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I have looked into routing the lines through the front body work as well and see no real path of merit. Let us know if you find anything different. I agree that this is all due to the weight of our cars. Let’s face it, there are much better track cars out there—Porsche Gt4 anyone? But hey, they are so much fun out there and I do enjoy running and keeping up with much more track focused equipment; that is half the fun! I am also guessing that our carbon ceramic shod brethren don’t have to deal with such issues—Curse them!
i am heading to Thunderhill tomorrow for a track run on Friday. Should be smoking hot but lightly attended. Videos and results to follow soon after that.
... Let’s face it, there are much better track cars out there ... I am also guessing that our carbon ceramic shod brethren don’t have to deal with such issues ...
i am heading to Thunderhill tomorrow for a track run on Friday. Should be smoking hot but lightly attended. Videos and results to follow soon after that.
Yeah, the C63 S is more challenging to drive well, compared to some of the more track-focused cars ... but that's part of the fun. For me, track days are about "me against me vs (my) machine."
I've read mixed things about carbon/ceramic brakes. Some say that, on the track, they don't last much longer. If that's the case, then they'd be hellishly expensive for track use!
Hope you have a great day at the track. Looking forward to the videos.
...The pumps are at the far end of the pit but even that distance was not much help as when I parked at the pumps, smoke started rolling out of my front wheel wells. I checked the brakes and was so alarmed that they may catch fire, that I drove around the paddock to cool them. Once I stopped again, the pads were nearly gone and their material totally white. Clearly toasted them. So my day was done and just grabbed my lunch and headed home....
Kurt, I forgot to ask... When you "smoked" the original OEM pads, did you discolor the red calipers also? That would like seriously **** me off...
When you "smoked" the original OEM pads, did you discolor the red calipers also?
I've "smoked" both OEM and street-track/track pads with no discoloring. I have, however, warped a set of front plastic wheel-bolt covers (aftermarket wheels, not AMG), due to the heat and I'll soon be replacing the rubber caliper-piston dust-boots on the front calipers, since they're sort of "bubbled" from the heat.
Ok guys, I have not been very good at my follow up here but I promise a much better, full video will follow soon. We just got a new puppy here and he is taking all my spare time to train and keep from destroying the house. In the interim, here is the best lap from the day that, once again, ended early. As the tire photo below shows, I nearly had a catastrophic event. I had three sessions in the morning and they all felt pretty good. In the first session, my front tires got to about 41psi so I pulled in early to let some air out. All seemed fine. I started the next session with much lower pressures but they still got into the high 30s (psi) so not really that high but I was starting to lose front end grip. By the third session of the morning, it was dialed in. I was flying! The car felt great. The brakes felt great and stopped the car with authority! The correct track pads and ducts I installed really worked their magic. Wow was it fun. We had a brief red flag and I ended up being the first in line for the re-release and pushed it a bit for the two laps we had before the checkered waved given that there were some pretty quick cars behind me that I did not want to slow up. Plus, we spaced out well so I never did hold anyone up. For this event, they waved the checkered at both the start/finish and Turn 10. I caught the flag at 10 so basically dialed it way back to cool the car and then went straight into the pits. It was lunch time so I hit that and started doing some emails. I had more time to kill so I decided to check over the car and when I looked down from the front to the rear, I saw an unusual shadow from the right front tire. I decided to provide the courtesy reach around and felt this:
Holy snickies!
I almost fainted thinking about what could have been should I have taken another corner in anger. Wow! Just wow. I will discuss this more in the full video to be posted later. So let's bring this back to the fun part. Here is the video of my quickest lap. According to my lap timer, it was 2:05.41. To put that in perspective, this is about a second quicker than my 2008 Corvette Z06 on Hoosiers. Now, let's face it, a Corvette SHOULD be quicker than the AMG but I never could trust the Vette. It did not communicate well and it would bite me periodically. I could never get myself to do more than about 7/10s in that car and this proves it. For more context, I have only driven my 600LT once so far at Thunderhill (on Hoosiers as well), and without too much effort, I pulled a 2 flat. So I think I can say, with all humility, I was hauling a$$ in the AMG. As you can see in the video, I was actually held up by the open wheel spec racer so my true lap time may have been closer to a 2:04. So enjoy this one for now and I promise to have the full video up soon; puppy willing.
I have submitted a claim through TireRack and they are to pick up the tire soon. I realize you are joking about the rumble strips but, seriously, I did not run over anything that I know of nor did I leave the track either. I think it must be a defective tire as in all my years of track events, I have never encountered anything like this.
On the other hand... testament to improvementsa and advancement in tyre technology that it did not give up with that much of the sidewall coming away.
So glad that you only came away with a great story to tell rather than it ending up so much worse.
I have submitted a claim through TireRack and they are to pick up the tire soon. I realize you are joking about the rumble strips but, seriously, I did not run over anything that I know of nor did I leave the track either. I think it must be a defective tire as in all my years of track events, I have never encountered anything like this.
k
Hey Kurt,
Just wondering if you heard anything else regarding the tire failure? I've never seen a tire fail like that. Curious as I historically have run RE-71R's on track as well.
Ok everyone. I am heading back to Thunderhill and this time, I will be running Hoosiers on my Finspeed wheels. My hope is that the added traction will actually decrease my need for hard braking given that I should be able to carry more speed through the corners. Yes, that should translate into a bit more straight line speed but probably not by that much. I will be posting picks and some videos to follow. I cannot wait as with my Finspeed wheels, I was able to fit massive 265s(!!) up front and 295s in the rear. The weather looks to be a perfect 70F by midday so this too should help keep the brake temps down.
Kurt, out of curiosity, why don't you go with slightly wider wheels like 275 in the back and 255 in the front for a little better grip?
Good question and Hoosier provides the answer: Hoosier's sizing goes from 265 to 295. I tried the 295s in the back and they just would not fit; they rubbed the brake lines and fender liner at the "11 o'clock" position as the shoulder of a Hoosier is much more square than the 285 Bridgestone 71Rs that I had last used. This is despite all of the "measured" parameters being equal between the two tires including the width, tread width, and diameter. I figured it was a long shot to get them to fit and turns out they would not. So, I used a square 265 setup all around. Now you are correct in that I could have gone with a narrower tire up front to create a little balance but, the next size down is a 235/35-19 and here is the catch: The load rating on that tire is only 963lbs while the 265/35-19 is 1168lbs. Now, in the grand scheme of things, that is not that much of a difference but remember from my previous posts, that Bridgestone delaminated on me and while Bridgestone gave me another one for free and I am very convinced that this was due to a manufacturing defect, I did not want to risk having a tire which such a low load rating. Thus, I went with the 265s all around. So how did the Hoosiers do? Well, the felt great except for the rear where they felt a little loose and "floaty". I need to go back through this thread to see what my old times were as I doubt I beat any of them. My best time of the day was a 2:05.29 on the West Track with the cyclone. The weather could not have been more perfect as it started in the low 50s and then peaked around 70. Bright blue sky so the track warmed up with the day. My buddy was running his Audi R8, with a full track suspension and Hoosiers and barely broke into the 2:04s so my time was pretty good considering. In fact, we chased each other in the last session and he pulled about 2 tenths a lap on me. I think the car had another 1 and a half to 2 seconds in it but the tail made me too nervous and as I drove it to the track on another set of tires, I did not want to risk going off and having no way home. I will work on the videos this week and post them shortly. For now, here are a few photos.
That is my buddy in his R8 behind me. You can also see the air ducts below the car to channel some cold air to the brakes. I believe this is coming out of Turn 11. I pulled the rear cover off the brake caliper as it kept falling off. My attempt at a little photo shopping of the numbers on the door and windshield.
Just wondering if you heard anything else regarding the tire failure? I've never seen a tire fail like that. Curious as I historically have run RE-71R's on track as well.
Thanks.
My apologies for not responding earlier. I am convinced it was a manufacturing issue. That does not give comfort for those of us the run those tires often but I may have contributed by pushing it too much on a super hot day as well; as I recall, it was well into the 90s and I pushed it hard from the start. I have looked into this tire more lately and from what I have read from other pros and tire testors, you have to warm the RE71Rs up gradually. I did not. So I think we are all still fine to run it but just get some heat into them in the first two or three laps before you beat it like a redheaded step child.
.... So, I used a square 265 setup all around. ....Well, the felt great except for the rear where they felt a little loose and "floaty".
I pulled the rear cover off the brake caliper as it kept falling off..
The floatiness can be easily explained since you were running a square 265 setup. The suspension engineers set the car up with staggered tires in mind. So clearly, you had more front grip biased in.
Did the rear brake cover come off due to the heat? And still no caliper discoloration from the heat? That's impressive if so. Since we have the same exact car, I can pretend this is me on the track... But I really want to take the AMG on the track for curiosity. But I will likely take the C8 instead which I just got.
The caliper cover came off during the last event and fortunately, it fell out in my set up area in the pit. I removed it to be safe for this event. I am not sure why it came off the first time but I can say it does not fit that snugly. As for the discoloration, I have never had an issue with the red calipers. The sliver ones did discolor on me though.
I agree on your thoughts on why the rear felt loose but I didn't want to risk smaller front tires given the decreased load rating. I doubt I will run Hoosiers again as I was not that much quicker due to the insecurity with the rear feel. Thus, I will go back to an R compound street tire.
As for tracking yours, you should try it at least once as they really do communicate well and are completely tossable and controllable on track. But when you have a new C8.....well, gotta run that puppy first! I hear they are fantastic but with horrible understeer from the factory so check the corvette forum for alignment suggestions. I had a C6 Z06 that I stupidly sold about 6 months ago. I wish I had it back. Then again the new Z is just around the corner.....
Impressive report as usual Kurt, thanks. One of those pics looks like you're about to roll the bead on the front right too.
As for the rear caliper, it's probably a topic for another thread but that single pot, floating rear just does not compute for me and I can't understand why AMG chose it, especially if it's cost related.
My apologies for not responding earlier. I am convinced it was a manufacturing issue. That does not give comfort for those of us the run those tires often but I may have contributed by pushing it too much on a super hot day as well; as I recall, it was well into the 90s and I pushed it hard from the start. I have looked into this tire more lately and from what I have read from other pros and tire testors, you have to warm the RE730s up gradually. I did not. So I think we are all still fine to run it but just get some heat into them in the first two or three laps before you beat it like a redheaded step child.
Kurt
No worries Kurt.
A manufacturing defect is a very reasonable explanation for the failure. Between my friends and myself we've run hundreds of set of RE-71R's on track is this is the first time I've ever seen that happen. This is also a very popular track\ autocross this.
Your warm up theory is interesting. I typically take the first 2/3 to full lap easy to allow build heat into the tire. I've had the back end break loose on acceleration if I don't. However have friends that like to go ball's out from the get go with no issues.
Impressive report as usual Kurt, thanks. One of those pics looks like you're about to roll the bead on the front right too.
As for the rear caliper, it's probably a topic for another thread but that single pot, floating rear just does not compute for me and I can't understand why AMG chose it, especially if it's cost related.
I have always wondered/worried about that issue as well and have been assured that it is nearly impossible to have the bead seat come loose under these conditions. I suppose seeing NASCAR, IMSA, F1, etc. all running and producting many more Gs than we will ever generate gives me some comfort that this will not happen without some sort of impact trauma. But yeah, I have always wondered about that as well.
So here is my final report from the past Thunderhill event with Hoosiers. First, the day was perfect and the peak temp was around 70F with very little wind and a bright, clear sky so the track was perfect. Some recent rains probably cleared some rubber but for the most part, the conditions could not have been more perfect. As usual, I had the aftermarket 2-piece rotors, Porterfield track pads, Castrol SRF brake fluid and the self-made air ducts for the two front rotors to bring in some fresh air. I have to say, the brakes felt great for the most part but were a little soft in turns 5 and 6. This is somewhat perplexing given that 5 is the slowest entry and 6 is not that fast. My only guess is that there was some heat soak occurring due to turns 1, 2 and 3 and then very little fresh air getting in to the brakes to cool them by turn 5/6. By turn 8, they were fully back and zero fade on the high speed stuff which is most important. I was a bit timid most of the day with the brakes especially when in traffic going into heavy braking zones. I didn't want to rear-end anyone! By the end of the day, I finally threw caution to the wind and fully trusted the brakes and man did they perform! I was standing on them during the last session and they worked so well that I was stunned and a bit miffed at myself for not trusting them earlier. As I mentioned in my earlier posts and as others have pointed out here, the car did not like the square set up from the tire size. I guess I should have known that the AMG engineers staggered for a reason but I thought it was worth a try and as Homer Simpson would say: "You learned a very valuable lesson today. You tried and failed and the lesson learned is never try." It is too bad Hoosier does not make a size between the 265 and the 295 as this would ideal for this car but I guess they know the market and feel it is not worth it. So my best lap time came in the second session of the day and that was to be expected given the new tires and temps. It was a 2:05.29 and rather disappointing given that my best with the Bridgestones during the last event was in the high 2:05s. I was really hoping to get close to a 2 flat but several items to consider:
1. As mentioned, the square setup is the most likely culprit and my lack of confidence in the rear was responsible for at least a second or second and a half right there. A more competent driver could have gained more I am sure.
2. My lack of trust in the brakes until late in the day wasted the "golden" laps from the tires. By the time I fully trusted the tires, their best laps were behind them.
3. Traffic. Even though I was in the unlimited group, there was quite a bit of traffic and I only had a few clear laps all day. I was constantly in a group of GT3RSs and a few other quick cars. I had the measure of most of them in the corners given that most were on R compound street tires but it was difficult to pass them on the straights given my car's weight vs. theirs.
Overall, I just cannot say this enough: This car is such a blast to drive on the track! It is so quick and has so much torque that it surprises most folks. During the last session of the day, I was chasing my buddy in his track prepped R8 V10 with Hoosiers and he had me by a few tenths per lap. At the end of our run, several of the track stewards and Hooked on Driving folks came over to tell us that enjoyed watching us out there and were simply amazed that I was basically able to hang with the R8. They had no idea the C63 was that capable.
At this point, I have at least one, maybe two track day's worth of potential left in the Hoosiers so I will likely head out again but may try different tracks such as Sonoma or Laguna. For now, here is my best lap below. I will post some additional ones to compile some passes and other things I saw on track such as a couple of cars spinning off in front of me. Enjoy!
Here is a compilation video of several passes and offs ending with me chasing my friend in his track prepped R8--I like pointing that last part out as an excuse for not hanging with him closer. Wait for the end and he spins off. I don't have all of it as I blew turn 2 and got off in the marbles but I still managed to capture a little of it to make sure he remembers it!
08-05-2020, 11:37 PM
But I really want to take the AMG on the track for curiosity. But I will likely take the C8 instead which I just got.
