shiners780

For those using coilovers (without torsion bars), what spring rates are you using front/rear? Please specify your car's weight (wet, w/ driver).

I need to bump up my rear spring rate but I'm not yet sure how far to go. I am curious what others are using and how the car feels.

Here's some pics from today and yesterday at Watkins Glen as eye candy. Seven hours of open track each day, no run groups, open passing...I'm exhausted. Got a personal best lap time, on brand new full tread RA1's no less...go figure? They felt a lot better out of the box than past sets I've used.

Anyway, responses about spring rates would be greatly appreciated.

Ski

750# in the front - going to 900#, 650# in the rear going to 800# during our rebuild, well we're talking about it. 2550# 1/2 tank of 104, and each driver 215.

333pg333

Nice pic's there Shiners. What was it like with the speed differential out there? I've been out in similar circumstances and the GT3 Cup cars just seem to appear from no-where and just as quickly disappear.

95ONE

[QUOTE=Ski]750# in the front - going to 900#, 650# in the rear going to 800# during our rebuild, well we're talking about it. 2550# 1/2 tank of 104, and each driver 215.
QUOTE]

Seriously large numbers. up from Seriously large numbers!

what is "swaying" your decision to go up in spring rate? and did you reinforce the rear upper shock mount? neccessary?

shiners780

Bret, what tire widths are you running, if you don't mind my asking?

333pg333, no problems with the speed differential. This is a great group of experienced guys that play real well together. As long as everyone maintains their track awareness and predictability, speed differential is a non-issue. But yeah, some of those guys were closing in on me at 40+ mph. I took lots of in-car video. Once edited, I'll post some up.

Anyone else care to share their spring rate secrets?

ehall

650# FRONT 550# REAR driver 210 no idea car weight, but very close to stock w a/c.

Ski

255/40/17 F and 275/40/17 rear.

Getting a bit faster with the car and it does seem to roll a bit harder now but we're just talking about it, we haven't done it yet. No reinforcing yet, neither one of us are big riders of curbing at the track and so far so good. After the fire, it's getting a good going over. Charlie arms are on with all new Racers Edge shperical bushings and castor blocks.

Kevin M

Shiners,
600 front 700 rear, 2375lbs wet, driver adds 205 lbs. to that, 285/30/18 F and 315/30/18 R

Kevin

Skip Wolfe

Front: 550
Rear: 750
Weight with driver: 2700 lbs.
Bilstein Escort Cups/Tarrett Sways/all sphericals. Jason at Paragon advised a 100 - 150# differential between front and rear.

Also check out this thread:
https://rennlist.com/forums/racing-and-drivers-education-forum/345391-so-is-inside-front-wheel-lift-inherent-to-the-944-968-chassis.html

Skip Wolfe

Hey Bret,

Curious as to why your going with higher rate in the front that in the rear. Conventional wisdom seems to be to go higher in the rear based on the lower spring rate to wheel rate ratio that the front. I know Cervelli was/is a big fan of going with very high spring rates to reduce/eliminate the transition period in a turn. I believe he was running 1000+# spring up front but not sure what he was running in the rear.

333pg333

Yes there seems to be varying opinions of front to back #rates. I think it also must come down to the shocks and the valving?
PS Are there no Americans under 200lbs? What's in the water over there?? Meat must be cheap huh?

reno808

Link is no good

DDP

Hoosier Daddy?

What I have heard as far as effective rates at the wheel on the 944 chassis, due to the different mounting points, is the fronts register 90% of their rate the rears are 56%.

With that in mind I chose 400lb springs up front 90% of that is 360lbs
and 550lb springs in the rear 56% of which is 310lbs,
Bilsteins, full spherical bearing, 225/40-18 & 285/30-18.
That's in my street car so it's full weight plus me @ 240lbs (not just another big American, I'm a Texan, ha ha).

My track car is in pieces so, not sure what will go in it yet. I love my car on the street. It's very predictable with the current set up. Nice to see what everyone else is running.

pete95zhn

Please keep in mind that a stock '89 951 has WHEEL rates of F 144lb/in & R 175lb/in and it's an understeering pig. a 968CS w/ M030 has WHEEL rates of F 144lb/in & R 253lb/in ( approx ) and it's claimed to be very good.
So, from that one could think that if you have front springs rated 300lb/in at wheel then you should have 500lb/in wheel rated springs at rear.