one of my mates made his RB30E into a RB30 supercharged+turbo'ed the supercharger was on 6psi and turbo on 4psi and made 370hp at the wheels. he used a side mount vortex supercharger and a GT35/40 with 1.06 rear ar and it seem's to work fine for him as he put the superchager just befor the turbo to help spool it.

im sure he could make a SHITLOAD more power but it took him like 1 year just seting it up properly and tuned right

for those that dont know what a RB30 engine is its out of the old skylines pre 1990



in reguards to this


(In theory turbo's are 'limitless' but engines can handle so much and for a factory engine you would be lucky to get past 300BHP with an aftermarket turbo before having to change out internal parts. A lucky few engines can go past 400BHP before the engine becomes a ticking timebomb. )

have u ever heard of a RB26 or 2JZ ????

and you dont allways need more compression for more power :P lower compression and more boost + Water meth is the way to go

Quote from Christopher Raemisch :

A supercharger will always lose efficiency the higher the RPM when compared to a turbo. They have much more rotating mass that the engine has to overcome before it can increase power.

There's much more kinetic energy spent on a turbo than a supercharger, look at the difference in rpm. The main difference is that turbo's convert some of the otherwise wasted heat in the exhaust back into compressing the air, so they are more fuel efficient.

The advantage of superchargers is they generally take up less space, and don't radiate the high amount of heat that turbochargers do, plus the reponse is near instant, but that's mostly important for high end dragsters.

http://en.wikipedia.org/wiki/Turbocharger

http://en.wikipedia.org/wiki/Supercharger

I did say there are a select few engines that are able to be run over 300BHP but the vast majority of mass produced engines do not have the tolerances or materials required to operate at that much HP. For those people that do get those engines they are lucky indeed =)

The advantage of water-meth is lower air temps which increases air density, the same idea behind a turbo, this allows you to throw more fuel into the mix, thus increasing your compression during the power stroke which gives you the increase in power.

A big downfall of superchargers is at higher RPM's they lose a good portion of their efficiency because the faster the screws turn the more power is needed to turn them. They routinely go from 90% to 40% or less in the higher RPM's.

Superchargers are great for making tons of torque but not so great at making HP when HP is made in the higher RPMs. V8's work fairly well on superchargers and GM even put one on their cobalt i4, but the engines powerband has to be low enough not to fall too far down the screws efficiency.

Superchargers are good for broad power figures, they cut the peak off and feed it to the lower end of the spectrum, but a turbo will always give you more power.

I find it hard to believe a turbo is heavier than a supercharger. A supercharger sits over the whole head, or most of it, while the turbo sits back in a corner somewhere, usually lower than that of a supercharger. When racing even 10 pounds in the wrong spot can throw off handling enough to reduce your times. This is professionally; club level would see less of a difference.

I think you are right that it might take more engergy to turn a turbo thinking about it good, but I am not sure. Screws on a supercharger are heavier than a turbo and thats not including the pulleys, belt, and housing. The major weight though is the rotating mass. True turbo's spin at a much higher RPM than a super, 15,000 compared to 130,000 but there is less mass in a turbo which makes this revolution possible. This operating RPM though may make the turbo use more energy than a supercharger though, advantage though it's using otherwise wasted energy instead of leeching it from the power coming from the crank.

Heat is more on a turbo for sure, turbo's do increase backpressure from between the engine and the turbo but not to a huge degree. But even a roots at a boost level of 10+ PSI makes enough heat to almost require an intercooler to keep efficiency up.

Superchargers are easier to tune, there isn't much to it besides changing out pulleys and they are easier to install, guess it what a driver wants =) They usually live longer too =)

lol u musent know what a centrufigle and vortex superchager is they dont even attach any bolts to a head the ones your thinking of are tunnel ram superchagers like the 671 :P

and for outright power nothing beats a superchaged V8

personaly id rather have a TT V8 for a useable car

oh and some superchagers run at 60+ psi

Quote from MAD3.0LT :

they dont even attach any bolts to a head the ones your thinking of are tunnel ram superchagers like the 671

You mean 6-71? The reason that it is called a "6-71" blower is because the design for that blower was originally for a Detroit Diesel 6-71 engine. 6 cylinders, "-" designates inline, and 71 means 71 cubic inches per cylinder. To make a supercharger designed for a two stroke, 6.9L diesel engine work on a gasoline engine actually takes a bit of work. Because blowers for large diesel engines require more efficiency at high flow rates, but low pressure ratios. But again, the reason that that blower is used on a diesel engine is not just to build boost to get more air into the cylinders. It's because the supercharger is actually more efficient at getting air into the cylinder then the piston itself, because of the high compression ratios of diesel engines.

Quote from MAD3.0LT :

lol u musent know what a centrufigle and vortex superchager is they dont even attach any bolts to a head the ones your thinking of are tunnel ram superchagers like the 671 :P

and for outright power nothing beats a superchaged V8

personaly id rather have a TT V8 for a useable car

oh and some superchagers run at 60+ psi

For anyone wanting to make any sort of power they would not be using a centrifugal supercharger. They are primarily used in low boost situations where high air volume is needed to achieve efficiencies. These chargers do not provide low RPM boost like a roots, so they behave like a turbo, but they also are parasitic to engine HP, requiring more HP to turn faster, so the top of the RPM powerband is cut off as well. They incorporate both negative effects from both the supercharger and turbocharger into 1 package, not sure why anyone would want to do that but go knock yourself out. They are also prone to air backtracking back past the centrifuge during low RPM deaccel.

I know some Mustang owners use them but if your going to supercharge the roots is where it’s at, at least then you get the low RPM power. True a centrifuge will have linear boost, but you could get a turbo to do that too if you really wanted to with changing the tune and using a wastegate at competition RPM levels.

Turbo’s can run up to that man PSI too if they have enough exhaust flow, not sure why running 60PSI is an advantage for a supercharger.

A v8 will make the most power on a turbo setup, but it would be more peaky than a supercharger and thats one reason why you see more V8's blown than turbo'ed.

lol u oviously havent seen topfuel dragsters in action mate


the fasted turbo record atm isent even held by a v8 its held by a turbo 2jz in a camry i beleave 6.67 and the next fastest is a SR20DET with 6.87 . im yet to see a V8TT run a 6 low 7's yes but the supercharged V8's are now running mid 4's


btw the 60ish psi i was talking about is on around 15.1 / 17.1 compression on methanol + nitromethan (spelling)


we have alot of centrfugil charged cars in australia making 600+ hp on inline 6's and v8's but i agree i would rather a roots blower on a V8

Quote from MAD3.0LT :

the fasted turbo record atm isent even held by a v8 its held by a turbo 2jz in a camry i beleave 6.67 and the next fastest is a SR20DET with 6.87 . im yet to see a V8TT run a 6 low 7's yes but the supercharged V8's are now running mid 4's

You're comparing two completely different things..

lol hows that i was mainly responding to this


A v8 will make the most power on a turbo setup, but it would be more peaky than a supercharger and thats one reason why you see more V8's blown than turbo'ed.



as im yet to see a turbo'ed v8 make more then 2800 HP

Quote from MAD3.0LT :

lol u oviously havent seen topfuel dragsters in action mate

...which can barely run for 5 seconds. When you've got that much power and that short a run the slight efficiency loss of a supercharger is academic compared to any lag.

Quote from ajp71 :

...which can barely run for 5 seconds. When you've got that much power and that short a run the slight efficiency loss of a supercharger is academic compared to any lag.

They use 1600 HP just to turn that blower over, then the engines get a full rebuild after those 5 seconds. To get a turbo to run that kind of HP numbers it would hae to be so large that I doubt that it would be fully spooled by the time the car made it to the end of the track =)

Only a country full of idiots would enjoy drag racing, or believe it could be used to discuss the ability of road cars. Oh...

Superchargers are limited by RPM before they explode. Whilst the same is true of turbos, it's a much higher rpm (half a million in some cases). Whilst one is driven from the crank (plus gearing), the other is driven via exhaust heat. This means for low revving applications, or where 'lag' is an issue a supercharger is often better, with high rev applications or situations where lag isn't an issue turbos would be preferred. But in some cases the turbo required gives too much lag, and this is where sequential turbos (one smaller than the other) can 'bridge' that lag. Alternatively, a supercharger could be used to 'bridge' the lag, but it most cases it would need to have a clutch system so that it is disengaged (and out of the system) when it isn't needed.

All very basic stuff that's been around for at least 90 years in its present form.

Quote from tristancliffe :

Only a country full of idiots would enjoy drag racing

To quote Garfield, "I resemble that remark".

Quote :

... ability of road cars

I'll take odds the 11 second 1/4 mile road car over the 14 second 1/4 mile road car any day, for example Corvette ZR1 versus a Subaru WRX STI, on most race tracks.

Well the ZR1 is a totally different class of car so they can't 'really' be compared to each other =P

I would take the vette over rex anyday too.

Between these three forced induction types I guess you have to ask what your aim is.

Smooth Powerband: Roots
Fuel Economy: Turbo
Highest HP: Turbo
Highest Torque: Roots
Instant Response: Roots

An in-between of all of these: Centrifuge

For DD's a turbo is your best option, you get greatest power output, but also the greatest MPG. When toodeling you don't need a ton of torque or power in the low RPM ranges and the turbo don't make much in the low RPM.

Drag racing you can use either, I have seen quad turbo setups on buick gran nationals run 8-9 second 1/4's but a roots would probably be better because torque is whats needed to launch a car properly.

Fuel economy is shiet with a roots so people have started moving to the centrifuge. They sacrifice low RPM torque for a little more high end HP with better fuel economy thrown in because a centrifuge doesn't load down the engine as much.

Cost is a huge factor for this, ideally they should have gone turbo, it would give the greatest HP gain with the best fuel economy, but with a turbo you now you have to buy an exhaust and intake and possibly an intercooler as well as the turbo instead of just an intake with a new accessory belt and couple brackets to hold the centrifuge.

I can keep going but basically people use a centrifuge because of the costs involved with turbo's. Initial purchase is higher as well as maintenance.
.

Quote from Christopher Raemisch :

Drag racing you can use either, I have seen quad turbo setups on buick gran nationals run 8-9 second 1/4's but a roots would probably be better because torque is whats needed to launch a car properly.

I think that a quad turbo setup is more for show then anything else. You can get more then enough torque from a turbocharged engine to "launch" a car in a drag race. Look at this video: http://www.youtube.com/watch?v=-dh7iU_gaGY

And, here is a grand national running in the upper 7 second range:
http://www.youtube.com/watch?v=P6kIwJRNWKc

As for the ZR1, I'd rather buy a Z06, and then send it off to lingenfelter, and get their 660HP package installed. So, 74kUSD for a Z06 corvette. Tune it to have 660HP for 10kUSD. It would be up to 84kUSD now. Still 20k less then the ZR1. Anyway, you can't beat the sound of a high-powered, naturally aspired V8 engine.

Hehe I agree about the quad =)

I would take an N/A anyday, I miss driving V8's.

Quote from Christopher Raemisch :

Hehe I agree about the quad =)

Although, quad turbo sort of makes sense on a V engine. Because you can have two sequential twin turbos for each intake/exhaust manifold.

Quote from Christopher Raemisch :

I would take an N/A anyday, I miss driving V8's.

I personally don't even see any point in having over 250HP in a road car anyway. My car has ~124HP. It's plenty for me. Sure it's slow and 12 years old, but it's cheap and easy to fix and maintain.

So say I got a Z20LET (200bhp stock) and done either one of these two to it.

1. Smaller turbo and a bigger turbo. What would be the final amount of bhp achieved?

2. Supercharger and a turbo. Again, what would be the final amount of bhp achieved?

Quote from sam93 :

So say I got a Z20LET (200bhp stock) and done either one of these two to it.

1. Smaller turbo and a bigger turbo. What would be the final amount of bhp achieved?

2. Supercharger and a turbo. Again, what would be the final amount of bhp achieved?

Anywhere between 0 and 500HP. I mean, how do you expect anyone to answer that? And it depends what pressure ratio(s) the turbocharger(s) / supercharger would be running.

Quote from wheel4hummer :

Anywhere between 0 and 500HP.

300bhp from two turbos or a supercharger with a turbo. Seems a bit untrue to me.

Quote from sam93 :

So say I got a Z20LET (200bhp stock) and done either one of these two to it.

1. Smaller turbo and a bigger turbo. What would be the final amount of bhp achieved?

2. Supercharger and a turbo. Again, what would be the final amount of bhp achieved?

impossible to predict, like w4h said, anywhere between 0-400 bhp

Also, if you had a supercharger running at 3psi, and a turbocharger running at 7psi, that DOES NOT add up to 10psi. 7psi and 3psi actually add up to about 11.5psi. This is because pressure gauges read the pressure difference between the atmosphere and the compressor.

Quote from wheel4hummer :

Anywhere between 0 and 500HP. I mean, how do you expect anyone to answer that? And it depends what pressure ratio(s) the turbocharger(s) / supercharger would be running.

I was asking for a rough estimate that's all.

Quote :

impossible to predict, like w4h said, anywhere between 0-400 bhp

Ok. Wouldn't having two turbos, one smaller and one bigger produce anything from 0-300/350bhp because they dont produce as much power as a supercharger do they, I would of thought they dont.

What parts would you have to change with the engine? With a supercharger you would have to get a better cam and get a intercooler wouldn't you? But what would you have to change with having a two turbo's? Would you still need a intercooler with a turbo?

Well, you haven't even said what boost level it would be running. For a two liter engine, I'd guess 1 bar of boost to make about 240HP or so. That is just a very rough estimate though.

Quote from wheel4hummer :

Well, you haven't even said what boost level it would be running. For a two liter engine, I'd guess 1 bar of boost to make about 240HP or so. That is just a very rough estimate though.

If you had to guess that doesn't sound too far off. I have a 2.4 that runs 1 bar of boost and makes between 230-240.

I agree nobody needs more than 125HP for a street car, but where's the fun in that? =)