[Cookae]

Originally Posted by johnnyd34

RESOLVED FINALLY:::: Thanks to all!! I bought all new oem plugs/coil packs and o2 sensors. She’s running amazing now and DAMN she’s got new life for sure!!! I guess my only question left is…..anyone out there that can sell me a higher performance tune through bootmod3 than the precanned ones?

The sigh of relief was much needed after reading the thread OEM coil packs are more than good enough for most applications and they're always the safest bet, for tuning options past the available ones I guess you can try messaging a few of the custom tuners on there to see if they're willing to tune a m850 not sure what the cost will be but there's only one way to find out.
Excited to see if you can tame this beast since im looking at taking this path too

[Duta569]

Originally Posted by johnnyd34

RESOLVED FINALLY:::: Thanks to all!! I bought all new oem plugs/coil packs and o2 sensors. She’s running amazing now and DAMN she’s got new life for sure!!! I guess my only question left is…..anyone out there that can sell me a higher performance tune through bootmod3 than the precanned ones?

Sorry bud... I could have helped, i have a M550i which has the same engine and trans.

I went through all that already. The only reason i went on this forum is to see if any M850 owners know Xhp released their trans tune for our transmission.

The M5 guys use Hcp tuner and Utku noa.

The M3 guys use Paul Johnson and Cary Jordan.

I have a 2021 M550i running a custom E50 + 100% methanol tune.

Our hpfp is good for E50 by the right tuner.

[johnnyd34]

Originally Posted by Duta569

Sorry bud... I could have helped, i have a M550i which has the same engine and trans.

I went through all that already. The only reason i went on this forum is to see if any M850 owners know Xhp released their trans tune for our transmission.

The M5 guys use Hcp tuner and Utku noa.

The M3 guys use Paul Johnson and Cary Jordan.

I have a 2021 M550i running a custom E50 + 100% methanol tune.

Our hpfp is good for E50 by the right tuner.

Ty. She’s running great now. I hit about 609hp on perf app.

[Dasky_spas]

For the m850 how is Sergey at ECMtuner? Theres no dyno there so purely street pulls with logs.

ECC Canada looks good but their tune is not planned for use w xhp, neither is carbahn.

Dme has zero instances of dragy or dyno,just anecdotal feedback.

RK has choppy tq curve.

Custom tune possible through halim at hcp.