i want a reeally fast spooling turbo
full potential at about 3000 rpms, with HKS 272 twin cam

the reason is, im making a compound turbo setup and this will be the smaller one that is just there to get the power so the big one can kick in at 3000+
im looking for 1000rwhp with both of them so i guess maby i can get 400-500hp from the small one

i want alot of reliability, whats better turbonetics or garett

 

I like the compound idea a lot. Especially for 6cyl engines. I think the problem you may face is the primary turbo may have a small turbine to support 1000rwhp. How would you go about plumbing this so it doesn't choke the motor? Nitrous is also a good option. What is your secondary turbo?

 

What he said.

Single turbo route= Billet wheel, ball bearing. Dual scroll turbine housing and spool valve.

 

My question is going to ultimately be what is your application? For road racing you could probably use the enhanced power band, but for a drag application the likelihood of needing it is minimal especially if you use modern electronics to try and spool up the turbo at the line. As an example if you have a V161 and go from 1-2 you're going to drop to around 4200 RPM if you're shifting at 7K.

I had a buddy lay down 690 at the wheels with a 67 on 27 PSI through a manual on a stock cubed VVT-I engine with BC272s. Not 4 digits by any means but it was a simple single turbo setup with what I wouldn't call a huge turbo.

By all means not trying to deter you from doing it. If you do, pics are awesome. I'd be looking for something like a

 

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, there will be a bypass valve so the secondary turbo can feed straight into the intake at higher rpms(going around primary), for the secondary i was thinking Y2k or super thumper. im not really sure on the turbine compressor wheel, and a/r sizes for either of them

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this will just be a street car, that i take to a track sometimes. i guess the small turbo will only be used in 1st gear, but i was not planning on going small on the secondary(probably 85mm+)

 

^^^Has this ever been done? Curious to see how it works out. I think a 54mm inducer with stage 3 t31 would work for the primary turbo. Should spool instant on a 3.0l.

 

How serious are you about the 1000hp total goal? That will take 40 psi and 8000 rpm to be close to reality. I understand it "appears" 1200 hp 2jz's are a dime a dozen, but its not quite as automatic as youtube makes it appear.


If you are serious about 1000hp/3000rpm peak boost/3.0l of displacement then compounds are the only thing that will make that happen.

 

this is basicly what i want to do(execpt i want a intake bypass valve so the secondary can breathe). what a/r do you think would work? also i was looking at the grand national cheetah by turbonetics 60mm comp., 57mm turbine, 63 a/r, how fast you think it will spool?

 

http://www.supraforums.com/forum/sh...al-Twin-Turbo-Design&highlight=Compound turbo


I'm not sure if this is similar to what you want to do, but it's a good read.

 

If I'm not mistaken Cheetahs are old school tech so not the fastest spin up. In the ballpark for size of the smaller turbo though.

In terms of using valving with the larger turbo, if the smaller one's spinning it's a restriction but not as big of one as you'd think. Using a valve is dangerous in the fact that you're going to potentially surge a turbo (you have to equalize out pressures then open the valve.) This has been done with an RX7/MKIV Supra already from the factory. Supposedly it can lead to shaft life compromise due to the surge of the valves opening.

http://www.max-boost.co.uk/max-boost/supra/boosting_the_beast.htm

For your goal and your preference to keep this threshold I would likely consider something in the 60ish mm range (hell even a Holset HX/HY35) and something like a billet wheel 75mm S400 with the big turbine housing. Should give good area under the curve and be at your goal.

In terms of it being a street car, even so I doubt it will be. As mentioned with the levels of boost you need to run you'll be on either E85 or race gas constantly. You may be able to get away with methanol injection though especially with it being a 2 stage setup. Intercool the big to the little turbocharger, then run alky at the small turbo to the engine. I would also be very paranoid about having anything between the alky nozzle and the engine well secured. A pipe blowing off and spraying alky everywhere would be very not cool.

 

So, lets say the first turbo's wastegate bypasses it at any psig above 20psi. What happens on the intake side? i.e. is it still in line with the 2nd turbo, or is it bypassed too? Does the 2nd turbo have to draw or force air through the smaller compressor?