just thinking what the best way to utilize 2 turbos ?exhaust into the first turbo then to the second turbo ,and compressed air from the first turbo to the second turbo air intake spool then to the intake track .or could you take the compressed intake air from the first turbo to drive the exhaust spool of the second turbo ?this would allow for lower air intake temps with out a intercooler.whats flawed with my thinking ?

 

Compound turbo isnt a bad idea. But exaust from first (bigger)turbo drives second turbo but second (smaller) turbo spools up first then the first turbo spools up. Theory behind this is when the smaller turbo spools its multiplying air IE 1:4 CFM ratio over NA so for every pound of boost you make the CFM is multiplied by 4~~~ Then when the first bigger turbo spools up it multiplies the smaller turbo's boost more yet say its a 1:6 ratio. So you flow 200 CFM factory X4 800 X6 = 4800 CFM. Many have argued that when the bigger turbo spools full boost that it overruns the second turbo but plenty of compound turbo setups have done this with plenty of power and no problems. My buddies cummins we built last winter made 2000 FTtq and 1400 HP at the crank with 375 injectors, pump work and 2 different chips stacked... If im wrong on any of this somebody chime in and correct me please. Hope this helps

 

We have a compound turbo cummins at our shop too. The thing is a beast. 85psi ruins transmissions. LOl

 

actually a compound system.....

exhuast drives the small turbo first, then drives the second bigger turbo.

Air comes in the bigger turbo first then goes to the smaller turbo then to the intercooler.

I run compounds on my cummins (12 valve), with three intercoolers as well.

 

most gas engines simply are not strong enough to do it. I ve been wanting to for years, but I would do it with the idea that everything would get throw away by catastrophic failure.

A cummins is only 359 inches.....and it weights about 1200 lbs......the bore in mine is 4.020.
Find a gas engine that can hold up.....and maybe. I ve thought a 7, 7.5 to 1 motor might get away with it.....on methanol........and say 50-60 psi....

 

didnt fords compound set up on the powerjoke have issues? I seem to remember hearing about one of the turbos getting stuck and not making boost.

 

^^^ I dont remember hearing about that problem they use a different system for the turbos i cant tell you the exact name of it but the turbos wernt spoolin at the right time and shooting flames out the exaust!!! We had one in the shop i worked at when the problem first arose...

1320 that statement is not true there uis a guy in a DSM that is running a compount turbo with no problems...my eclipse was compound before i went to a large single for simplicity. I will find the thread for you...

 

http://www.youtube.com/watch?v=bINtzDBl2mE

 

Would the ratio be the same if say you had a turbo pushing air into a blower? Seems like the possibilities are endless if the engine could hold up to the pressures. Would be cool to see a car with a turbo in the front and a blower sticking out the hood.

 

dear god, I remember when that setup was first being fabricated. its nucking futs

 

what statement? I didnt say it couldnt be done.....I didnt say that it hadnt been done......and please find the thread....How was your eclipse done?

 

http://www.dsmtuners.com/forums/cust...o-set-up.htmlf

My setup was close to his buy my first turbo was pointing up and the second one was below it similar to the cummins settup. but poor turbo choice and only using a SFMU for fuel management limited me so i went with a single and nitrous.

Your statement about gas engines not holding up it what I didnt think was true. Any built engine will be able to hold boost. thats all i was disagreeing and my eclipse was a 420A chrysler engine that i built up for boost with JE pistons Eagle H beam long rods and cams nothing spectacuar but enough that i could beat on it and not have to worry about pushing 25# boost through it and have the wastegate line come off like it did with a factory bottom end.... Ya **** hit the fan when that happened...

 

I think it was the old detroit diesels the military used were "twin charged"
Also there is plento of buick and pontiacs with 3.8 SC charged cars that they add a turbo on and make them beasts.

 

25 lbs of boost? Thats nothing....just single. A lot of guys are seeing 40+ now out of singles.....but compound twins start at 50+....Most of the cummins runs 60+ psi....on the low side(common 75-95 in street trucks). Some are in the 150+ psi area.....

 

That 25 lbs of boost was on my eclipse before i had a built motor i blew the ringlands out the bottom of the engine im suprised the rods were able to hold up. Most guys with 420a stock can safely run 7-9 lbs boost without problems.