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      11-29-2012, 03:01 AM   #31
Private First Class

Drives: 2012 BMW X6 50i
Join Date: Nov 2012
Location: Michigan

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Originally Posted by idnan View Post
Good luck, please give some feedback when you get it.
Hi idnan!
Just wanted to give you an update with JB4.
So I received my JB4 at work today in the morning and without a hesitation, since we have a warehouse/garage at work, I started the installation process right away.
Upon 2.5 hrs of installation here is my feedback from the beginning.

Fairly easy process... Although removing the whole ecu to feed the USB cable through firewall was pain in the a$$... Ran into couple problems here and there such as broken power wire pin on JB4... So I had to improvise with a wire nut.
Overall, it should've taken less than 1 hour but I was fighting with ecu for a while...

JB4 G5 User experience:
After installation, I can definitely feel the difference! I went straight to map 5 went on a couple WOT runs. First run was impressive. Huuuuuge pull hitting aprox. 13psi. Second run, hitting nearly 16psi peak then back down to ~14psi and then all of a sudden, it felt like I hit a wall then JB4 threw a code at me. HPFP pressure code. I immediately pulled over and researched this issue. Found out that it was a common issue so reset and switched to map 1 and did couple more WOT runs. No codes were followed.
After work, my friend and I, who owns 335i JB4 G4 map 5 running 20/80 e85 did couple pulls from 50-120, 0-80 and I was behind by a car or two every time. I was running map 2 93 octane at the time. Then I mixed 30/70 of e85/93, switched to map 5 and I was peaking at 16 psi and down to ~14 psi.
With the mix of e85, there was a huge difference in WOT. It pulled much harder than just 93 octane for sure however, it wasn't very consistent... Couple runs, I will peak at 18 psi down to 14 psi. The other runs, I'll be steady at 9 psi even with e85.

Overall, I was satisfied with the gain but the inconsistency of holding the boost as well as fluctuating boost was frustrating. I also felt bogging and lag of boost.
Maybe there are few settings that I need to adjust but for now, this is my feedback. I will drive around for couple more days and give you guys a final update.

Is JB4 usually inconsistent with boost? For example, you'll boost at 15 psi first run but the next run will be maxed at 9 psi and so on and so forth...
Is COBB tuning more consistent in back to back pulls?
More questions to come...