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Author Topic:   wheel base length
36modracer
Dirt Maniac

Total posts: 126
posted August 31, 2004 09:23 AM  
what does everyone run for wheelbase on 1/4 3/8 tracks and why. mainly wondering as on our grt the cage is set back enough we cant run a 4bar on left side. our wheelbase is 108 and we can go 112 per rules so if we did lengthen it would the car still work ok with the longer base? right now were running swingarm with the lr locked down so like a two link. still drives down and under a bit but not as much as we would get for a 4bar.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted August 31, 2004 09:42 AM  
we have always run 110. I think the shorter cars would turn better. Also if you stretch the wheelbase but dont move the engine setback or anything else you will be losing rear%

Have you thought about trying a short 2 link setup that wort of mimics a 4 bar LR

36modracer
Dirt Maniac

Total posts: 126
posted August 31, 2004 11:02 AM  
wouldnt what we have on now be like a 2link sort of?(lr locked down with no trailing arm)(on original post) we thought about putting the spring on top of rearend as we have a screwjack bracket on chassis, then just get the bolt on stuff for rearend tube and put a bar on instead of swingarm. thanks

zeroracing
Dirt Forum Champ
Total posts: 1875
posted August 31, 2004 11:07 AM  
too help your car right now, put a short lower link on the lr, and clamp the spring on the front of the housing so it indexes up when on the gas, that will help the car a bunch.
but if you want to 4 link it i would just run a short upper bar and a long lower. i do all the time.
as far as wheelbase make sure to keep the motor 72 inches from the rearend(i think 72)
shorter wheelbase turns easier, i run 108 3/8ths the 3/8 is because local tracks are dumb and measure off a bent rim to bent rim for wheelbase and tried to dq me already for it.

tilley88
Dirt Forum Champ
Total posts: 879
posted August 31, 2004 11:09 AM  
The longer wheelbase cars usually have the engine set back to spec, and usually get better rear % because of it. I have a cousin who converted his GRT to 4 bar on the left rear, and his had a set back cage. Try to keep in mind that your lower link usually is shorter than the upper link. Check GRT's website for the correct link lengths. As a racer I'm sure you'll figure out a way to make it work. Also, you may want to consider the short 2 link setup as dirtbuster mentioned above. If it's setup right it will mimic a 4 bar setup. The links on those are usually 12.5"-15.5" heim to heim center.

36modracer
Dirt Maniac

Total posts: 126
posted August 31, 2004 11:37 AM  
thanks for the replys so quick. i did forget to mention it is a grt and has the cage set back and over to left. just looking for ways to improve this car rather than buying something else. the springs are currently on sliders on the swingarms in front of rears. thanks again.

zeroracing
Dirt Forum Champ
Total posts: 1875
posted August 31, 2004 11:40 AM  
i run 15 upper and 20 lower most the time, yeah i know backwards but does the job.
talk to njantz on here, he converted a grt.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted August 31, 2004 12:07 PM  
Others have already covered this but i was meaning a short bar like 12" for a trailing arm on the LR with about 12-15 degrees angle and I would put the spring on a clamp bracket in front of the axle on the LR.

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