"Misfire" under WOT

[Bumm3r]

Hey guys first time poster, have had my 2015 f80 for about 2 years now. Bought it with the mods already and ran great for a long time. About 4 months ago it started to “misfire” under WOT. hasn’t thrown any codes or drivetrain malfunctions related to the issue. Mods are basic full bolt ons with Vargas GC turbos and Paul Johnson tune. Car runs great cruising and half throttle and what not, but say in 3rd gear at 2500/4500 rpm’s if floored sometimes it will feel like it’s hitting boost cut and black smoke comes out the exhaust. Sometimes it will do a full pull all the way with no problems. So far I’ve replaced spark plugs (NGK 97506 gapped to .020) new Delphi coils, and new oem maf sensors.

https://bootmod3.net/log?id=64f60c65d10b4306799c509b

Attached log doing a pull in 3rd when it happened.

I’m not sure what the next move would be other than to keep throwing parts at it? (o2 sensors, injectors) maybe change tunes to rule that out? Again it drives perfect when cruising/half throttle and even sometimes doing a full pull with 0 hiccups. It just seems to happen when boost comes on fast and under heavy load. (TC fully off so not that)

I can take another/longer datalog if needed, but to the experienced people, do you see anything wrong with the current one that could cause this or be an issue? Everything looked “okay” to me but I’m not sure what to be looking for.

Thanks

[dezzracer]

You can always go back to stock if you have the original tune and OEM spec parts and see if that fixes it. These cars have good stock power unless your a track rat. Prolly not what you wanted to hear though.

P.S. As I peruse various F80 forums, it seems like tuned BMW straight 6 motor has fair amount of issues. Just a broad observation on my part tho.

[Dj_Quik]

just some initial observations based on your log:

-your intake temps get up way too high hitting almost 123 degrees
-high intake temps causing your ECU to pull timing across all cylinders and hence you feel that "boost cut"
-the black smoke is because of the extra fuel that your ECU is dumping to cool your cylinders
-you may have a bigger issue with you charge cooler. check your coolant levels and if youre still on stock charge cooler it may be leaking if its not controlling your intake temps anymore

[Bumm3r]

Dj_Quik it is a vrsf cooler, I have checked levels and it doesn’t appear to leak. I am in Texas so that doesn’t help. I will look into getting a CSF cooler.

[Dj_Quik]

Originally Posted by Bumm3r

Dj_Quik it is a vrsf cooler, I have checked levels and it doesn’t appear to leak. I am in Texas so that doesn’t help. I will look into getting a CSF cooler.

Skip the csf. Get wagner or mishimoto

[WhiteFox]

May want to check the turbos as well as these cars stock have plenty of power unless you are horse trading at a speedway setting qtr mile results.