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Author Topic:   Rear Oversteer
A&M Motorsports
Dirt Maniac

Total posts: 117
posted January 26, 2005 12:18 PM  
How much rear oversteer is too much by shortening the length of the left lower link on a 3 link suspension. I know there are a ton of variables involved, I am just looking for some input from you guys. Currently my LR is led forward .5". I am looking to square the rear up and design roll oversteer into the left link to get the car through the middle of the corner as it rolls over.

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Artie Perilloux
A & M Motorsports

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted January 26, 2005 12:40 PM  
It all depends on how long your corners are, and what length and angles your links are.

For starters-

Make your Left rear link From Heim to Heim around 14 Inches, that gives you about an 11 Inch tube. Run it with about 20 degree's of uphill angle

On the Right Rear, run a link that is around 21 Inches Heim to Heim, and Trail this tire 1 full inch. Run it with about 10 degree's uphill angle to start. The other thing you might want to run is a Short Panhard with about 4 Inches of rake to start. It'll help get the car up on the left rear bar faster. If you tune it right it won't drive anything like the nightmare's people scream about "how radical" and "how uncontrolable" they are.

Shryock cars run about a 10 inch HEIM TO HEIM panhard bar, its all in the angle and getting everything else right. Try a 30/30 Shock on the left rear and a tie down on the right rear.

NJantz
Dirt Forum Champ
Total posts: 755
posted January 26, 2005 01:05 PM  
I've got mine to produce 2" of rollsteer on my left rear on a 4bar/zlink. Have a good idea of what your driveshaft is doing. You definitely will need the long yoke if you don't have it already. As far as how much oversteer is too much that depends on the limits before things start binding up and what the car needs.

A&M Motorsports
Dirt Maniac

Total posts: 117
posted January 26, 2005 01:32 PM  
Currently my RR bar is 21" long and the LR bar is 20.5" long. My j-bar is 19" long and has 6" of rake. My thoughts are to build an extension bracket for my LR trailing arm and shorten it to somewhere in the 16 to 14" length or maybe even shorter and add some upward angle to it.
How about a little theory about trailing the RR so much.(I know there is an ongoing post about this)
I would also like to hear from my friend WPP, who I havent seen since the nationals in McAllen Tx.

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Artie Perilloux
A & M Motorsports

FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted January 26, 2005 05:19 PM  
First off you will need more led/trail on a 3-link to produce the same amount of roll steer as a 4-link during X-amount of roll over. When I ran 3-link I trailed the RR 1/2" It worked pretty good. But roll steer all depends on the track and the line you drive and a thousand other variables. The best thing I can tell you is trial-and-error. (I hate hearing that) Thats all I would know to tell you others probably have better insight on this than I???? I know there is a computer simulation for 4-links to figure out roll steer amounts but I don't know about 3-links. Does anyone know of that?

A&M Motorsports
Dirt Maniac

Total posts: 117
posted January 27, 2005 06:22 AM  
FlynLo, yes there is a computer progam for 3 links, that's what I am using to experiment before I start modifying anything. I also have a program for the front end geometry. There aint no speed secrets there but it helps to understand how everything works and where everything needs to be located.
See ya Sunday.

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Artie Perilloux
A & M Motorsports

340duster
Dirt Maniac

Total posts: 195
posted January 27, 2005 01:42 PM  
What is the three link program called? Does it allow for a pull bar on the upper link?

A&M Motorsports
Dirt Maniac

Total posts: 117
posted January 27, 2005 02:21 PM  
The program is called rear suspension geometry for windows by Auto-Ware and I think that I bought it from Steve Smith for around $120 or so. The program requires input for the upper link but doesn't matter whether it's a solid or spring bar, it's just for geometric purposes. It's a pretty neat program. The one for the front end geometry is even better. www.auto-ware.com of Steve Smith

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Artie Perilloux
A & M Motorsports

waltonjr1
Dirt Forum Champ
Total posts: 516
posted January 28, 2005 09:24 AM  
Artie, get that 727 ready for next weekend. Were going to Menge to play around a little bit. Feb 5th. DeanJr


A&M Motorsports
Dirt Maniac

Total posts: 117
posted January 31, 2005 07:08 AM  
Dean, I might could make that happen. I'll have to see how big Mickey is working.

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Artie Perilloux
A & M Motorsports

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