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Author Topic:   3 link set-up
Still Learning
Dirt Roller

Total posts: 21
posted May 05, 2004 08:31 PM  
Here are the details...

DW8 3 link (2002). 175 rr spring(behind housing) 200 lr spring (in front of housing). 650 lf spring 700 rf spring. lf shock 74 rf 75. lr shock 94 rr shock 94. panhard bar 8 1/2 inches on frame and 3rd hole up from bottom on pinion side. Monty style pull bar with blue biscuit. cross weight 51%. I have scales and scale the car often.
Question... When I first bought the car it hooked up great. Not really fast because the lf was off the ground way too high. It done this for me two races last year. Ever since I can't get the bite it once had. Lf won't come off the ground at all. New ball joint, sliders, etc. Not in a bind that I know of.
What am I missing???????

mod70
unregistered Total posts: 21
posted May 05, 2004 08:49 PM           send a private message to Still Learning   Edit/Delete Message   Reply w/QuoteBBBBBB
Springs and shocks sound about right, but I think you're a little light on cross. It really depends on how much rear % you've got, but most guys have closer to 52%-53% cross. The more rear you've got, the more cross you want. Generaly, I run closer to 58%-59% rear and around 53% cross. As for your pan bar, I tend to go by deg. because your ride hights can affect the angle. Mine is usually around 17 deg. One more thing to consider is how old is your biscut? They do wear out after a while, and you might need to check the pre-load on it. You shoul have 1/4 in. pre on it. Hope this helps. Anybody else want to jump in on this one?

udecide66
Dirt Freak

Total posts: 229
posted May 05, 2004 09:01 PM  
Are you running on old tires, new tires hook up a lot better than old ones. they do get harder the longer they sit.

zeroracing
Dirt Forum Champ
Total posts: 1875
posted May 05, 2004 09:07 PM  
if it was doing it and does not now. then replace the bisuit, they are only good for about 5 races total or less. make sure it has preload on it. check the shocks for dead spots.

de94wcc
Dirt Forum Racer

Total posts: 87
posted May 06, 2004 08:32 AM  
We have had several DW 3-link cars, and this is kinda how we ran ours (just noting the differences from what you gave). Here is what I would try:
1. 150# RR and a 225# LR spring.
2. 750# RF spring
3. You need to lower your panhard at least 1" on both ends.
4. Don't worry about cross. Rear percent is your friend, don't leave home without it! At least 60%.
5. Try to get your hands on a spring style pull bar to try it out. The biscuit bars do not remain consistent over time.

I hate to throw ten things at a guy, especially ones that could cost you money to try. Just my two cents, though.

Good luck!

tilley88
Dirt Forum Champ
Total posts: 879
posted May 06, 2004 12:17 PM  
Time to get a new biscuit if its rubber, or check the pre-load if its an x-factor.

XC man
Dirt Full Roller

Total posts: 39
posted May 07, 2004 07:02 AM  
On a three link , what does the torque arm do other than control pinion angle setting ?(Bar angle ) ?

mod70
unregistered Total posts: 39
posted May 07, 2004 09:30 AM           send a private message to XC man   Edit/Delete Message   Reply w/QuoteBBBBBB
It helps to keep you from what's known as 'shocking' your rear tires. When you get back in the gas it allows the rear end to pivot slightly, and acts like a shock absorber for your throttle, helping to keep you from breaking the rears loose. It also contributes to adding 'rear steer' in the car.

xhubby
Dirt Freak

Total posts: 376
posted May 07, 2004 02:47 PM  
Exactly what effect does it have on the car when you move the pullbar up or down on the chassis mount? How long are uerothane (spelling?) biuscuits good before they need to be changed? Thanks.

Still Learning
Dirt Roller

Total posts: 21
posted May 08, 2004 08:31 AM  
Everyone... Thanks for the input. I have changed out the biscuit 2-3 times and even went with the blue biscuit which I was told would last longer. How about the rear end offset? When I originally bought the car the only thing I changed out was the panhard bar and I did not know how long it was. I just measure from the dampner shock bracket over to the right side frame rail and put it on spec at 13 7/8". Is this good or should it be more to the right or left?

mod70
unregistered Total posts: 21
posted May 08, 2004 11:08 AM           send a private message to Still Learning   Edit/Delete Message   Reply w/QuoteBBBBBB
Still learning: I line up my right side tires, but some guys I know run them out of line. There is a complicated formula for finding your rear roll center. Let me look through my Circle Track magizines (www.circletrack.com) and see if I can find it. I might not get back to you today, but check in tommorow or mon. to see if I found it.

xhubby: You just hit 2 things I can't help you with. I know the rubber bisc. only last about a half dozen races or so, but I'm not sure about the uero, euro, gyro... not rubber biscuts last. I also can't tell you just what changing the pullbar angle will do, I believe more angle will help with forward bite, but don't quote me on that. Maybe someone else has some info on this. I'd like to know too! If we don't get a good response here, we might have to post that as a seperate question on the main page.

mod70
unregistered Total posts: 21
posted May 10, 2004 05:21 PM           send a private message to Still Learning   Edit/Delete Message   Reply w/QuoteBBBBBB
S.L.: Well I looked up the info on rear moment center and roll centers, but there are too many varriables to even begin to figure this one out for you. As best as I can figure (to maybe get you a decent starting point) is to measure the distance between the center of your rear tires, find the center of that distance, and set that center 4 in. left of the center line of your chassis. (found by the center point between your front ball joints at ride height, and carried straight back in a square line along the length of the chassis) Hopefully this will tell you where the rear end should be centered in your chassis, which will dicate how long the panhard bar needs to be. If anyone can give a better idea than this, please do so. Good luck, S.L.

Still Learning
Dirt Roller

Total posts: 21
posted May 10, 2004 08:40 PM  
DFR: Thanks for the input. I will try that. One last question for now. What hole should I put the panhard bar on the pinion side? I have heard it should be level with the center of the pinion?????

tilley88
Dirt Forum Champ
Total posts: 879
posted May 10, 2004 10:13 PM  
Put in the hole just below pinion centerline.

mod70
unregistered Total posts: 879
posted May 10, 2004 10:14 PM           send a private message to tilley88   Edit/Delete Message   Reply w/QuoteBBBBBB
It's a matter of what feels best, however I do mount my short bar below the pinion 2nd from bottom.(4 holes) It seems to help to get the car to roll over the top of the rear end more and plant the RR. Helps on a flat slick track. GL.

jrf3
Dirt Full Roller

Total posts: 28
posted May 11, 2004 08:28 AM  
what holes do you have the trailing arms located in? The rt rear trailing arm on a 2 link plays a big factor in traction and steer. Also I strongly agree that you need to move your pan bar down to the second hole up from the bottom on your pinion. Rear steer and forward bite control the lft front lifting. You should have your rt trail arm in the second hole up and your lft bar all the way to the top. Run about 85lbs of lft rear bite. And throw that rubber pull bar away. A spring pull bar on a 2 link is way more consistant. The rubber ones most generaly are to radical and inconsistant.

Still Learning
Dirt Roller

Total posts: 21
posted May 11, 2004 09:02 PM  
I have the left link on the very top hole and the right link on the 2nd hole down from the top. Do I need to lower the right another hole? If I bought a spring type pull bar what kind and what spring rate?
Thanks abunch.

mod70
unregistered Total posts: 21
posted May 11, 2004 11:32 PM           send a private message to Still Learning   Edit/Delete Message   Reply w/QuoteBBBBBB
S.L. - if you lower the RR control arm too much, you'll lose rear steer. Once the bar goes past horizontal when the car rolls over, it will begin to pull the rear tire back toward the front. I had a post for another dude who asked how the rear end moved, you might look at it. (post:rolling over posted by:modracer15 on:may 6 about 3/4 the way down)
Most spring arms use around a 1000# spring with a 1/4 in. pre load on them. Softer for dry/slick, stiffer for a heavy track, but jrf3 is right, much better than buscuts.

[This message has been edited by mod70 (edited May 11, 2004).]

Ego Racing
Dirt Forum Champ
Total posts: 724
posted May 12, 2004 10:49 AM  
Is your panhard bar a J-bar? If it is make sure it is exactly the same as the old one. Our Late Model stopped rolling over and we couldn't figure out what happened. After checking everything we found the 3 J-bars we had were all different heights. The one that was on the car got the bearing broken in a wreck, the one we put on was 1 1/2 inches taller on the pinion end, when our pit help put it on he set the angle the same as the other the only problem was the chassis end was about 2 inches higher. Our other spare bar (New never put on the car) is about 1 inch shorter than the first. It would not even make it to the bottom of our mount without hitting the pinion.

Ego Racing
Dirt Forum Champ
Total posts: 724
posted May 12, 2004 10:51 AM  
Also when you replaced it did you get it back in the same hole? Rasing the pinion or chassis mount rasies the roll center and stops the weight from rolling over the roll center.

XC man
Dirt Full Roller

Total posts: 39
posted May 14, 2004 10:49 AM  
What is a good angle to run on the thrird link ? And how does the angle affect handling ?

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