Quote:
Originally Posted by smoked240
Alright guys school me on compound setups! I've researched it all and have seen the few setups people have done. I've even checked out our quadtrac case at work with compound turbos 
My only concern is finding the right turbo to match. My engine is Rb25 with rb26 internals and a precision 6266. Supporting mods up to 800hp but capping it roughly around 500 until I add a metal head gasket.
Thanks and I'm sorry if this was the wrong section. Carry on. |
1. Ditch the 6266 and get a 6466. No point in running a smaller less capable turbo that spools roughly the same as a better one in a compound setup. Run at least a 1.15 turbine housing.
I've helped build two compound setups that were both on a successful drag car that continues to run mid nine seconds.
2. A common mistake is to run too small of a low pressure turbo (small), and to run too small of a turbine housing on the high pressure turbo (big).
3. I'd recommend running something like a V-band GTX2860 for the low pressure turbo, with the primary wastegate venting to atmosphere.
4. 800hp in a compound setup is a LOT of torque for an RB25. You're going to break things, even with RB26 internals. Better build that thing to the hilt, and hope you have a proper oiling system if you're wanting that much power.
Quote:
Originally Posted by Def
There's no point in a compound setup on a spark ignition engine. You're too octane limited to make use of the stupid high boost pressures that'd create.
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While I generally agree with you in that modern technology can overcome the classic "tons of lag and tons of top end power" turbocharger dilemma, there is a place for compound. If you can fabricate, you can create an engine with a fantastic powerband with two super cheap turbochargers. Especially with E85.
Quote:
Originally Posted by tb13
Compound turbo setups are sweet, you can get that sweet top end that a big turbo gives you and keep good response with a rich low end/mid range.
A guy here in AZ, Jon, who owns a shop called Future Fabrication built a sweet compound setup on his 1jz S13 a while back. It fucking ripped, I don't think it was ever dyno tuned, but on the track it proved it was able to throw down. The setup was super simple, modified stock manifold with an external waste gate, stock CT15 turbo and a big ass turbo set on top using a simple "up-pipe" from the stock turbo's outlet. The big turbo stuck out the hood, but it was awesome proof of concept.
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Yes, Jon had an RB25 compound setup before that, but it met an early end.