Unexplained power loss. Anyone else?

[Laertes]

I just posted this message in the technical forum, but thought I'd put it here too just to get more eyeballs on it. Mods, feel free to delete/move if appropriate.

I took my F82 to the track last week and experienced serious power loss over about 85 mph, predominantly while accelerating down the straight. My friend in an E92 was right behind me and thought I was lifting to warm tires or something as he said I was holding him up substantially. My lap times were 18 seconds/lap slower than what I have done in that car in the past. That's a huge gap.

Background: Car is stock other than pads and brake fluid. No engine/exhaust mods whatsoever. I used the car on track about 6-7 dates 3+ years ago, but it hasn't been on track since until last week because my regular track car is in the shop. When I tracked it a few years ago it was FAST. The car is throwing no error messages. Power feels fairly normal at regular street speeds; it's only when taking it up to track speeds that the power loss manifests, but it's a big drop off. I've taken it to the dealer, but because it's not throwing any errors they don't know what to do.

Anyone else experience anything like this?

Thanks.

[AlmondJayRoM3]

Heatsoak, bad gas, boost leak. Could be anything. Best way to troubleshoot this is with a datalog replicating the conditions. Bootmod3 comes to mind but since you aren’t modified a scan tool that can show data might help. Things to focus on initially are fuel trims, knock sensor events, misfires, fuel pressures (requested and actual).

[G35POPPEDMYCHERRY]

im so sorry, but maybe your tire pressure was off by 1-2 PSI

[CanAutM3]

I had something similar happen to me. Would go on track, car would drive perfectly fine and after a lap or two it would significantly drop in power. Ended up being a leaky intercooler. Best indicator of this is low intercooler coolant level.

[TractionControlDelete]

Yes, I dealt with this before on a 2015 M4. In my case, the car was weak in the higher part of the RPM range which was affecting hard acceleration as you can imagine. It was a fueling issue - specifically the fuel filter was clogged. The car was under warranty and so the dealership replaced the entire fuel pump. As they explained it, the high pressure fuel pump has the filter within the fuel pump and that was clogged (and possibly collapsed)… as such the car wasn't getting the fuel it needed.

[Gxmmtme]

Originally Posted by G35POPPEDMYCHERRY

im so sorry, but maybe your tire pressure was off by 1-2 PSI

I vaguely remember this i think. There was a funny post about tire psi right a bit ago?

Makes me think is there a collection of all the funny/freakout/legendary threads?

[G35POPPEDMYCHERRY]

Originally Posted by Gxmmtme

I vaguely remember this i think. There was a funny post about tire psi right a bit ago?

Makes me think is there a collection of all the funny/freakout/legendary threads?

haha yup, people would attribute the wildest things to the tire pressure being off 1-2 PSI. Car wrapped around a pole=low PSI

good luck with your problem man