Help with sporadic boosting, FBO w/ MHD

Sprygsxr14

Lurker
Oct 2, 2017
16
7
0
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e90335xi
This issue has started happening after I upgraded to PR coils and N20 plugs (I believe to be unrelated). Not like I can just switch the stock ones back real quick either. Majority of the time when I log a 3rd gear pull I get decent results even tho I can feel a little missing. If I ramp up the throttle during accel I will see 24 psi on the boost gauge and it pulls like a freight train. If I just flat foot the pedal I get 22 psi if im lucky. Here are 2 logs, 1 is decent with 22 psi tapering down which appears good to the tuner, but something is up. The second log was the strangest the car has ever felt so Im glad I caught it.

Stock Turbos
Port Injection w/ AIC
PR coils
3.5 bar MAP

Any help would be greatly appreciated!

https://datazap.me/u/sprygsxr/log-15...og=0&data=3-22

https://datazap.me/u/sprygsxr/log-15...og=0&data=3-22
 

08_335i

Sergeant
Nov 3, 2016
372
217
0
28
Ride
2008 ST 335i
Your tune needs work. Your "normal" log, the only problem really is the boost target needs raised where it's getting flatlined during spool up. The other log, i'm not a tuning expert so i can't really say what's going on. it looks like this is a Motiv tune? I would contact who ever does your tune with these logs to get it figured out and smoothed out.
 

Sprygsxr14

Lurker
Oct 2, 2017
16
7
0
Ride
e90335xi
Your tune needs work. Your "normal" log, the only problem really is the boost target needs raised where it's getting flatlined during spool up. The other log, i'm not a tuning expert so i can't really say what's going on. it looks like this is a Motiv tune? I would contact who ever does your tune with these logs to get it figured out and smoothed out.

I was told by my tuner that the boost target is not something that is set but it is more so based on load and wgdc. I dont really know crap about tuning tho so thats why im trying to get others (hopefully some tuners) opinions.
 
Apr 1, 2017
142
24
0
Ride
E92
I was told by my tuner that the boost target is not something that is set but it is more so based on load and wgdc. I dont really know crap about tuning tho so thats why im trying to get others (hopefully some tuners) opinions.

You can do something about the boost target beside load and wgdc.
 

08_335i

Sergeant
Nov 3, 2016
372
217
0
28
Ride
2008 ST 335i
I was told by my tuner that the boost target is not something that is set but it is more so based on load and wgdc. I dont really know crap about tuning tho so thats why im trying to get others (hopefully some tuners) opinions.
Who is your tuner? Theres always ways to fix spool up.
You can do something about the boost target beside load and wgdc.
this, Chris does my tuning since I have the BB and any time we have the target flat line the spool up it takes on revision for him to fix it.
 

PUTC

Corporal
Oct 14, 2017
206
68
0
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08 335xi
Your lpfp is falling off big time, looks like down to 30psi at one point on first log and a few timing corrections at different points in 3 cylinders. I’d pull back boost and lower timing .5-1 degree at higher rpm/load maybe.
 

08_335i

Sergeant
Nov 3, 2016
372
217
0
28
Ride
2008 ST 335i
Your lpfp is falling off big time, looks like down to 30psi at one point on first log and a few timing corrections at different points in 3 cylinders. I’d pull back boost and lower timing .5-1 degree at higher rpm/load maybe.
didn't even look at this, it's dropping significantly hard at the top, not sure if pump is failing, or if something is wrong with it. Either way, it's diving extremely hard, quickly up top.
 

PUTC

Corporal
Oct 14, 2017
206
68
0
Ride
08 335xi
Maybe have it taper more at the 5500-6800 rpm will do the trick also. Sounds like a custom tune time or a upgraded fuel pump is in order if you don’t have one already