Good Guys Dual in the Desert- CSX3170

[Cobra #3170]

Originally Posted by Snake2998

Thanks for posting - I enjoy your notes re suspension set up - am always amazed that you find that even 1/4" difference in ride height makes a noticeable difference in handling. You have certainly taught me something. (I know that my driving skill level is way below being able to notice the impact of such changes - you have convinced me to concentrate more at increasing my sensitivity to what my car is doing on track days)

Keep posting with lots of detail.

Thank You,
We actually adjust ride height by as little as .1" and it will effect handling.
It shifts the roll axis which in turn shifts tire loading between the front and rear wheels. Once you are happy with spring and bar rates it becomes a fine tuning tool that can be used on the grid very quickly. We normally operate in a vary narrow range +/- .1 " but in this case we had to get a major shift to over steer so the big difference in ride height. I would rather do it with springs and keep my roll centers at optimum location but this worked well and did not hurt power down. We also found that a 3.73 rear end ratio with a Trac Loc differential was the best choice at Good Guys, We tried a 3.54 and a Torsen TR-2 Diff. but it did not like the amount of torque we put through it.
I would go back to the 3.31 for big tracks and use this set up for Good Guys only because a high ratio is actually slower than a low ratio that does not spin the tires so easily. We found that starting in second was faster than using 1st on the big american autox courses. We also ran a Salisbury diff but found that it under steered too much on tight corners. Robby Unser loves them but they don't seem to work well in a Cobra weight vehicle. We are discussing running the early March event in Scottsdale with this set up so we can develop it for the entire event then we will have something that works
on Friday morning in November 2016. Rival is changing their tire construction next year and Bridgestone is coming out with a 285x18 so some tire testing will be in order too. I don't know if I mentioned it but we are pulling over 1.45 G's now in corners on concrete we have gained .1 g every year
since 2014. We also get 1.2 G acceleration to about 60 mph and are still pulling .9 at 93 mph, all on concrete of course, with 200 TW tires.
We only got 1.31 at Scottsdale but not bad on asphalt.