOV.

Again, I don't condone a leaf blower rig, but this is theoretical, at least I thought it was.

Don't apologize for a mistaken thought. I'm sure you are learning something, from the others, if not me.

I made a mistake one time. I thought I was wrong about something or other, and found, later, that I was right, so, you see, I was wrong.

( That's a joke. I've been wrong on other things, too, I am not perfect.)

Cheers,

George

Curtis73,
Actually, engines do not ingest air at atmospheric pressure, they're always under a vacuum.

True, but my point was that the source of the air is atmospheric. The fact that they are always in a state of vacuum is a function of its operarting parameters.

1 pound of "boost", from any source, will help a little.

Correct, however I don't think that a shop vac or leaf blower can provide that pressure.

And, as for the leaf blower, or shop vac, they absolutely make pressure. You're confusing the air flow stopping when you put your hand over the wand with it not being much pressure. If it was actually NO pressure, then you could put a pice of paper over it with your hand, lift your hand, and the paper would keep it sealed. Just saying that sounds silly.

Again, this is confusing flow and pressure. If you put a piece of paper in front of the nozzle, of course it will feel the flow and act accordingly. That is NOT to suggest that any pressure is there. Think of it atmospherically. Winds of up to 60 mph can be created by as little as 1mm Hg differential. That's 0.0193 psi. There is almost no pressure behind that wind, but it will rip a roof off a house. The problem is, getting flow to make pressure is darn near impossible. Getting pressure to make flow is as easy as opening a valve.

Ah, well, still interesting. And, I'm not fighting, I'm trying to make a point, but don't seem to be doing too well.

You and me both :) I am the king of wordy posts that don't explain a single thing :D I understand your posts and we are both dancing on opposite sides of the same topic.

The problem is, getting flow to make pressure is darn near impossible. Getting pressure to make flow is as easy as opening a valve.


This confuses me. The reason is because a pump does not create pressure. A pump creates flow it's the restriction in whatever system you are producing the flow that creates the pressure, so flow would create pressure.

This confuses me. The reason is because a pump does not create pressure. A pump creates flow it's the restriction in whatever system you are producing the flow that creates the pressure, so flow would create pressure.

Maybe this is a circular argument but I thought a fan, compressor, and pump created pressure. For example in a centrifugal fan the pressure difference across the blades causes the working fluid to move from the inlet to the outlet. The pressure or flow after the outlet is function of the restriction.

Anyone got a donor leaf blower? I'll settle this thing....

Already tried it on an old subie. it doesn't work. That was a 1.6l engine.

There must be pressure to increase flow. No pressure, then what's gonna make the engine flow more air? Question is what will the leaf blower flow under what pressure? What does it flow under 5psi?

The simple problem with a leaf blower is that it is a fan, not a compressor.

Since what is taking place in your engine is a chemical reaction, the stoiciometry of the reaction is based on the moles of reactants, not the volume of them. Compressors increase the mass of air in a given volume (density), therefor increasing the moles of air supplied to the reaction. This means that the reaction can consume a larger mass of fuel, and from a thermochemistry perspective, produce more energy in the process. Leaf blowers just move air and do not compress it at all so you still have the same mass of air entering the cylinders and it will react with the exact same mass of fuel.

I understand your line of reasoning, that the air being accelerated into the manifold would build pressure. Go get your blowdryer, turn it on and press your hand against the outlet; VERY little pressure is built and you can hear the fan lose its effectiveness as the air begins to back up out the inlet. Your reasoning is that a larger fan would build more pressure, but that is not true. Once the fan encounters pressurized air backing up towards it, it loses its effectiveness and stops pumping air.

While the very small pressure supplied by the leaf blower may help the engine breath under very limited conditions and a very limited RPM range, even this would likely not even produce a measureable power increase. It is more likely however that the leaf blower would just obstruct the intake and you would end up losing power.

WORD WORD WORD

I really am tired of trying to educate you all.

GOOD GRIEF!!!

How in the HELL can you not create pressure when you move air?

We have 1 mm bariometric pressure drop causing 60 MPH winds that tear shingles off houses. It AIN'T the 1 mm that does it, it is the 60 MPH wind. It HAS pressure.

You have 1 PSI increase in the leaf blower, or the shopvac discharge, blowing into your manifold, you say, "Nah, can't possibly help, or I wasted a whole buncha money on this 10,0000 buck rig."

So, yeah, you might have wasted a whole buncha money. But if you are happy, BFD.

What part of pushing air into any kind of restriction do you people have a problem with that causes a rise in pressure. Any goddamned time you push air into a restriction, WILL cause a rise in pressure. It might be 1 pound or 2 ponds or 100 pounds, but it WILL be there.

I went out to the garage, before the net, my part at least went down, took a plastic bag, stuck it over the wand, and turned it on. Guess what? It blew the bag up. Not flow, damn it, PRESSURE. Burst the damned thing.

400 CFM WILL supply you more air than your NA motor can use, I don't give a damn if it is only 2 inches of water column.

You don't like that, go spend another 10 grand.

Again, I am not saying yo should go buy a leaf blower, as they are really innefficient. Burn a lot of gas.
Cheers,

George

Axial flow fans are not designed to create pressure. When strong winds hit houses, they do not stop blowing as soon as pressure is created...this is because strong winds are not created by axial flow fans and therefore can't choke the blades. Axial flow fans do suffer from this problem however. You are right that high speed air can create pressure, hence the ram air effect, but the thing you keep neglecting is that the fan will stop moving air as soon as any pressure is created. I'm not saying that no pressure at all will be created, just that the amount created is not very large.

I understand that you are arguing the principle of it, not the practicality of it, and you may be right about creating some sort of power increase but my point is that it will be small.

Once finals are over I will put together some sort of test rig to test the pressure at the outlet of a leaf blower.

Maybe this is a circular argument but I thought a fan, compressor, and pump created pressure. For example in a centrifugal fan the pressure difference across the blades causes the working fluid to move from the inlet to the outlet. The pressure or flow after the outlet is function of the restriction.


Nope all a true pump does is create flow, I just looked it up in my fluid dynamics book. :cool:

"Once the fan encounters pressurized air backing up towards it, it loses its effectiveness and stops pumping air."

By this reasoning, you seem to imply that, if you take your old bicycle pump, plug the hose, push as hard as you can, till the piston stops, you are not making pressure, because no air is moving, just "choking" the piston.

No, I don't think you mean that.

Where, except in the rebuts to the OP, did we start to discuss axial flow fans?

I think most of the posters know ( I hope they do, anyway ) that leaf blowers and vacuums are centrifugal, therefore, radial flow.

A turbocharger is a radial flow device.

A leaf blower is a radial flow device, as is any vacuum cleaner you can name, whether it be Shop Vac or Hoover, or Orek.

Radial flow COMPRESSORS have been built for a 100+ years.

Your shop Vac may not make the pressure you desire, due to limitations of speed, design of the impellor, clearances in the compressor, itself, but that does not mean it does not compress air.

Good grief, just try to squeeze the Hoover bag, after you turn it on!!!

And, that is from the COMPRESSOR trying to compress the air into a container (the filter bag and the containment vessel, the outer bag ) that are designed to let filtered air escape, so it can continue sweeping up more dust. It would work the same, for about 2 feet of travel, if you had a hose attached to a 100 gallon drum outside the house. Except, you would have to go outside, release the pressure, dump the dust, reseal it, then go inside and clean 2 more feet of the carpet.

I wrote elsewhere, that a well designed centrifugal, radial flow, compressor ( much stricter tolerances, and much higher rotational speeds ) will double the input pressure. ie, atmospheric, after 1 stage, 30 PSI, 2 stages, 60 PSI, 3 stages, 120 PSI, up to as many stages as you need.

One company I worked at built centrifugal compressors that produced 10,000 PSI, for use in floating oil rigs, drilling deep. That will push oil up a 25,000 foot oil well casing.

Fans and centrifugal compressors, if you want to call a leaf blower or a shop vac OR a supercharger, such, DO NOT choke when the flow is restricted. They MAINTAIN the pressure. So long as the air can't escape elsewhere, the pressure is held. Lift your hand a little bit, air comes out, instantly. It IS compressed.


Curtis,

"There is almost no pressure behind that wind, but it will rip a roof off a house."

It has been scientifically proven that 60 MPH winds do not blow roofs off houses. The vacuum caused by those winds cause a house to explode, due to the difference in pressure, inside to outside. Tornados, for instance, cause a low pressure area to develop over their path. Houses blow apart. Warnings in all tornado prone areas advise you to open your windows to allow pressure to equalize. Minimal damage results.

Even axial flow fans, like your typical 4 bladed air circulator,you know, that 10 buck thing that oscillates in your den, creates pressure. Put it up against the wall and turn it on. It can't move the wall, so it tries to knock itself over from the force.

They use axial flow air turbines, read really big powerful fans, in wind tunnels. Not supersized superchargers, ie, centrifugal compressors. These babies can blow some air. They can tear the skin off an improperly designed aircraft fuselage.

If any fluid dynamics savvy people are here, they could tell you what the potential pressures these devices would be capable of are.

1 mm Mercury differential means a hell of a lot more over a couple thousand square miles than in an engine manifold. It means cubic miles of air rushing in to fill that void. The amount of work, or of havoc, is stupendous.

Hypsi,

Correct. I have had this problem with hydraulic metal working machinery. Pumps putting out plenty of flow, but no work being done.

Bad pump, still moves the oil, but so much slip, due to bad vanes, the machine wouldn't run, change the pump, all's well.

Same with air, only easier to "stall" the "pump", after all, it's air. You get to the max pressure it is capable of, it just lies there in wait, you bleed off a little air, toe the throttle, take the piece of paper off the discharge hose, it recharges to the max pressure it is capable of.

Why this is so difficult to understand, I don't know. How can anyone say "No flow, no pressure."?

You take a 3" leaf blower wand, flatten the end to a 1x3 nozzle, you have a restriction, you have pressure, you have speed.

You stick it in your intake, without the nozzle, you have more air than an NA engine.
I give up,

Gotta go to bed.

Cheers,

George

we need to test it, but what kind of blower would you use? It has to be alot better than a leafblower though..SOMEBODY TEST IT!!

A bicycle pump is a piston pump. Your trying to compare apples to grapefruit.

Doesn't matter.

A centrifugal "stalls" because the pressure in the outlet is at the highest it is capable of. The pressure is still there, but, whereas, a centrifugal can slip, it will hold the pressure, and when you bleed off a little, it rebuilds.

A piston pump will stall by coming to a stop, period, maintaining the pressure, and when you bleed off a little, will advance to its stall point.

The efficiency of the centrifugals you guys are talking about is low, so naturally the pressure developed and held is low. But, it IS there.

Why you cannot understand this is beyond me.

Cheers,

George

But when the pump stalls, it isn't flowing anything. When it "stalls" on a centrifugal, the air just backs up in the housing while the impeller spins. Pressure+no flow=no more power. Flow+no pressure=no power. Exactly the same as the HP vs Torque arguement.

But when the pump stalls, it isn't flowing anything. When it "stalls" on a centrifugal, the air just backs up in the housing while the impeller spins. Pressure+no flow=no more power. Flow+no pressure=no power. Exactly the same as the HP vs Torque arguement.

I think the point that gmatov is trying to make is that the total pressure created by the fan is sum of the dynamic and static pressures. So when the flow is restricted to the point that it stops, the dynamic pressure will go to zero and the total pressure will equal the static pressure (and be non-zero).

Below is a typical fan curve for a centrifugal fan with forward curved blades. It shows static pressure on the vertical axis plotted again flow rate on the horizontal axis.

http://img252.echo.cx/img252/3651/fancurve0oy.jpg

I understand gmatov 100%. He's just more persistent at explaining than I am.

Now why did the term "static pressure" slip my mind? Thank you.

I think, instead of just saying "It ain't so!", just doing a little experiment would be enlightening.

Start your ShopVac and cover the exhaust hole. Harder to hold back the pressure than you might think. The motor slows. It's trying to force more air out the volute, is compressing denser air, but slipping.

Now cover the intake. Sucks your hand tight, and, no air to move, motor spins faster, as it's no longer doing any more work than trying to build vacuum in the tank. Again, not efficient, due to slip from clearances and impellor design.

Have to revise a post on another board, same subject but different application. Posted results there with 1 1/4 hose attached. Corrugations in the hose change things tremendously from open port.

Cheers,

George

I have always agreed that some pressure will be created. What I have been arguing about is the magnitude of that pressure.

Now that my finals are finished I will have some time to do a little experimentation and hopefully get some answers a little more definative than my speculation. I will try to find time to do it within a week or so, but if it turns out to be more work than a couple of hours I might not do an experiment at all. I don't care enough about the argument to spend more than a couple of free hours on it. When I do the experiment I'll document everything as fully as possible and take as many pictures as I can of the whole thing to lend some credibility to whatever I find. Whatever I find I will post, even if that means disproving my argument.

The experiment is going to also be limited by what materials I have on hand; I'm not going to go buy an industrial leaf blower just to test an argument.

Slut,
When they put 100,000 bushels of grainn in a silo, they do not use turbochargers to push air through it to prevent spontaneous combustion, they use axial flow fans, granted, with a little larger motors than you have in your home. 50 to 100 HP? And, they will force cooling and drying air through all that grain, 100, 200, 300 foot tall silo.

But you still insist you can put your hand over it and it's all gone. The blades do NOT cause a pressure rise, just a volume rise.

Come with me to a steel mill and walk close to one of the fans. It will blow your hard hat off, and, if you are not prepared, will blow you over. You'll be leaning into, a 60 or more MPH wind, and you will think differently.

I wouldn't ask you to go buy a leaf blower, though I may, If I do, I'll post my results, here.

I think those results will surprise all of you, also.

Cheers,

George

I know nothing of grain silos so it is pretty hard for me to respond to that, however I never argued that the pressure simply disappears when you cover the outlet. What I have been arguing all along is that the fan will stop pumping air when the static pressure builds as a result of the blockage and that the resulting static pressure will be small. I think we have misunderstood each other, because the more you elaborate on what you mean, the more it sounds to me like what I am trying to argue.
the pressure developed and held is low. But, it IS there.I'm not saying that no pressure at all will be created, just that the amount created is not very large.

I have a leaf blower, and that is what I will be doing the experiment with. The leaf blower I have is electric and capable of approximately 300CFM (one of the things I will do is find out more precisely what the airflow is), which is shy of the 400CFM you have been talking about and is why I said I would be limited by the equipment I have. I feel however that it is close enough to give us a general idea as to what kind of pressure can be built by a leaf blower.

Hey,

I just read this whole topic (Hense my eyes hurt). I want to see if it does make any difference! Even if it's just a little, for the hell of it. A 1G Mitsubishi turbo produces 405 CFM, but at 14 PSI, pressure matters alot in the game of turbo's so I don't think the blower will add much. Just a little, because it is giving more air than the engine requires........

_C.Jackson

I just finished reading this entire thing and now my head hurts. What George is saying is simple physics if you just stop to think about what happens in your turbo. Now I don't have years of experience working with turbos, compressors, turbines, fans or anything close, but I do have a good understanding of physics (without all the fancy lingo :) ).

First off George is in no way saying that your run of the mill electric (or gas for that matter) leaf blower is going to come anywhere close to doing what your low end/cheap/stock/high end/whatever turbo you've got on your car will do. He is simply saying that increasing the airflow (and therefore the manifold pressure) will help no matter how small it might be.

Now lets cover some of the arguments that have been made here. We need to keep in mind that we are comparing apples to oranges here, so when trying to make a comparison it helps to try and equalize the equation. Realize that your turbo has been designed to do everything much better than the leaf blower. It is much more powerful, built with much higher tolerances, built to last much longer and therefore it also costs much more.

Could an electric turbo be made that makes the power that your current turbo does? Sure it could be. Replace the impeller that sits in the path of your exhaust gases with a big electric motor and bingo, you're golden, right? I suppose advantages would be that you have more control over the speed of the compressor and you could locate it in a more convenient place. The downside is it's FAR less efficient than your traditional turbo. You need a larger alternator to supply the current needed (weight and energy loss via heat), larger wiring to carry the current (more weight + heat + energy loss), and then the large electric motor on the turbo (even more weight and energy loss via heat). The question is why would you want to do that when we already have a better alternative?

Now for a new way of thinking about the solution that George is offering with the leaf blower. We have a 350 that flows ~500 cfm at 5k rpm. That puts the manifold pressure at some negative number. Instead of putting the 400cfm leaf blower in the already existing intake, lets just add another hole right on top of the intake manifold. Now the leaf blower isn't going to get in the way. Hey I have a better idea! How about instead of your normal intake, we change it to ram-air! Now you have your extra pressure at low rpm and at high speeds. ghetto rigged? Well yes, maybe =) But we don't want to spend the money on a turbo to do it right now do we?

It's late so forgive my rambling. One more thing to address though.

Lets talk about pressure. What is pressure? Everyone here seems to be thinking of pressure as something bottled up. Pressure in a hose, pressure in a tank, pressure in a bottle, pressure in the intake manifold... Well, when a fan is spinning, why does the air move? Because as the vanes move through the air on one side the air is compressed, while on the other side there is a slight decrease in pressure. The weight of the air in the atmosphere pushes air in to replace the air behind the fan blades, while the higher pressure air in front of them expands to equalize, creating that nice breeze you feel. Sailboats use pressure from the wind to move. Extremely low pressure over a very large surface area equals a very large force. See what that low pressure difference making a 60 mph wind does to a sailboat.

Centrifugal fans work differently, they spin the air and use centrifugal force to move it. As the air is 'slung' outwards a negative pressure is created in the void where the air used to be. Again, atmospheric pressure forces air to replace it, which is then slug outwards and the process repeats itself, creating the airflow you feel.

There was a lot of talk about 'stalling' blowers and turbos. I think covering the outlet of your turbo with your hand is a bad example. You've got a lot of force driving the turbine that is pushing the air out and I don't think anyone is going to be strong enough to stop that. I think it would be better to imagine what would happen if you COULD stop it. For the sake of the argument, lets forget that we want to use the air coming out of the turbo to make our engine perform better. Lets just say the engine makes 200 hp without the turbo, and we just hooked one up to it to see if we could stop it. Without a waste gate (that also messes with my theory) if the engine has enough power the same thing would happen with your turbo as happens to the leaf blower when you put your hand over the outlet. It will reach a maximum pressure and then fail to make any more pressure. If your engine isn't strong enough to continue to drive the turbine at this point it's likely you'll stall it due to the lack of a place for the exhaust gases to go. I imagine having that happen depends on many different factors such as engine speed, angle of the turbine blades, and some other things I can't think of right now - but it would be an interesting experiment!

And finally, for the original poster - Why not just invest in Nitrous for the power on demand application your looking for? Cheap, lightweight, fairly safe and big horsepower gains.

If anyone has made it this far I commend you! I will end my ramblings here. Good night all!

-Randy

rquenthner,

Welcome to the forum, and thanks for the backup, although I did not think up the leaf blower, simply tried to argue that they WILL put out pressure, even when "stalled".

I don't really think it would be hard to "stall" a detached real turbo. How you do this, considering that it assists the engine to make more HP, I won't speculate.

They are still going to put out 14.7 psi at max. If you can't stop that pressure, from a small nozzle, you're rather weak.

If it is a rather large nozzle, and those are the technical terms, whether they be 1 inch, or 36 inch diameter, excuse me, say 4 inch diameter, now it takes some effort to hold back, as it is 185 pounds of "force" pressing against your hand. If it's a blowgun on the end of the hose from your 125 psi compressor, all you need do is force your thumb down over the 1/16 exit, and you will, if not stop it, severely restrict it.

Try it. Some air tools actually work this way, particularly cutters, like pneumatic bolt cutters, which are used to cut rod to length for fabs such as grates. Finger on the trigger, plug the exit, the pressure works on the piston, lift your finger, the exhaust flows from the trigger.

Ah, well, no one is going to suggest that anyone throw away their 10 grand blower to put a 100 buch leaf blower in the intake, instead. That was not the point, to begin with. The point was that, when you raise the presure of ANY compressor, compressor, mind you, it is still maintaining, as you say. Pressure does not drop to zero as some of the prior posters said.

Thanks, but I doubt that any of the other posters will admit such.

Cheers,

George

But when the pump stalls, it isn't flowing anything. When it "stalls" on a centrifugal, the air just backs up in the housing while the impeller spins. Pressure+no flow=no more power. Flow+no pressure=no power. Exactly the same as the HP vs Torque arguement.

Nissan,

I am really sorry you bought 10 grand worht of turbo.

When you kink the hose from your 125 psi compressor, yours only, I presume, there is no longer any pressure, ie, dead tank.

When you disconnect the hose from the tank, entirely, and run the compressor, you have flow, but low (of course not NO ) pressure, so no work done. Absolutely no help, huh?

Pressure, into a manifold, or flow, into a manifold, WILL help to shove some, SOME, air, I must reiterate, into the vacuum created when the valves open.

At idle, you are at 21 inches of mercury, right?

ie, about 12 psi absolute, ie, the engine is sucking like hell to get a full cylinder, but it can't, right?

You can supply 1 MORE psi, and you do not think it can possibly help? 400 CFM more, from the git go, will not help? Simply to overcome inertia?

It will, naturally, not suck in those 400 cfm, they are just there, if needed. But, they are there RAT NOW. Not when you take your piece of paper off the nozzle. The one that is holding in the pound or so of pressure the vac or the blower can produce.

Can you understand this?

Cheers,

George

i highly doubt fanatic spent 10grand on his turbo setup...

Then, 37 bucks, though his pics show more.

Point is, ANY more air helps.

Under less vacuum, there IS more air there, regardless, available to be sucked in.

As to the post with the Oxy, and the poster who says you will turn the combustion into a cutting torch, BS. 10 % Oxy, mebbe, adding some O2, negative.

Ah, well, live and learn.

Cheers,

George

Then, 37 bucks, though his pics show more.

Point is, ANY more air helps.

Under less vacuum, there IS more air there, regardless, available to be sucked in.

As to the post with the Oxy, and the poster who says you will turn the combustion into a cutting torch, BS. 10 % Oxy, mebbe, adding some O2, negative.

Ah, well, live and learn.

Cheers,

George


First of all o2 is oxy... oxy=oxygen which would melt pistons... You must be thinking of accetleine (sp) Second of all keep your posts on topic. That is why there is a different thread.

You missed the point. I mean if you add 10% Oxy, also called O2, you might cause way too hot a flame front in the cylinder. That would be an atmosphere of 30% O2, rather than the sealevel average of just about 19%, 50% more. You might not even have enough fuel for all that O2 to combine with, run lean, and raise the temps that way.

After that it should be interpreted as "adding SOME O2, also called Oxy, negative."

This is basically what you are doing with a turbo, anyway, forcing a greater charge of air, 20% of which is O2, into the cylinder, whether you are boosting just to get to atmospheric, to fill it, or to get a couple pounds of compression into the cylinder, overfilling it a little.

As to off topic, you're right, didn't even realize this was not that thread when I wrote that.

Cheers,

George

lol, I wish I could spend 10k on a setup. Shit I wish I could spend 5k.

About 2.5k.

I may be new to this forum, but I am not new to performance.

I read some of the posts on this subject (not all of them) and some of you are a little off base – no offence intended.:smile:

First of all, an engine does NOT suck air. Get that thought out of your heads.

Ideally speaking, an engine “displaces” the air behind the piston leaving a place in front of the piston with nothing in it.
The engine then depends solely upon atmospheric pressure to push air into the empty space. Any restriction to that flow reduces the total charge that gets pushed into the engine. Likewise any reduction in atmospheric pressure (altitude) reduces the total charge the engine receives.

There are many factors that affect the total charge, but it all starts with atmospheric pressure. Without said pressure, nothing goes in.

On my turbo Beemer, if I crack the throttle just enough to slowly spin up the snail and watch the manifold boost gauge that measures pressure between the throttle plates and the intake valves, I will feel a definite seat of the pants thrust as the gauge approaches zero pressure and inches into only ½ psi boost.

Take my Dodge V10 that I tow a fifth wheel with.
At sea level, it makes 345Hp, or so dodge says.
At 3500’ altitude where I live it does not. This is because the atmospheric pressure is 1-2psi lower here than at sea level.

If one were to put an electric blower on that engine capable of 300-500cfm AT 2psi pressure, the engine electronics would think it was back at sea level, apply the appropriate fuel to the charge and make 345 hp again.

If that pressure is more than you want, just back off the throttle and restrict the flow into the engine.

If I ever found a practical 12v blower that could do that it would be worth while topping a mountain pass towing a trailer.

Mark
Crew chief over 2 Bonneville land speed records that stood for 14 years.
http://www.automotiveforums.com/vbulletin/C:\Documents and Settings\User\My Documents\My Pictures\bonneville 89 tuchec up thumb.jpg