18 minute Track Day :(

[MaynardZed]

Back to http://arizonamotorsportspark.com/ again for another track day with the M4. Things were going great in the first session, running mid 1:55's only about a second off my PB for this track. Chasing my buddy in his C6Z with new coilovers and running down an E92 M3 in the advanced DE group. Expecting to get gradually quicker as the day goes on, but..

...same Chassis malfunction problem and limp mode appears towards the end of the first session. Code cleared for second session, but showed up again on second lap. Parked the car and sat and watched the rest of day. First time back to the track since BMW "fixed" the problem by replacing a faulty sensor. Obviously that didn't work. I don't think they actually know what the problem is. Service saga chronicled here:

http://f80.bimmerpost.com/forums/sho....php?t=1092996

Not so happy camper today. Will be taking it back to the dealer again...

[Woodengun]

Maybe suggest they try changing to board containing DSC control unit?

[FTS]

So very sorry.

[MaynardZed]

Originally Posted by Woodengun

Maybe suggest they try changing to board containing DSC control unit?

DSC is completely off on the track. Its something with the M-adaptive suspension that's giving the fault. Not sure if those two systems are somehow integrated though.

[Woodengun]

The DSC may be the culprit. You have switched it off but the control unit is not completely off. The sensors are always on - thats how you can get so much information out of the car while tracking/racing.

It is a stretch but the DSC control unit could be off - it won't intervene - but the sensor side is still active and wants to intervene. It cant so it goes into limp mode. It could be a fault with the physical cpu or a fault in the software where a line or two is screwed up.

Once you start producing thousands of units it is bound to occur that a faulty chip (physical - or perhaps board got damaged slightly during shipping and install) gets through QC or a bit of programming gets incorrectly copied.

Just trying to give alternatives since I would think a sensor fault should give you limp mode all the time even when doing daily driving.

[Flying Low]

Sure hope you get this sorted out soon. When it goes into limp mode, does it slow the car so dramatically that it is a danger to any cars on track closely behind you?

Also, what brake pads are you using? They squeal as bad as the Pagid RSL1 pads that I tried to use at a track day.

Good luck

[MaynardZed]

Originally Posted by lo flyn

Sure hope you get this sorted out soon. When it goes into limp mode, does it slow the car so dramatically that it is a danger to any cars on track closely behind you?

Also, what brake pads are you using? They squeal as bad as the Pagid RSL1 pads that I tried to use at a track day.

Good luck

Yes, real slow and sucky, puts it in efficient power and puts all DSC back on. My first hint that it's in limp is usually brake squeal while trying to accelerate out of a turn (rear brakes kicking in as part of stability control).

Carbotech XP 12/10 that I use squeal worse than Padigs. They stop great though. You want them? I've got two sets with some life left in them. Might be selling my track wheels/tires too. I'm considering retiring my M4 from the track.

[Cloud9blue]

Sorry to hear this, I know how much it sucks to go a DE event and have the car not running right at the first session...

Different chassis, but I had similar DSC malfunction on the iDrive last year. Was lifting off the throttle in the middle of a fast left hand sweep while chasing down a slower than expected S2000, which sent the car into a 360 spin in the grass... "DSC malfunction" warning came on right after that, which I thought was weird since I always drive with DSC fully off. But was able to clear it off after restarting the car in the pit.

I really think this is more of a software issue than hardware, where the software for the DSC module couldn't make sense of the incoming data from a spin or highly aggressive driving and throw itself into a safety mode.

[Flying Low]

I'm going to try the Pagid RS29 pads when they became available again. I'm going to try the M4 for a few more track events but I think I like my turbocharged M3 better. The M4 just seems so BIG. Would you stick with the E36 M3?

Terry

[MasterC17]

If you think it is EDC related, why not just disconnect the EDC connections on the front struts? It's super easy to do. At least that would help rule it out.

[MasterC17]

Originally Posted by lo flyn

I'm going to try the Pagid RS29 pads when they became available again. I'm going to try the M4 for a few more track events but I think I like my turbocharged M3 better. The M4 just seems so BIG. Would you stick with the E36 M3?

Terry

I ran a 2:09.67 at Watkins Glen in the F80 on street tires and KW HAS, and ran a 2:07.97 on a full-blown E46 race car that weighs 2,600lbs on coilovers and r-comps. The F8X is more than a capable track-car with a little setup.

[MaynardZed]

Originally Posted by MasterC17

If you think it is EDC related, why not just disconnect the EDC connections on the front struts? It's super easy to do. At least that would help rule it out.

I think just disconnecting them might throw a code and maybe put you in restricted chassis function also? KW EDC module would probably be the way to go?

loflyin: Hard to beat the E36 for a track car, but give the M4 a go. Its big, but very well balanced and super powerful. I think tracking the M4 some can only make you better track driver overall. I was working on some techniques with the M4 that are a little more difficult to do with my E36 with Rcomps, etc.

[mid-corner fun]

Originally Posted by MaynardZed

I think just disconnecting them might throw a code and maybe put you in restricted chassis function also?

On the e9X disconnecting the EDC connectors forces the suspension to the hardest setting (Sport). Yes, it throws a code but it doesn't affect anything else.

Give it a try if you can, to rule this out. And thanks for your (and others) track feedback so far, I'm thinking of moving to an F8X later this year which will definitely see some decent track use

[MasterC17]

Originally Posted by MaynardZed

I think just disconnecting them might throw a code and maybe put you in restricted chassis function also? KW EDC module would probably be the way to go?

loflyin: Hard to beat the E36 for a track car, but give the M4 a go. Its big, but very well balanced and super powerful. I think tracking the M4 some can only make you better track driver overall. I was working on some techniques with the M4 that are a little more difficult to do with my E36 with Rcomps, etc.

False, mine are disconnected and I DO get a chassis malfunction but it does NOT restrict the car in any way.