I raced a 2004 Z06 last night from a red light. We were dead even till about the top of third gear then we both hit the brakes because of traffic. I have a procharger (7psi), exhaust, and 20" wheels. I put down 369.8rwhp and 298 rwft. I was impressed with the car. I also raced a E55 AMG this weekend from a first gear roll. He pulled away about a half a car then I caught him at the top of 2nd gear and kept up with him until 5th. It was also a good race. My car lacks torque so I will be working on that next. I'm thinking about headers, test pipes, and methanol and maybe more boost. Any suggestions on getting the torque up?

 

FI grinded cams & plenum, be careful with higher boost.
nice run with the Z06 BTW

 

Should have went turbo...

 

I agree about the turbo. If I were to do it all over again, I would go with the Turbonetics single turbo kit. Why is it that a turbo makes so much more torque compared to a S/C? I make great power per psi but the torque isn't really impressive. I'm guessing it has to do with the headers and test pipes on FI. How much power / torque can I expect with headers and test pipes? Also has anyone used methanol on their FI Z? Methanol would be a must if I turn up the boost.

 

Probably due to the type of supercharger you have. It makes more boost with more RPMs, so you won't get much down low. A turbo, however, builds boost based on exhaust flow, so you can get them to make some pretty good low-end power, presuming they spool easy... or just brake boost.

 

I do understand the difference of a centrifugal S/C and a turbo. I just don't understand why at the same boost level, even if mine is at a much higher RPM, the turbo makes so much more torque? I believe my Procharger makes more HP then any other forced induction system for the VQ35 at equal psi of boost. Does any turbo kit for the 350z run at 7psi or less?

 

Evidently, the intake charge of the turbo is cooler, allowing for more air at the same boost level (denser).

Run a bigger intercooler on your SC, that will allow you to spin it faster.

 

I believe the GReddy TT kit runs stock at 5.5psi.

 

It's because on a turbo you can have full boost at a lower RPM and hold it till redline. This is why a turbo will produce more mid range torque with exception of may be a good roots blower. A centrifigal blower like a Vortech it builds boost with RPM, you may not see full boost till redline, and only half that at a lower RPM, even at WOT.

It's basically the same concept. Think of it like one of those helicopter-like fans on a stick that you used to see as a kid. You can blow it and it will spin up quickly and hold speed till you run out of breath. Or you can build it up to speed with by spinning your fingers like a centrifigal blower. Wow....bad analogy?

 

Your all wrong (mostly). A supercharger is the ultimate "accessory" drain. Remember it is belt driven and thus takes torque (twisting force) from the motor to spin. Imagine it as the exact opposite of adding a lightweight underdrive pulley. You are adding an extra pulley to the mix that requires some serious turning to spin the turbines fast enough to make boost.

Now the boost more than makes up for the accessory loss, but you take that accessory pull out of the equation when you drive the turbine with spent exhaust gases instead.

Edit: KJR makes a lightweight same-size-as-stock crank pulley that might give you a little bit of that torque back.

 

YEah right, like putting a converging venturi and a turbine in the way of the exhaust gases doesn't take power away from the engine...

Both S/C and turbo use power from the engine. Both will, over all, increase the total output by generating more power than it takes away.

 

As stated above, I would work on a bigger intercooler as the colder the air going in the better.

 

I guess you could read that into what I wrote b/c I left it out, but the point is still valid that more engine torque is lost to a supercharger than a turbo. It's a generally accepted principle proven by the numerous posted dyno charts on this forum.

Just so you don't read anything else into this: I'm not advocating one system over the other nor am I recommending to the original poster that he swap his supercharger for a turbo. Both systems have there pros and cons—up to the individual to decide.

 

Okay, I was just making sure nobody was thinking that a turbo runs on "free" power.

As for efficency, that is totally dependend on the actual setup, turbo or S/C. Like I said else where, turbo system have seen much more RnD money and are thus easier and cheaper to build for similar output.

 

TQ is the nature of the turbo-I make 300ft/lbs @ 3000rpm. Say you did 430whp @ 9psi and I did 390 @ 9psi, Id guarantee Id beat you in a race, its not all about peak #'s. I am getting ready to show this to a Vortech owner very soon(417whp) <---he thinks 20 or so whp above me means hes gonna win cant wait to see his face.