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Author Topic:   Custom Performance Setup Info
Dirt Freak

Total posts: 464
posted August 05, 2002 05:47 PM
Here is some basic setup info on my car.
mid gm metric frame w/ 2 link rear

wheel offsets 4" lf rf 3" lr 4" rr 4"
stagger 1" front and rear
springs 750 lf 850 rf
225 lr 200 rr
long pullbar w/ 600lb spring centered in chassis
short j bar with 10 deg angle down to rearend 2nd hole up on pinion
shocks 93 lr 94 rr
75 lf 76 rf
trailing arms in rear both in middle of frame brackets
scale #'s
52% ls
52% cross
55% rear with 15 gallons fuel

Dirt Freak

Total posts: 464
posted August 05, 2002 05:49 PM
As soon as i get more feedback from #93 i will be posting some of the ford car with swing arm info as well.

Dirt Freak

Total posts: 390
posted August 06, 2002 01:50 AM
Richard, I run a pan-bar behind myself, but was thinking......that 10 degrees on the that from bolt to bolt. Or is that 10 degrees measured from the flat part of the J-bar??? I would assume from the flat (straight) part of the J-bar. This may confuse people like me.....Thanks

And if it's measured on the straight part, what is the length from the center of the straight part to the hiem that bolts on the rear housing or bracket??? If that is longer or shorter it would throw off the roll center. Just a thought I was curious about, Thanks for you thoughts.


Dirt Freak

Total posts: 464
posted August 06, 2002 06:48 AM
10 degrees with level on straight part.

Dirt Full Roller

Total posts: 40
posted August 06, 2002 11:02 PM
Jeff, you just opened a life long argument for the "J" bar. Where is the roll center, at the attachtment points, at the flat of the bar, your guess is as good as mine. I have heard both arguments and agree with both. I agree more that the true roll center has to follow the attachtment points, not the flat on the "j". The best thing to do is talk to your chassis builder and try different angles for your self. The "J" bar is far more reactive than the long bar, so make small adjustments. An inch up or down can change a car that is close, to a car that is way out in left field. It sounds like Richard is starting to get feed back from some of his cars. Try his suggestions, he doesn't want to give you bad info which will in turn make him look bad. Always remember, what works for one driver, may not for another. All you can do is keep exact notes of track condition, set-up, and handling. Good Luck

[This message has been edited by Dirt2race (edited August 06, 2002).]

Tom Asmus
Dirt Maniac

Total posts: 161
posted August 06, 2002 11:59 PM
As a driver of one Of Rich's cars I will tell you we are experimenting with alot of stuff to get me comfortable in a new car! Rich has a lot of good Ideas!!! I have been real competitive with the chassis he has built, plus it being a new design that I am doing some R & D for Rich, We talk every weekend after we are done racing to compare notes. Rich being a racer and a builder he can relate to what a car is doing, A big plus in my book!!

Dirt Freak

Total posts: 221
posted August 07, 2002 07:20 AM
the angle between the mounting points is the 'true angle' does the j-bar know it is bent? it is my belief that it is bent for clearance purposes? 2 cents--------ford5

Dirt Full Roller

Total posts: 26
posted August 07, 2002 03:46 PM
My 2 cents are that the angle is between the 2 mounting points and the lateral rear roll center is half way between these 2 points and the vertical rear roll center is the height above the ground at the above mentioned lateral roll center. Just my thoughts.

Dirt Freak

Total posts: 464
posted August 07, 2002 05:31 PM
Yes the true angle is between the mounting points, the person helping me over the phone on installation since i had never built a car with j bar never mentioned setting the angle on the flat part or the line between the 2 mounting points(just said 10 deg angle to start). i went with the flat part of it but i will check the angle between the 2 mounts and yes it is bent for clearence .

Dirt Full Roller

Total posts: 26
posted August 07, 2002 09:32 PM
When anybody gets their J Bar set where they like it and put a protractor on the flat part and record that angle I see no problem with that, it's a lot easier than doing the measuring and doing the math to figure the real angle. We supposed to keep this stuff as simple as possible huh!

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