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Discussion Starter #1 (Edited)
Wasn’t planning on taking my 2008 M5 6 speed to Daytona track day, but since my Subaru is missing its engine…

Did a quick tire rotate, oil change, and brake bleed…filled it with petrol and pointed the 60,000 mile car toward Daytona Beach…2 hour drive for Halloween.
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Great write-up! Gearbox warning on a 6 MT? Is that for overheat? Does the 6 MT have a transmission oil cooler? When I had mine at Pikes Peak Intl Raceway a couple summers ago, I got loud "tinks" upon pulling into the paddock, but I figured it was the engine/exhaust components. Didn't consider it to be the rotors. I had the hood up cooling it, and had scary loud "tinks" coming from around the engine.
 

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DinanS2+ e60m5 6MT, s38b38 e28m5 TT/ST3, e30 TT/ST4
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Great write-up! Gearbox warning on a 6 MT? Is that for overheat? Does the 6 MT have a transmission oil cooler? When I had mine at Pikes Peak Intl Raceway a couple summers ago, I got loud "tinks" upon pulling into the paddock, but I figured it was the engine/exhaust components. Didn't consider it to be the rotors. I had the hood up cooling it, and had scary loud "tinks" coming from around the engine.
No...our 6MTs do not have a tranny cooler.

With that said, I've run track side temps of 110 degree plus, without ever over heating my 6mt at CalSpeedway.

OP~ sounds like you had a blast. RDSport Sways will dial out that understeer you're experiencing. Do you have any video?
 

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Discussion Starter #5 (Edited)
Video...if it works:

14 10 31 Daytona Lap BMW M5 - YouTube

Couple of notes:

Understeer-sway bars would certainly help, but believe a simple alignment for more front negative camber would really have helped.

Limiter: I hit 165 mph indicated in 5th at over 7000 rpm...I thought the US cars were limited to 155 mph? Is the speedo that inaccurate? I short shifted on the banking...it threw my expectations of stick out of whack so was concerned about exceeding the limit at that speed. IE the car is faster, but not with me driving it that day.

Tinking: Likely the exhaust/engine was making noise on cool down, but my main 'tinking' was the rotors...you could see the brake 'ash' come off after each contraction...I did a thorough cool down so was not concerned. Although the car is ready for a set of brakes...as these have covered 60,000 miles with only a brake bleed a couple of times. I did get some mild shudder, although I did not push the brakes (started braking at the start/finish line for turn 1.

Gearbox: I believe the warning actually stated "Transmission Temperature Increasing / Reduced Engine Power." I believe I recall reading this was more a clutch/flywheel overheat...ie too much slipping, in my case poor heel/toe downshifts. Ambient temps were ~78 degrees so...

Yes, I giggled like a girl on the banking and bus stop when I hit it right...this is the 19th track I've been on and the banking is unlike any other-worth doing once in a lifetime!
 

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Definitely looks like fun. Good job at 1:48 not taking out all the pylons LOL
 

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Nice, looks like a great time. The closest track to me is Summit Point, I need to do an HPDE one day to get involved.
 

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DinanS2+ e60m5 6MT, s38b38 e28m5 TT/ST3, e30 TT/ST4
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Video...if it works:

14 10 31 Daytona Lap BMW M5 - YouTube

Couple of notes:

Understeer-sway bars would certainly help, but believe a simple alignment for more front negative camber would really have helped.

Limiter: I hit 165 mph indicated in 5th at over 7000 rpm...I thought the US cars were limited to 155 mph? Is the speedo that inaccurate? I short shifted on the banking...it threw my expectations of stick out of whack so was concerned about exceeding the limit at that speed. IE the car is faster, but not with me driving it that day.

Tinking: Likely the exhaust/engine was making noise on cool down, but my main 'tinking' was the rotors...you could see the brake 'ash' come off after each contraction...I did a thorough cool down so was not concerned. Although the car is ready for a set of brakes...as these have covered 60,000 miles with only a brake bleed a couple of times. I did get some mild shudder, although I did not push the brakes (started braking at the start/finish line for turn 1.

Gearbox: I believe the warning actually stated "Transmission Temperature Increasing / Reduced Engine Power." I believe I recall reading this was more a clutch/flywheel overheat...ie too much slipping, in my case poor heel/toe downshifts. Ambient temps were ~78 degrees so...

Yes, I giggled like a girl on the banking and bus stop when I hit it right...this is the 19th track I've been on and the banking is unlike any other-worth doing once in a lifetime!
Thanks for sharing your video!

I've said it before, and I'll say it again about understeer on the e60: RDSport front and rear sway bars will dial out that understeer.

I went from Dinan front roll control and RSB to RDSports -- after a weekend at the track, my front tires looked and felt normal.
 

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Discussion Starter #12
Gearbox overheat: is this actually the gearbox oil overheating or the flywheel/clutch? I have the oil to do a change...purchased it for the track day prep, but ran out of time. 60K on it...it is time for a change anyhow.

No doubt some suspension work would improve its performance. My comment is the alignment is likely set at 0 camber (eyeballing it too)...just -1 would save the outside edges and improve the grip to even it out. I wasn't able to really turn with the DW tires...they are fresh, but just looking at the tread...very open for wet performance. Just a set of OEM Michelins would have been a decent improvement.

It really ran quite good, IMO. The V10 surge on the banks was great fun-wish the video could pick that up better-I should have tried with the windows up...but 78 degrees at end of October-too nice.

The bus stop jiggle was entertaining. I only get to do one track day a year anymore so the last thing I wanted to do is scratch the better half's car!
 

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Gearbox overheat: is this actually the gearbox oil overheating or the flywheel/clutch? I have the oil to do a change...purchased it for the track day prep, but ran out of time. 60K on it...it is time for a change anyhow.
As far as I know, this has never been hashed out by a board member with definitive results posted. The 6MT is similar to the one in the E39 M5, and having been on the board forever, I've never heard of a failure of a 6MT due to power/track use...saying "power" here since there are some E39s putting out way more power than the S85 and WAY more torque, etc, with no 6MT issues.

On the E9x M3 6MT tranny is identical almost except the BMW installed a tranny oil cooler whose heat exchanger resides in the right front of the car.

We can assume that the very high revs these engines sing at had BMW worried about the transmission temps I suppose, but when you think of a typical HPDE track session, they typically aren't longer than 20-25 min. I seriously doubt any major issue would occur if the temp sensor was bypassed...at least that's what I'd do if I had one.
 
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Discussion Starter #15
Trans overheat: Interesting. Why Daytona? is it the amount of WOT in higher gears in a short amount of time? I suppose an autobahn run typically doesn't last but a few minutes...although I've held 150 for 20 mins before...not in this car though. I understand that more heat is produced in the higher gears (overdriven nature vs the under driven lower gears).
 

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Trans overheat: Interesting. Why Daytona? is it the amount of WOT in higher gears in a short amount of time? I suppose an autobahn run typically doesn't last but a few minutes...although I've held 150 for 20 mins before...not in this car though. I understand that more heat is produced in the higher gears (overdriven nature vs the under driven lower gears).
Well, the 6MT was a USA only solution, that although some people claim was a "last-minute-slap-it-in-for-USA-market" type of thing, I've pointed out many times that before it was offered in the 2007 model year, I talked with Larry Koch at the 2005 Oktoberfest where he spoke of driving the development 6MT mules, etc. Anyway, overheating concerns at high speeds wasn't really a concern due to the expected duty cycle of the USA market (no need to worry about the Autobahn since the 6MT cars won't be sold in Europe). Hence they decided to forgo adding a transmission cooler to the 6MT cars. It was a cost/benefit decision that the bean counters won I suppose.

The prior board member who I posted that link from had the problem at other tracks too I believe, one being VIR. If you search the board, there are others who have run into the issue at various tracks.

Seriously, speaking from my distant, lol, but detailed engineering background, if it was my car, I'd "fix" the problem and never worry about it again. :) It might be as simple as figuring out if it is a typical resistive sensor, measuring the resistance at normal conditions, buying a connector and a resistor to mimic that state, unplug the sensor, plug in the resistor "solution." :) As long as you keep the 6MT fluid fresh, and drive the car with mechanical respect, I would guess the odds an additional 10 minutes in an HPDE session at Daytona would be 100% harmless.

Regards,
Chuck
 
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DinanS2+ e60m5 6MT, s38b38 e28m5 TT/ST3, e30 TT/ST4
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Well, the 6MT was a USA only solution, that although some people claim was a "last-minute-slap-it-in-for-USA-market" type of thing, I've pointed out many times that before it was offered in the 2007 model year, I talked with Larry Koch at the 2005 Oktoberfest where he spoke of driving the development 6MT mules, etc. Anyway, overheating concerns at high speeds wasn't really a concern due to the expected duty cycle of the USA market (no need to worry about the Autobahn since the 6MT cars won't be sold in Europe). Hence they decided to forgo adding a transmission cooler to the 6MT cars. It was a cost/benefit decision that the bean counters won I suppose.

The prior board member who I posted that link from had the problem at other tracks too I believe, one being VIR. If you search the board, there are others who have run into the issue at various tracks.

Seriously, speaking from my distant, lol, but detailed engineering background, if it was my car, I'd "fix" the problem and never worry about it again. :) It might be as simple as figuring out if it is a typical resistive sensor, measuring the resistance at normal conditions, buying a connector and a resistor to mimic that state, unplug the sensor, plug in the resistor "solution." :) As long as you keep the 6MT fluid fresh, and drive the car with mechanical respect, I would guess the odds an additional 10 minutes in an HPDE session at Daytona would be 100% harmless.

Regards,
Chuck
Chuck,

I know we have been back and forth on this in the past -- with no clear answer, but do you think that Dinan's tune on my 6mt altered the parameters of the transmission sensor?

Our tracks out West are not nearly as long as VIR or Daytona 3+ miles.

Laguna Seca and Sonoma are about 2.2-ish, Auto Club is 2.5-ish (with the Infield at 1.5), and Buttonwillow is barely at 3 miles. I've never had any issues.

I should switch back to my stock tune -- and see if I overheat the next time out. Hmmm...that might be a thought.

Cheers!
 

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Chuck,

I know we have been back and forth on this in the past -- with no clear answer, but do you think that Dinan's tune on my 6mt altered the parameters of the transmission sensor?

Our tracks out West are not nearly as long as VIR or Daytona 3+ miles.

Laguna Seca and Sonoma are about 2.2-ish, Auto Club is 2.5-ish (with the Infield at 1.5), and Buttonwillow is barely at 3 miles. I've never had any issues.

I should switch back to my stock tune -- and see if I overheat the next time out. Hmmm...that might be a thought.

Cheers!
It wouldn't surprise me if the tune slightly upped the limit it would trigger at as it seriously seems to be a boderline event, meaning if you upped the trigger point something like 10°C it might make it go away for good for most everybody. However, the longer the straights on the track, it would make sense the more likely a signal would trigger it. Just look at the amount of time the car is wide open up through the gears at Daytona as a percentage of the lap. :eek:oohhh: :) Also at VIR there is the 4000+ foot back straight followed shortly thereafter by the 3000+ ft front straight. :M5rev:
 

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Discussion Starter #19
CSBM5: 6 speed US spec...I know this...posted before thinking!

No worries...the warning gave me a reason to curtail the sessions-probably a good thing that day.

It really ran well-other than the warning-no issues whatsoever. For a car that has only oil changes for its 60,000 mile life-a good product. Of course it made me look like Jeff Gordon or at least in my world.

I had invited folks, but the holiday negated attendance. Would be great fun to have full load of passengers on the banks!

Thanks for the comments!
 
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