I finished street tuning my AFR across the board for my GSR with T3 turbo running 6psi low boost and 10psi high boost. AFR is high 11s all across boosted area (tuned with uberdata). I use step retard ignition timing.

I noticed (using my butt dyno) that the torque is not any better above 5k rpm than it is compared to 3k-5k rpm. When it was not boosted, actually the power lies above 5k rpm.

What are some reasons for no power on high rpms?
Also I noticed that running 10 psi yield only slightly more torque than 6psi, isn't there supposed to have big difference?

 

There could be a few reasons. One, 11:1 AFR's might be too rich for your setup. It is certainly possible, and you do lose power when you go rich. People only go rich to avoid detonation. (You should always run on the verge of detonation, IOW)

A more likely scenario is that your timing is too retarded. Don't play it too safe and start pulling 10° of timing, or the engine will make pitiful power.

 

Butt dyno measure abrupt changes in torque and your torque is supposed to be flat across the RPM range.

using butt dyno

get on a dyno and then you can diagnose

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adseguy &raquo;</TD></TR><TR><TD CLASS="quote">Butt dyno measure abrupt changes in torque and your torque is supposed to be flat across the RPM range.

using butt dyno

get on a dyno and then you can diagnose</TD></TR></TABLE>

Yea i know. I guess i'm to cheap to go dyno, but I will as soon as i'm ready with everything.