finished my peakboost turbo kit install. Set up with their FTW turbo kit which includes items listed below


-ram horn manifold
-garrett gt3082r ball bearing turbo
-3" exhaust
-tial 44mm wastegate (had 11psi spring; currently 7psi spring)
-hks ssqv bov
-hondata s300


having a problem with boost spiking higher than normal. Boost will hold close to 11psi(on analog gauge)until about 5800-6000rpm before the pressure spikes higher than 11psi(using stock map sensor[hondata 4 bar on order]). Hondata S300 will basically cut me out and back me off with the over boost cut out. The shop that was helping me tune mentioned they had seen issues like this before; especially with certain ram horn style manifolds. The stated that the wastegate's angle (close to a 90 degree), will not promote smooth wastegate flow causing the turbo to continue to suck the exhaust through causing unsteady boost pressure. They suggested i tear drop the wastegate outlet to have smoother transition to the wastegate. I found during my inspection, the turbo's compressor housing bolts were loose(thanks to the shop). I tightened compressor housing bolts and exhaust housing, road tested and found same over boost and cut out issue. Does anybody have any insight to my problem???

 

ah i have a similar issue with my 84.5mm b series and peakboost ftw with tial 44. i will hold a steady boost until around 6500rpm then it starts to creep, not spike. i see between 1 and 2 psi more at 8600rpm than i do at 6600 rpm.


i think that your setup is just going to behave like this, shy of using 2 44 gates. you can either retune to account for the higher boost in the upper rpm and raise the boost cut once you get the 4 bar, or lower the boost overall so that the higher psi you make up top is right under your boost cut in the meantime