Question for track only 4 corner coil over 914s...., what spring rates are you running? Options

[nine14cats]

The Beast is built for coil overs on all 4 corners. What spring rates are you guys with 4 wheel coil overs using?

I know TimT has coilovers if memory serves....

And if you have Fr / Rr weight distribution that would be great.....

My previous track 914-6 had T-bars front / springs rear.

Thanks,

Bill P.

[nine14cats]

(IMG:style_emoticons/default/icon_bump.gif)

[9146R]

Bill,

I have koni yellow shox in back on adjustable perches. 2.4 litre motor - car weighs 2069 without me. Running 250 lb rear springs. Let me know if you want anything else.
Greg

[nine14cats]

Hi Greg,

Are you running coil overs in the front? On our first track only 914-6 we ran 23mm T bars up front and 400 lbs springs in the back.

For The Beast, I'm looking for what spring ratio front to back guys are running. For example: Fronts 550lbs, rears 450lbs...etc....

Thanks,

Bill P.

[Andyrew]

I vaugely remember a cali guy with a 2.0 in his car that ran 300 front and 250 backs....

havent seen him in a year and a half...

[9146R]

Bill,

Front shox are (older) green Bilsteins. Were in car when I bot it 5-6 years ago...not adjustable but still feel pretty solid. I have 22mm front torsion bars. Just had it aligned at Roger Krause shop, corner wtd lf=512lb, rf=454lb, lr=687lb,rr=608lb. With me in car total weight 2261. Front wt 966, Rear wt 1295. Car handles nicely with the 225x45x15 R3s0s Hoosiers.
Look fwd to seeing you up there this weekend...we are leaving Alamo ~5am Sat.
Greg

[db9146]

Bill,

Have you reinforced the front strut towers to take the load that was being carried by the torsion bars?

I am going to run coil-overs all around but I will not have a cage with the usual suspension pick-up point re-inforcements...this will be just a hot street car. I'm very interested in any responses as well.

[Jeroen]

Cary Eisenlohr (from ERP) posted on the PP board a while ago that even a 911 (which has weeker front shock towers than a 914) doesn't need reinforcements to run coilovers

[nine14cats]

My car has been reinforced in the front with camber boxes and tubing.

Here is a pic of it.

Bill P.

[slivel]

I have run as high as 450 front and 350 rear but have been going softer over the last two seasons. This year I am trying stacked springs - a main and a tender. This gives a progressive rate and feels good on the tracks that I run. For linear rate springs I liked 350 front and 250 rear a lot for my setup. Car weighs 2050 minus driver. I have both front and rear sway bars but selectively hook up the rear bar at certain tracks.

Steve

[TimT]

Im running 450# front, and 350# rears. I found this combo works well on all except really rough tracks.

When I bought my car it had 600# all around (IMG:style_emoticons/default/screwy.gif) that was a bit much

[nine14cats]

Thanks for the info Tim. What I find interesting is how much different the coil overs spring rates are in comparison to T-bars and spring combo's.

On my previous 914-6 the equivalent front to back rates had the softer setup up front, similar to a 911. But I've heard from a couple of people including yourself that they have a heavier rate in the front. I wonder what the physics are behind that? The way T-bars transmit resistance versus a coil spring?

Thanks again!

Bill P.

[slivel]

Part of the answer is found in the motion ratio and wheel rate. The front on a coil over car is .83 and the rear is 1.86. So multiply those numbers times your spring rate to get an approximation of what rate the wheel is experiencing.

[byndbad914]

But I've heard from a couple of people including yourself that they have a heavier rate in the front. I wonder what the physics are behind that?
Bill P.

Bill, with my V8 car I had 300 fronts and 450 rears as a "starting point". I can tell you this much - I needed heavier rate fronts for sure. My car was 2305lbs without me in it and 59.5% rear weight distribution. With equal sized 9" wide tires all the way around it oversteered like no other car I have driven!! I maxed the Tarret sway bar in the front to stiffen it up and still had oversteer, but could throttle in understeer slightly.

Ergo the desire for a higher front spring rate for me with that combo. Slivel is correct about different length "advantages" f to r, but rates are dependant on a lot of factors. If you are running the same size tire front and rear, and have a 60% rear weight with an aluminum head 350 Chevy, I would guess a 400-500lb/in front rate with a 450 rear rate would be good to start with. Now I will have 1.5" wider rear tires than fronts, so I may not have to change the front spring rate much to tune out oversteer.

Spring rates will have to be tuned to your combo and what feels good to you, no other way around it and there is so much flex in a tub car anyway.... Some like a car with a little oversteer, others a little understeer. That can be tuned in with spring rates and and adjustable bar(s).

edit - I just realized your "beast" is a six... so somewhat irrelevant on the rears - maybe around 350-400 rears with 350-450 fronts.

[KenH]

Bill,

Stop by the RV Saturday or Sunday and we can discuss some Spring Rate ideas.

Ken

[nine14cats]

Hi Ken,

I will see you this weekend.

Thanks!

Bill P.