WTF no turbo

Screw type??

AlexCisneros

isn't http://www.yawpower.com/ also making a supercharger application for the Speed World Challenge GT class?

http://www.speedsourceinc.com/ is also working on a GT car, no idea what configuration they'll use though (I think it's a different series).

Hymee

iTrader: (1)

I reckon I'd like to see a blower like the high efficiency twin screw ones they have been using very effecitivly on the LS1's. They are an inherently "high end" performer (if you call 5,500RPM high - hehehehe)

I wan't to see something that will fry the rear tyres when you go WOT at something like, say, 2 or 3k RPM. That would be wicked.

Bit worried about them (supercharger) having to work in such a wide power band.

Cheers,
Mark.

PetersonPeleRx8

Thanks for all the replies guys... that was pretty in depth.

So now I don't want a supercharger, which is good, cause I wanted to make a decision.

I guess I just thought that because my mom has a Saab 9-3 Turbo, which is real smooth and has high end power like you said. And my dad has a Pontiac Grand Prix GTP (Beast)... The GTP means its supercharged BTW. And his car is pretty quick off the line, so being the non-car-smart person I am I just figured that was the difference between the two.

So, thanks for writing all that for me.

Later,

Brit

XDEEDUBBX

im just a bum...hahhaha

Hornet

Forgive me if anybody has posted this already but within this link there is a pic of a rotary engine with a turbo on it. It is just on a display but may give some clue about what Mazda is planning with the RX-8 then again maybe not.


http://forums.evolutionm.net/showthr...threadid=54847

ranger4277

That is a really pretty photo. Makes my knees weak seeing such a beautiful motor.

AvitalBlue8

Thats the hybrid hydrogen/dino fuel renesis engine that mazda showed off at the Japan Auto show, pretty sure it needed a turbo when running on hydrogen to make 150ish HP (someone correct me if i'm wrong). It takes a significat HP loss when switching from gas to hydrogen.

Hornet

Well....Just smash my dreams into little bits and pieces!

So basically that is the rotary that has been mentioned that kind of runs on water?

Kas

just to add something here. From the way your talking about "low end" performance, try and drive an FD or FC with 0 boost and then you'll see what "low-end" performance is.

13B-MSP

firstable, don't worry, this is not another turbo vs supercharger debate thread. I know they both have advantages over another and disadvanges. But which one of the FI produces more engine heat?

Genom

Since turbo's are based off hot exhaust gas, I would venture to guess it does. But then again, I have no clue and am just tossing out the obvious response.

bureau13

Well, the hot exhaust gasses are there whether its turbocharged or not...in that case we're just asking them to do work. The exhuast gasses don't really interact with the induction side at all. The turbo MAY put out more heat...I really don't know...but I don't think it would be for the reasons you suggest.

Most modern turbo systems use an intercooler to remove some of the heat generated by compressing the intake air. The supercharger systems I've seen, or at least most of them, do not. Is this because it is difficult to squeeze one in there between the compressor and the intake manifold? Or do superchargers just not need them as much?

jds

wakeech

the heat energy made in an engine is a waste product of generating mechanical energy.

using either a supercharger or turbocharger isn't going to make an enormous difference in your engine's efficiency (some, not huge). in fact, even if you don't use one, it's not a huge factor in determining how much heat your engine is producing.

on a specific engine with a relatively fixed efficiency (yea much chemical energy becomes yea much mechanical, heat, sound, etc energy) you're going to generate a relatively similar proportion of that energy into heat, no matter your method.

ok, so what i'm saying is that it depends on how much power you're making in a specific kind of engine. you can't compare a 500lb V8 making 300hp to a sub 200lb p-port rotary making 300hp, because there are far too many differences (especially concerning conductive mass, and cooling systems, and lotsa stuff), but from one engine to another, speaking basically, the more power you make the more engine heat you'll have. how you make that power isn't a huge factor in how hot you'll make your engine (from what i know).

the most important part of all of this is really tempurature management, and that has less to do wiht the amount of power being made as it does the details of the cooling system.

rx7tt95

Actually the mechanical energy is the byproduct of heat caused by the combustion cycle. While a turbine utilizes this heat, it also has more surface area than a plane jane header system inside the engine bay which raises the ambient temp under the hood. Additionally, rotaries do not like backpressure which a turbo helps create. In the end, a turbo system will be more efficient when measuring mechanical and thermal losses. Frictional losses as the result of mechanical movement and add a small amount to the overall heat output of an engine. Rotaries rely on oil for cooling more than they do the coolant system itself. Notice the 8 has TWO straight from the factory when the non-R1 model 3G RX7's only had one.

Rotary EGT's (exhaust gas temps) are significantly higher than piston engines as well. When you apply the tuning fork to a rotary and ask it to produce more hp, you're essentially asking it to produce more BTU's of heat, regardless of forced induction method. This is true of any engine.

wakeech is definitely right by stating it's all about thermal management. There's the tuning side which also contributes. In the end, however, a supercharged 8 will probably have lower EGT's due to less mixture contamination of the intake charge by recycled exhaust gasses. The gasses will pass through an efficient header system whereas a turbo will essentially stuff a potato in the exhaust path and create higher backpressure. Lower EGT's mean an engine with less stress internally regardless of cooling system efficiency. The cooling system (oil and water) goes a long way (for obvious resons) to keeping the motor in one piece :-)

neit_jnf

Actually, very little of the heat in the induction side of the turbo system comes from the exhaust gas heat. Most of it comes from the actual compression, which raises the air's temperature. Since turbos are generally more efficient compressing air than most superchargers, the air temperatures are lower. Even with cooler compressed air with the turbos, most sistems include intercoolers which help lower this temperature even more. Most supercharger systems heat the air more and push it to the engine like that without further cooling.

TargeT

Turbos,, hmm..

ok turbo's are more efficent yes. but the air temps wont be lower with a turbo, its generaly lower with a supercharger

difference?

turbo uses energy already produced (exhaust exiting the combustion chambers) no HP loss, TONS gained (but there's a spool up lag) they also get V E R Y hot, when i would pull over after a spirited run in my evo, the turbo would be glowign red like a cherry

superchargers use the engine to spin up the screws (lose some HP to gain LOTS with no lag)

If you want more info there's tons on the net

Heat is just a byproduct, it is your turbo/superchargers enemy, because it causes detonation (thats why people spray N20 or use big intercoolers (front mount or side mount) to cool the air after the turbo

recap,
turbo's DONT Like heat! & have good ways to get rid of it
Turbos are more efficent than Superchargers, but take time to spin up
Superchargers are nearly instant but use the engine to drive the compressor (so you sacrifice some HP)

wakeech

recap, this has all been covered, you don't know as much as you think you do, as on some points you are wrong.

at equal levels of airflow and compression, air temps will be lower with a turbocharger.

RotorMotor

DOH! I read that and thought "This sounds way too simple. Wakeech is about to bust out all over this." And so it was...

PS. Just curious, what's with the cape Keech?

Edit: NM, just saw the "Rotor Man"... Haha

TargeT

I know how much i dont know thanks

it has been covered, your right..


and air temps are generaly only lower with a turbo because of the use of IC's

I dont even see how you can add boost to this car, so im prolly not going to buy one, might just go back to another evo definatly not as sexy as the 8 tho

kthnx troll again

neit_jnf

You should search the forum and study a bit more your thermodynamics. "Maximum Boost" by Corky Bell is a great read, very informative.
We're talking about the air just outside of the compressor, even before it gets to the intercooler. Because of its superior thermodynamic efficiency, the boosted air outside of a turbocharger's compressor will be at a lower temperature than with a supercharger at the same pressure and airflow levels. I believe the only exception would be a centrifugal supercharger which compresses air much like a turbocharger.
Another way to say it would be that given the exact same piping, intercooler design, airflow and psi levels, the car with the turbocharger will be ingesting cooler air than the car with the supercharger.

TargeT

who said i was talking specificaly about screw SC ?

reguardless, i would nvr take an SC over a turbo on anything smaller than 3.0L

i thought i was trying to be helpful, just popped in replyed then read a few pages back and saw it was answered much more thuroly elsewhere (woo spelling!)

doesnt look like this engine is going to put out many more ponies that it does stock, too bad, i'll just stick with what i know good ole 4g63

wakeech

...says the turbo motor expert.

TargeT

godamn, friendly bunch we have here?

sorry to have tread on your ground oh technical master

I know a couple of things about turbo engines & forced induction in general, enough to get by

your not making the best impression of your "community" everyone here waiting to shoot someone down when they post?

neit_jnf

don't take wakeech too seriously, he's always like that :p