'03 Cobra stock susp help?
 

Hey all. Name's Jake. I joined here a little while ago to poke around as I'm amazed at what some of you guys accomplish. I do not race a class so to speak but kinda sticking to the roots of the car (stock motor from 2003). Im having a little suspension issue that I thought I had figured out but its back to haunt me.

Specs on car

2003 Mustang Cobra
3250lbs w/ driver

stock style suspension
FRONT
Tokico 5 ways drag struts (full loose)
14" 150lb springs

REAR
UPR dbl adj uppers
UPR single adj lowers
Anti roll bar
Afco shocks
mustang v6 springs uncut

MOTOR
OEM Stock longblock
all accessories removed
put 520hp / 480tq to the tires on a dyno

TRANS
Frank Lupo C4
4800 stall

I shift at 6400 and cross the line at 6800.

Tire is a 28x10.5 stiff and i set them to 10.25psi in the staging lanes.

Here is the problem

I went and put in some afco's in the rear of my car to replace strange units I had in there to get a little more adjustability. I first set the afco's to what I felt the strange's were at but the car seemed worse. Then I set them to Afco's recommended starting points (15 extension / 6 compression) and it seemed a bit better but looking at the video I don't think its the shocks.

Hitting the tire too hard maybe? Seems to bounce on the tire.

here are my 4 launches from yesterday in real time and slow motion. which were 1.36-1.38. then at the end of the video isa pass 2 weeks ago with the strange shocks in the car, everything else the same and it cut a 1.35 and seems bit smoother on the launch.

http://www.youtube.com/watch?v=8aCtRQ3Ku4A

any help is appreciated.

Re: '03 Cobra stock susp help?
 

170 views and no replies??

Re: '03 Cobra stock susp help?
 

Note, Alot of folks were traveling to and from races this past week, someone that can put a finger on your problem will see it and answer. Just a fast look and I would say the car squats in the rear to much and needs stiffer setting but I am not a mustang person so wait for one to answer.

Re: '03 Cobra stock susp help?
 

I thought the same thing Bob. To me it looks like the shocks may be bottoming out on launch.

Re: '03 Cobra stock susp help?
 

Looks like you have the rear tires to low on pressure. Looks to me that thats what is causing the car to bounce. Tighten the front shocks a bit so the fron t end does not hit the stops so hard. Looks like you have some bump steer going on or you are turning the wheel when you leave. Nice looking ride and the leave is really not bad

Re: '03 Cobra stock susp help?
 

thanks Bob

Re: '03 Cobra stock susp help?
 

the tire is my amateur thought also but it seems to like that pressure. I guess I will try adding 0.25psi each pass and see when it spins or the 60 falls way off.

its bump steer...fox stuff on an sn95 car.

Re: '03 Cobra stock susp help?
 

I think the suggestions here are reasonable. I would ad you should forward the video to AFCO and see if they have any input.