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Author Topic:   Slow off the corners
Dirt Newbie

Total posts: 4
posted August 11, 2003 08:30 PM  
Trying to help a friend with his bomber, but unfortunately I'm relatively new to the racing scene...

He's always slow off the corners, however the car is fast in general. Motor's good. We run at a quarter mile high banked dirt.

Couple questions: What is cross weight, and how does it help? He usually runs faster down low, but he says it's a lot easier for him to spin the car down there, any general tips to help with that? We're planning on tilting the rear end this week (only allowed 3.5 degrees) will that help?

Interesting point: We had our car and another car both out on pavement and both floored it. Other car stopped spinning tires in half the distance ours did. That car has the rear end tilted already.

I realize I'm not giving all that much information, but even general tips and things to look for would be greatly appreciated.

Dirt Forum Champ
Total posts: 5390
posted August 11, 2003 10:09 PM  
Twisted, Steve Smith publishes a book "Street Stock Chassis Technology." It has helped many a new racer understand the basics of how and why a chassis works. Buy it! If you don't feel like it's worth what you paid for it..send it to me. Mine is falling apart due to the many, many times I have refered to it over the years.

Dirt Newbie

Total posts: 4
posted August 12, 2003 04:22 PM  
I meant pinion down. All I know right now is he's running a 1.68 box and he turns about 6000-6200 at the end of the straight away.
He says it doesn't have enough bite, so I'm guessing he's breaking the tires loose.

I also found out the following: We aren't allowed to add weight or have shims on the springs. He's running 235s on the right and 225s on the left. He also said he wishes it was a little looser in the handling department.

Oh yeah, thanks for the recommendation on the book, I think I'll pick that up

Dirt Freak

Total posts: 263
posted August 21, 2003 12:21 AM  
Twisted, you need to get the car scaled and tell us the weight %'s. What are the spring rates in the car? What kind of car is this, metric or a leaf spring car? You said the car was tight to'em but where at in the corner? Everywhere, entry, apex? Is he running any stagger? There are a few things that may be the problem but we need to know more. One more thing the amount of pinion angle in the car does not affect your forward bite so I would look elsewhere to solve the problem. Man, I hope I didn't open up a can of worms with that last comment, lol.

[This message has been edited by justin (edited August 21, 2003).]

Dirt Administrator

Total posts: 6243
posted August 21, 2003 12:32 AM  
About the pinion angle. Putting myths to rest is not opening a can of worms. Pinion angle does nothing for forward bite. It is the location of the instant center of the rear suspension that afects it. Now the angle of your pendulum effect, get that right and you will fly!!!

rico 08
Dirt Forum Champ
Total posts: 1139
posted August 21, 2003 07:17 AM  
I like running up to six degrees of pinion angle,whether it just uses up horsepower or makes it bite i don't care,it works.One thing i noticed is you are running alot of stagger front and rear,to much rear stagger takes away from forward bite.

Dirt Freak

Total posts: 370
posted August 21, 2003 12:07 PM  
If pinion angle does nothing for forward bite or axle wrap..... why does every class allowed run lift and pull bars to take advantage of it.......Towman

Dirt Maniac

Total posts: 113
posted August 22, 2003 06:26 AM  
Because the pull bar relocates the INSTANT CENTER of the rear suspension. Physics 101

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