CRX Si Turbo questions

[TurboRex90]

I have a Turbo'd D16Z6 with forged internals (rings/rods/ 8.5:1 pistions/seals etc) running 20psi but no head work done. I have a t3/t4 turbo (.63/.50 trim) and it starts to spool at 3k rpm and doesnt reach a peak boost til 4500k and when i shift at the boost cut of 20psi its usually at 6k rpm but it lets out most the power and it struggles to respool. I wanted to change turbo's and get a smaller turbo that spools faster and holds the same amount of boost, because the car doesnt actually pull as hard as it should on 20psi. What kind of turbo should i look into that possibly has a smaller housing then my current turbo, but still spools fast and hard, and gets mid-high range of power. I've been told a T3, a K04, a Gt28.. any ideas?

Also i plan to have the head port and polished whihc should let through more exhaust gases and in turn help spool it faster.

 

[GO-AUTOWORKS]

Why are you shifting so early at 6k??
A 50 trim and Z6 is an excellent combination. It should make power to and beyond your stock redline which is 7200, there's no need to shift before that, even with a stock head.

 

[TurboRex90]

well i have a boost cut set at 20 psi.. and it normally is at about 6k rpm and drops my throttle so im left with nothing else to do but shift..... maybe i should have the turbo balanced and possibly check the turbine? maybe it needs to be looked at.. or should i have my boost cut higher then 20 psi..

 

[TurboRex90]

this is a old post but, i had the car tuned a few times and got every straightened out, but i still havent gotten any head work so i could use more flow but im not putting out 235whp at 19psi and my boost cut sticks all the way till redline but my torque starts to drop off about about 6500 so i have to shift anyways.

 

[BrokenRex]

you dont "have" to shift. the correct method of finding out what rpm to shift at is dynoing your car, then using excel to plot your torque curve multiplied by the active gear ratio you're in (that's the gear and the ring/pinion) and plot it for all gears. if the multiplied curve in any gear drops below the multiplied curve in the following gear at any RPM, you should shift there. you should know however, on a honda, ESPECIALLY one with a moderately large turbo, that should never happen. shift at redline. hondas have crazy high(numerically) gear ratios because of their higher rev limits, giving lots of torque multiplication in lower gears.

 

[TurboRex90]

I'm guessing you didnt understand, by tuned i did mean dyno'd. And my torque starts dropping off at around 6800 rpm. I started getting valve float.. thats why my torque started dropping down, so once i get a new valvetrain and new EM then im sure i wont have the problem.