Project DLM Day 4

Dirt Late Model setup

Posted May 19 2008 11:20 AM by cted
Filed under: Editorials, World Of Outlaws Racing

Day 4 on Project DLM brings an evaluation of the chassis setup.

As many of you know Project DLM started out as a wrecked 2002 CJ Rayburn chassis. Well before that wreck the car was always loose. So we were pretty sure that the front end geometry was not were it needed to be. So our resident chassis setup guru Bob Bolles broke out his computer, calculator and tape measure and went to work.

What he found was astounding, the front moment center was nowhere close to where we knew it should be. A quick measure session and entry of the data into a computer program told us that the static MC was at 0.416 inches high and 25.511 inches to the right of centerline, and at mid-turn attitude it went to 1.635 underground and 44.012 inches to the right of centerline.

Close up of the upper control arm mounting points

That's bad...really bad. It's no wonder that the car was alway loose. Anyway Bob developed a plan to take care of that problem. He details it in the forthcoming issue of the magazine so be sure to check it out on the newstand or, better yet, subscribe to Circle Track by clicking the subscribe now buttom on this page.

Stayed tuned to circletrack.com as we report on Day 5 of Project DLM!

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Reader Comments:

1. Are you serious? This is a complete joke. There are so many real racers out there that can use this help. I have nothing against the guy, but really I think you are wasting your time and money. I guarantee you everyone agrees.

Butterball - Posted May 27 2008 05:46 PM

2. Actually we are serious, when Circle Track builds and races project cars the specific purpose is to develop meaningful technical articles that help our readers improve their personal racing programs through our experiences in the shop and at the track. It doesn't matter who drives the car.

If Circle Track readers gain new knowledge and/or learn something from these articles (and judging from our letters to the editor - they are) then we are neither wasting time nor money.

cted - Posted June 5 2008 11:16 AM

3. And this... Bobby Clark IS a real racer. His program is very similiar to 95% of the racing that takes place in this country. He: 1) doesn't have a huge budget, 2) he does not have a big money sponsor, 3) he is learning and gaining experience (just like anyone else no matter what level), and 4) he is passionate about racing and just wants to go race his car, become faster and finish better. What we do to help him translates over to many other teams in his situation, and we are happy to do that.

CtTech - Posted June 5 2008 12:24 PM

4. Just read latest article.
Have Rayburn just like your project
would like to see photo of rear end set up without ladder bar
how does new pull spring mount ?
Do you still use Rayburn pull spring ? We still have ladder bar like your one photo where you say you will remove it all
Thanks

jschrader - Posted June 17 2008 05:26 PM

5. We are using a pull bar that was developed by Bert Industries some ten years ago. The unit is adjustable for preload on the stacked springs. I believe there is a 2500 and a 3500 lb. spring installed. Together they rate at 1458.

If you preload to coil bind the smaller 2500 lb spring, then the rate goest to 3500 lb. This unit never bottoms out on the track and controls the rear whereas other units do go into coil bind and become a solid link.

CtTech - Posted June 18 2008 08:31 AM

6. Did you keep Rayburn ladder bar and spring on car ?

This bert pull bar is used to replace Rayburns small spring alumium housing that is in some of you photos ?

In middle or like the info in your article. We race at I/55 it has 16* banking simular to where you are testing

Thanks

jschrader - Posted June 18 2008 12:43 PM

7. We removed the spring and shock from the ladder bar. We are only using the Bert pull bar and the two shocks.

What we did not do and should have is to check the two shocks that control the pull bar movement for Comp and Rebound. In our haste to get this car on the track we didn't test the shocks.

One reader just wrote that we could have the C and R backwards because the shock may have been intended to be mounted in front of the rear end instead of behind like we have them.

CtTech - Posted June 23 2008 08:04 AM

8. Is there a software package to check the "suspension points" or does Mr. Bolles do it himself "as a consultant?"

Why was the moment center off so much on your car intially? original design, wreck, etc.

Thanks
Anthony

Tywebb - Posted August 10 2008 07:32 PM

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