Whiteline and koni adjustable setup

[Reddog]

I have a full Whiteline adjustable suspension setup with adjustable koni yellows, Roush 1 inch drop springs, and adjustable UCA/LCA/end links. I have the front and rear sway bars and koni's set at medium stiffness at the moment. Should I set a stiffer setting in the front and softer in the rear (4 position settings available)? Also, should the Koni's be set to full hard setting for track use? I am still using the P-Zeros at the moment. Thanks for any advise for getting the most out of my GT track pack.

 

[k98dave]

I'm using Ford racing P springs, rear lower control arms and relocation brackets and adj panhard bar, but still on stock sway bars. I would suggest stiffen up the front bar and leave the rear where is is, or leave front as is and set rear to softest. I have the stock shocks/struts set 5 F 4 R. Your going to try the different settings on the bars to see what feels best.

I still have P zeros for street use (not a daily driver) For track days I went down to 18"wheels & Dot R tires.

 

[F.D. Sako]

It would be tough to recommend a setup without having some feed back on how the car handles on track with your current settings (e.g. over/under steer).

What are your tires sizes, front and rear?

 

[Grant 302]

I wouldn't use the Konis at full stiff with relatively low spring rates. My understanding is that backing off even a little from full makes a difference.

Anyway, I see this as a common issue with getting more adjustability than one knows how to adjust. Honestly, got into that myself when I upgraded to the DA/JRi coilovers. The learning curve for tuning was very steep at first.

Before you change anything, can you describe how the car feels compared to stock to you?

On the stock 255 P Zeros, I'd try running full soft first and adjusting up from there.

 

[kcbrown]

I have a full Whiteline adjustable suspension setup with adjustable koni yellows, Roush 1 inch drop springs, and adjustable UCA/LCA/end links. I have the front and rear sway bars and koni's set at medium stiffness at the moment. Should I set a stiffer setting in the front and softer in the rear (4 position settings available)? Also, should the Koni's be set to full hard setting for track use? I am still using the P-Zeros at the moment. Thanks for any advise for getting the most out of my GT track pack.

A good target for the rebound setting on the Konis is 65-75% of the critical damping value, which is dependent upon your spring rates.

Up front, setting the rebound to maximum would get you 65% critical damping for a spring rate of 415 lb/in. I very much doubt the Roush springs you have are that stiff. As such, I would avoid going full stiff in the front.

Similarly, the rear at full rebound damping will hit 65% critical damping for the crazy spring rate of 1400 lb/in. But that's because the rebound increases dramatically in the last turn of the knob, compared with the rate increase you get below that.

Most lowering kits put the rear rates at around 200 lb/in or so. A good setting to use for that would be 3/4 turn from full soft, which would get you 75% critical damping for a 250 lb/in spring. Up front, for a 250 lb/in spring, a setting of 1 1/2 turns will get you 68% critical, while 1 3/4 turns will get you 78% critical. 1 5/8 turns should thus get you about the right amount of rebound damping. But, of course, that assumes a 250 lb/in spring up front, which may or may not be what you've got.

If you want to see the raw numbers I'm using, plus the formulas you can use to compute these things, you can see my message on the subject at s197forum.com here: http://www.s197forum.com/forum/showpost.php?p=2139662&postcount=76. I'll be happy to copy that message to this thread if that would be convenient for people.

 

[Grant 302]

[quote author=kcbrown]
There's probably enough variability in the actual rates you'd get from your shocks that these settings would be ballpark anyway, but it should be clear that getting sufficient damping to properly control the rebound doesn't take much adjustment above full soft in the general case for these performance springs.
[/quote]

Great data and info in your linked post. My understanding is that the yellow rates on full soft are comparable to Koni 'Orange' non-adjustable units and that full soft is a 'safe' place to start when adjusting yellows.

 

[Reddog]

Thanks for all of the info. I'll try a setup with a little more stiffness in the front and reduce stiffness some in the rear for the Koni's and see how it feels. Do you recommend the same plan with the front and rear sway bars. I've read that the rear doesn't need as much sway bar. I have been set to mid stiffness at the HPDE events and it feels much better than stock but I still have a little over steer (probably caused by my mediocre driving skills, 5.0 power, and pinching off the turns!). Thanks again

 

[Grant 302]

I'd have the tendency to try the next softer bar setting in the back, but I don't recall the rates of the Whiteline bar.

I know you said 'full' suspension, but do you have the brackets too? Whiteline's single adjustment point may be too low for a 1" drop in the rear. That could also be compromising your grip a little with too much roll-oversteer. I like a little...too much makes the rear less predictable and can be prone to brake-hop.

 

[Reddog]

Ive got the BMR LCR relocation brackets set in the middle to compensate for the 1.4 inch drop in the back. Also adjusted pinion angle with adjustable upper control arm.