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4th gen spring rates?


Glenn

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being as there are no other 4th gen CMC cars currently running in the Texas area, i have no other cars to use as a guide for set-up. would some of you west coast guys mind letting me in on what spring rates you run? also free length would be nice also if you have it.

Al - i have what you run, but feel free to post again.

i have an idea what i'm gonna run, but just need that sanity check.

hows 700/175 sound to you guys? this will be w/ 32mm/19mm sway bars w/ car @ the 3200lb minimum weight.

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I am moving from AI to CMC for 2005 in a 1995 Firebird. FWIW, my plans are:

 

Bars: 35/21

Springs: 650/175

 

...and I suspect that I will be around 3450lbs.

 

Like I said, for what it's worth.

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You guys are right on with your numbers, but let me say one thing..I don't care if you run bone stock springs or the trick set set up from who knows where..the better driver will always win at the end of the day.

So once again, driver seat time is where its at,and come to the track with set ups like you guys will have and you will just get faster and faster, and it won't be because of what parts that are under your car.

Good luck and keep the questions coming, as we are all happy to help.

Tony Guaglione

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Glenn...I had that setup under my car, and it worked very well. I went up in spring rate all around because I am physically incapable of leaving well enough alone. I have no scientific evidence that my current 800/225 combo is any better than the 700/175 setup.

 

Either way, I think both of you guys have setups that could win races

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Tony and Al - you are both right. My brain is a weird thing. I have built this setup in my mind as my "ultimate setup". Therefore, I will always blame the car for lousy driving until I get this setup complete. Once it's in there, I will completely be focused on driving. This is exactly how I progressed in autocross.

 

Think of it as the guy from Spinal Tap - His amp goes up to 11!

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Its an important point you bring up though Keith. Regardless of the setup, you have to be confident in your car. I know when I started I had to keep reminding myself that Tony had won races in my car, so therefore if I finished 2nd to last it was all on me!

 

Of course Tony could probably win races in a Pinto, but that's another issue.

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Welcome, Mitch. I was wondering when I'd see you around here...

 

As you probably saw over at frrax, I haven't settled on a rear spring length yet. I want to get the ride height adjusted after the mods are done and the of the car is known. At that point, I will know what to do for the rears.

 

Fronts are 10 but the old 8's would have worked, too. They would have been pretty high up on the GC threads, though.

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Keith, thanks .... I've been lurking for a while ...

 

Is there any issue with suspension travel having the lower perch adjusted so high up the collar?

 

Is my thought process correct in that given the same spring rate, a 10" spring would allow more suspension travel than an 8"? Is it because it's lower perch is, theoretically, 2" lower on the shock collar?

 

That might sound like a very simple and "no-brainer" question, but I just need validation on how I am seeing all this working in my mind's eye ...

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...I could be all washed up but...

 

I can't imagine there being much of a difference from the driver's seat whether you have 8" springs way up the threads or 10" springs 2" lower... The load is vertical...

 

As far as spring travel is concern, I can see where a 10" would have more distance to travel before being fully collapased, but I would hope that the bump stops come into play before this difference would be noticable...

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Well...there are pluses and minuses to the spring setup I have. The car is definitely a lot more tossable than it used to be, and more stable under braking. Unfortunately it is also a lot twitchier than it used to be. I had the chance to drive Tony's mustang before he made it do acrobatics and I was really surprised how much easier his car was to drive fast. It reminds me of an article I read in GRM about Turner Motorsports and the difference between their WC BMW and their Grand Am BMW. The WC is much stiffer and much more difficult to drive...the GA car is softer and easier to maintain on edge.

 

If you already have the 700/175 setup I'd probably say keep it and concentrate on driving. Also, I think the 800 (or more) fronts push a stock Koni beyond its limits, requiring custom damping or more expensive shocks (within the rules limit eh? )

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well i'm running 700/200 w/ bilstine HD's and the shocks are not working w/ this rate. so i'm ready to get something that will work @ whatever rate i end up w/. i only want to do this once. i was thinking 800/225 would be the way to go w/ a re-valvable shock set-up w/ those rates.

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Really? Thats interesting and unfortunate for us 4th gen folks. The nice thing about springs is that they're dirt cheap if you know where to shop (and I know you do) so its worthwhile to play a little.

 

If you have to revalve anyway, go for the meaner springs. I think thats a really good rate for the tires, hp, and weight we have.

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