Weight percentages

[MiniStocker]

Hello, The car I'm working with is a circle track car and the track is requiring me to add approximately 350lbs to get to 2100 lbs. with driver included.

My question is, what is a good front to rear percentage? I've ran Mustangs in the past and they really liked rear weight in the 51%-52% range. With front wheel drive, I'm not sure where the weight should be. I've got a locked external ratcheting differential and GoodYear slicks. I have little wheelspin coming off the corners, but lift the LR wheel about 6". Should the weight go in the LR? LF? If so, how much? Should I try for a 50-50 front-rear split?

Hope I've been technical enough in my explanation, you guys always give the best tech...

Scott

[racer_tim]

For a circle track car always turning left, 50-50 would not be the trick setup.

In road racing setup, 50-50 diagonally is the best measure.

If your current car handles the way that you want it, I would advise to breakup the 350 evenly to all 4 corners. That might not be practical.

Tim

[philstireservice]

Originally posted by MiniStocker:
Hello, The car I'm working with is a circle track car and the track is requiring me to add approximately 350lbs to get to 2100 lbs. with driver included.

My question is, what is a good front to rear percentage? I've ran Mustangs in the past and they really liked rear weight in the 51%-52% range. With front wheel drive, I'm not sure where the weight should be. I've got a locked external ratcheting differential and GoodYear slicks. I have little wheelspin coming off the corners, but lift the LR wheel about 6". Should the weight go in the LR? LF? If so, how much? Should I try for a 50-50 front-rear split?

Hope I've been technical enough in my explanation, you guys always give the best tech...

Scott

A 50% cross weight is what you are looking to achieve. The rightt rear should be 50% of the left front.


------------------
Phil Phillips
94 Acura Integra GSR #4
ITS/H3/ST2
www.philstireservice.com
www.imprintedorginals.com

[Knestis]

The "50% crossweight" rule of thumb is a no-brainer compromise set up that assumes that the left-hand and right-hand corners are of equal importance. I won't argue that this is a less-than-perfect assumption even on a road course but it is a LOUSY premise for a circle track set up.

Many budget class circle track rules limit the left side weight bias - why? Because generally speaking, the more static mass you can have supported by the left side tires, the better. (Presuming we are on US ovals, turning left.)

Seems like the best answer - assuming the rules don't say otherwise - would be to put your lead on the left side of the car, near the center of mass (to maintain a low polar moment of inertia). I can't think of a compelling theoretical reason to plunk it at one end or the other...

Kirk

[MiniStocker]

Since I only turn left, I use crossweight to help tune the suspension for push or loose conditions.

My only concern was where to place the lead. My thinking is on the front, the car may develop a push with the car being already nose-heavy, or would it give more front traction and push less with it on the front.

The tire temps are hotter in the front by about 10-15 degrees. RF 195 RR 180 LF 135
LR 90. The LR is very cold as it lifts in the corners. I was wondering if the lead would do more good above the LR in an attempt to get that tire working to give the other three a break. We are limited to 55% left side weight. Top three finishers are weighed every event.

Just thinking... Any input appreciated, thank you to those that have taken the time to answer, it is appreciated.

Scott