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Author Topic:   4 bar setup
Dirt Roller

Total posts: 11
posted November 27, 2003 06:47 PM  
We have a 97 model 4 bar chassis (Masterbuilt??) with 2002 front spindles on it. We could use some help with the setup. We have been running spring type late models and were leaving the rest of the pack in the dust this season. We just cant seem to get the 4 bar to handle. We need to start from scratch on the setup, I think. HELP???

Dirt Freak

Total posts: 209
posted November 28, 2003 03:00 AM  
i learned the hard way last season (my rookie year in dirt latemodels) and can only offer a few things to look for as we're still pretty hit and miss at the moment but some of the biggest and most important things that we checked and changed were:

contact your chassis builder and ask his recommendations for set up.

set your rear end "side to side" measurement correctly (diff offset in chassis).

check your bird cages are located correctly along the axle tubes. Your 4 bar rods should all point slightly inward at the frame.

check your lift arm spring (5th coil setup) is sraight up and down when viewed from the back and the side. Start off at 38" long.

industry standard starting spring setup seems to be LF-500, RF-400/450, LR-275/250, RR-200/225. shocks - 5 valving on the front, 4 valving at rear.
bottom 4 bars at 0 deg (level) LR top arm at around 12-15 deg and RR top arm at 15-17 deg.
j-bar mounted at yoke height at diff and 3-5" higher at the frame (to start with). Right side arms 1/2" longer than left side.
front ends seem pretty standard at RF -3.5 camber, +3 caster. LF +1.5 camber, +2 caster. 3/8" toe out.
percentages we start with are:
left 54%, rear 54%, X 52.5%. we have just learned to mount the ballast up high (including the fuel cell).

These are pretty generalised starting points.
personally i prefer to use the LR spring mounted behind the axle on a 0 valve shock with the control shock in front, over a left rear clamp type setup but thats just me. I also prefer the soft right front spring having used equal rates and a stiffer right over left.

hope that helps some, like i said, I'm pretty new to it too.

Dirt Roller

Total posts: 11
posted November 30, 2003 04:02 PM  
Thanks, Rocket every little bit helps. I've seen the car run with the previous owner. He would like you to think he is a racing genius always spouting alot of technical info but when we went to the track he usually didnt make it to the feature. Needless to say I wasnt impressed. The car never handled well. It is a Masterbuilt chassis by the way. I havent checked for a website on them yet though.

GO 24
Dirt Freak

Total posts: 366
posted December 02, 2003 10:37 AM  
Your best bet is to get their setup off the internet site & start over. Check to make sure nothing is bound or bent and go from there.

Dirt Roller

Total posts: 11
posted December 06, 2003 10:41 AM  
Does Masterbuilt Chassis have a website?? I cant find anything on them?

Dirt Forum Racer

Total posts: 90
posted December 06, 2003 06:05 PM

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