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Author Topic:   How close to the axle can you get?
ratracer10
Member
posted January 28, 2004 11:46 AM
The 42 inch bar makes the chassis think you are running a lift bar.


zeroracing
Member
posted January 28, 2004 02:35 PM
Harris went to the 42 inch bar for the reason as they say in there flyers is it reacts like a 31 inch lift bar on the chassis because of where it ties to the chassis it is so low and far enough forward. They reccomend something like 17-23 degrees.
If you run your lower links a 5 degrees uphill it promotes forward bite and creates a little roll oversteer. (The top link should connect at the center of the weight mass of the chassis). If the top link is mounted at the proper height (12 - 13 inches above and 1 - 3 inches behind the centerline of the rearend) a 41 inch top link angled down at 20 degres will attach to the chassis at exactly the instant center of the rear trailing arms. It makes the chassis think you are running a 36 inch torque arm. This setup increases the torque cushion on the contact patch of the tire and reapply it over a longer time frame.
Measure the rear track width of your chassis and multiply by your left side weight. (60 inch with 53% left 60 X .53 = 31.8) This is where your third link should mount to your chassis if meassured from the center of the right rear tire. This is the center of the chassis weight mass left to right. The same can be done front to rear to give you the exact center of mass for the chassis.


ratracer10
Member
posted January 29, 2004 07:47 AM
If you move the mount in front of the rear centerline it will increase the leverage the rear has on the bar. The idea location is 12-13 inches above centerline and 1-3 inches behind the centerline. This should get the 42 inch bar slose to the weight center. The more you move the bar left to right will loosen and tighten the chassis drasticaly.


zeroracing
Member
posted January 29, 2004 05:03 PM
I am missing something! The Top link on the rear is refered to as a pull bar or a push/pull bar. The rear rotates under acceleration and tries to lift the pinion. With the toplink mounted behind the centerline the rear pulls up on the chassis and the mount on the rear moves back and down.
If the mount was in frount of the rear centerline when power was applied and the pinion tries to climb it would pull up on the chassis the mounting point on the rear would move back and up. This would increase the leverage on the chassis and the chassis mounting brackets but it seens it would react more violently on the chassis and at the point where a typical bar finds a medium where the mounts try to level the load, If it were in front the rear the rotation would be quite abit more and may start to cause problems with the universal joint on the rear.


zeroracing
Member
posted January 30, 2004 11:04 AM
The way we run the bar we don't get that much rotation, I could understand that if the spring was to soft. We run our sliders with the left behind the axle and the right in front of the axle. With an 800lb spring in the bar when power is applied, the rear rotation also increases pressure on the right rear spring helping the car bite off the corner. When power is dropped the rear rotation helps plant the left rear and set the car in the corner.


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