4 link dragster help

[Bubstr]

On a solid mounted rear end in a rear engined dragster, is there a way of figuring IC?

Or said another way, is there a way to make it hook better since there is no adjustments?

Yep what Billy said, and I've seen perfectly good Hemi heads ground on to drop an engine a couple inches on the FEDs There is always moving Center of gravity forward or back also.

The instant center is found by drawing a line from rear contact patch to a point over the front axel at a hight of center of gravity. Then half way between the actual center of gravity and the ground, is your neutral or 50 percentage of rise ( squat/ anti squat neutral). That is what I was taught, but I'm sure with more flexable frames and slippy joints, this could change by some.

[BillyShope]

The instant center is found by drawing a line...

This line is the 100% anti-squat line. If the IC is anywhere on that line, the ca will neither squat nor rise.

...from rear contact patch to a point over the front axel at a hight of center of gravity. Then half way between the actual center of gravity and the ground...

...is a point through which you should draw another line, again passing through the rear contact patch. This is the 50% anti-squat line and, if the IC falls anywhere on this line, 50% of the weight transfer will be taken through the suspension links and 50% will be taken through the suspension springs. Any other percentage anti-squat can be pictured as another line passing through the rear tire patch.

That is what I was taught, but I'm sure with more flexable frames and slippy joints, this could change by some.

Unfortunately, none of this is directly applicable to a suspensionless dragster. With a competition 4link, you can, in the side view, draw lines through the upper and lower links, with the intersection being the IC. But, if there's no suspension, the IC is simply the front tire patch.

Anyone familiar with dirt track karting knows that you can make a frame act like a fairly decent sprung setup, but, without links, it's well nigh impossible to accurately predict anything other than the front tire patch.