I got a car tuning question guys. The car seems to work and feels good on sealed asphalt but I ran on a gripper surface on saturday and the car was very loose on corner exit! I took two clicks of front rebound out and it made the car much better but still not "perfect." I'm about out of adjustment on front rebound so I don't really have much more I can take out. What else could I do to help with calming the car down on corner exit without effecting the handling during other phases of a corner?

I can post video comparison if needed...

 

Car settings currently.... (Stock Diff car)

Ride height is pretty much even all the way around, it was corner balanced to be 50/50

Front-
springs 900 lbs
rebound 3/14
HS compression 9/14
LS compression 5/6
Solid Gendron Bar 6/6
-3.1 camber
0 toe
6.5 caster

Rear
springs 800 lbs
rebound 9/14
HS compression 9/14
LS compession 3/6
Gendron .095 bar 3/5
-2.7 camber
.28 degrees toe per side (.25" total is what that works out to in inches)

 

Without driving the car or seeing video, I would ask what is your rationale behind lowering front rebound? I would not try that.

If the car went to a grippy surface, it will roll more compared to your previous lot. With a stock torsen diff, it sounds like you could now be getting the rear inside wheel light mid corner, causing the diff to open a bit, and creating a loose/twitch condition at exit. I adjust for this in my BS car both on Hoosiers and Street Tires depending on surface. If if it's the diff opening up that is causing your problems, there are many things you could do to help keep that inside wheel loaded. What I would try (in order):

- Take some rear rebound out
- Add a little rear LS compression
- Add front rebound
- Go down a click on the rear bar

 

Agreed. Remember this dumb rule "c before r" meaning compression before rebound because compression has the biggest affect on entry, rebound on exit.

 

The thought process of my change was decreasing front rebound allows the car to transfer weight faster to the rear tires during on throttle corner exit. It's worked well in the past to solve corner exit oversteer. :/ whats the logic/thought process between taking out rear rebound?

My understanding is decressing the rebound (turning the knob towards negative side) increases the rate of the shock bouncing back. Increasing the clicks of rebound slows the rate at which the shock bounces back. Right?

I'll put together a quick video to compare...


The problem is the car is loose during exit. So are you suggesting a rebound change?

 

Heres the video comparison... First event in the video, I took 6th pax behind a bunch of guys that run nationals, second event I got second in PAX behind a CMod.

https://vimeo.com/66529664

I wish we had a good write up that states "this changes does this, and this change does that" I have a sheet like that wrote out that I got from another member but your disagreeing with the change he suggested on my sheet for corner exit oversteer. lol

 

yes, that's why i said "agreed". I could have said "+1", or "I'm with this guy" or "That Nick Barbato guy, he's f@#king smart" or maybe "CR HAZ TOOO MUCH POWER, PUT BLOCKS UNDER THROTTLE"

but yeah. it's in the rebound. Don't get me wrong, these are gross generalizations which may or may not be applicable if you have something else binding in your setup, but the nice thing about having too much compression is that it lets you know early in the corner. So if you're blowing it earlier than you think, than you might also just be overloading the tire too quickly.

Also, if the rear is already fairly soft on compression, and you end up removing rebound to settle the rear, you could try adding a little compression back in to keep the back end calm by giving you more feel feed back during all phases of the corner. If your shock has good blow-off/bypass characteristics and the low-speed/high-speed transition is smooth, then I would do this anyway, and run as little rebound as you can tolerate. You want to keep the tire on the ground. However, this will require much slower hands and inputs, but should be faster.

I think your car is over sprung also. It probably didn't feel like it on RS3s, but it probably is in general.

 

I agree, may be alittle over sprung, I should of gone 800/700.


Stupid question, sorry, but how will removing rebound, causing the rear shock to bounce back faster increase rear grip? Wouldn't it decrease weight transfer to the rear wheels?

Just trying to understand. I'm slightly confused...

 

You could also remove rear comp to allow the rear to squat a bit, similar effect to rebound but I think it's more effective.

If you are noticing loss of grip immediately after throttle application then definitely compression.

If the rear is starting to loosen on entry and gets worse by throttle application point then you can increase front comp and possibly rear rebound.

 

This is why I'm confused, conflicting info from three people...

Nick
mLeach
Mac
you all said to take some rear rebound out then Mac came in and said to add rear rebound. ugh. Then Nick said to add rear compression and Mac said to decrease it. Conflicting again. Why does this have to be so confusing!

BTW my video is onine now, so you all can watch it