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MZ3 Autocross Test & Tune (shocks) (archive)

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Posted by Chris in Atlanta on February 26, 2001 at 09:08:53:

WARNING: Hopefully interesting, but no solid findings.

I did a Test & Tune on my front sway bar, front toe, and SuperTrapp exhaust about two weeks ago. Important info, see the archives if you missed it.

I did the "Dial-In" McKamey school the Friday before Nationals this weekend in Meridian, MS. I had the chance to do a ton of runs on the same course, so played with my shock/strut settings. I did enough runs to stabilize my times, then started playing.

I have double adjustable Konis, which I had custom valved over the Winter. Valving shocks/struts is very complex, as there are many variables. At least four values (Bleed, Bypass, Piston Size, and Piston Orifice) were significantly changed from standard in mine.

Apparantly Mark Sipe went through three iterations before he found a valving setup he liked. I ended up asking for the "Mark Sipe special", but a little less rear rebound, as Mark thought he went too stiff the last time.

Also, no gas added, to drop the car a bit. Gas isn't needed, and this makes the car sit a hair lower and thus helps give us a bit more negative camber. At a recent alignment, I appeared to have an average .3 degrees more negative front camber on each side (more than I think I should have gotten, so I'm not sure. . .).

Last year I discovered that my car was fastest with all shock/strut settings set to max - strange but true. Mark recommends all settings to max even at the stiffer values I now have.

So my methodology was simple. I did the initial runs at my normal "full max" settings. Then I started backing off two clicks (there are a dozen clicks or so) on each setting. So, my first run had two clicks from max of rear rebound, and max at everything else. If it slowed me down (after a few runs), I went back to max for the next try. My plan was to leave a setting where it was if it sped me up, then go through the rest of the settings, and come back to that one to try two MORE clicks.

Actually, since I told Mark Sipe that my car was oversteering a bit more than I liked, he told me to reduce my rear compression a bit - which I tried first. Note that with regular double adjustabel Konis, going from medium soft rear compression to max rear compression sped me up quite a bit last year.

I found. . . well, nothing. Only going two clicks (1/4 turn on top) softer on any of the settings had no significant influence on the times on the course. My times were up and down, regardless of shock/strut settings.

What does this mean? Well, as I have said, I am an intermediate level driver. It appears that my level of driving skill is not up to appreciating modest changes in the shocks/struts. Bummer.

"Normal" shocks/struts? I also suggest that you autocross your car with all settings set to max.

Tire pressures: I am now running 45 front and 39 rear (quite a bit lower than last year), and have a bit of oversteer. At temps up to 70, the fronts still aren't rolling. We'll see what happens when we get up to normal summer temps.

How did I do at Nationals? Badly. It is interesting to note that I beat the normal C4 and C5 guys, but everyone with an RX-7, Z-06, or Boxster S beat me. And I have been telling people that my car is now as fast as an RX-7 on a fast course, too. Well, the car is, but I can't match these national level guys (and gals!). Interestingly, the Z-06's didn't do that well. Well, it took a while for folks to find "the" setup for a C5. . . I am proud that my first run Sunday morning was one of the fastest in class. Too bad everyone else then got (a lot) better.



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