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View Full Version : GRT Swing arm mod i need some advice



Racnj22
01-13-2011, 04:02 PM
Hey everybody i just picked up a 03grt swing arm mod and nd some advice on a starting point on what to try as far as setups weights shocks and so forth just to get me rolling any knowledge would be appreciated thank you for your time teddy652001@yahoo is my email thanks again

dirttrackrocker
01-13-2011, 07:12 PM
This is what GRT recommends.. I personally think the front springs are a little heavy, but, thats me....


SWING ARM OR 3-LINK SUSPENSION

RIDE HEIGHTS: ( Wide Metric Suspension ) From ground to bottom of frame
LF: 5-1/2"
RF: 6"
RR: 3 to 3-1/2" between axle tube and right rear lower frame

FRONT SUSPENSION: ( All reference points measured same as standard suspension )
Springs:
LF: 900 lb. RF: 1000 lb. LR: 300 lb. RR: 275 lb.

Shocks:
LF: 75 RF: 75 LR: 94 RR: 94

90/10 over rear end mounted as far right as possible 10-12 degrees angle up front of car

FRONT WHEEL ALIGNMENT SETTINGS:
Caster: LF: 1-1/2+2+ RF: 3+4+
Camber: LF: 1-1/2+ RF: 3-

REAR SUSPENSION SETTINGS:
Bar lengths from center to center are as follows:
Left upper 30"
Right Upper 30"
Left Lower 15"
Right Lower 15"

Lower bars should be in the second or third hole up
NOTE: Raising bars usually promotes forward bite.

TORQUE LINK:
39-1/2" center to center
1/4" preload on 850 lb. - 900 lb. spring

J-BAR:
Length 18-3/4" center to center
7" from bottom of frame rail to center of hole on frame mount
Third hole on the rear end
NOTE: Raise J-Bar on frame for more side bite


( Optional ) Straight panard bar
Length 30" center to center
2-3" higher on frame
NOTE:
8 degrees pinion angle
Watch body roll 2-1/2 to 3" on RR 1-3/4 to 2" on RF
More left rear to correct loose condition coming off turns
When car is loose on entry, not enough right rear or not enough body roll

PERCENTAGES:
52% to 53% left side
56% to 58% rear
Keep cross between 48% to 50%

COMMON SET-UP PROBLEMS:
Car Tight: Soften front and stiffen the rear
Car Loose: Stiffen front and soften the rear
NOTE: LR clamp bracket usually corrects a loose condition and requires a 25 lb. stiffer spring.
Shock rates are important in tuning a car and softer shocks will improve lap times on smooth slick tracks.
Lap times improved by keeping the car straight and using a smooth throttle application
**All these set-ups can only be justified with proper maintenance and checking all suspension components on a regular basis.

texas racer
01-14-2011, 10:07 PM
go with a 900 lf 800 rf