blah

Im not sure if you have devised a plan on how to run the super/turbo. My idea of prevent the supercharger from over-revving and stalling, is to use the same idea as engaging/disengaging an airconditioner. You would have to put a large pulley on the supercharger to compensate for the mechanism on the fron of the air compressor unit. You would also have to have it electronically preset at a certain rpm level (4000 rpm). Plus, with the turbo and supercharger intake, it would have to be two tubes into one, with a bypass flap closed by the intake pressure. That is so there is no extra air, or too must strain on the supercharger caused by the vaccuum from thye forced induction.

Your a day late and a dollar short, it's been done and it works great on a street car. At cruise it uses no power, and when you touch the gas, full boost.

Albert

Turbo's are still better.... :P

Turbo's are still better.... :P

Please be as so kind as to provide us proof to this statement as I have somewhat of a difference of opinion.
I know it must be a personal feeling as it isn't fact.

Albert

Well.. turbos make more power, both peak and average, so yeah that pretty much says it all.. But sure, if you prefer less performance, superchargers are better... :biggrin:

Turbochargers can provide more boost just by adjusting a controller. More efficient(unless you count a lysholm). They don't take as much energy to drive. A single turbo can support over 1000hp without taking a 1/4 of that from the engine.

awesome...
i love when we do this.

(you know what im talking about)

awesome...
i love when we do this.

(you know what im talking about)

Nothin like starting the 14 millionth turbo vs super thread on AF. I don't think we've covered every possible aspect yet.

Well.. turbos make more power, both peak and average, so yeah that pretty much says it all.. But sure, if you prefer less performance, superchargers are better... :biggrin:

Gosh, you mean if I pull my Whipple supercharger off and install a turbo I'd have more peak and average power? I have 3 300ZX TT and on two of them pulled the turbo's and installed screw type superchargers. I also removed my intercoolers. On the dyno I made more power and had cooler inlet temp. didn't need as much nitrous to overcome the lack of power I had at low and mid range as I had with the turbo's. My Delta temp. was almost 50F cooler.
I wish I'd talked to you before I spent 100's of hours on a dyno and 100's of hours changing different setup's and mega bucks only to be told turbo's make more power.
Your statement is like saying Ford has more power than Chevy and Dodge, or Honda makes more power than Toyota or Nissan. I've read many story's on turbo's and superchargers and most are written by people pushing their product, in other words the turbo say there's is best, and the supercharger people say there's is best, but the bottom line is how there installed and there intended use. Both well make more power than most engines can handle.
Do yourself a favor next time your at the drag races and walk into the AA/Fuel pits and tell the owners there blowers aren't worth a crap and turbo's make more power.
Then to really fuck-up your day run over to the Indy track and ask them why they aren't using superchargers.
Both groups are working with unlimited funds and are seeking as much power as can be extracted from there engines.
My street car is a street legal 300ZX using street legal DOT tires with a automatic and turns the 1/4 in [email protected] which aint too bad for a lead sled. But if you want to get serious I've got one not street legal that runs 3 second's faster. :grinyes::biggrin:

Albert

http://www.dragtimes.com/Nissan--300ZX-Drag-Racing.html

was the drop in temp at the same boost level ?

was the turbo a factory or something you set up ?

I just got a inlet tempature gauge to test my blower setup and just wonder what you have seen ..............

was the drop in temp at the same boost level ?

was the turbo a factory or something you set up ?

I just got a inlet tempature gauge to test my blower setup and just wonder what you have seen ..............

It was alittle higher boost but lower temps.
And I just got tired of changing turbo's everytime I upgraded.

Albert

Gosh, you mean if I pull my Whipple supercharger off and install a turbo I'd have more peak and average power? I have 3 300ZX TT and on two of them pulled the turbo's and installed screw type superchargers. I also removed my intercoolers. On the dyno I made more power and had cooler inlet temp. didn't need as much nitrous to overcome the lack of power I had at low and mid range as I had with the turbo's. My Delta temp. was almost 50F cooler.
I wish I'd talked to you before I spent 100's of hours on a dyno and 100's of hours changing different setup's and mega bucks only to be told turbo's make more power.

Didn't mean to offend you, but there is zero arguement that a s/c makes more peak power than a turbo. Your change in delta temp is most likely a result of a damaged or incorrectly sized compressor, or just a poorly designed one. The difference in efficiency between a turbo compressor and a screw type supercharger is not that great.. IIRC a centrifugal compressor is more efficient than a screw type, but I'm not positive on that. I know a roots runs roughly 50% efficiency, a turbo runs around 70%. The best turbos push 80%.
I've read many story's on turbo's and superchargers and most are written by people pushing their product, in other words the turbo say there's is best, and the supercharger people say there's is best, but the bottom line is how there installed and there intended use. Both well make more power than most engines can handle.
Do yourself a favor next time your at the drag races and walk into the AA/Fuel pits and tell the owners there blowers aren't worth a crap and turbo's make more power.
Then to really fuck-up your day run over to the Indy track and ask them why they aren't using superchargers. Both groups are working with unlimited funds and are seeking as much power as can be extracted from there engines.
I'm sure they wouldn't be there if turbos were allowed in their class, or they'd be running turbos. When turbos were allowed in indy, anyone who had a chance was running one.

My street car is a street legal 300ZX using street legal DOT tires with a automatic and turns the 1/4 in [email protected] which aint too bad for a lead sled. But if you want to get serious I've got one not street legal that runs 3 second's faster. :grinyes::biggrin:

I ain't puttin down your car, believe me. For any application besides max output or equipment regulated racing classes, both systems will be more than enough. Pushing everything to its limit, a turbo system will make more power than a supercharger. All you have to look at is where the energy to drive the compressor comes from. Turbos largely use wasted heat energy, superchargers take energy directly from the crank. Clearly the turbo will create more power.

I didn't mean to offend you, I was just messin with ya. Nice job on your car!

Boy I love this conversion. I hope some boys with a physic background join in with some input. This was part of the subject matter for my masters degree from the University of Utah school of Engineering
First it takes a giving amount of energy (Power) to compress a giving amount of air.
Example: I want to move 500CFM at 20PSI. Now we have 4 ways of doing this. With a Axial, Screw, Centrifical or Roots supercharger (Compressor). Now any of them can and are driven off the crankshaft or off the exhaust as is the Axial and centrifical superchargers. Now all 4 are to be driven in the test with a engine to the point of 500CFM@20lbs of boost and the power measured to see how much power it takes to develop these figures. Guess what the results were? All 4 required the same amount of power to develop 500CFM@20lbs boost. The difference being efficiency which is directly related to the Delta temp. The more efficient the supercharger the lower the DT. The Axial being the most efficient at 98+% had the lowest DT and is no longer being built for cars as the Lathem is no longer built due to high costs, but is still being used in aircraft jet engines. Next is the Screw type which has a 90+% efficiency and the next higher DT. Now the popular Centrifical with a 70-80% efficiency and a higher yet DT, and last with the lowest at 50+% efficiency and the highest DT the Roots.
Now as stated before we have two methods of driving these superchargers. With the crank or the exhaust. For engine designers it's much easier to use a turbine or turbo and dump the exhaust to control the compressor output than it was to develop a system to control the output on a engine driven supercharger so the turbo supercharger has held the top spot for many years. But that is changing rapidly as engineers have developed a clutch similar to the one used on a cars A/C so the supercharger isn't using any power when not needed but there on demand, whereas the turbo is always inline and restricting the exhaust.
Which supercharger well make the most power. Well I'll put it this way, the screw type compressor can develop 150# boost where a normal turbo supercharger starts loosing efficiency rapidly above 35# boost. Now you can stack the turbo's and get more boost but then you run into other problems. But who the hell would ever need over 35# boost?
Someone came across a web page that described various DIY home brew octane booster formulas. One of which used toluene as its main ingredient. As a Formula 1 racing fan of many years, I recalled that toluene was used extensively in the turbo era in the 1980s by all the Formula 1 teams. The 1.5 liter turbocharged engines ran as much as 5 bars of boost (73 psi) in qualifying and 4 bars (59 psi) in the actual race. Power output exceeded 1500bhp, which translates into 1000bhp/liter, an astronomical figure.

A motorsports journalist, Ian Bamsey, was able to obtain Honda's cooperation for his book "McLaren Honda Turbo, a Technical Appraisal". The book documents the key role that the toluene fuel played in allowing these tiny engines to run so much turbo boost without detonation. The term "rocket fuel" originated from the Formula 1 fraternity as an affectionate nickname to describe its devastating potency. Thus I concluded that I should focus my research on using toluene for my octane boosting project.
With engineering moving forward in leap and bounds it won't be long we'll be seeing very high boosts on very small engines developing unreal power. When you can take a 150cu.in engine to a 300ci.in power we haven't even scratched the surface yet.
When engineer's develop engines for everyday use making 1000hp per liter you can kiss turbo's goodby.

a turbo runs around 70%. The best turbos push 80%.

I don't really want in on this match but I have been watching the turbo cars on the dyno that I help at and none are anywhere close to 80 % most are 60 to 65 % when messured before the intercooler ........

I don't know about you guys, but I've been in wayyy to many of these arguements; one is far too many. Let me reiterate, I was joking. You can believe whatever you want, I'll believe what I want, neither of us are going to change our minds, so lets not waste our time, alright? I have zero problem with you liking superchargers better. But if you like getting in arguements, I can continue. Personally, I'd rather not.

I have a few questions for you though. What specific boost #s and IATs did you get with the turbo and supercharger systems? I ran a few numbers, and in order to get a 50*F temp difference with a change in efficiency from 65% to 90% was 25psi. This is with the same boost for both.

Whipple claims around 85% efficiency from their screw type superchargers. I was wondering if you knew what Eaton's screw types run.. the whipple looks much better made, which usually means more efficient. Eatons are just cheaper and I'd like to run a few little experiments.


Once the CVT is able to hold enough power, perhaps we'll see the demise of the reciprocating internal combustion engine alltogether. Gas turbines are significantly more efficient at their peak, but they drop of quickly on either side of their peak; they're not very good with a fixed gear transmission, since they have such a narrow powerband. They've only made an appearance in road vehicles back in the '60s in prototype big rigs with lots of gears. With a CVT the turbine could stay at its peak efficiency. I'm not lookin foward to that, despite the faster accelleration and better gas mileage... Whats the fun if you can't row through the gears, watching the tach fly up, hear and feel the engine roar.

That's the problem. I don't like or dislike eather. I'd run a roll of toilet paper if I knew it would make my car faster, but I find it wild anyone would come to a forced induction thread and say there's wayyy to many arguements, and it's mostly do to lack of knowledge. And your right, peoples belief system sometimes plays tricks on their though process and even truth is unacceptable. I too have ZERO problem with whatever you think. I just state fact as I know them, and that's it.

Now to your questions. The engines were running tests on right now are the VK45DE engines with 10:1 forged pistons. We were shooting for 28#boost with no more than 180*F IAT which leaves out the turbo's. We were sucessful not only in reaching this figure but at a lower IAT without intercooling or water/alky injection.

Whipple claim is low at 80% efficiency, it was more like 92%, and I told them this and there response was they would rather be low than put out a false claim.
As for the Eaton 81% was tops but it was right in there, just wasn't able to provide the volume and boost we needed for our needs.

I suggest you look at the following sites and expand you knowledge base.

http://www.whipplesuperchargers.com/content.asp?PageID=68
http://www.opconab.com/index.asp?langID=1&cID=14&spage=1

As for the CVT's and Turbiine engines start another thread and I'd be more than happy to discuss that with you also, as I have much knowledge in this area also. Ford and Chrysler tried them in there proto type cars as well as GMC in their trucks.

Albert

I didn't mean to say there are too many arguements, I meant I've been involved in enough of these threads to know they usually go nowhere. Unless the people in the thread realize this- then it turns into a nice debate outlining the pros and cons of both systems.
I've read both those sites in the past. I won't deny the efficiency of a screw supercharger, as I said in my post I thought centrifugals are more efficient, but wasn't sure. You provided the data and proved my faulty recollection wrong. Thanks.
In most boosted street car applications, people aren't running 20psi boost, so the difference between a 70% efficient compressor and a 90% isn't terribly great, probably in the range of 10-30* IAT, depending on boost pressure. In these cases, these are the main advantages of each system:
turbo:
Does not sap power off the crank, does not side-load the crank
Easier to use an intercooler
Does not boost unless engine is loaded
whipple:
Easier to install, no complex tubing
Intake pressure greater than exhaust(although very possible on a turbo, most mild applications don't see this very often)
Lower IATs
Slightly better response time

Let me know if I forgot any or am mistaken... As for response time, I don't consider turbos to be at any large disadvantage. A properly sized turbo will provide full boost through the usuable RPM range, and will only take a fraction of a second to get there.

I hope I didn't come off as abrasive in any of my other posts, I've been trying to be as friendly as possible on AF. Its really difficult to tell a poster's tone... Any knowledge I can gain is good.
And to show I'm not a die hard turbo guy, I'm planning on grabbing an eaton m45 supercharger for a still undetermined 4cyl project. Car is probably going to be a mid 90s honda or VW, but I'm hoping to be a Karmann Ghia. I like the older cars. Plus mid-engine RWD and an engine that is cheap to build. Its supposed to be my daily driver with some balls. I'll start a new thread on CVTs and turbines.

this is kinda off topic, but duplox if you are looking for a mid engine rwd 4 cyl i can only see two options for you (neither are a honda or vw). Im sure you already know its gotta be a toyota mr-2 or a fiero (rumored to be slightly flamable). some of the first gen mr-2's came with supercahrgers on them.

Mr. Duplox I think you've hit the nail on the head about 80% correct. One correction. You stated turbo engines doesn't boost, unless engine under load, nether does the Eaton or Whipple, in fact with the BYPASS VALVE they only consume 1/3HP while crusing, where as the turbo is still in the exhaust line causing backpressure.
Generally a screw type supercharger don't require a intercooler but most turbo's come with them.
As for response time talk to any serious street or track drag racer and the'll tell you a few hundreth's is a lot.
As for side load on the crank I don't have this problem as I use a VSD on the crank that can be changed from 1:1 to 1:3.5 so I can change my boost level as I need.

For what your looking for I'd consider a MP62 or MP90 and underdrive it and you'll never have any heat problems and when ever you want, change the pulleys and upgrade your boost. What ever you get let me know and I'll figure some way to get you a drawing to show you how to modify your supercharger and increase it's efficiency 15%.

Right now I building a car to try for the land speed record with a door slammer, (stock production car) I want to go 300MPH and well be using a 300ZX Z32 car with a VH45DE supercharged V8 engine. In wind tunnel testing it well take 1,944HP to get this speed with the Z's drag coff. of .26. Afterwords the gear ratio and tires well be changed and used for the drags.

Albert

I don't know why I put turbos not boosting unless under load.. any s/c with a throttle body before the compressor won't produce much of anything at low-throttle positions. Without a bypass valve, it'll boost sooner in regards to throttle position, but when cruising neither system should produce any boost. With a bypass, no appreciable difference between s/cs and turbos.
If a turbo is creating any noticable backpressure at cruising you have a horridly undersized turbo(for performance purposes), like something you'd find on an OE car like the turbo dodges or saabs. If you keep your budget the same, for the cost of a whipple charger you would be able to get a VATN turbo, then you should have absolutely no problem with backpressure even with the turbo spooled up. Very common to get higher boost pressures than exhaust pressures with VATNs.

As for the supercharger, thats fine with me! If it'll work better, I'll certainly go for a m62 or m90. They're much more common and therefore cheaper anyhow. I was just going by the recommended displacements on Eaton's website.

MUAHAHAHAHAHA.... early MR-2's having superchargers, well yes since a turbo is calssified as a supercharger. MR-2's that where FI where always turbo.
HOW MANY TIMES MUST WE GO OVER THIS. turbos chargers are much MUCH more efficent compared to even the most efficent of superchargers. positive displacement (blower) superchargers being the lease efficent of all.
whay then do top fule dragsters use roots? well regulations clearly stipulate the only type of FI alowed in the top fule class is a postitive displacement roots supercharger.
Turbo's will create just as much heat as a superchargers when running the same boost. difference? well turbos and cyntrifical superhcargers can be run through an IC to bring intake temp down closer to ambient air temp.
I, myself have been in many of these Turbo v. S/C arguement threads. and, well frankly i am not going into elaborate detail about why turbos are more eficent and create more power compared to a s/c at same boost levels. im not going to go into detail about why turblag is a thing of the past and a thing of rice boys putting overly large turbos an their small 4cyl.
not agreeing with me? well here are som people to PM about turbo's (and MR2's) (excuse spelling please ,these are just people i know from the forums who know what they are talking about, im talking college degrees in physics, chemistry, engineering, etc... and madd experence with car specefic HP)
JekylandHyde
Saabjohnson
Curtis73
Hypsi73 (bad assed grand national, he is a Mod, if youve been i nthe street racing forums you know him)
Polygon (another mod who likes the buicks)

and there are plenty more who havent seen this thread or saw it and where smart enough to prove to another S/C lover why turbos are better. simply search and find, end of my contribution to this thread.

MUAHAHAHAHAHA.... early MR-2's having superchargers, well yes since a turbo is calssified as a supercharger. MR-2's that where FI where always turbo.
HOW MANY TIMES MUST WE GO OVER THIS. turbos chargers are much MUCH more efficent compared to even the most efficent of superchargers. positive displacement (blower) superchargers being the lease efficent of all.
whay then do top fule dragsters use roots? well regulations clearly stipulate the only type of FI alowed in the top fule class is a postitive displacement roots supercharger.
Turbo's will create just as much heat as a superchargers when running the same boost. difference? well turbos and cyntrifical superhcargers can be run through an IC to bring intake temp down closer to ambient air temp.
I, myself have been in many of these Turbo v. S/C arguement threads. and, well frankly i am not going into elaborate detail about why turbos are more eficent and create more power compared to a s/c at same boost levels. im not going to go into detail about why turblag is a thing of the past and a thing of rice boys putting overly large turbos an their small 4cyl.
not agreeing with me? well here are som people to PM about turbo's (and MR2's) (excuse spelling please ,these are just people i know from the forums who know what they are talking about, im talking college degrees in physics, chemistry, engineering, etc... and madd experence with car specefic HP)
JekylandHyde
Saabjohnson
Curtis73
Hypsi73 (bad assed grand national, he is a Mod, if youve been i nthe street racing forums you know him)
Polygon (another mod who likes the buicks)

and there are plenty more who havent seen this thread or saw it and where smart enough to prove to another S/C lover why turbos are better. simply search and find, end of my contribution to this thread.


Wow...I'm so impressed I can't shit. Your knowledge of the compressors should be placed in the Book of Knowledge.
I'm at a disanvantage as I only have 2 masters degrees in engineering and did grad. work on this very subject.
I also have a car in the National Hotrod museum, hold 6 world records, drive a street legal 10.16 second car, and have a mid 7 second Pro Import car.
I personally don't think you should go into elaborate detail, as it's very appearent you have know idea what your talking about. The information provided here was for the benifit of those with reading ability and understand what they read and chose to contribute useful information and not garbage.
For your information before the ROOTS rule in NHRA was in affect, a guy by the name of Don "Big Daddy" Garlic tried turbo's (4) on his AA/Fuel dragster and guess what? He pulled them after about 4 lose's.
As for being a S/C lover, hate to pop your bubble but me and alot of me's would run a roll of toilet paper if it made our cars faster.
Being in the Research and Development for years before going full time racing, I have much information and facts I'd be more than happy to post. I deal in facts not bull shit.
Also FYI in the Racing Forum in the Turbo's vs Superchargers you'll find a post I made that's gone unchallanged as it's fact and anyone with half a brian knows it's true.

Albert

Hahaha Owned!!!

haha, not. Jesus christ you would think someone who truely had 2 masters in engineering would admit turbos are more efficent.... but anyway. if you wan to be a bull headed my penis is bigger than yours Ahole then go ahead.

haha, not. Jesus christ you would think someone who truely had 2 masters in engineering would admit turbos are more efficent.... but anyway. if you wan to be a bull headed my penis is bigger than yours Ahole then go ahead.

It's really sad your unable to post something more useful than compearing sizes of peckers and aholes. What's even more sad is there's some really neat people on AF who have alot to offer to those that would like to learn more.
So as not to corrupt this thread anymore I suggest you PM or eMail me at [email protected] as I would be willing to try and teach you the basic's of the automobile so you may carry on a conversion with some level of intelligence.

hmmm, ok, ya sure. well Why dont you grace us all with your superior knowledge that, obviously, no one else knows. i mean taking torque and energy directly from the power you are trying to produce to produce more power is always going to be more efficent then taking energy form a wasted energy source. I mean after all thats why most european performance cars (the people who actually know how to build a car) that have FI are turbo and its really only bull headed "american V8" lovers that deffend superchargers like they where gold.
I understand your quest for maximum speed and power. i mean i would run off of flower and talcom power myself if it ment a more reliable and more powerful engine compared to liquid fuled vehicles that largely use Gasoline, Ethnyl, and NItromethane. But, as i said before, one who truely does have a record as you stated would at least admit that energy taken form a basically wasted energy source would be more efficent than takein energy from your energy source yo uare trying to improve upon.

Now, your your entertain ment, reasons thy i would turbo long before i would supercharge.

-Boost Controll. plain and simple. im low on cash i fill up with plus or regular and i cut my boost. i save cash. or i dont want to be dumping a ton of fule into my car while daily driving. well i turn my boost down. one one chanlenges me on the street or i go to the racetrack going from 1.8-18psi is as simple as a turn of the wrist. Granted most s/c can change boost as easy as a pulley swap and belt replacement or a pulley swap and idler adjustment. but turbo boost controll is easyer.

-Turbo's get most of their energy form exaust heat and expansion. only a very small ammount of the turbo's energy is from the pistons exaust stroke. the key to quick turbo spools is maximum exaust velocity intothe turbo and minimal back pressure after the turbo (in other words, the largest exaust diamereter in reason which yourself and surrounding vehicles can stand sound wise). Many will say that with a s/c there is no lag. with a properly sized turbo, proper fluid dynamic calulations form maximum exaust velocity, todays electronic boost controllers, diverter valves and waste gates, a torque curve can be painted any way the driver pleases. no lag. turbo fully spooled by 2-3,000.
-Turbos have the advantage of an after cooler when compared to positive displacement s/c's. now you said intake temp droped after swiching to s/c w/o intercooler. well if it was your stock turbo, likely it was sized for economy and emmisions rather than exaust and intake flow. so a large amout of your boost was created from the heat of compression rather than the flow the the compressor. with a properly sized turbo ran through and intercooler you should see an intake temp drop when compared to supercharger w/o IC.
-its my opinion, but i would rather hear a turbo screaming than a s/c wineing like al ittle baby. besides, overly rough idles in street cars due to all out performance cams just piss me off... (that last statement was focused on roots loving 'american muscel' lovers who have no respect for imports or any other car that wasnt build pre 1970).
-turbos, to a point, become self feeding. a supercharger has its limits when creating power. the more power you want to make the more power you take form the power you are making. turbos feed more air into the engine, there fore there is more fule, more heat, more energy for the turbo to flow more air and mor fule....the cycle continues.
-as for turbo's on top fule dragsters, no turbo being built today is going to like having the tempatures of nitro methane burning in its turbine housing. if the guy did run quad turbos the reason he wasnt succesful was mostlikely improperly sized turbos not making enough power. intake temp is crcial in top fule. certianly a roots will compress air cooler than a turbo with 7000 degree exaust gasses passing by the intake by just a few inches. on top of the turbine would become white hot and brittle. my solution? well coat the turbine blades with tungsten.... your the college grade...you tell me why...

I'll take this one statement as it seems now your trying to speak with some authority.
Most european automoblies are N/A but the ones that use superchargers , a good share of them use the Eaton or Lysholm screw type supercharger, and I wouldn't know about bullheaded "americanV8" lovers as I own a Ford pickup, a Boss 351 Mustang and 5 cars are Jap import, and definding superchargers like they were gold, sorry I have to go with facts, not opinions without something to back it up.
As for changing the boost in 2 of my cars, I can change the boost from 1# to 65# with just a twist of a knob. I have a VSD on my crank that takes care of the problem of having to change pulleys. And to top that off I use a laptop computer looking at my EGT,o2 sensors and MAF and I'm able to adjust my A/F and timing for any gas or condition needed. I can adjust for economany, power, weather changes you name it, I can adjust it. So tell me how a turbo is easier?
Now you state some truth. The turbo gets it's energy from exhaust heat and expansion (but this is where fact ends), at the cost of 28% energy loss due to backpressure, where as a screw type supercharger uses 35-40% energy and the roots 50%+. This is a plus for the turbo's.
Now here's where you get your fact's alittle mixed up, but it's OK cause your close, it's the hot exhaust gas expanding not velocity that creats pressure on the inlet side of the turbo and the low back pressure on the outlet that drives the turbo, thus being said you'll always have the turbo restricting the exhaust even when it's not making boost robbing the engine of that 28% energy, and until it makes boost (2-3000) it's a power robber.
Now the screw type supercharger is a positive displacement compressor, meaning it puts out a giving amount of air per rev. As soon as the engine starts it's making boost.
Now we get into Tempature. The inlet temp. of air ITA is very important as it's what it's all about. The cooler the air the more oxygen it contains, hotter less. It's called Density Altitude. The higher the IAT is the higher the density altitude and the less power a engine makes.
A turbo good designed turbo has a Delta temp. of 190F at 15# boost.
A screw type s/c has a DT of 130F at 15#.
Why the difference. The turbo has a 70-80% efficiency, and the screw s/c has 80-92% efficiency, and this is important cause the more efficient a compressor is the less heat it makes when compressing air. A major plus for the screw s/c.
I'm now even going to go to your personal likes or dislikes, but it does seem you have a issue with high performance cars with cams.
As for turbo's being self feed and S/C it's limit's to making power, WRONG. A S/C can make more boost at a higher volume than a turbo.
Now for you last statment about the 4 turbo's on Don"Big Daddy" Garlic AA/Fuel dragster. Trust me they were sized properly and I told you I have a masters in Metallurgy. Thats the science of metals. I personally invest casted in a vacuum a metal called Tibor which is a combination of Titinum, Tungsten and Boron which can handle more heat than any metal known. Everything was setup right, just couldn't make the boost.
Now you've been picking on my education and records I've made, I'd like to hear about your education and areas in the high performance field where you've excelled, outside of making statements without any facts.

CB, you're not helping the turbo's cause... please stop.

I was thinking more about my 4cyl experiment/project... I think an m45 would work better not because of efficiency levels, but impeller speed. I was going to attempt to put an exhaust turbine from a larger turbo(probably t04) as well as a pulley on the driveshaft of the supercharger. I'm very skilled with an autocad-type program, I could quite easily design a way to rig this up. I would surely need to hire a professional fabrication shop to make some parts. As good as I think I am, I just don't have the tools. The supercharger would be driven by both the pulley and the turbine. This way it will achieve full boost as a normal screw supercharger would. The wastegate on the turbine would be controlled by a simple computer and a couple of pressure sensors - one on the exhaust, one on the intake. It will hold exhaust pressure a few pounds less than intake. While this is a shoddy system of controlling boost on a typical turbo, in this system the speed of the supercharger is ultimately determined by the crank. The turbine is there simply to reduce the ammount of power taken directly from the crank as much as possible while still maintaining higher intake pressures than exhaust. Perhaps with the delta t efficiency of the screw compressor and a very efficient turbine(I wish I could afford a VATN to tear apart), it will be able to power the compressor entirely. If it can, then any extra power the turbine produces will actually be added to the crank. Obviously since I am no engineer(yet.. sophomore year), I can only guess that this will work, and the only way to find out would be to try it.
Back to m45 vs 62 and 90.. A turbo's turbine is designed to be used at high speeds, so obviously the less displacement of the supercharger, the faster it will be required to spin to produce the desired boost. I'd want to bring the turbine as close to its intended usage range as possible. Although again, I'm not an engineer, and as far as I know a turbine could work just as well at low speeds. Just a hunch that it wouldn't, otherwise no one would design a turbo to spin at those speeds if it didn't have to.
If you have any input on this topic Zgringo I'd appreciate it. You can respond here, or preferably send me an email or PM me. email is [email protected].

Oh, and hows that Boss running? What have you done to the cleveland? I have a cleveland in my '69. Right now I'm fabricating all the parts I need(and some I don't..) for a twin turbo system for it. I hope to have it running by mid-January so I can put a few hundred miles on the motor(which I still have to build.. last motor went kaput due to some steel shot that the machine shop kindly hid in my intake manifold.) before the warm weather comes.

:uhoh: i never claimed to have any higher education :lol2: . However i do have expereence iwth Roots, Screw, Cyntrifical, and of course turbo chargers on many differnet types of cars being that i have been around cars for as long as i can remember and worked at a local performance installer and craving any information on cars and performance i could/can. as foy the cam thing. i love cams, its the first thing i reccomend when someone startsl ooking for performance. cams show one the the best and cheaper bang for buck power adders. what i dont like is 'Muscel' cars used as daily drivers with very rough high lift high duration cams that cant idle woth a damn with louder exaust than any honda you will ever find. Id much rather hear the semi smooth tone of a honda with a fart can and stock cam than the "pop GRUm pop pop POP pop GRUM pop pop" its like you can hear each exaust stroke individually with the snap open and snap close of each valve. so anyways.
you are right, if i was going to use a s/c i would most deff. use a screw type over a roots, cyntrifical, or screw. i note the downfalls to the cyntrifical type compressor used in turbo's. however you lost me when i said 'fully spooled by 2-3000. by that i mean, unless you are making hugemongo non daily driver boost, the turbo is making full boost by that RPM below that it is making boost, some even at idle. and when racing who ever drops below 3,000 anyway? well unless that is where you car makes maximum power which would mostl ikely be in a carburated v8 which are a pain to turbocharge in the first place. though it can be done.
as for your lap top. well im geussing you have one of thoes $2,000 programs that go with your $1,500 specialy tuned ECU. well you can get thoes for turbo'd vehicles as well :) .
oh, and exaust velocity comes from expansion and partially the exaust stroke. but you already knew that.
you dont have to explain to me what a science is about. i myself am looking forward to a degree in theoretical physics, modern phyics, along with an engineering degree and a few graphic design classes on the side. only thing im too lazy to stay 8+ years in college so im getting out by 6. them if i want to persue masters i will do it on my own time after i am out of college and financailly secure.

Mr. Duplox, I think your idea is super and if done right should consider placing patent's on your idea and submit drawings to the patent office.
Some things to consider with this project is RPM's. The M45 Screw S/C likes 18,000RPM and the turbine wheel likes 100,000RPM, so if you put a 5.5:1 reduction drive on the turbine you'd be in the right ball park, plus have lots more power off the turbine to drive the S/C than a the turbo has to drive it. By installing a drive off the engine also you'd have low end boost till the turbine started making power, and if it was connected right the extra power developed by the turbine would go back to the crank of the engine
The M45 uses 18HP and has a Volumetric Efficiency of 90+% with 400+cfm's and a Delta Temp. below 180F. The turbine with a 5.5:1 reduction drive well have a increased efficiency and drive the S/C very good and you well be able to make the power your looking for and then some.

The Boss 351 is prue stock and only has 931 miles on it. I got it new and used it 5 times to run on the Salt Flats and set a class "C" production record of 197MPH with it and it's been parked ever since. Once in awhile I fire it up and take it for a short spin, but other than that, just sits.

WOW!! Original Boss 351 with under 1000 miles.. that is rediculous. Do you have any pictures of it? I'm part of a 335-series forum that I'm sure would love to see it.

I'll keep my eyes open for a cheap m62 so I can better visualize a way of doing this and have something to work off of. Clearly using pulleys would be the best approach, and the more I think about it the simpler it becomes. Thanks for your help.

he CBFryman:

The MKI SC was introduced to the US in 1988 as a supplement to the MKI NA. It carried a 145hp supercharged and intercooled engine this being the main difference between it and the NA.

no argument on the turbo vs supercharger thing but dont make things up about mr-2s

aw11 i think is the engine code

your tlaking to me about MR-2's. they only came in NA and turbo versions. never s/c to my knowledge in america.

i just said they came with the aw11 engine that is a supercharged engine. in america in 88

the mk2 came with a turbocharged engine with the 3sgte and it came NA

"Changes in August 1986 saw the T-bar option added along with modifications to the rear suspension, brakes, rear lights, front bumper and interior. The most noticeable change saw the introduction of the 1.6ltr 4A-GZELU supercharged version raising the power from the NA models from 112hp to 145hp."
http://www.toyotaimportsforum.co.uk/mr2/index.htm

oh yeah my bad aw11 is the chassi code i think

Its a bit confusing... seems like they had 2 engine codes for every engine... like this:
"The early models came with a choice of engine and transmission, the slightly underpowered 1.5ltr (AW10) 3A-LU engine from the Corolla and the 1.6ltr (AW11) 4A-GELU engine from the Levin/Toreno. Transmission choices were either a 5 speed manual or electronically controlled four-speed automatic."
So yes, the 1.6L is an AW11. Perhaps the AW11 is the name for the basic design... like the shortblock. Add a supercharger and whatever heads/intake and its called 4A-GZELU. The combo that came in the Levin/Toreno is the 4A-GELU... Both are AW-11 style motors. Who knows, I'm just guessing. If you want to see a nightmare of engine codes, try to figure out Ford's from the 60s and 70s. Its a huge mess... Often they didn't bother to change the engine codes on lots of parts when they made changes, so you pretty much have to take apart the motors to figure out what you have exactly.