[zer0zg]

Hey all.

Long time car guy but new to the BMW game. Recently got a great deal on a '11 e93 6mt that was previously owned and lightly modified by a pretty young kid but not necessarily done well, and I'm trying to get it back to baseline. Never having owned one of these cars it's a little tricky to know when I'm there so I thought I'd get your guys' take.

Mods:
catless DP
intake
Turner ignition kit(coils/plugs)
charge pipe
MHD tune (previously 1.84 Stg2, though I have flashed it a couple times since, I'm too old for burble, currently on 1.6 stg2 91 tune)

When I got the car I could tell it wasn't running quite right and had more vibration than I thought it should. After some googling I landed on engine/trans mounts which indeed were needed. While doing this, I noticed that the o-ring for the charge pipe was missing entirely. Honestly it's shocking it was running as well as it was. Got it back together and it's definitely making good power and running a lot smoother, but it still has a bit of a hesitation on tip in, and I still feel like it should be a bit smoother under hard accel than it is. I checked the guibo and its slightly dry rotted, but doesn't look too bad.

I have a new set of stock coils/plugs, but didn't install them when I saw the aftermarket set that appeared to be very recently installed. No codes, so now I'm looking at logs. This bit is new to me, but one thing that jumped out at a glance is the fuel rail pressure looks kinda spiky to my eye, but again I don't really know what's normal for these cars. Glad to hear any thoughts. Log below.

https://datazap.me/u/zer0zg/log-1708...ata=3-10-11-13

[minulache]

From what I can see at a first glance, you have quite big timing corrections under load. Can you try it again with a higher octane fuel just to rule that out?
Also, it looks to happen mostly at the 6th cylinder, so it could be a bad spark plug, ignition coil or even fuel injector.
The intercooler is stock?

[zer0zg]

Originally Posted by minulache

From what I can see at a first glance, you have quite big timing corrections under load. Can you try it again with a higher octane fuel just to rule that out?
Also, it looks to happen mostly at the 6th cylinder, so it could be a bad spark plug, ignition coil or even fuel injector.
The intercooler is stock?

This is after a full tank of shell 93 unfortunately.
Good catch, I have the plugs/coils, I’ll swap them all out to see if that changes anything.
Intercooler is stock, though ambient temps were in the 20s-30s.
Since posting I did reflash to stock as a test and it does not seem to have the same tip in hesitation at all, vibration seems significantly reduced.

[minulache]

With a stage 2 I would really go for an intercooler. Altho' in the logs, in doesn't seem to have high IAT's so what's causing it is not coming from the IC, but something to keep in mind for the long run

[zer0zg]

Originally Posted by minulache

With a stage 2 I would really go for an intercooler. Altho' in the logs, in doesn't seem to have high IAT's so what's causing it is not coming from the IC, but something to keep in mind for the long run

Yeah absolutely, an IC is the next thing I plan to do on the car. In a vacuum I probably wouldn’t have put the stage 2 tune on it, but the PO already had so I figured I could get away with it at least in the winter in VT. Incidentally, I’m seeing conflicting info on whether n54 and N55, or pre and post LCI cars use the same IC.