Boost issues..

[Collector1313]

Nice Info Skym

Thats what I was trying to get at when I mentioned if the actuator was changed, any change in the air/fuel supply should be met with the proper tunning adjustments in the ecu. All new parts need to be recognized by the ecu, your getting more air which is starving for fuel(rb20 injector are inadequate with raised boost).
All this info is getting me ready for my build, all I had read in the last month points to what Skym pointed out, but I didnt want to quote hearsay from the various internet sites I have seen and lead you wrong

[Skym]

I thought stock injectors were 259cc going by a list of stock injectors. But are 276cc when flow tested. Same as what somone else mentioned about stock GTR injectors at 440cc when they are actually 480cc.

Stock RB20DET injectors, stock ECU tune can handle a hybrid RB20DET turbo at 12psi with 11.8:1 A/F ratio at peak hp. But with hybrid RB25 turbo that you have, it moves alot more air on compressor side than hybrid RB20DET turbo and engine could go extremely lean (into 12's at peak hp and way leaner, maybe 14's at lower rpm's). If have FMIC it makes A/F ratio leaner as more air reaches engine.

Another way and probably the cheaper of the 2 options is to use a stock auto R33 RB25DET actuator and run a boost controller to drop boost level. Can run it as low as 7psi with boost controller until you can fix the ECU tune.

Can get a cheap HDI Type-R boost controller from here -

http://www.performance-wise.com/page42.htm

From what I understand, the switch option on HDI Type-R boost controller allows you to turn boost controller off, so turbo free boost's.

[beacher1B0]

Throw on the Rb25 actuator and see what happens.
If his ecu was seeing knock, would it not retard ignition across the whole rpm range? And why would it not see any knock at the point where he goes into boost(4500 +). That 4500+ rpm boost transtion seems alittle too repetitive.

[dundoot]

after checking the wastegate, I finally figured out what was happening... wasnt wastegate, turbo is siezed... seized enough that it wont spin freely under light throttle but will boost under hard throttle... took off intake and sure enough barley spins... Oh well, i guess a new plan of attack is in order...

any suggestion on a new turbo?

[beacher1B0]

Thanks for posting the problem.