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      01-08-2013, 06:12 PM   #13
Kgolf31
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Drives: 2007 Z4MC, 2012 128i
Join Date: Sep 2008
Location: Ohio

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Quote:
Originally Posted by cgroppi View Post
I run my Z4m in AS. I am certainly not a national champion level driver, but the car can be reasonably prepared.

I run Koni DAs from TC Kline, and looked into getting AST 4200s. I eventually did not, but they will happily build you a set for stock springs as long as you're willing to wait for a few months to get them. You need to send them a pair of donor struts so they can cut off the spring perches.

I have run two tire setups: 285-30R18 Hoosier A6 all around, and 245/275 Goodyear Eagle RS. The Hoosiers mount just fine on the stock wheels, and there are no clearance issues at all. In the rear, a 5mm spacer is required to clear the fender liner.

With the Hoosiers, I ran a UUC front bar. With the staggered Goodyears, I use a Ground Control "race" rear bar to bring more weight transfer to the rear to help get rid of understeer. I think I like the second setup the best, but they're not too hugely different. I think turn in was better with the big fronts, but I can get the overall balance much more loose with the rear bar and the staggered tires. I had to have the compression maxed in back and full soft in the front with the hoosiers, and I still got understeer. With the rear bar, I have the rears full soft and the fronts about in the middle of the range. I have no issues with the big rear bar limiting traction. The M LSD is really good.

Now that Goodyear has bailed from autocross, I am pondering what to do next: Go back to the square 285 A6 setup, try a staggered A6 setup (maybe 255/285) or try Kumho 710s (245/285). The Kumhos are obviously worse in the grip department, but they do last a long time. It's a battle of cheap vs. fast .
Did you just order Koni DAs from TCK or did they do anything special for fitment? I was quoted $2k for DAs from them. I was also told that I cannot transform the DAs to accept linear springs and act as coilovers based on the perch design, right?

Do you have a trailer hitch to transport the tires?


EDIT: Found your thread: http://www.zpost.com/forums/showthread.php?t=574966


Do you have any problems trailering the tires?


Quote:
Originally Posted by z3papa View Post
Based on what you are suggesting, have you considered the BFG R1S in the 265/35-18 front and 285/30-18 rears. I've heard from several Nat'l guys the R1S are just as fast as the A6's but hold that level of grip longer in terms of life. By the way, anyone seriously interested, there is a thread on SCCAforums where a guy in a fully prep'd M Coupe is soliciting co-drivers for Nat'l events.
Any link?

Last edited by Kgolf31; 01-08-2013 at 06:20 PM..
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