Forum: HoseHeads Sprint Car General Forum (go)
Moderators: dirtonly  /  dmantx  /  hosehead

am wondering if anyone uses a scales to set up the basics on a sprint car. if so what wheel weights do you use ?

Way too many variables in a sprint car set up; the wheel offset, air pressure in the tires, steel vs. aluminum motor, tire width, amount of fuel in the car, and the level of your floor/scales will all affect how your car scales out....

Buy Jimmy Sills' book and tape from Steve Smith Autosports; Jimmy explains just how much a lot of factors affect weight. He advises that you should set the car up like you normally do, get a base line weight, then make changes to see what and how much they affect you car. But using someone else's baseline will just head you in the wrong direction.....

Chuck.....

thanks chuck i have jimmys book ill chck it out

ramjet..your way ahead of yourself...the easiest solution for you is to simply ask the chassis manufacturer for the info....he'll tell you where to position each wheel/tire,give you torsion bar rates,shock combo's and blocking heights...based on your chassis. If you carefully watch Sill's video-you'll see he sets the car up,then verifies where the weight is with the scales....you don't need scales to set a car up and if you don't know how to use them in relationship to a sprint car set up-they could hurt you.....a lot of sprint car schools have set-up classes..one on one with a knowledgeable person is the only way I can learn sometimes..good luck

thanks guys great answers . we will pay attention

1) You can also use your scales in reverse logical sense.

After you race for a while and you get a setup that seems to work. Put the car on the scales

and see where you are at. Keep that in your pocket book for future reference.

Sincerely,

Larry "O"

Another interesting thread.

Ramjet, I think you have already received some good advice. There is no magical setting that will apply to every race situation. The chassis builder's setup sheet will get your wheel weights in the "ballpark", but then you need to adjust each corner depending on the track conditions and driver feedback.

I have more to say, but before I talk more about scales and setups, I'll share another lesson that I've learned from personal experience. You need a hard hitting motor, that's tuned properly! There is no magical setup or wheel weight suggestion that can replace a strong power plant. I'm not saying you need the most expensive motor, or one that has an impressive dyno sheet, but the motor needs to "take off", it needs to accelerate or pull all the way down the straight away, and it needs a fresh valve job. An adequate power plant will not only increase your ability to compete, but it will simplify your setup equation.

There are so many racers that ask their setups for all of the answers, yet things like their power plant, tire condition, rear end measurements, weekly maintenance, etc, get overlooked. Make sure you address all aspects of your operation.

Using scales on your sprint car in the shop can help teach you how specific changes to wheel spacing, front axle geometry, cross weight, stagger, fuel load, and ride heights, can affect the weight that is applied to each wheel. This understanding won't set your car up for you, but it will improve your ability to make good decisions at the race track. For example, if your car is loose at corner entry, you will learn from scaling your car that if you move the right rear wheel in towards the chassis, or if you add some RR cross weight, you will add weight to the right rear corner. That extra weight can help tighten the chassis at corner entry. Understanding how adjustments affect the car, will help improve your setup decisions.

It's also important to understand and identify the handling condition that you are trying to address. Many racers come in and say my car is loose, so the crew instantly moves the RR in towards the car and lowers the RR air pressure. Unfortunately, many times, when the driver says the car is loose, he means the car is loose on exit. Moving the RR in, won't help the car exit, in fact it may hurt the car on exit, because when you move the RR in towards the car, the RR gets heavier. When the RR gets heavier, it steals that extra weight from the LR and actually makes the LR loose traction. My point is this...when you make an adjustment, you need to clearly understand exactly what the handling condition is and at what point on the race track the condition occurring. If you can't identify those specific characteristics, and make generic adjustments, they could actually be hurting you.

Sorry I wrote a book!

Disclaimer: I am not a sprint car expert! The above explanation is my personal interpretation and may or may not be factual.

dam never thought id get such intelligent answers to my question. i will print this out and keep it for further references really appreciate the time and effort thanks bunches.