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jamesmurray jamesmurray is offline
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Car: 335i
Default Boost oscillation at part throttle - 10-26-2020, 04:47 AM

Hi, I'm experiencing an issue where I get a weird surging/oscillation at part throttle when accelerating. The car feels like its straining against itself, however when I go WOT the car takes off. I've managed to catch it in a log (see pic below). If I disable the JB4 it runs smooth on the BM3 back end flash. Any help on his would be appreciated.

Im running on my M240i;
JB4 with EWG
Meth on Map7
BM3 back end flash

Thanks

James
Attached Images
 
Attached Files
File Type: csv Oscillation.csv (115.4 KB, 26 views)


2016 UK F22 M240i Alpine White

JB4 with EWG, BM3 Back end flash, BMS meth kit CM10, 4.5" dpipe, BMS filter and heatshield
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KnifeEdge87 KnifeEdge87 is offline
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Default 10-26-2020, 07:03 AM

Why is your ecu psi higher than your boost1/2 numbers?
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Ke90 Ke90 is offline
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Default 10-27-2020, 05:56 AM

Why don’t you use a BEF from Terry? I am guessing you had BM3 first then bought JB4?
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jamesmurray jamesmurray is offline
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Default 10-27-2020, 06:36 AM

Thanks for the replies. Yes I bought the BM3 first, before adding the meth kit. Am I able run terry’s back end flash without MHD?

James


2016 UK F22 M240i Alpine White

JB4 with EWG, BM3 Back end flash, BMS meth kit CM10, 4.5" dpipe, BMS filter and heatshield
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Ke90 Ke90 is offline
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Default 10-27-2020, 09:35 AM

No you need MHD to run the BEF, I am not 100% sure but that is his instruction per the BEF support page.

I would wait and see if a tuner responds to it about your options. I have same car and you have like no timing there. I would back off on running car hard until an actually professional steps in to advise, just my .02 cents.

Also, by the look of it can’t tell if you even having meth flow? Try to upload the actually .csv file for them.
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jamesmurray jamesmurray is offline
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Default 10-27-2020, 12:59 PM

Thanks for the info. Terry looked at my setup a couple of months ago, and everything is fine. At WOT everything works as it should, and meth is flowing without issue. The issue above is under part throttle pedal (30-40%), where the BM3 targets 15psi (ecu psi) but the jb4 is targeting little or no boost which is causing the oscillation at part throttle. The .csv is included in the first post. Thanks

James


2016 UK F22 M240i Alpine White

JB4 with EWG, BM3 Back end flash, BMS meth kit CM10, 4.5" dpipe, BMS filter and heatshield
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Ke90 Ke90 is offline
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Default 10-27-2020, 01:10 PM

Haha! I do see the .csv, my bad man! Also, I didn’t realize it wasn’t WOT. I’m curious to see response and will be following. Hope it all works out well!
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KnifeEdge87 KnifeEdge87 is offline
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Default 10-27-2020, 05:58 PM

i too would be very interested in how this turns out, please keep us updated
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KnifeEdge87 KnifeEdge87 is offline
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Default 10-27-2020, 06:15 PM

Quote:
Originally Posted by jamesmurray
Thanks for the info. Terry looked at my setup a couple of months ago, and everything is fine. At WOT everything works as it should, and meth is flowing without issue. The issue above is under part throttle pedal (30-40%), where the BM3 targets 15psi (ecu psi) but the jb4 is targeting little or no boost which is causing the oscillation at part throttle. The .csv is included in the first post. Thanks

James
the jb4 target is an additive target though no ?

surging/oscillation are also entirely different things, it's doubtful you're experiencing surge and the oscillation in boost pressure though noticeable in the figures, don't seem to be extreme (you're going from 9.5 to 10.5 give or take, even on my regular logs i see psi readings fluctuate by 0.5psi from timestamp to timestamp all the time)

again, if you're experiencing something you don't think is normal

it's worth it to check it out

do you have a gopro ? maybe a video would help clarify what you're seeing
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