Racing Services -> Precision
Chassis Alignment
- Precision Chassis Alignment
- Getting the best handling from your car means not only aligning it correctly but understanding all the interactions within the suspension system and adjusting them accordingly in relation to the car and in relation to the type of driving that is done with the car. It all starts with caster, camber and toe but goes on to take into consideration aspects like how much the toe or camber changes when the suspension goes through its travel. Does the suspension cross the line between toe-in and toe-out during its travel and how much weight is actually carried by each tire.
- Know Your Suspension
- Once you know what your suspension is doing you can then make intelligent
decisions on how to optimize your grip. Let's get started.
The procedure may be as simple as adjusting camber and caster then toe, ride height and setting corner weights. But in the real world each adjustment effects another so the procedure can be better described as slowly adjusting everything a few times and thus bringing all the settings eventually to optimal.
- On The Straight and Level
- First you need to establish a level and friction free platform to begin your adjustments. This is the easiest way to achieve repeatable results. If, after road testing, you feel the handling would benefit by a little more negative camber you have a baseline to go back to and start your tuning adjustments.
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The following photos show scale pads and levelers being placed in front of each wheel. (Click on the images below to view larger images.) -
- Next we set up and level the laser transit. This will assure all the scale pads are level and indicated weights are true. Each pad is leveled in relation to plumb and all the other pads. (Click on the images below to view larger images.)
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- We now have a level platform on which to work. Next we slide expandable bridges between the scale pads and outward from them front and back. Since this is the first time for a total suspension analysis on this vehicle we also place turnplates on the scale pads and raise the bridges accordingly. (Click on the images below to view larger images.)
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- Next we'll lower the car onto the bridges, zero the scales and slowly roll the car onto the scale pads. Once we remove the turnplate pins we now have a level and frictionless platform on which to do our work. (Click on the images below to view larger images.)
- Now we start to gather the suspension data. Camber and caster on all four wheels, toe on both front and back wheels, corner weights and ride height. If any adjustment is far adrift we correct it now to bring it closer to optimal. Here we're checking camber and caster and toe. (Click on the images below to view larger images.)
- Next we record the corner weights and check ride height. (Click on the image below to view larger images.)
- Statics and Dynamics
- We now have the static data on how the suspension is currently set up. Our next step is to evaluate the suspension as it moves from full droop to full bump on both the front and rear suspension. For this we will need to roll the car off the scales and jack up one front and one rear tire in succession and remove the road spring. Then we attach the laser bump steer equipment, jack the wheel through its travel and record the changes in toe and camber. We now know the bump steer and bump camber change characteristics of the vehicle. (Click on the images below to view larger images.)
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- Evaluation - What We Have and What We'd Like
- GT40 Present Alignment Specs
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Wheelbase -
Wheel track (fr) (ctr) - 57.5"
Wheel track (re) (ctr) - 59"
Tire Pressures (lbs) -
Front - 24
Rear - 28Weight (no dr.) - 2506 lbs.
LF - 496 lbs.
RF - 547 lbs.
LR - 747 lbs.
RR - 716 lbs.Camber in degrees
LF - (-1.00)
RF - (-0.75)
FR - (-2.38)
RR - (-2.00)Caster in degrees
LF - (+6)
RF - (+6)
FR - (+7.8)
RR - (+8.0)Toe in minutes
Front - 1.5 min. toe-in (.004")
Rear - 7 min. toe-in (.030")
Ride Height in inches
Front - 4.87
Rear - 5.18
- Bump Steer and Camber Characteristics
