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View Full Version : airride tuning advice--based on what you see here, does my analysis make sense?



formula
10-18-2010, 09:58 AM
Alright guys, I finally have a vid of my car running at RTTH from the outside (many thanks to leadSSled for the vid), and I am still learning how to get the most out of my current setup, but I'm hoping wiser eyes can help me go from here.

So here's the vid....I'm not at 10/10ths here because it was my girlfriend's first ride in the car and she was freaking out on me, but there's still enough that I think some good analysis can be made.


http://s105.photobucket.com/albums/m206/LeadSSled/RTTH6%20AutoX/?action=view&current=AutoXCar72.mp4

and here's what I notice immediately:

--the front looks to be having trouble transitioning from turn to turn and recovering after a turn--there's a little extra bouncy-bounce after each major front suspension event.
--there's a lot of body roll in the back (so much so that both tires were scrubbing, hence the ridiculous jacked up stance to keep the fenders off the tires).
--The back is sticking all day long and the front is pushing.

Setup: ridetech shockwaves with their newest shocks (master series double adjustable), but the non-remote reservoir ones. SPC ucas. Ridetech lcas. ridetech airbar rear, prodigy bar brackets, air ride front swaybar, no rear swaybar.

alignment: -.75* camber, 5* caster, 1/32 toe per side

shock settings: front 95 psi, rear 85 psi (110 in this vid, but normal setting is 85), I lost my actual setting log on the shocks (will check my backup files tonight and hope it's there) but the fronts are at 3/4 to 5/6 of max compression, 1/2 to 3/4 of max rebound and the rears are at near-max to max compression, around 3/4 rebound (compensating for rear roll)

Based on what I'm seeing:

--a rear bar would help with rear control, allowing me to stop overcompensating with too much spring and shock in the rear.
--more camber would help with the understeer
--I need a little bit more rebound on the front? This one I'm least confident about. More compression and spring too? Or even more bar?

Does this sound right to you guys? What else do you see?

bret
10-18-2010, 03:26 PM
I think you are mostly on the right track. Here is the items I would look at:
1. more front rebound seems reasonable...the car looks like its bouncing a bit in front.
2. I usually run about 1.5 neg camber for autocross stuff. It seems to be the best compromise between performance and tire life. Even then I sometimes air it down a little to increase the camber. At that point it is a matter of what makes the car faster for a given track surface and driver.
3. I usually start increasing the rear compression until the car starts to oversteer. IF I get to a point where I am maxed out on compression and the car still pushes, then start thinking about a rear swaybar. In my experience that car doesn't really need one unless you tub it to get a much larger rear tire on it. Right now I think you maight be band-aiding a tire clearance issue with ride height, at the expense of overall performance. You might actually have better luck with a smaller rear tire that had no clearance issues. You might be topping out the rear shocks which would upset the car rather suddenly [and probably right at mid turn].

Tough to tune from the cheap seats but I think you are close to the right path.

formula
10-19-2010, 09:52 AM
Thanks alot for the advice and confirmation Bret! I should have added that I'm already minitubbed with 325s...so maybe time for a swaybar after all, but I'll work on getting the tire clearance sorted first before I decide.