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Author Topic:   roll over help (too much)
FASTLAP
Dirt Maniac

Total posts: 171
posted May 23, 2004 09:15 AM  
I'm running a metric front, 700lf 750rf, pair of 225's on the rear (4bar spring behind on left, z link spring on top right). Big half mile track. Problem is the car seems to roll over too much. It doesn't 3 wheel, it just lays over on the right side alot. Maybe 1/2" from bottoming the rf out, right rear is rubbing the quarter panel. Running a shorty panhard bar, 2nd hole up on pinion side, 5" up on the frame side, ought to be around 2" rake. Car is tight on entry to middle, chewing up right rears. I was thinking about moving the panhard bar up on both sides. What do you think?

badfastjr
Dirt Maniac

Total posts: 193
posted May 23, 2004 01:05 PM  
raising the panhard bar raises the roll centers. raising roll centers makes more body roll. I'd lower the whole thing.

mod70
unregistered Total posts: 193
posted May 23, 2004 01:25 PM           send a private message to badfastjr   Edit/Delete Message   Reply w/QuoteBBBBBB
Almost sounds like you've got a couple of blown shocks. Have you checked them?

dluna
Dirt Freak

Total posts: 334
posted May 24, 2004 08:19 AM  
Raising the panhard bar raises the rear roll center. Raising the rear roll center makes LESS rear body roll.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted May 24, 2004 08:37 AM  
Dluna is right, raising the bar raises roll centers and decreases roll. Not sure what your holes on the pinion match up with but id put it either level or just above the pinion shaft, then about 3" rake to the fram. Do you have any lead on the car and if so where is it? How much left% is in the car?
I'm not real familiar with metrics but those front springs sound kind of soft maybe someone else will help out more there.

[This message has been edited by dirtbuster (edited May 24, 2004).]

NJantz
Dirt Forum Champ
Total posts: 755
posted May 24, 2004 09:54 AM  
On my metric front end I'll run front spring rates from 850-1000lbs. Yours sounds a little soft.

If your shorty bar is too low you'll be tight just like your described and the car will roll over on its right side. When you lower the panhard bar you in effect lower the rear roll center which gives the chassis a longer lever arm to rotate the car about its roll axis. This is why you see more body roll with lower roll centers.

Just by going off the information provided, I'd raise it up.

I don't have much experience with 1/2mile tracks but is it common to run a shorty bar on a big track?

badfastjr
Dirt Maniac

Total posts: 193
posted May 24, 2004 10:21 AM  
sorry guys i didnt know what i was thinkin when i typed that. meant to say it the other way around. sorry for the mistype.

cd2
Dirt Maniac

Total posts: 161
posted May 24, 2004 11:20 AM  
Fastlap if the car is tight in an to middle why not soften the L.F.some or add some cross weight to help loosen it so it can turn better an it will help on the R.R.tire. Also it could be you do not have enough L.S. weight. cd2

FASTLAP
Dirt Maniac

Total posts: 171
posted May 24, 2004 06:38 PM  
Sorry it took so long to reply.
mod70-I had the shocks checked, they're ok.
dirtbuster-Ihave one piece f lead on the left rear rail, and one in front of the fuel cell. I have 52.3% left, 57% rear.
NJ-I have been considering the same about soft fronts. I (when I had time) was checking the archives to get an idea, but couln't really get a solid idea of what rates to use. This is all metric spindles and lower a's. Din't know if that made a difference compared to the pinto stuff on a metric. From the pics I saw from the track last Saturday, it does look like the car is kinda nosed over to the right coming off the turn. As far as the straight shorty, yeah it is real common on the mods and the lates. I have the new afco pinion plate with the hole below the pinion. That's why I went to the shorty so I could raise the roll center up. Had a longer straight bar mounted to the hole under the pinion, but felt it had to be too low. But the car is doing the same thing, made no difference.
cd2- I thought of the LF spring change, but as NJantz mentioned, I din't want to soften it if my fronts were already a bit soft. That's why I turned to you folks on the Dirt Forum for advice. It's the best place for honest, solid advice. And it's well appreciated. Hope this extra info helps you all. Thanks again

FAST

[This message has been edited by FASTLAP (edited May 25, 2004).]

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