Primary turbo consistently hits 11psi regardless of gear (But it will creep higher in high gears on a long full throttle pull). As far as max boost in 1st and 2nd gear, which is what I am assuming you are asking, about 15psi in 1st, and 17-18 (full boost) in 2nd.randy said:Does anyone know what max boost you are getting with the 1st turbo? Also how much boost do you get on 1st and 2nd gear?![]()
I assume you are running the J-spec ceramic turbo's. I would expect your turbo(s) to blow apart at any moment with that level of boost.randy said:Thanks for your response Mike/Ben! The reason I am asking is cause I will be doing the HPF boost mod and this will make my first turbo boost as high as18/19 psi, just wondering how much the first turbo on BPU would boost compared to first turbo HPF mod.
Aprox boost levels with HPF mod according to a friend.
1st gear-17/18psi
2nd gear19/20psi.
3rd gear 21/22psi.
5th gear 25psi.
6th gear 27psi.
You can see I really have to control the boost with the accelerator. and a boost guage with peak hold warning buzzer.
The general consensus with J-spec car here in the UK is restrict boost to 18psi, I know of people that have lost turbo's within hours of turning the boost up too 18psi and one guy at stock boost levels..randy said:That is the reason I'm hesitating doing the HPF mod! Currently my car feels real fast hitting boost cut on 3 gear at about 5000 RPM. Infact it accelerates so hard the wheels spins even when I am rolling on 2nd gear when it hit the metel. I'm told that boost cut on jap spec is at 16psi. Boy I hit boost cut real hard. Quite shocked the power increase after my custom 2 1/2 front pipe and 3 inch midpipe with no cat. Will check my boost level when I install the 60mm boost gauge and BCC.
I would buy a boost controller, set it too 19psi and leave the HPF mod well alone.randy said:I have been advised by quite a few mkiv nz members who own supra jap spec not to go over 19psi! What do you think my best options are? cause I dont yet have a boost controller and wanted to do the HPF mod. But guess its not worth risking my turbo? Do you think I should buy a boost controller and be done? Is 18/19 psi good enough power?