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FD guys, track suspension setup -- experienced guys chime in

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FD guys, track suspension setup -- experienced guys chime in

Old 07-25-13, 06:10 PM
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FD guys, track suspension setup -- experienced guys chime in

hey guys,
i bought my FD ~4 months ago with the intent of making it a weekend/track/HPDE car, so i did a lot of work to it (see my build thread here for more info: https://www.rx7club.com/build-thread...ng-me-1032831/)

anyway, i successfully completed a full track day at Road Atlanta and had a lot of fun. the car performed very well --and was way faster than i am as a driver-- but i am basically clueless about how to get good baseline suspension settings.

the suspension setup is:
stance GR+Pro 12k/12k coilovers
superpro poly bushings all around, and new pillowball mounts in the rear
racing beat front swaybar support brace


i ran all 4 shocks at full soft for the track day thinking i would change the dampening when i got a chance, but i ended up focusing on my driving line, and didnt really consider changing suspension settings until after i got a lot of time on the track. also, this was the first track day this car has been to, so i really wanted to make sure everything was working correctly before tweaking.

so what are some general settings that most of the track guys use, or how would an experienced driver suggest setting the suspension for a novice like me? i have pretty deep knowledge of most things automotive/motorsports, but when it comes to suspension, i know enough to know that i don't know enough.
fritz suggested stiffening the dampening in the front to about 1/2 and leaving the rears at full soft, but i'm not really sure why.

i'm looking forward to getting some good input from some of you guys who are at a level at which tweaking suspension really makes a difference.
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Old 07-26-13, 12:02 AM
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A really great read full of info is the Howard Coleman thread on setup. It's a sticky in the suspension section.

BTW: you picked a good idea to focus on driver first. Get lots of seat time before making many changes.

There are other threads on suspension setup too, including guides to alignment settings.
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Old 07-26-13, 11:45 AM
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+1 on the suspension setup thread. its actually been edited really well, so 90% of the good info is right in the front.

you are on the right track though, concentrate on driving! the driver is the most important suspension part
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Old 07-29-13, 11:12 AM
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after reading howard coleman's suspension thread i'm convinced these 12k/12k stance coilovers are way too still. this was my initial thought when i originally looked up the spring rates...

i PM'd howard asking if he'd recommend getting replacement (lower rate) coil springs from Stance (8k and 6k for example) or just run different coilovers...

i always heard that the shock valving should be specifically matched to the spring rates that are running with them. we'll see what he says.
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Old 07-29-13, 11:46 AM
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i haven't done the math on the FD, but with actual slicks 12K springs might be in the ballpark.

if you want to go racing, the tires dictate the alignment, and the spring rate, and then the springs and weight of the car dictate the shock valving.

although its a little more complex, for instance the FD has good suspension geometry, so the spring rate is less important, as it'll still work if its too soft.

the anti roll bars i don't have a really good formula for, and it depends on the car too, IE we've run an integra, and the relationship between the rear suspension spring rate and the bars rate is really important, however, we are trying to get it to lift one wheel off the ground, so its different!
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Old 07-29-13, 11:48 AM
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Pretty sure he'll say yes - shocks and springs gotta match.

How serious are you about track vs street?
What tires and wheels are you running?
And, a key point, what is your suspension budget?

It wouldn't be a bad thing to drive for a season before changing a lot, but I know how the obsessions go!
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Old 07-31-13, 01:29 AM
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Those are great spring rates for roadrace, especially with slicks. I run 1400 lbs. Remember the spring sits very close to the inner pivot point of the control arm and thats why you need a stiff spring. Your wheel rates will be good.

Use an adjustable swaybar (s) to fine tune handling at the center of the corner, and use your shocks to fine tune entry and exit balance.

On compression start near the soft end and keep going stiffer until the car hops under side load , and back it off 1 or 2. On rebound have someone watch the car go over a curb at speed. Keep adding stiffness untill the tire stays up inside the wheel well after the bump, then back off 1 or 2.
From here soften the shock on the area that you want to change. Example, if your car is loose going in, soften the rear. If your car pushes going in soften the front. From there you can also play with camber, etc and start measuring tire temps.

When I first got my Penskes I ran them full stiff and the car was horrid. Oversteer in, understeer out. Car was jacking down. And before that it was great with cheap shocks. The more adjustment the more knowledge and effort needed!
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Old 07-31-13, 11:29 AM
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Your spring rates are fine. Listen to Fritz. Firm the front shocks, leave the rears a few clicks from full soft, and get a tripoint front sway bar and start it in the middle hole. This is a good, safe starting point. You can adjust the set up from there based on feedback from the car. This is a good baseline for RA, BMP, and VIR. CMP is a little different.

Tire pressure is a big deal as well. I think I was running 29F, 27R when I ran street tires like the Z1 Star Specs. Slicks I start out cold at like 25F/23R.
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Old 08-19-13, 03:03 AM
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if you need help building and tuning the supspension, i used to run penske coilovers on a hillclimb and mountain FD for a couple of years. now i tinker around on an FC and suspension is my favorite part of tuning a car. pm me for support.
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