Quote:
Originally Posted by take1step
It's been a few months now I've been running the Pure Stage 2 turbo on my 2016 428xi at 25 psi. I recently updated the JB4 firmware to "N20_OBDII_EWG_5_T2.hex" and like some others here my default boost safety changed to 36 psi and the N20 tmap sensor turned on.
I knew the car could push more and with this new range of PSI from the JB4, I did a few runs on map 6, targeting 27 psi & 30 psi and then on Map 7 (30+psi). I haven't really seen or read about other people raising the boost on the N20's, but I've posted a few logs for references and a list of my mods below.
It seems like 27 psi is the limit these little engines are happy with. On the 30 psi Map 6 run and the Map 7 run, I was getting misfires around 55k RPM and 45k RPM respectively and had to let off the throttle. It wasn't any better if I tried raising Meth additive to 75. That being said, I had a few runs reach 30+ psi but it was very inconsistent, if anybody has any other input to safely increase boost, it would be appreciated.
Mods: Pure Stage 2 Turbo, JB4, Eurocharged Back End Flash, Fuelit LPFP, ER turbo CP, BMS Methanol Injection kit (50:50), Injen Intake, Wagner Catless DP, AWE Quadtip Exhaust. BMS spacers, H&R springs. 94 Oct pump gas
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I'm actually surprised you're brave enough to run an upgraded turbo with that fragile engine and without building it.
You'll probably have to get your EC BEF revised for higher boost. The misfires you're getting may be coming from running too rich up top or your spark plugs aren't gapped correctly or not iridium.
Try unplugging the MAF and do the run again, if it still misfires, then it's either the tune or plugs.