SportMod Adjustment Guide

Problem/Adjustment

Tight on Entry Loose on Entry Tight in Middle Loose in Middle Tight on Exit Loose on Exit
LF Spring Soften Stiffen
-
-
-
-
RF Spring Stiffen Soften
-
-
Soften Stiffen
LR Spring Stiffen Soften
-
-
Soften Stiffen
RR Spring Soften Stiffen
-
-
Stiffen Soften
LF Shock Less Comp. More Comp. More Rebound Less Rebound More Rebound Less Rebound
RF Shock More Comp. Less Comp. More Comp. Less Comp. More Rebound. Less Rebound.
LR Shock More Rebound. Less Rebound More Rebound Less Rebound More Comp. Less Comp.
RR Shock More Comp. Less Comp. More Comp. More Rebound More Comp. Less Comp.
Ballast Height Lower Raise Lower Raise Lower Raise
Left Side % Increase Decrease Increase Decrease Decrease Increase
Rear % Decrease Increase Increase Decrease Decrease Increase
Cross Weight/Wedge Increase Decrease Decrease Increase Decrease Increase
Air Pressure

Increase RR

Decrease RR
Increase RR
Decrease RR
Increase RR
Decrease RR

Notes:

1. Keep in mind when making an adjustment that almost any change is a compromise.

2. Make changes in one area at a time to understand the results.

GM Stock Mount QA1 Shocks  Shocks Tacky/Rough Track
FC1948P 8/8 valving (Heavy)             Front  LF - 40/40     RF - 45/55 Setup 1
FC1947-3P 7/3 valving (Easy-up)       Front  LR - 40/40     RR - 40/40
FC1684P  4 valving (light)                   Rear LF - 40/40     RF - 30/50 Setup 2
FC1685P  5 valving (Med)                  Rear LR - 50/30     RR - 40/40
FC1683-5P 3/5 valving (Lock-Down) Rear Shocks Tacky/Slick Track
  LF - 30/40     RF - 30/50
GM Stock Mount Bilstein Shocks     position LR - 30/50     RR - 40/40
AK1043 358# / 219# Linear             Front Shocks Dry Slick Track
AK3050F 131# / 206# digressive      Front LF - 30/50     RF - 50/30
AK3060F 110# / 233# digressive      Front LR - 20/80     RR - 50/30
AK4040F 197# / 154# digressive      Front  
AK5555F 245# / 190# digressive      Front  
AK6565F 325# / 220# digressive      Front  
AK1051   393# / 172# digressive      Front  
   
AK1044   254# / 141#  Linear          Rear  
AK2020R 70# / 70# digressive         Rear  
AK2040COBR 70# / 140# digressive Rear  
AK3030R 158# / 117# digressive      Rear  
AK5030R 300# / 120# digressive      Rear  
AK6010COBR 185# / 70# digressive Rear  
AK1052  324# / 112# digressive        Rear  
   
GM Stock Mount Afco Shocks GM Stock Mount PRO Shocks
AFC1022 7/4 valving Easy-up 80/20 Front SS100 Front
AFC1021 6/6 valving Heavy              Front SS201 rear
AFC1020 7/7 valving Extra Heavy     Front  
AFC1035 3/5 valving Lock-Down 40/60 Rear  
AFC1030 5/5 valving Med 50/50 Rear  
AFC1031 6/6 valving Heavy 50/50 Rear  
   

1. The shock package should be softer overall when racing on dirt and when the track is flatter when on asphalt.
2. Get your basic setup close to being balanced before trying to tune with shocks. Shocks cannot solve basic handling balance problems.
3. Higher-banked tracks require a higher overall rate of shock as opposed to flat tracks. This is because of the higher speeds and the extreme amount of downforce.
4. Shocks that are mounted farther from the ball joint should be stiffer than if they were mounted close to the ball joint. With each inch of travel of the wheel, the shock mounted farther away will move at a lesser speed, meaning less resistance to both rebound and compression.
5. Tune entry performance first. If there are no entry problems, make small changes if you want to experiment to see if entry can be improved. Entry problems include a tight car or a loose car. The worst problem, by far, would be the loose-in condition. Nine times out of 10 this is an alignment problem and not shock related.
6. Tune exit performance last. If there are no exit problems, don't make any significant changes. Exit problems can include a car that pushes under acceleration or one that goes loose under power. Be sure that you do not have a tight /loose condition where the car is basically tight and goes loose just past mid-turn.
7. On dirt tracks, reduce rebound settings on the left side and decrease the compression rates on the right side for dry, slick surfaces to promote more chassis movement. This helps to maintain grip as the car goes through the transitional phases of entry and exit.
8. On asphalt tracks, once the car has been tuned with shocks for optimum entry and exit performance, increase the overall rebound rates a small step at a time, especially on the left side, to possibly increase overall performance. This is especially good for low- to medium-banked race tracks. For highly- banked tracks, the added rebound is not necessary or advisable.

SPORTMOD CHASSIS BASELINE (DIRT) 

RIDE HEIGHTS (GM Chassis)

RIGHT FRONT: 5.00"

LEFT FRONT: 5.75"

REAR: 6.25"

SPRINGS (Heavy / Dry Track)

LF:650# / 600# RF:700# / 650#

LR:225# / 200# RR:200# / 175#

Weight 

(50-100 lbs Left Rear Weight)

LEFT SIDE: 52.5%

REAR: 56-58%

CROSS: 49-50%

BASED ON 20 GALLONS OF FUEL AND NO DRIVER

FRONT END ALIGNMENT (Tie Rod Spacers 1.5")

CASTER:

LF:+2

RF:+4

TOE: 1/4 TO 3/8 OUT

CAMBER:

LF:+1.5

RF:-2.5

WHEEL OFF-SETS

LF: 3" RF: 2-3"

LR: 3" RR: 3-4"

(INCREASE RR TO 4" OFF-SET ON EXTREMELY SMOOTH AND/OR DRY-SLICK TRACKS)

TIRE PRESSURES

LF: 8# RF: 14#

LR: 8# RR: 10-12#

1"-2" Stagger in tire size

Updated Jan. 2011