Silver'nStripes
Member
So, I installed adjustable valve shocks in my 2006 GT and I'm looking for some tuning advice. I took the car to the track and made a few adjustments, but I'm not sure I'm on the right track. My 60 ft. time improved some, though I think more due to tire pressure adjustments, and it's still slower than with the stock shocks, though I've eliminated some nasty wheel hop.
Here's my setup:
Engine:
4.6L V8 with 5.0L stroker kit
2.8L Kenne Bell Mammoth, 13 psi boost
540 rwhp, 500 rwtq
Shocks and Springs:
2013 Cobra Jet Drag Spring Kit front and rear
Strange single adjustable shocks in the front
Viking double adjustable shocks in the rear, AJ valving
Rear Suspension:
Adjustable Lower Control Arms
BMR Lower Control Arm Drop Brackets (bottom hole)
BMR Adjustable Upper Control Arm w adjustable mount (bottom hole)
Tires:
Mickey Thompson ET Street
26x10.5-15
Run 1:
2.152 60 ft
Shock Settings:
Front - 2
Rear Rebound - 6
Rear Compression - 10
Tire Pressure - 20 psi
Launch RPM - 2500
The car spun pretty immediately. It looked to me like the front didn't came up very much, so I softened the front extension. The rear also seemed to drop and then come back up, so I increased the rear compression.
Run 2 spun really badly, so I dropped the tire pressure and went again.
Run 3:
1.902 60 ft
Shock Settings:
Front - 0 (Lowered from 2 on the first run)
Rear Rebound - 6
Rear Compression - 12 (raised from 10 the first run)
Tire Pressure - 15 psi (lowered 5 psi)
Launch RPM - 2500
The launch felt a lot better, it still spun. A little bit at first, and then a lot by the time I got to the top of first gear. Decided to stiffen the rear shocks some more since that seemed to help.
Run 4:
1.902 60 ft
Shock Settings:
Front - 0
Rear Rebound - 8 (raised from 6 on the previous run)
Rear Compression - 14 (raised from 12 on the previous run)
Tire Pressure - 15 psi
Launch RPM - 2500
Pretty much the same results as the previous run. The best way I can describe it is it spun a little bit off of the line, and then progressively more throughout first gear, until I feel like I need to pedal it near the top of first gear.
Overall, I'm not sure if my shock adjustments made that much of a difference. It seems the tire pressure made the biggest change in 60 ft. time. The car attitude seemed to improve, but the 60 ft time didn't follow. Perhaps there was too much tire spin for it to really make a difference? I'm also not sure if the front is coming up too quickly on the 0 setting.
I'm also aware that I'm running a lot of anti-squat with the upper and lower control arm brackets in the rear. Could this be problematic? I'm also pretty sure that a taller and wider rear tire is in my future, probably 28 inches.
Thanks for the long read, I really appreciate any insight! Even if you think I"m on the right track tuning-wise and I just need to keep after it that would be great to know.
Here's my setup:
Engine:
4.6L V8 with 5.0L stroker kit
2.8L Kenne Bell Mammoth, 13 psi boost
540 rwhp, 500 rwtq
Shocks and Springs:
2013 Cobra Jet Drag Spring Kit front and rear
Strange single adjustable shocks in the front
Viking double adjustable shocks in the rear, AJ valving
Rear Suspension:
Adjustable Lower Control Arms
BMR Lower Control Arm Drop Brackets (bottom hole)
BMR Adjustable Upper Control Arm w adjustable mount (bottom hole)
Tires:
Mickey Thompson ET Street
26x10.5-15
Run 1:
Shock Settings:
Front - 2
Rear Rebound - 6
Rear Compression - 10
Tire Pressure - 20 psi
Launch RPM - 2500
The car spun pretty immediately. It looked to me like the front didn't came up very much, so I softened the front extension. The rear also seemed to drop and then come back up, so I increased the rear compression.
Run 2 spun really badly, so I dropped the tire pressure and went again.
Run 3:
Shock Settings:
Front - 0 (Lowered from 2 on the first run)
Rear Rebound - 6
Rear Compression - 12 (raised from 10 the first run)
Tire Pressure - 15 psi (lowered 5 psi)
Launch RPM - 2500
The launch felt a lot better, it still spun. A little bit at first, and then a lot by the time I got to the top of first gear. Decided to stiffen the rear shocks some more since that seemed to help.
Run 4:
Shock Settings:
Front - 0
Rear Rebound - 8 (raised from 6 on the previous run)
Rear Compression - 14 (raised from 12 on the previous run)
Tire Pressure - 15 psi
Launch RPM - 2500
Pretty much the same results as the previous run. The best way I can describe it is it spun a little bit off of the line, and then progressively more throughout first gear, until I feel like I need to pedal it near the top of first gear.
Overall, I'm not sure if my shock adjustments made that much of a difference. It seems the tire pressure made the biggest change in 60 ft. time. The car attitude seemed to improve, but the 60 ft time didn't follow. Perhaps there was too much tire spin for it to really make a difference? I'm also not sure if the front is coming up too quickly on the 0 setting.
I'm also aware that I'm running a lot of anti-squat with the upper and lower control arm brackets in the rear. Could this be problematic? I'm also pretty sure that a taller and wider rear tire is in my future, probably 28 inches.
Thanks for the long read, I really appreciate any insight! Even if you think I"m on the right track tuning-wise and I just need to keep after it that would be great to know.