Blown 4-banger

Who cares! They make 8000 hp so 200 hp is negligable (sp?). I'm not sure how much it takes to turn a turbo but I know the back pressure created by a turbo hurts power. It takes power to make power, no getting around it.

chipmonk212121

ya, do you really think a 4 second top fuel drag car running 10,000 HP can afford 3 seconds of turbo lag? lol

Cobalt_Supercharged

Those are modified Lysholms. The new Whipples are out sourced with each part coming from different companies with minimal source control, making them POS's. If Whipple would make some tighter source requirements they wouldn't be as bad.

TurboBlackBalt

I build boost on the line and I have a manual transmission. Turbo lag at a drag strip is a joke.

L.P.

You arn't that bright . Foxbodies by far are some of the easiest cars to make go fast, and will out run many F-Bodies all day long. Supras are way overated, of course they can handle 1000 hp on stock bottom end, but are so expensive to get to that point. I would much rather have a fox body mustang than a supra or f-body.

Matty

That's the reason I chose cetrifugal. Vortech's have a wicked sound.

charged_sunfire

its nice to have instant boost with a charger but my honest opinion is that a turbo can make more power all in all, chargers are too limited. Only reason i went with a charger on my beater is cause its reliable for the time being.

Blown 4-banger

Turbos make more power on the streets, but in unlimited competition blowers are better, they may requires 1,000 octane gas, but you can always put a bigger blower on it and make ungodly power an not have 20 seconds of lag like the 1000 hp supras do.

JMH

If my memory serves me correctly, It was a Weiand 6-71 mated to a big-block CHEVY (twin screw).

Blown 4-banger

A weiand 6-71 is a roots blower

p7x

S/C = whipple (relistened, roots does sounds good but knowing its inefficent gotta go with twin-screw)
Votech = the most annoying thing I've ever heard
Turbo + exhaust = best sounding car.

CTCOBALTSSS

A twin screw sounds nasty but there is something wicked about the roots blowers.
They sound like a siren. It almost scares people. Gotta love that.

JMH

-With twin screws.

All "Roots style" blowers use air screws. Thats What a "ROOTS BLOWER" is.

Some have 3.

So, according to the question..........what is your issue?

BLKblurr06

centrifugal superchargers are best applicable for engines that already make good low end torque because the major power curve is going to be on the high end. Roots blowers kick the boost in early but are slightly limited on the high end flow. The new eaton TVS should have the best of both worlds, builds power on the low end and high end. bottom line it probably wouldnt be the most suitable for a cobalt if thats what we're talking about.

Cobalt_Supercharged

Twin screw has great power from low-high rpm. Even at 3.0 bar (~30 psi) the volumetric efficiency is ~70%. Eatons are typically capable of peak volumetric efficiency of 65% at 8-12 psi. It only goes down from there.

TurboBlackBalt

Eaton= Roots style Blower.. Just like a Weiand

Blower - Air movers. Compression occurs externally (in the intake manifold). Port the intake manifold and cylinder head (removing restrictions) and the PSI drops

Supercharger- Centrifigal. Vortech, Procharger etc. Compression occurs inside the unit itself.

Turbocharger- Same as a centrifigal using exhaust gas instead of engine rotation and drive belt to spin compressor wheel. Compression occurs internally.

Twins screws (circa KB and Whipple) are not blowers. They are superchargers. Compression occurs internally on a twin screw supercharger.

Adiabatic Efficiency of forced induction devices-
Early Roots blowers (6-71, 8-71 etc) = 50%
Early Eaton Roots style blower = 60%
Late model Eaton Roots blower (circa cobalt/GTP etc.) = 60-65%
Twin screw superchargers = 70%
Centrifigul and Turbos (properly sized) = 70-80%

Nope, they arent screws.

Twin screw supercharger



Three Lobe blower



Another difference between a twin screw and a blower. Twin screws compress air down the along the center axis between the two screws. Blowers move air around the outside of the case. (Watch the arrows http://www.pneumatica.be/productie/rootscomp.htm)

SSSC

Twin Screws also move air along the outside of the case. The screws mesh together in the center not permiting back flow of air.

TurboBlackBalt

The twin-screw type supercharger is a positive displacement type device that operates by pulling air through a pair of meshing lobes not dissimilar to a set of worm gears. The intake is located at one end of the two screws, which overlap, but not completely, leaving a small pocket open. As the screws turn the pocket moves towards the exhaust side, pulling air in from the intake. The screws are machined so the pocket gets smaller, compressing the air as it moves through them.

SSSC

I know man, this is one of the things I work with for a living. I just didn't want people to get confused thinking the air was being pushed between the screws. It actually rides along the screws in the open slots between the threads, which has tighter clearances as it procedes from one end to the other creating internal compression.

Blown 4-banger

This thread was intended for discussion on which whine people liked, not the technical specs of different types of FI

TVS_SS

Personally, i'd rather not hear my boosting device.

TurboBlackBalt

NOS!!!!

or if you prefer

NAWZZZZZ!!!!

NJHK

Backpressure created is from restriction on the rest of the exhaust system. When you get rid of restriction, backpressure is not an issue. Just like you guys increase exhaust systems in diameter, this relieves backpressure but unlike you guys, they aren't really effected (sp?) by the lack of velocity during boost pressure (above atmospheric pressure).

There is alot of misconceptions of "waiting for boost" and stuff like that. There is alot of factors that play into response of a turbocharged vehicle but the main thing is how well matched a turbocharger is to an engine. If you put a damn T4 on an 1.6L engine, yeah, it's going to take a while to spin a turbocharger's turbine at a high rate RPM to create x PSI of boost pressure on the compressor side.

There are turbocharged vehicles that have turbochargers that can support up to 400 HP and respond just as fast, create more boost pressure and more efficient than a roots type supercharger BUT this doesn't make one better than the other, that's the point I'm making. Everything has it's purpose. Not everyone needs some 800 HP drag car just to go down the street and honestly, no one really wants that much power or want to deal with an highly engineered piece of machine (atleast in our age group).

People just need to stop this whole "This is better than this" because when it comes to modifying, it's not about whats better but what someone prefers. If someone prefers a Supercharger, then let them & vice versa. What I will say is that if you're going to mess with any form of forced induction, you NEED to make sure that what you're using is EFFICIENT for whatever you're trying accomplish.

TurboBlackBalt

Im confused by that. While backpressure after the turbo is bad, as it increases spool time, there is no way to get around the massive amount of backpressure created by a turbocharger. Exhaust manifold pressure does go up IMMENSLY because of a turbocharger being placed right there. Even with a 1.0 A/R turbine side on a Gt42R, I garuentee you can measure an ass load of backpressure in my 300ZX manifold. Thats why us turbo boys see such pre turbo EGT's compared to you blower boys.

HunterKiller89

iTrader: (1)

back pressure from a compressor wheel doesnt drop HP a whole lot though, whereas another device to feed power into (supercharger) DOES eat up a lot of HP

its all about favorites...i cant say i have one...i need to drive em both 1st