Compound boost.

[Wicked One]

Planning my off season and was considering this option.

Kenne bell 3.6 liquid cooled with dob intercooler. And then a small turbo to feed the kb.

Or the Hell with the kb lq and go with a mammoth for the gt with a turbo to feed that.

Just brainstorming now.

sent from my Damn phone

 

[JeremyH]

Do it, its just money lol

But its usualy works the other way around smaller blower to get a bigger turbo spooled and the the turbo brings in all the power up top.

 

[stkjock]

Greg, get ur current junk running right and enjoy it for a bit.

the if u get board, TT5.0 swap....

 

[Wicked One]

How is that? The twin screw is the last line of induction. I figured a small turbo to spool quick and feed the screw. Oh wait. A screw for low end and then the turbo to take care of the upper rpm.

Just brainstorming to see if it is worth it at all or just get a larger blower.

sent from my Damn phone

 

[JeremyH]

Yup the twin screw with that instant boost hit down low will spool up the turbo and then the turbo will make all the peak power with out having to over spin the blower so you can jsut run a larger blower pulley. Aka blower pulley that makes 10psi and turbo with wastgate set at 20psi etc.

 

[Synister500]

Do some research. The KB and whipple compound boost setup has been tried many times with a lot of disappointment and $$$ waisted. There is a reason why it is mostly done with the eaton, sometimes ported eaton. For a WOW factor It's a badass idea. From a performance standpoint it's a disappointment. The twinscrew will become a point of restriction. Not to mention the tuning nightmare it will become. I have a buddy that is one of the largest precision turbo distributors in the south central part of the US. He's willing to do the setup for his cost on the turbos; everything else custom fabbed, but our research has been a hurdle.

BJ

 

[JeremyH]

True I have usually seen it done with roots blowers not twin screws, but I havent done too much research on the subject.

 

[Full_Tilt]

The beauty of compound is an increase in scavenging due to having significantly higher pressures in the intake manifold than in the exhaust manifold. Which means you get supercharger like detonation resistance but you also have the nearly free power of the turbo.
For this reason, youre actually better off going a little large on the turbo. Its going to spool faster than it would normally because of the supercharger, and of course, it will make more power.
You will need to be running a fair bit of boost to insure both compressors are up in their efficiency island.

Im not sure about tuning. It would be business as usual with speed density, but maybe this kind of thing is difficult with mass airflow.

 

[r.barn]

Basically what you are doing with a compound boost twin screw + turbo is creating a massive cubed turbo big block.
You would want to size the turbo the same way you would for a 500 ci motor.

I could see how a roots blower would work much better, since all a roots blower is doing is shoving more air through and compressing the air in the intake manifold. While a twin screw actually compresses the air in the rotors. This could be a restriction in how the air flows through the super charge when the turbos come on line.

 

[blacknlte]

Stock SC like whats on the GT500s are the only way for it to truly work. Ask me how I know, just look below. vvvv

 

[r.barn]

Stock SC like whats on the GT500s are the only way for it to truly work. Ask me how I know, just look below. vvvv

Yeah it has to be a roots. It should work with the new TVS blowers too since they are still a roots blower. makes since that a twin screw would be a restriction

 

[GreenTerror]

Sounds like double the fun to me!

 

[05mustang_TT_charged]

Stock SC like whats on the GT500s are the only way for it to truly work. Ask me how I know, just look below. vvvv

You could have made the same or better numbers with the restrictive Eaton out the way and just the twin turbos. Even Hellion showed it in a dyno video. Car made more power and a little less torque with just the turbos.

 

[blacknlte]

You could have made the same or better numbers with the restrictive Eaton out the way and just the twin turbos. Even Hellion showed it in a dyno video. Car made more power and a little less torque with just the turbos.

True but turbo lag makes the car drive like shit!! The Hellion kit was made to use the stock SC and still drive around as stock as can be.

 

[05mustang_TT_charged]

True but turbo lag makes the car drive like shit!! The Hellion kit was made to use the stock SC and still drive around as stock as can be.

I hear that. My buddy has the same kit on his 2007 GT500 and it is fun to drive.

 

[Full_Tilt]

You could have made the same or better numbers with the restrictive Eaton out the way and just the twin turbos. Even Hellion showed it in a dyno video. Car made more power and a little less torque with just the turbos.

Thats nothing a bigger supercharger couldnt fix.
Plus, from what Ive seen of Hellion, I have no interest in any objective comparison they make.

 

[908ssp]

Compound boost would be ideal on a factory turbo car. No install of an aftermarket turbo is as neat and clean as a factory install.

You have to be careful to maintain some back pressure on a turbo or they can over rev and it will blow up. So a small turbo into a large displacement PD SC is a bad idea. One or more big turbos into a small SC is a good idea. The SC will compress the air no matter what the incoming pressure is but will have trouble if the air is restricted coming in by a small turbo. Once the PD SC gets some air flow going the turbos will spool up and make some big power.

Compound SC has been done for 100 years. Usually two stage PDs like in the Alfa Romeo GP cars of the late 40s.

 

[fdjizm]

I see it as cool, but a waste and not really necessary.
Your turbo's just slamming air into the supercharger that it can't swallow fast enough, never thought it made any sense but cool indeed.

 

[JeremyH]

It's actualy not that way at all, the roots blower isn't a restriction. Its an idea setup really, pd blowers have huge gains when you unrestrict the inlet since they can pull in air faster, what better way to allow it to pull air faster than feeding it 20 lbs of pressure with a turbo? hehe

Take a look at blacknlte's dynograph, I don't see that stock gt500 blower being a restriction anywhere, do you?

I think its a very efficient option, you could dump your money into a hige 3.4-4.0 blower and then the 8-10 rib kit, upgraded intercooler heat exchanger, longtubes and exhaust, and so on, or you can leave it stock, save some coin and feed it with a turbo or 2 and do this.

 

[CPRsm]

Take a look at blacknlte's dynograph, I don't see that stock gt500 blower being a restriction anywhere, do you?

Well, yes. But they aren't bad numbers by any means. But those peak HP numbers really closer to about 928rwhp with the correct correction factor for that elevation. Just turbos and no blower has it's advantages. The intercooler isn't in the engine, so it works better. And on 500's 25% of the cooler is blocked a good bit by the lower. MAF sensors get HOT because they are before the cooler, and in some cases ruin or actually melt the plastic on the sensor. A hellion customer had a custom pulley for the blower made to slower it down. It made the same power at some 4-6 psi less iirc. Even then he still pushes 40psi!