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Author Topic:   Jet Mod 4/swing setup HELP!
sdracer12
Dirt Maniac

Total posts: 180
posted June 13, 2005 10:18 PM  
I'm trying to help my buddy get his new Jet Mod Lear to work well, and we are having some problems getting the car to turn. No matter what he has tried, it seems like the car is just too "stuck" on the RR at entry. He has talked to Jet about it, but he needs more help.

The car is a long 4-bar left w/spring behind, and a swing arm right with spring on slider in front of the cage. 250# left spring, with 225# right spring on the arm. 100# LR bite, on Hoosiers and Amer. Racers both. Front springs are 700 left/800 right.

My thought is the problem is with the panhard bar. The car has a long panhard bar mounted behind the rearend. The bar is around 26-28" long mounted to the right side of the rearend. The setup sheet calls for the clamp mount on the rearend to be mounted 1-2" below center, with only 2-3 inches of rake up to the frame mount. We have moved the panhard bar up to level on the rearend, with 2" rake, and it did get slightly better/freer, but not much.

It seems like the car lifts well, and it does pull the left front off the ground sometimes, but only around 2-4 inches off, so it's not radical. But it looks like on entry, the car won't rotate, the rr is planted, and the front tires slide up the racetrack.

Does anyone have experience with this brand of car, with the long panhard behind? Or does something jump out that we are missing?

I'm open to any and all suggestions. We are toying with the idea of totally changing the setup to a 4-bar left/2-bar right, or putting a J-bar in front of the rearend if he can't get this thing to turn... Thanks.

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted June 13, 2005 11:18 PM  
I'm having some problems too with my car, but not much. Seeings they are different, nothing I did will help you...
But

I'd try to put a J bar on there to start. If it is sticking the RR, you might lighten up the rr spring 25-50 pounds...


You might be ablet o help me on this one. 2 weeks ago I busted out the short 2 link lr long 2 link rr with J bar setup. Car was pretty fast, a tick tight but very fast on the tacky track.

Last week, I put a different shock on the lr, same rate, and moved the J bar down an inch on the frame side. Car was very tight in the heat...

For the feature I moved the J bar back up where I had it, put the same shock back on the LR and then put a 4" offset on the rr along with 2 turns of Left rear into the car. Track was pretty dry slick, and I was sliding the Rear real bad getting in, causing a tight from the center off, and loose off the gas and tight on the gas unless the car was completely sideways and off the LR bar. What are some things I should do to get that bite back. I didn't mind the car sliding into the turn like that, but not on a Dry track like that. I'm wondering if taking a turn back out of the LR, raising the J bar another inch on the frame... I also have no idea why the car wouldn't stay up on the LR bar either, probably because I was so loose getting in and then sliding and the rear wasn't getting any bite so the car couldn't lift up and get on the bar.

Both Rear bars have a decent amount of angle in them, I'm not far off, just need to make the car more consistent. I'd like the thing to roll in almost straight, turn it and t hen go, but I don't know how to get side bite while taking away throttle push??

rpm20
Dirt Freak

Total posts: 338
posted June 14, 2005 05:51 AM  
hey xtreme......why would you lower the bar for slick and raise it for dry ??

seems to me you need to go the other direction, maybe???

personally for me in my dw8 ....we raise the bar for tacky tracks and lower the bar when it gets slick and that makes it hook better.

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted June 14, 2005 09:04 AM  
I had my roll center too low, which was causing the push. Any time you get more angle in your panhard you should see a tighter effect somewhere on the track. What you are doing is the same thing I did, moving the roll center lower.

dirtywrench13
Dirt Freak

Total posts: 324
posted June 14, 2005 03:31 PM  
IS HE USING A LIFT ARM OR A PULL BAR?

sdracer12
Dirt Maniac

Total posts: 180
posted June 15, 2005 01:53 AM  
quote:
Originally posted by dirtywrench13:
IS HE USING A LIFT ARM OR A PULL BAR?

This Jet car has a pullbar. He is using an Afco single action pullbar with a 1050# spring.

dirtywrench13
Dirt Freak

Total posts: 324
posted June 15, 2005 06:42 AM  
TRY MOVING THE FRONT OF THE PULL BAR TO THE RIGHT, JUST OFF CENTER OF THE DRIVESHAFT.CENTER THE REAR AT FIRST,THEN MOVE IT A LITTLE AT A TIME TO SIUTE HIS TASTE.

wfoondirt
Dirt Forum Champ
Total posts: 505
posted June 15, 2005 11:50 AM  
225 rr seems really soft if it is indeed mounted on the swingarm. If so then you would be transfering all the weight onto the right front possibly overworking it and causing your push.

What do your tire temps look like?

Also I would take some rake out of the panhard bar.

Without further information thats the only things that jump out at me.

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