Boost - hitting target then loss - log attached

[liagrisj]

Good morning,

This is my first post and am happy to meet everyone. I generally post over at e90 as my tuning and boost posts are seldom. However, I seem to have an issue that isn't common and possibly doesn't have a known cure?

Basically, I've been told my MAF is being capped and what appears to be a boost leak is not. I'm hitting my target psi, but then falling rapidly after 5k. The boost mean stays more on target. My load req and load actual separate by a good amount as well.

Since this is my first post, and am not allowed to post links, you'll have to copy and paste the links below:

Here is the response I received from the other post: e90post.com/forums/showthread.php?p=22502868

Datalog: datazap.me/u/savannahz/possible-boost-leak-new-log-parameters?log=0&data=3-4-5-12-13-19

I'm currently FBO running mhd. I've reset adaptations and tried a few different versions with the same results.

If I require a custom tune, who should I contact? Is Wedge the company who provides mhd their tunes?

Thanks for all the help!

[RSL]

#2 of the 3 I've seen is about 20 threads down.

http://www.bimmerboost.com/showthrea...t-over-5500rpm

Wedge does the MHD OTS tunes, but may be faster to contact several tuners, show them your logs and your thread and see if they've dealt with the issue before. It seems (to me) limited to I8A0S and cool times of the year, which is why I recommended a tuner now while the issue exists, as it may disappear come Spring only to return next Fall/Winter.

Rob mentioned fueling and MAF calcs years ago, so changes that effect either or both may have a positive effect it: AFR, scalars, VANOS, VE, etc. Maybe just some changes to the MAP conversion would help. Then again, maybe they'd just make it worse Good luck.

[Sticky]

If I require a custom tune, who should I contact? Is Wedge the company who provides mhd their tunes?

Thanks for all the help!

You have a lot of options regarding tunes. You can choose from several guys here. Wedge isn't exactly recommended but it is up to you as it is your car and money.

Welcome and repped. You can post links now btw.

[liagrisj]

One of the two tuners I reached out to responded. He said I have a boost leak or tired turbos. The car has 69k miles and I've been tuned for 20 of those.

I don't understand how I'm able to hit target boost and follow the target with mean if it's leaking. It hits boost, actually overshoots a little, within 300-400rpm.

At this point, since my throttle is showing to not close throughout the run, what could be limiting the maf numbers? It isn't the tune as I looked back at mhd 7.1 I had in July and the boost is perfect. I've recently tried both beta 8 and 7.1 with the same bad results.

Here is the latest log:

https://datazap.me/u/savannahz/throt...-5-18-19-22-25

Thanks for the assistance!