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glyts glyts is offline
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Posts: 4
Join Date: May 2019
Car: E92 335i xDrive DCT
Unhappy N55 JB4 & Boost inconsistency Problems - 05-10-2019, 02:01 AM

hey guys,
First time posting in a forum. Usually, the rest of the threads were enough to cover my questions.

I recently bought a 2010 335ix, 90k kilometres, N55 engine(PWG). Last week I installed a JB4, which I managed to get to work last night. Never underestimate software updates people.

Now lets jump straight to the issue. I have attached a video showing the strange behaviour of my engine after running on Map 1.

Boost Bouncing Around.mov - Google Drive

Boost is inconsistent, making me believe that there is a boost leak somewhere. However, when JB4 is disabled, the car runs butter smooth again. Could it be that my pneumatic wastegate is faulty? any input, advice appreciated.

Last edited by glyts; 05-10-2019 at 07:24 AM..
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T_H_O_M_A_S T_H_O_M_A_S is offline
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Posts: 150
Join Date: Oct 2017
Car: M135ix
Default 05-10-2019, 06:16 AM

its pwg , so do expect a little more action on that part .
jb4 works best with a good BEF , and surely the pwg models

M135i PWG , FBO , PS2 , LPFP st2 , HDP6 custom for N55 , wedge MHD mapping , XHP AT8
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Dave @ BMS/Fuel-It!'s Avatar
Dave @ BMS/Fuel-It! Dave @ BMS/Fuel-It! is offline
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Car: E92 335XI
Default 05-13-2019, 12:04 AM

Can you just upload the CSV direct?


e92 AT 335xi 2.0
Doc Race Kit 6062
Fuel-It!Platinum DIY PI Kit + Stage 2BL
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glyts's Avatar
glyts glyts is offline
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Posts: 4
Join Date: May 2019
Car: E92 335i xDrive DCT
Default 05-13-2019, 05:41 AM

Thank you for the replies guys. I have been thinking about getting a BEF and it seems to be the best path to go once you're FBO. I just got a data cable for the jb4, i will be posting logs as soon as i have something.

Map 1 has been rough and unreliable on my 335. I tried running 102 octane fuel to see if power delivery will be smoother but no luck.

I have now switched to map 5 and currently running the following settings on the JB4:
(10)DWP set to 0 rpm, (11)Pedal input set to 0 rpm, (12)Base duty cycle to 3000 rpm.

The car seems to be running more smoothly now. The above settings somewhat gave the linearity that the car is missing. I will be logging the car once i have the time and update the thread.
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