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Author Topic:   New 3 link lack forward bite
HIGHVOLTAGE
Dirt Roller

Total posts: 7
posted September 22, 2002 06:49 PM
Just coverted car from stack leaf to 3 link.Kinda puzzeld here.Lr trailing arm at 5 degress uphill,rr at 5 degrees uphill,3rd link at 25 degrees,axle damper at 5 degrees uphill,j-bar at 15 degrees angel downhill toward pinion.Lr spring 200 rr 175,both are mounted behind axle right now.56% rear.Car has 75 lbs. lr in it.Will not set good going in and getting lot of wheel spin down straights(529 gear).Last night cars let off in front of us when he let off gas car all over track,never had nothing like this happen before.Any sugestions would be greatly apreciated.If i raise both lower bars up at the same angels would this not give me forward bite?

CUSTOMPERFORMANCE
Dirt Freak

Total posts: 464
posted September 22, 2002 07:45 PM
Put the left spring ahead of axle and the right on top of axle. run about 10-15 deg in left trailing arm and about 5-10 deg in the right. run about 10-15 deg in the j bar with the pinion in the second hole up from bottom.rear % about 56 and the left at 52 and the cross around 51-51. do you have a spring or a rubber biscuit toplink? i am using the spring bar and use 600-700lb spring in it and have had the best luck this way. lr is about 140 lbs of bite.

[This message has been edited by CUSTOMPERFORMANCE (edited September 22, 2002).]

tilley88
Dirt Full Roller

Total posts: 64
posted September 22, 2002 10:00 PM
CUSTOM, how long is your pullbar, and how much pre-load do you run? Ever try a solid bar?

HIGHVOLTAGE
Dirt Roller

Total posts: 7
posted September 23, 2002 07:52 PM
Running spring loaded toplink with 700 lb spring.Put about 1/2 inch preload on it.Ours is mounted at the drive shaft loop.

CUSTOMPERFORMANCE
Dirt Freak

Total posts: 464
posted September 23, 2002 08:30 PM
I run the afco with a 600lb spring and its mounted off the drive shaft loop at about 15 deg angle centered with driveline.

CUSTOMPERFORMANCE
Dirt Freak

Total posts: 464
posted September 23, 2002 08:31 PM
I just snug the plate up with no preload on the spring on the top link. Also the main key is the length and angle of the lower trailing arms.

tilley88
Dirt Full Roller

Total posts: 64
posted September 24, 2002 07:21 PM
I've got the afco pullbar but can't find a rating on the spring. I believe it's 600 or 700 lbs. I also put 1/4" preload in it. It's mounted on top of the loop w/20-22 degree downhill angle. I'm not sure of the angles of the lowers, but their on the 4th hole up.

HIGHVOLTAGE
Dirt Roller

Total posts: 7
posted September 24, 2002 08:43 PM
Custom we moved the lr spring in front of the axle.Our lower trailing arms are set at 15 degrees on the lr and 10 degress on rr.The length is 15 inches.This is the changes that you suggested what can we expect from this.Our track is a 3/8 mile track with moderrate banking that gets black by the end of the heats.

dirttrackracer
Dirt Forum Racer

Total posts: 77
posted September 30, 2002 05:23 PM
1/2 inch preload is too much on torque link,go to 1/8 and put rear percentage up to about 59% without driver.

[This message has been edited by dirttrackracer (edited September 30, 2002).]

bogged
Dirt Full Roller

Total posts: 53
posted September 30, 2002 05:41 PM
Custom

What kind of frame heights are you using with this setup using a metric frame?

dirttrackracer
Dirt Forum Racer

Total posts: 77
posted September 30, 2002 07:12 PM
HIGH VOLTAGE, I should of went more in depth in previous reply.The 700 spring is very close for a three link type suspension,a 600 would be good for tracks that get very slick.You complained of a forward bite problem,which with everything else being close, a 1/2 preload and lack of rear percentage could very well be the only problem you have.I do not like to run any up hill angle in the right rear bar,but when track slickens will raise left rear bar as far as I can.(up to 2o-25 degrees) Make these small changes and let us know what happens,I think you will be pretty happy.

[This message has been edited by dirttrackracer (edited September 30, 2002).]

HIGHVOLTAGE
Dirt Roller

Total posts: 7
posted October 01, 2002 07:29 PM
Dirttracker ran the car friday night and pulled off our first win.Feels good too be going in right direction again.Took some of the preload out and upped rear percentage haven't got real radical on lower bars yet.We are gonna pull a little gear out of the car this weekend and see what that does he beleives he can put the pedal to the floor through the corners.When our driver is more comfortable with all these changes gonna try different bar combos.

CUSTOMPERFORMANCE
Dirt Freak

Total posts: 464
posted October 02, 2002 05:34 PM
I am using frame heigths of 6"-6.5" from bottom of frame to ground in front and 3"-3.5" frome bottom of axle tube to top of rear underslung bars for the mid metric chassis i build.

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