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Author Topic:   Lift bar/pull bar?
mavrik82
Dirt Forum Racer

Total posts: 93
posted January 08, 2005 07:53 AM  
We are putting together a chassis with a 4 link and z link option. It has a BIG engine making a lot of medium rpm torque and the car is also a little heavy (but balanced). We run a 1/2 mile fairly flat track with a decent lengthed front straight and a long mildly curved back straight on IMCA tires. All my experience is with pull bars but someone once told me that while a lift arm will not hook up as quickly, it will hold traction longer down the straight. I see the late models running them, but they have real tires. Sure would like it if some racers with lift arm experience could get a little dialog going on the subject.
Thanx,
Brett

sdracer12
Dirt Maniac

Total posts: 180
posted January 08, 2005 08:08 PM  
I've run both, and I agree the lift arm didn't seem to have the "instant" bite like a pullbar, but it did hold the bite longer on a 4/10th track with long straights. Admittedly, I didn't run it enuff nights to really get it dialed in though.

Anyone who has run a liftbar with a 4/4 car or 4/z car, what kind of spring rate did you use? I used a 300# spring, 1/4" preload, 73 shock.


joeltjen
Dirt Maniac

Total posts: 182
posted January 08, 2005 11:45 PM  
we have a long lift bar (42") ran a progressive spring with a 4010 bilstien.(the shock adds like 25# to the spring rate. we have a swing arm on both sides. the thursday night practice for the fall classic we tried a new setup in the car and it was awesome. we stiffened the fronts, softened the right rear and move 50# from the left side to the right. the car three wheeled all the way down the back stretch! everybody told us this was not the fast way to go but we picked up 300 rpm on the tell tale! we had over 3 1/2" of compression on the spring. cant wait till april to start the year with that setup cause last year kinda sucked. sdracer12, you comming over to viking next spring??? stop over and say hi. later, john

sdracer12
Dirt Maniac

Total posts: 180
posted January 09, 2005 01:10 AM  
Yes John, we will be back at Viking a couple times next year. It was a fun, fast 1/2 mile track.


What kind of progressive spring did you use on the liftbar? I was only getting around 2" of travel on the 300# spring.

joeltjen
Dirt Maniac

Total posts: 182
posted January 09, 2005 12:17 PM  
hi. we used the afco PR spring. its like 10 1/2 inches long so we had to make a spacer for it. i have the specs from afco on it somewhere, i can find them if you want. we are thinking of having bluecoil make us a 13 inch for it. we are also putting in mounts this winter to run the pull bar also. we struggled all year with the car as we changed it over from a wishbone to a swing arm last winter. yah, most of the year we were only getting around 2 or 2 1/2 travel on a 250# spring but i was always lacking the forward bite i thought we should have. we always got murdered on starts and restarts since they moved the start cone over to turn 4. alex is a tough place to hook up at though, cant explain it to anybody till they've been here. later, john

mavrik82
Dirt Forum Racer

Total posts: 93
posted January 10, 2005 05:23 PM  
Thanx, and if you can come up with that progressive spring rate it would be appreciated. Any one else out there had any experience with them? I have never played with them and I'd like to experiment.
Thanx,
Brett

6WRACN
Dirt Newbie

Total posts: 2
posted January 18, 2005 10:05 PM  
in our experience the best sping rate was determined by adding the right front and left rear spring rates and dividing by 2. i.e. rf 700 lr 200 = 450 spring. that is with a 39" long lift arm with a dampener shock of 94. not saying that is the best method, but it had worked on our sportsman when we ran before mods. (basically a mod with 10" tires and a little heavier.

joeltjen
Dirt Maniac

Total posts: 182
posted January 19, 2005 10:18 PM  
quote:
Originally posted by mavrik82:
Thanx, and if you can come up with that progressive spring rate it would be appreciated. Any one else out there had any experience with them? I have never played with them and I'd like to experiment.
Thanx,
Brett

hi, the spring we used was rated : 180# @1", 290# @2", and 400# @3" . i was looking at the car tonight and i'm thinking the 3 1/2" of travel we were getting was putting us at or almost at coil bind!! i'm going to take the spring out see how close it really is.

GRTWallbanger
Dirt Maniac

Total posts: 196
posted January 20, 2005 11:30 AM  
Afco told me the progressive lift bar spring is not avaolable anymore?I had the part number and everything for them?

sbateman
Dirt Full Roller

Total posts: 46
posted January 20, 2005 10:19 PM  
i have a car with a z-link and a lift bar setup and was thinking about making it a 4-link and a pull bar instaed , its a new car and im looking for pros and conns
its a modified with small tires on a 3/8 mi track dry slick by feature

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