I'm lost

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I'm lost

Postby elloco54 » Tue Jul 21, 2015 9:56 am

Put a set of 255/40-17 Bridgestone RE71 on my 06 STR car, But now I have lost the setup to get these tires to work. Had the Dunlop ZII star spec dialed in but that is not working with these. So I have 2 questions. 1) What is he effective dampening range of the Ohlins with 9K frt 7K rr springs. 2) How much camber is too much camber, right now I have -3.1 frt and -2.8 rr but the wear pattern on the tires look like I could use more.
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Re: I'm lost

Postby elloco54 » Tue Jul 21, 2015 10:00 am

Also a question directed to Brian,is your Progressive frt sway bar actually stiffer then the Hotchkis
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Re: I'm lost

Postby Brian » Tue Jul 21, 2015 10:13 am

The tire might need even more camber but what are the tire temps across the hide telling you?
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Re: I'm lost

Postby elloco54 » Tue Jul 21, 2015 11:48 am

Haven't got temps yet just got my temp probe back.I'm running between 30-31 psi hot thinking I may need a little more press. But I also wonder if I am overcompensating for the stiffer springs by running the shocks too stiff, I'm at 2 clicks frt 6 rear. As far as camber I have alot of adjustment left.
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Re: I'm lost

Postby Brian » Tue Jul 21, 2015 12:24 pm

I would start with the tire temps and see if you really do need more camber...or less. Once the tires are happy in terms of temp spreads (so we know camber is good), then I would play with damping settings. My initial reaction is that having front 2 off full stiff doesn't actually tell me much because it depends so much on surface conditions (rough surface will need softer setting for best times, smooth surface might take full stiffest setting for fastest time).
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Re: I'm lost

Postby elloco54 » Tue Jul 21, 2015 1:57 pm

Since the switch to RE71 the only surfaces I've run so far are concrete. Toledo is smooth and the courses are fast, Grissom is pretty smooth, and Oscoda has a few dips and 2 different concrete surfaces. Guess what is really throwing me is my competition is running a 06 MX5 that was run/owned by Joe Calder and I was consistently beating him up till the point we both switched to Bridgestones and suddenly I'm 8 tenths behind.
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Re: I'm lost

Postby Brian » Tue Jul 21, 2015 3:41 pm

Sounds like the car was nicely dialed in for the old tire choice, just need to start over and dial it in for this choice. Start with tire temps as a guide to what you need to do next on Camber.
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Re: I'm lost

Postby elloco54 » Wed Jul 22, 2015 6:26 pm

OK so I just returned from my top secret test area with tire temps and it looks like I can use more camber. the front temps came to 207 outside and middle and 157 inside, the rear was 139 outside and middle and 108 inside. I'm thinking another 0.5 deg front and rear. I was surprised the temps where equal left to right.
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Re: I'm lost

Postby Brian » Wed Jul 22, 2015 6:53 pm

Sounds like good data, those are BIG differences.
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Re: I'm lost

Postby Curves » Wed Jul 22, 2015 10:42 pm

How many runs have you had on the new tires? If you have never run anything stickier then it takes some time to find the limits. I got 60 runs now and the last event, I pushed the limits more than before. You have to have some faith that these tires will hold. Faster speeds also magnify driving errors e.g. if you are late turning for the next element then coming out faster would magnify that error which then leads to further trouble down the course... You have to be even more proactive in looking ahead and using smaller inputs.

I have not changed my Ohlin setup with these tires. Any adjustment I made, I went back to what I have. I am running 32 PSI all around, -3 Front, -2.5 rear. Two problems I have. First, I feel I need a stiffer spring rate at El-Toro with these tires due to the much faster speeds between transitions. Second, faster means hitting the top of 2nd more often and having to shift to 3rd more often on our fast local courses. The problems with the 6-Speed magnified. I can't believe how early I have to shift to 3rd compared to the 5-speeds and S2000's.

How is Calders car different from yours?
5 or 6 Speed?
Spring Rates?
Do you have to shift to 3rd on your courses?
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Re: I'm lost

Postby elloco54 » Thu Jul 23, 2015 8:59 am

The main difference between the 2 cars is he has the full race Ohlins with 13K and 8K springs. My car is probably a little heavier as it's a GT and I have a roll bar. He has a OSG diff me Tomei. Same frt sway Hotchkis but his rear is stock mine is Hotchkis. I think I have an advantage in that I have complete powerflex bushings a little taller tire 255 vs 245 and a higher rev limit 7750 vs 7500,plus a stiffer chassis with the M3 sport roll bar. As a note of interest I ran an event against John (Woody ) Rogers from Tire Rack in his second gen S2K he was a second quicker but was on the limiter as much if not more than me as they changed the gearing on the gen 2 cars. I think I'm going to add some camber and work on my driving style to suit these tires.
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Re: I'm lost

Postby Curves » Thu Jul 23, 2015 6:11 pm

You could ask the driver of the Calder car to drive yours for a couple of laps. An occasional drive from a top driver is always a good reference to judge where you are.
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Re: I'm lost

Postby elloco54 » Thu Jul 23, 2015 10:59 pm

The current owner of the ex calder car is not a top driver all he did is buy a nationals prepped car. Here is a comment from a friend of mine who has driven both cars and is a top driver. "I liked your car better, personally. Maybe it was the surface, but Ido's car is really pushy for my driving style. The bright side is I could be on power 100% with almost zero fear of oversteer."
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