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Author Topic:   ? from new mod racer
riffraff
Dirt Roller

Total posts: 11
posted November 08, 2004 10:01 PM  
first year mod racing. I have a speedway four bar on birdcages with speedways torque arm. wondering if you guys could give some pointers. If I get the setup and have rear traction the car pushes, if I have no traction the front end is stuck nicely.I have 55% left,48% cross, and 56% rear with adding weight but now the car is 2600lbs ready to race. Running 600 gear with 500-600hp engine. springs=lf550,rf650,lr175,rr150and progressive in torquearm.Any advice helpful

badfastjr
Dirt Maniac

Total posts: 193
posted November 08, 2004 10:10 PM  
it really depends on what stub your car was built on, but even if its on a chevelle stub those springs in the front seem a little soft. Try going up a 100 lbs on both sides and possibly adding a little more rear percentage if you can.

------------------
"son this aint a car its a racin' machine."

paulickr
Dirt Maniac

Total posts: 110
posted November 09, 2004 06:39 AM  
quite truthfully, i think that 55% left side weight is too much, you need about 53% with the driver.
the setup will be a fine line between loose and tight depending on how you like it.
i like mine to be a bit tight and use the gas pedal and brakes to loosen the rear and set it for the turn, but thats me.
i would use less left(53%), more cross (about 49%),more rear (about 58%) and try about 70lbs of bite (left side heavier than right)
see how that works. i also would run front springs of 650lf and 750rf.

[This message has been edited by paulickr (edited November 09, 2004).]

Kromulous
Dirt Forum Champ
Total posts: 796
posted November 09, 2004 07:49 AM  
How far out (FWD) is the spring located on the torque arm? from the axle centerline ?

If its to far FWD it will cause a big throttle on push. We've been running a torwue arm all year and i have noticed there touchy concerning how far away they are from the axle cl when it comes to push and rear traction.

Your cross weight looks low to me as well, anyone else think so?

Ego Racing
Dirt Forum Champ
Total posts: 724
posted November 09, 2004 02:15 PM  
His left looks to high and the cross is a little low. 53%left and maybe down to 51% on a dry slick or flat track. 49-50% diag.

mod70
unregistered Total posts: 724
posted November 09, 2004 02:16 PM           send a private message to Ego Racing   Edit/Delete Message   Reply w/QuoteBBBBBB
Yeah, I agree with badfast and paul, go up on the front springs and take some left out. Cross might be a little low, try closer to 50% to 51%, but worry more about rear split.

riffraff
Dirt Roller

Total posts: 11
posted November 09, 2004 03:50 PM  
thanks guys, only fourbar-torquearm car I have ever seen.shocks=lfwb753,rfwb763,lrwb95,rrwb95.weights=lf672,rf494,lr757,rr689.bars lefttop+19,bottom+5,rtop+24,bottom-5.j-bar +11 9.75 rollcenter.both sliders in front of rear.teflon line cages,brakes not on cage.spring in middle hole of speedway torquearm.tried it with and withoutshock.3"of travel.dryslick track.no local help,thanks again for the help.

FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted November 09, 2004 04:42 PM  
I have a ? for you. The %'s your giving is that the setup that throttle pushes or is loose???? Also give the other setup your using that is producing an opposite effect, lets see what your changing and how much. We can probably dial you in better like that. But your left% is high, and like mod70 said worry more about the LR bite than the cross.

riffraff
Dirt Roller

Total posts: 11
posted November 09, 2004 06:39 PM  
The setup I'm giving is what I have now with a throttle push. The old setup was a two link on clampon brackets that I tack welded.I took that off and put the cages and the progressive spring and took the shock off arm. The old setup I had a terrible 4 wheel drift with no traction.Now I have lots of traction coming out of turn, but push going in.Changed angles a little but no real responce.I want to be able to come back in the gas sooner and stay on it longer. Thanks a bunch

FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted November 09, 2004 07:00 PM  
Do you have any shock travel measurements??

FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted November 09, 2004 07:02 PM  
Also how severe is the push going in and through the middle?? Is it something thats not so bad that maybe some bar length and angle changes might help??

mod70
unregistered Total posts: 753
posted November 09, 2004 07:05 PM           send a private message to FlyNLoIMCA17   Edit/Delete Message   Reply w/QuoteBBBBBB
I'm seeing 178# split at the front. With that much on the LF it will probably be the cause of the push on entry. What do you guys think? I don't really like to get into the 4-bar stuff too deep. I'll let you help him on the fixes.

FlyNLoIMCA17
Dirt Forum Champ
Total posts: 753
posted November 09, 2004 07:06 PM  
Yeah thats surely a problem. 178 lbs of LF bite is a little overboard.

riffraff
Dirt Roller

Total posts: 11
posted November 17, 2004 12:50 PM  
Sorry I have not replied, just got back from Vegas. WHAT A RACE! First time watching the BIG BOYS, will probably take the car next year if you guys help figure it out. But shock travel, about 2" on both right tires,I'm not set up to measure up travel on left side yet.The push is so bad,that if I come into the turn at any race speed I push clear up or off the track. I have plenty of traction coming out, but they kill me in the turns. What kind of split do I want across the front? Thanks Riff Raff

Kromulous
Dirt Forum Champ
Total posts: 796
posted November 17, 2004 02:15 PM  
So it pushes bad going into the corner?

How about coming out, middle of the turns to the straight aways? Does it continue to push ?

Post what shcoks your running as well please.

riffraff
Dirt Roller

Total posts: 11
posted November 17, 2004 03:03 PM  
I'm running pro shocks LF=WB753, RF=WB763, LR=WB95 and RR=WB95.Car pushes at every part of the turns. I can pretty much coast thru the turns and come out hooked up. They kill me in the turns. They can come back in the throttle a lot quicker than I can.I would like to be able to set the car real quick coming in and get right back on it. If possible. Thank you for any help RIFF RAFF

Wildside17
Dirt Maniac

Total posts: 119
posted November 17, 2004 06:17 PM  
I had 93 straight across on rear and 80 lb split on front and like 40 on rear. Some might not agree with that but it worked good that way. Thats on a 2003 harris. Good luck. It took us most of this last year to get it dialed in and comfortable to me. Sorry had afcos on. we played with a 94 then went to the 93 on the right rear.

[This message has been edited by Wildside17 (edited November 17, 2004).]

CD00
Dirt Roller

Total posts: 14
posted November 29, 2004 06:07 PM  
riffraff,
lf 750 rf 650 rr 200 lr 225. 75#lr
I've ran a 4-bar since 1996. This has
been a good starting point.
CD00

racer 4
Dirt Forum Racer

Total posts: 77
posted November 29, 2004 10:33 PM  
its hard to tell how much throttle push you have without seeing it.a quick fix in car would be dial in more rear brake. i would move my rf wheel offset in 1 inch and bring my lr wheel in 1 inch add 2-3 lbs air in lr and try that then start working your screw jacks rf and lr an equal amount until you feel better with it. remember adding left rear will loosen in and tighten off. if adding lr tightens it up getting in you have went to far.

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