Spring Chart for 2005+ Mustangs?
Thread Starter
1st Gear Member
Joined: Sep 2008
Posts: 60
From: Arizona
Thanks, Norm. I went to a local PCA Autox yesterday (as a guest) and got to try the new setup out. I started at my previous 39f/37r and ended up at 40/38 by the end of the day. I set the front Konis at +1 1/2 and the rears at +1 (from full soft). The front Steeda bar is set in the middle.
Perfectly neutral. I overcooked the entry to one fast sweeper (PCA likes more open courses than SCCA) and the rear came out......and by applying gas I was able to pull a "Dukes of Hazzard" drift. Not fast, but controllable. The car turns in very well now, much better "feel" and feedback, less "float".
I like these springs. They dropped the car evenly (about 1"), so the rear is still a little higher than the front. I was hoping for level.....do you think I could cut a half-coil off the rear to accomplish that since the bottom coils installed pretty much touch anyway? My thinking is that a level car would improve the weight balance and thus the handling.
I ran with Porsche Club once before on my stock springs, and I was measurably closer to the top PCA cars with these springs, and this was a much faster course. Yahoo!
More reports later.
Scott
Perfectly neutral. I overcooked the entry to one fast sweeper (PCA likes more open courses than SCCA) and the rear came out......and by applying gas I was able to pull a "Dukes of Hazzard" drift. Not fast, but controllable. The car turns in very well now, much better "feel" and feedback, less "float".
I like these springs. They dropped the car evenly (about 1"), so the rear is still a little higher than the front. I was hoping for level.....do you think I could cut a half-coil off the rear to accomplish that since the bottom coils installed pretty much touch anyway? My thinking is that a level car would improve the weight balance and thus the handling.
I ran with Porsche Club once before on my stock springs, and I was measurably closer to the top PCA cars with these springs, and this was a much faster course. Yahoo!
More reports later.
Scott
I'd start with what you're already used to. Otherwise you're probably adding at least one "iteration" to the process that may not be helpful to you individually. I think there is general agreement that there should be slightly lower rear tire pressure anyway. Lower rear tire pressure (to a point) tends to dial a little of the understeer out and probably helps rear mechanical grip (which lets you use a little more throttle a little sooner and isn't quite as sensitive to bumpy corners).
I think Sam runs about 4 psi more in the front than in the back in the F-Stock Shelby, which is sprung a little stiffer than the "normal" GT, although I don't remember what his exact numbers are. A search might turn them up.
Theoretically, I would guess that stiffer springs and possibly stiffer sta-bars might call for slightly less pressure, given that most venues are not dead flat and perfectly smooth. That sort of assumes that you're starting with a car that had already been optimized for that particular track, driver, and other things like weather conditions for the softer springs/bars.
Norm
I think Sam runs about 4 psi more in the front than in the back in the F-Stock Shelby, which is sprung a little stiffer than the "normal" GT, although I don't remember what his exact numbers are. A search might turn them up.
Theoretically, I would guess that stiffer springs and possibly stiffer sta-bars might call for slightly less pressure, given that most venues are not dead flat and perfectly smooth. That sort of assumes that you're starting with a car that had already been optimized for that particular track, driver, and other things like weather conditions for the softer springs/bars.
Norm
Last edited by azrampage; Apr 19, 2009 at 11:00 AM. Reason: Added Signature
6th Gear Member
Joined: Feb 2007
Posts: 7,635
From: state of confusion
Lowering the rear will not shift anywhere near enough weight distribution to ever notice. If your weight distribution is now 53/47, it might change all the way to 52.9994/47.0006 if you lowered the rear another half inch. Seriously (I ran the math).
But your rear roll center would drop, which if anything would introduce a little "push". Whether that's good or bad "depends".
What you have done is increase the car's frequency in roll, which generally gets the car to take its "set" a little quicker. And slightly reduced the total amount of lateral load transfer, which has probably bought you a little more grip.
Norm
But your rear roll center would drop, which if anything would introduce a little "push". Whether that's good or bad "depends".
What you have done is increase the car's frequency in roll, which generally gets the car to take its "set" a little quicker. And slightly reduced the total amount of lateral load transfer, which has probably bought you a little more grip.
Norm
Last edited by Norm Peterson; Apr 19, 2009 at 12:07 PM. Reason: added the math results
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