Long J-Bar compared to a short J-bar?

[4J Automotive]

How much of a change will I be looking at with a shorter alum j-bar compared to a long steel j-bar? Because of the heim I couldn't put the long steel j-bar in the bottom hole on the pinion, now with the new alum j-bar I can. How will lowering the J-bar on the pinion affect the car?

[rubbinsracin]

assuming you just go lower on the pinion without moving it down on the frame you are putting more rake in the bar which should tighten it up. how much shorter is the new Jbar? you might would to make sure you dont move the rear end to far to the left.

[4J Automotive]

Well we had been raising it on the frame and getting nothing. Overall we have been loose and thought this would tighten the car up all together. I think raising it in the frame is for the birds, but we haven't been able to try lowering it on the pinion so we are hoping it does what we expect which is it tightens the car on entry and middle. If you have it mounted to the frame with an old style mount (mounted straight to frame with out the curved settings to slide) would moving it on the frame disrupt rear end location?

[joedoozer]

If your mount goes straight up the frame, then it will move the axle to the left the further you go up the frame.

As for not seeing any results with your J-bar adjustments.....If it's too high on the pinion your rear roll center might be to high. You can raise it on the frame all you want. But if the roll center is too high, it simply will not roll over. Take a 4x4 and put it behind a cow, about 12 inches off the ground. Now tip the cow over. Take a 4x4 and put it behind another cow about 4 feet off the ground. Now try tipping that cow over.

A pole vaulter analogy is more accurate......but cows are funnier.

[dualdj1]

Going down on the pinion will definitely help. Just, as the other said, try to keep your axle side to side positioning the same when changing your rake (ie lengthen the bar as necessary)

[latemodel86]

Having a short j-bar will make the LR of the car hike up real quick/aggressively and the Lr tire will kind of jerk forward reall hard. I'm not a late model expert, but in my experience, that what it does and I also believe it tightens up as well, when it's short.

Watch this video and see how my car reacted when the car had a short j-bar on it.

http://www.youtube.com/watch?v=XjhocjjwBKU

[rubbinsracin]

looked like the car reacted well, but you looked like you didnt have any side or forward drive though. that track looked way to small for late models too, way narrow.

[sj valley dave]

Looked like the car had a push in it...Watch the front tires, he was pushing a lot, especially in turn 1-2, had to chop the throttle a couple of times...Get the entry right and the exit takes care of itself! LOL

[jedclampit]

A shorter panhard bar should loosen entry and tighten exit. ( the shorter the ph bar the more the rear end is displaced to the left with body roll, and resist body roll on entry)