For All That Want To Turbo The 2zz

[nismo]

Here's something that is interesting. This came off of the WRXfanatics website, a friend of mine is a member, he asked a question and here's a response"So how would an engine with a compression ratio of11:5:1. behave with a intercooled turbo on it? How canI determine how much boost the engine could takewithout forged internals?"It's not how much boost, but rather, how muchdetonation.Engines are also not built equally so "safe" boost ata "safe" compression ratio on engine A, may not be"safe" on engine B. It's far more complicated thanthat.As an example WRC Subaru cars use water injection and98 RON octane "pump" fuel and run over 29 psi withover 10:1 compression, but don't try that on your WRX.11.5:1 compression probably won't have very much roomto work with ... but if there is some room to pullignition timing, if it's intercooled well, if it iswater injected, and if the exhaust an intake are tunedwell ... I see no reason you shouldn't be able to runfrom 8-15 psi on exactly the same gas you were runningit on when it was naturally aspirated.Also keep in mind that when you raise the compressionratio on a turbocharged engine if your engine cantolerate high EGT you can run very retarded timingwith lots of boost and very lean fuel. That generallymakes for a lot of power, with a lot of heat. If theengine is built to take it, it's not a problem.

[drayday55]

yup, water injection is the shiznit!! i got it on my s/c vibe

[ToolGuy]

Alot of times people go nuts with adjusting the boost and then the big blow happens, cannot leave well enough alone and seek more power. With my factory Turbo car I could adjust the boost but will not. Its boost is set for longevity and reliable parameters. IMO if the engine is made for or with a Turbo all is good. Anytime you add one to an engine that was not originally intended for a Turbo, you may have issues. I have seen issues with V8 SC too. Usually if you mod one part of the engine you will need to do others.

[futseal04]

Well......most of your drag cars run high compression (estimates are around 17.0:1) and have FI. Like the article states, you could run a turbo on a stock 2ZZ, but you would have to fill it up at the airport at the very least. If the motor comes stock with FI, then adjusting boost isn't as big of an issue. The L67 in my Rivi is easily upgraded from 8 to 11# of boost just by changing the pulley, and there are no adverse effects. This translates to about a 35HP increase, all without changing anything else. Any more boost increases require an intercooler and stronger tranny, but could still be had on pump (93 octane) gas. The same applies to the 3.8L in the Grand National....original boost pressure was about 13.5, and it can safely be in the 17-20 range with everything else stock. On the other hand, if you look at any good engine builder, they will change internals for high levels of boost. For example, a stage I Lingenfelter Vette has 550HP with 4-5# of boost (can't remember exactly). A stage II (650HP) or III (427 cu in, 725+HP) gets custom pistons which lower the CR, so that they can up the boost to about 8-9. All this on super unleaded.All in all, I agree with MiVibe on this one.......if you are going to go FI on a 2ZZ, just save some more money and do it right the first time.