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05-29-2008, 09:21 PM | #1 |
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Am I the only jackass to take the run craps to the track?
Took the 135 to the track a two weeks ago. Had a good time in the car just a couple of issues with the brakes and run craps.
The brakes worked great on the track. If I was going to track this car more often I would need some pads with more initial bite. Tracking the car seems to have worn both rear pads in a radial pattern and are not making full contact with the rotor under normal street use. The run craps! I can't figure these tires out. I started with 34 psi cold all the way around. After my first session the fronts heated up to 54 psi and the sidewall was gone!! The rear tires only heated up to 44 psi and the tires didn't even touch the wear arrow on the sidewall. These things are going in the trash!! Chunks missing! |
05-29-2008, 10:43 PM | #2 |
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ugh. not good news. I will be autoxing my car starting in July. I will be running it completely stock for the rest of the season (at least 4 autox). That includes the crappy RFT.
I already have plans go buy a set of LTW5 17x8.5 wheels with Nitto NT01 tires for next season. I want to run the car stock this year to see how it feels. From the pics above I am going to guess the RFT are going to be my downfall this season. |
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05-30-2008, 09:02 AM | #3 |
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For auto-x Larry and I run the RFTs at 39f & 36r cold. It does look like your fronts were under-inflated, Brian (and this car needs more front negative camber!).
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05-30-2008, 11:51 AM | #4 | |
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I was hoping someone here would be running the RFT at an autox and would have a baseline tire pressure for me. Saves me from having to throw away the first event screwing with too high or to low tires pressures. |
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05-30-2008, 01:01 PM | #5 |
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You're welcome, and good luck at your first event. Have you removed the strut alignment pins to get a little more neg camber?
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05-30-2008, 01:30 PM | #7 | |
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Everything off. To get this car to move around the track, you quickly realize you need to turn all the traction crap off. |
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05-30-2008, 02:07 PM | #8 |
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Great tire for the money, I'll be going with them when the RFTs wear out but in 17" for even more bang for the buck.
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05-30-2008, 05:03 PM | #9 |
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You can not go wrong with the Z1's. I will have a set on order as soon as the nation wide 255's backorder is filled.
Also I have two track events on the RFT and they do not look that bad, I will have a third this next Thursday. Are you plowing the front through all the corners with understeer?
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05-30-2008, 05:18 PM | #10 |
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Looks to me like either too much entry speed or too much steering angle, or both. They may be giving you not enough turn in bite or feel (without the camber) and you are over compensating. You might try more trailbraking to get some rotation and ease the load on the front before mid corner.
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05-30-2008, 06:23 PM | #11 | |
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How are you finding the 135 does in the autox? A 135i coupe ran at the last BMW autox and it did not do as well I expected. It was a couple of seconds slower than the E46 M3 carbio I was running. And the 135 had even ditched the RFT for some proper 235/40/17 summer performance tires. |
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05-30-2008, 07:38 PM | #12 |
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Better than expected, but it does require changing driving style (slower corner entry and boost anticipation).
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05-31-2008, 08:00 AM | #13 |
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Definitely need to account for boost anticipation at autocross, especially when chipped. My turn in is a lot better with more camber (-1.6 deg.). 39F/36R seems to greatly aid in understeer too.
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05-31-2008, 11:56 AM | #14 |
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How were you able to get that much camber? From what I have read, even after removing the pin the car will have about -0.5* of camber.
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05-31-2008, 12:04 PM | #15 |
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My car is lowered, which adds more camber, plus I added an extra 1/6" to the adjustment slots. I'll get camber plates when I put coilovers in it. This will do for now.
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05-31-2008, 03:48 PM | #16 |
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40 PSI hot and 200 degree F hot is max for the RFTs on the track. Autocross you are looking at only a couple psi pressure rise. On the track anticipate at least 14 psi rise.
To that end I am looking for some 8 and 9 inch 17s so I can swap my 911 track tires (R1s and 888s -multiple sets 235/40, 255/40). I am sure a PS2 would be a great tire for the street and occasional track use. It is very easy to over drive the RFTs particularly if you start out with the pressure too high. Brake pads are definitely not up to the task of an extended track session. other RFTs at the track http://www.1addicts.com/forums/showthread.php?t=8086 http://www.1addicts.com/forums/showthread.php?t=6752 for what it's worth, I don't think I will be using the RFTs on the track again. Looking for 17s
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06-01-2008, 07:30 AM | #18 | |
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Not trying to contradict, just letting people who do autox know that they definitely need to keep a check on the tire pressure. |
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06-01-2008, 09:04 AM | #19 | |
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Understand -- I guess I wasn't clear on the actual amount of temperature rise -- the first time I tried them, I started out at 32 and ended after about 5 laps at 46 (left front) when the brakes were also very soft. I bled down to 38 and went back out within a few laps the left front had gone off again and was over 47. At the end of the day the warning light was not on and I did not add air. The next morning the RFT light was on and cold pressure was less then 20 (left front). The other tires were not as adversely affected. I actually have quite a bit of experience autocrossing; but, have focused on the big track for the last 8 years. The track tires that I use are and have quite a few of are 234/40-17 and 255/40-17 on 8 and 9 inch Fikse FM5 rims. Unfortunately, the bolt patterns are not interchangeable and then of course the offset is wrong. For instance I am going to the Shenandoah circuit this weekend and would like to swap on a set of 888s just in case I decide to go out and play in the instructor group. I the 911 is too stiff for the Shenandoah. The Shenandoah Circuit is like a big autocross with 20 turns in 2 miles.
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06-01-2008, 09:20 AM | #20 |
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Shenandoah sounds like a very fun track.
With my heat comment, I meant that we must be heating the tires similarly, if we are gaining similar pressure in the tires. I started with 39psi up front, checked after 2 runs and had 47psi which I bled back down the 39. I did a few more runs, and was up to 44, which I again bled back down. Hopefully by next event, I'll have a set of star specs mounted. |
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06-01-2008, 09:29 AM | #21 |
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Looking forward to your impressions of this tire for auto-x as it is what I'm looking to mount up for next summer and use them for street and auto-x.
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06-01-2008, 10:35 AM | #22 |
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Thanks for all of the feedback guys! I really appreciate it.
Next weekend, the Kansas City BMW Club is putting on a Auto-X school and I might take the 135 out for some laps if I get some new tires. After meeting and talking to atr_hugo and since the Dunlops are on backorder, I'm thinking of going with 225/40 & 255/35 Pilot Sport PS2s. I should be able to get some good video of the car in action! Good to meet you Hugo. |
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