Electric forced air induction?

[gmatov]

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

[curtis73]

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.

[gmatov]

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

[nissanfanatic]

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?

[gmatov]

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

[gmatov]

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]

Originally Posted by gmatov

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 I understand your posts and we are both dancing on opposite sides of the same topic.

[Hypsi87]

Originally Posted by curtis73

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.

[Alastor187]

Originally Posted by Hypsi87

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.

[Jet-Lee]

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

[nissanfanatic]

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?

[Sluttypatton]

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.

[nissanfanatic]

WORD WORD WORD

[gmatov]

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

[Sluttypatton]

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.