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      11-29-2012, 02:01 AM   #31
hellomyBMW
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Drives: 2013 BMW 335is
Join Date: Nov 2012
Location: Michigan

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Quote:
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.

Installation:
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.

Conclusion:
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.

Questions:
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...
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