anyone road racing a 99 ACR

PhilC

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I plan on road racing my 99 ACR a little more seriously in 2003. I would appreciate it if anyone racing 99 ACRs would give me some input on a good starting place for the suspension set up. I know that I'll likely make changes based on how things go at the track but a good starting point would help.

Oh and if you're using Hoosiers, what cold tire pressures have you found to be best.

Thanks in advance.

Phil
 

Mike H

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Phil,

What spring rates are in your car? This is what most swerious racers change the most depending on the track and your driving style. Remember that softer springs are more forgiving as a car with a stiffer suspension requires more finess.
Shocks are the next question. What type? Setting the shocks if adjustable can also make the car more responsive if you feel the car understeering at entry or oversteering at exit.
Finally having the car scaled properly can provide dramatic changes as you try to get the car pretty nuetral. With that also have the car aligned properly.
Tire pressures can be varied depending on how hard you drive the car, alignment, and setup. Go to Hoosiers site and you can print out what the proper tire temps are needed for them. I run somewhere from 29 to 33 front to 27-30 rear pressure and record tire temps to fine tune the pressure. We change presuures depending on track temps also.
GOOD LUCK!
 

toddt

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From the koni manual:

Setting up

Finding a good set-up for your dampers may seem a difficult task. It is not, as long as you keep in mind to;
-Make changes to the settings in small steps (1-2 clicks at a time),
-Keep track of all changes made and their effect, -Aim for a good chassis balance fir~t, and only
then start searching for outright performance.
Basic damper set-up

1. Set all dampers at their minimum adjustment po- sition for both Bump and Rebound.
2. Carefully drive the car a few laps and increase speed gradually so you can get a feeling for the car.
3. At this stage do not pay too much attention to ex- cessive body roll, a wallowing ride and possible loss of down force that may occur because of this.
4. Increase the bump settings by two clicks at a time only, on all dampers.
5. when you arrive at a Bump setting that makes the car too harsh, back off the Bump setting one click. Note: Front and rear may need different settings.
6. The standard bump settings have now been de- termined.
7. Next increase the Rebound settings on all dampers one or two clicks at a time. Pay special attention to changes in attitude of the chassis when entering corners or accelerating out.
8. Increase Rebound settings until the car feels precise and stable. Changes of direction or throttle position should not result in drastic changes of chassis-attitude. Too much Rebound generally results in loss of grip. Too much at the front will give understeer on turn-in, too much at the rear results in loss of traction and/or oversteer on
turn-in.
Note: Front and rear may need different settings. 9. Basic set-up is now completed for this car and
track.
10. To avoid mistakes, verify that the dampers are set correctly from time to time.

Additional tips

A. When you change spring rates, expect to change your basic set-up as well.
B. A damper only functions when it moves. When the suspension stops moving due to lack of travel, the damper will not have any influence on handling. A wheel that runs out of Bump travel loses grip sud- denly and viciously.
C. Try to stick to the balance between Bump and Rebound settings as found during Standard set- up. If you wish to tighten things up, start by increasing both Bump and Rebound settings. Beware not to end up in a situation as described
at B, caused by a damper dynamically jacking the suspension up or down.
D. An increase of damping forces at one end of the car will tend to make the other end move more.
 

toddt

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No problem! And make sure your shocks are working. I hated my ACR for a long time, because it was oversprung in the rear. It turned out that my right rear shock was almost useless, leaking. Once I got it fixed, I really discovered what an ACR SHOULD have felt like!
 

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