Thunderhill Track Day
No need to anything special just do following:
After cool down and you park and put car IN park just keep foot on brake and reach down to the brake release and HOLD it up while you turn car off and the brake will not be set.




Kurt




As you all may recall, I had several issues during my last event and endeavored to rectify them for this one. I was not very successful.
1. Tires. I am using Michelin Pilot Cup 2 tires and at the last event, I could not control the pressures and they would soar into the 50psi range. I even started them exceedingly low at around 25psi. This would keep them in the mid 40psi range but from my research, these tires should be kept a bit below 40. Let me know if anyone has heard differently. For this event, I had them filled with nitrogen (with several purges) but the results were the same. The tire company that filled them told me that I should only see a 1 to 2 psi increase. Assuming they were correct, I had all tires filled to 40psi with nitrogen. So much for 1 or 2; try 10 to 15psi! I started the with 38psi in the fronts and after the first session, they were at 55psi! I dropped them down by 10psi and then had significant roll over per this photo:
Note the roll over and the chunking of the tread.
As I did not have any nitrogen with me, I had to add some air. I finally was able to get them to stabilize at 43psi which seemed to be a reasonable compromise between roll over and pressure. I know it is a heavy car so maybe low 40s is the best compromise given all issues.
2. Tires again. If I was smart, I would have swapped the left and right fronts halfway through the day to achieve better wear between the two sides. Sadly, I did not think of this seemingly obvious thing while at the track and ended up with my right front being destroyed on the outer edge. You may have noticed the chunky of the tread in the first photo. Here is another shot of it:
This was by the end of the fourth session and in total, two track days; both at Thunderhill which is primarily counter clockwise. I did not pay enough attention to know if I used the same tire for the right front each time. The rears seem to be fine so I will be getting two new ones for the front.
3. Brakes. I had been working with racebrakes.com and they still cannot come up with a rear track pad. To their credit, they have been trying but apparently do not show the correct part number for the red caliper set up. I will send them a set of my worn pads so that they can make a set. The fronts they provided, worked great. What did not work so great is the Mercedes brake fluid. I have another post on the Forum where I incorrectly indicated that I wanted to use DOT 6 fluid. Sorry about that. I wanted to use the Motul 600 which, technically, is a DOT 4 fluid but seems to perform well my car. I will try it again for the next one because in this event, the fluid let me down. In just a couple of laps, the pedal started to get soft. I essentially nursed it the rest of the day and never achieved VMax in any straight and lifted/coasted in most just to be sure I didn't overwork the fluid. Once in the pits, I checked the rotor, caliper, and wheel temps. My laser thermometer maxes at 600F and I would get an "ERR" message on the rotors indicating a temp above 600F. Clearly, I need to address this issue. Better fluid and I will be engineering some cooling ducts before the next event as well.
4. Car in General. The rest of the car performed great. Fast as heck and a beast out of the corners. I still over drove it through many corners but so I need to work on that. Only a few track dedicated cars passed me. I passed all the Ferraris, a couple of C7 Z06s and practically everything else out there without a roll cage. Being humble, it is clear that a few of the cars I passed either weren't trying or had drivers with less experience as I was not "that" fast.
5. Analysis. I still have work to do even though I have driven several hundred miles on this track. I am leaving a lot on the table at turn 5 as most tell me I should be able to go 50mph over it. I think my best was around 38mph. I did make a lot of progress with turn 7 and entering it later and almost staying flat (almost). Turn 11 is another fun one as you essentially throw this one away but I have been going full throttle from the apex all the way through the esses and letting the traction control/eDiff sort it out; which they both did nicely.
Thanks for listening and more videos to come as well as an update once I do another event in the coming months.
Kurt
Last edited by kfehling; Sep 12, 2016 at 07:26 PM. Reason: Typo
Are you always using a hand air pressure tester as opposed to reading the MB readout on the screen ahead of the wheel?
I just wonder if it is accurate in a situation like this.








The Best of Mercedes & AMG




Ignore the notation in the video that it was the C63. For some reason, I could not get it to switch cars in the description.
Enjoy!
when i was searching for my car i drove 3 clk 230k and 2 c230k coupe. none of those where in a good condition i mean in a terms of performace. i bought 200k coz that one had perfect air - fuel ratio, good sc and insane performance. i was very impressed bye that car in that moment. even my friend with clk 230k couldnot get rid of my civic 1.4 1996 till the third gear.
better take a good look after your cars and make sure thay still perform like new.
the gap between 0-100 1 or 1.2 seconds isnot hidden in engine or cpu its elemental. your are thinking too much and cannot see whats in front of your eyes
Just replacing the factory discs with Girodisc to save both weight and money, considering the R4 pads from Porterfield with R4-S swaps for the street. I've been running EBC BlueStuff with no real issues but had some very uneven pad wear last track weekend and it may be time to upgrade to more of a dedicated race pad for track days. I'd prefer not to swap pads around, but what can you do?




My my best time was a 1:55. To put that in perspective, the PWC cars were running around 1:39 the weekend before. Here is the video.
Also, I forgot to change the car designation on the lap timer again so ignore the fact that it says Corvette.
Last edited by kfehling; Dec 11, 2017 at 09:47 PM. Reason: Additional info.
I just put A/S 3+s on my 4matic e63 with a Eurocharged Stg I tune. 255/35/19 and 285/30/19 And to respond to the OP these tires hold and grab traction incredibly. To be honestly the PS4s or another high performance summer tire may grip and handle better but these really are the best of both worlds. I had the rears on first and it made a substantial difference even in 40* weather, so much that my Race Start didn't even have to drop rpms when launched. I was speculating that the car was losing power due to maintenance but not anymore, you feel every ft.lbs. of torque advertised. That was only with the rears. Now I will admit I had a nasty bubble in the front drivers side Pirelli tire I had previously so I wasn't too thrilled with the holding in sweeping curves but on the Pirellis in the cold I didn't feel comfortable going 60+ in a certain curve and this morning on the way to work (In Mexico of course) I did 100 and still felt I could go faster. These tires are amazing and I'm glad I made the switch. No placebo effect over the Pirellis these things are awesome in the cold and even held traction in the wet too. I had used them before on my CL55 when I bought it from MB Chantilly and was very pleased with them. So my experience and .02.




I have to say, there is something very satisfying about running a five passenger family sedan on the track and spanking Corvettes and Camaros (full disclosure, I have a Corvette Z06 so I am not bad mouthing Corvettes...or Camaros).
I just love being on the track.
Kurt
I have to say, there is something very satisfying about running a five passenger family sedan on the track and spanking Corvettes and Camaros (full disclosure, I have a Corvette Z06 so I am not bad mouthing Corvettes...or Camaros).
I just love being on the track.
Kurt
Looking at doing this myself. Do you mind taking a photo of the duct setup?




Kurt.





