I dont want to cover N/A what I was trying to point out was the key to power with this car seems to be fuel and engine management. This could explain why the new kits are including more sophisticated fuel setups which increase reliability.

 

I agree on that. What do you mean by new kits though?

 

May still be too early to have a definitive upgrade path.

Looks like you need upgraded pistons/rings that slap for 550whp.

 

Yeah, i'm going to put up a disclaimer for that. But, for those wanting to do it now, they at least need to know a general idea of what's working so far.

Eh, that's only been with one case, i'd rather have at least 5 or so more people that have problems before I recommend that. Thanks for pointing out something I hadn't thought about yet though.

 

By the new kits I am referring to the APS ST and the Turbonetics. I recommend the first "upgrade" any FIer should do is read Maximum Boost by Corky Bell. Gives so much information on turbochargers and the intricacies of fuel managment. Corky also released a book titled Supercharged! Which I have yet to read.

 

The TT kits will generally build more trq at a lower RPM. Essentially, they have slighly more meat under the trq curve. I have seen the Turbonetics dyno charts, and the APS single T charts, and the power is really very impressive for a single turbo system. I also think you would be hard pressed to tell the difference between single and twin...maybe just a little bit less trq at the lower/mid range.

I think Nis portrayed it accurately. If your goals is 400whp, then any of the kits will do. But for the 500whp + club, I think the twins will provide more airflow for you, vs. one single turbo. Both the Greddy and APS twins will provide enough airflow for roughly 700whp. Airflow is simply the volume of air that the turbo can push...so it is more theoretical in nature.....since MAJOR modifications will be needed to get the VQ producing 700whp.

In regards to the question on wastegate springs and boost controllers. Boost controllers prefer to work best, when they are increasing boost no more than 100% over stock. They can work further, but they are more precise at this level. Many of us with the built motors, switched our wastegate springs to roughly 10psi (taking intercooler losses into account). So 10psi becomes out new boost floor. From this point, we use a boost controller to raise boost to 15-18psi. The boost controller has a solenoid, which puts postive pressure on the top of the wastegate spring. This keeps the wastegate closed until a user determined point, and then gradually releases the pressure and opens the wastgate. Boost controllers also dramatically improve turbo response, becuase the wastgate is held shut until the set boost level is met. The result is a faster spooling turbo, and more pressure at a given RPM. Without a boost controller, the wastegate will gradually begin to open as boost increases, which slows the turbo response.

Hope that helps.

 

Thanks for the explanation Sharif, mind if I quote you on that for the Turbo FAQ?

Bump, it's like pulling teeth to get you guy's to participate in threads other than "the build-up starts today."