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Author Topic:   4 LINK SETUP
A2KY2K88
Member
posted February 24, 2000 11:35 AM
I NEED HELP WITH THE SETUP OF A 4 LINK AS FAR AS CONTROL ROD PLACEMENT, TYPES OF PANHARD BAR OR J-BAR, AND SPRING RATES. ANY HELP WOULD BE GREATLY APPRECIATED. I KNOW THE BASICS, BUT AM LOOKING FOR OTHER OPINIONS. I HAVE ALREADY READ THE AFCO BOARD.


jammin
Administrator
posted February 27, 2000 09:51 AM
What do you want to start with? Maybe we can learn something here.

[This message has been edited by jammin (edited 02-27-2000).]

A2KY2K88
Member
posted February 28, 2000 12:20 AM
quote:
Originally posted by jammin:
What do you want to start with? Maybe we can learn something here.

[This message has been edited by jammin (edited 02-27-2000).]


1. WHAT CONTROL ROD SHOULD BE AT MORE OF AN ANGLE, THE TOP LEFT OR TOP RIGHT?
2. WHICH HOLES SHOULD THE BOTTOM RODS BE IN?(HOW MUCH OF AN ANGLE)
3. RECOMMEND SPRING RATES? I RUN A SMALL HIGH BANKED DIRT TRACK. I RUN A DW-8
4. HOW MUCH RR LEAD, IF ANY, SHOULD I RUN. OR SHOULD I RUN OPPOSITE??
5. SHOULD I MOVE THE TORQE ARM TO THE LEFT ON THE REAREND AND THE FRAME BRACKET??
IF YOU CAN ANSWER THESE, IT WOULD BE GREATLY APPRECIATED.



jammin
Administrator
posted February 28, 2000 07:10 AM
OK, first lets go to the Left Rear. For me personally (a lot of this setup stuff will depend on the driver) I like as much left rear bite as possible without the car pushing. So the Upper link on the LR will have as much angle upward from the birdcage to the frame as I can get in most cases. The bottom link will also be an upward angle from the bird cage to its link, but it doesnt have to be as an extreme angle to work. Now with this setup, when the car rolls into the corner, the left rear will not move as much as the RR, so most of your angles stay somewhat the same. If anything the angles will increase in the turn, this will help you bury the LR. Most of the time, I will set this and leave it that way. (My preference) Then I will manipulate the RR and panhard/jbar. I will let you reply to this before I go further.

Hope this helps.

A2KY2K88
Member
posted February 28, 2000 01:00 PM
EVERYONE KEEPS TELLING ME TO TRY CLAMPING THE LR. WHAT ARE THE BENEFITS OF NOT CLAMPING EITHER SIDE, KEEPING THEM FLOATING?
2. I UNDERSTAND ABOUT THE ANGLES OF THE CONTROL RODS. NEXT QUESTION.


jammin
Administrator
posted February 28, 2000 01:25 PM
When you clamp the LR, you use the actual pinion rotation to lift the left rear up extremely high, I have seen several cars with this setup, I think it can be useful if used within some limitations. Flatter tracks can benefit from this type of setup. When you clamp the LR, you eliminate the rotation within the birdcage. When you do this, you pull with the top link, and push with the bottom. This makes the car lift on the LR. When it lifts, it buries the LR in ground. I think this can be overdone though. Driveability is the key.

On the RR of the car, on the 4 link, is crutial. If your racing a tacky track, you can allow a little roll steer to help the car to turn and not have to manipulate weights very much. With this setup, you can get more forward bite than the others, but you gain some negative roll steer. You put upward angles on both rod as on the Left Rear, when the car rolls into the turns, the geometry of the arms will push the RR back somewhat. This will make the car a little looser than normal through the turns. On a tacky track you can afford to be a little looser than normal. Then you com off the turns, the rearend is trying to drive underneath the car when you are on the gas. This in return gives you a gain in forward bite.

On a dryer track, you want to try as much as possible to counter having too much roll steer in the car. If possible, make the rearend steer to the inside of the track when the weight is distributed in the turns. This in turn will make you tighter throughout the turns, which will also let you go in a little harder than normal. You can move the bottom bar down on the chassis side to counter the top bar's movement during this downward motion. This will help somewhat. If you want it tighter, just lower the upper along with the lower on the RR and it will make the car even tighter.

ok.....waiting for a reply.

A2KY2K88
Member
posted February 28, 2000 11:20 PM
OK. SO FAR IM RIGHT WITH YOU. I RUN ON A SMALL HIGH BANKED TRACK WHICH IS ALMOST ALWAYS DRY SLICK. KEEP THIS IN MIND WHEN ANSWERING.
IN YOUR OPINION SHOULD I CLAMP ANYTHING OR RUN FLOATING?
I HAVE A 3 HOLE BRACKET FOR THE LOWER CONTROL RODS. I AM GOING TO START OFF IN THE MIDDLE HOLE.
I WILL HAVE A LITTLE MORE ANGLE IN THE LEFT UPPER CONTROL ROD THAN THE RIGHT. DOES ALL THIS SOUND CORRECT SO FAR?
ANY HELP ON HOW TO SQUARE THE CAR UP IN THE REAR SO I CAN FIGURE OUT HOW MUCH RR LEAD I SHOULD USE. ANY SUGGESTIONS ON THIS? THANKS...


jammin
Administrator
posted February 28, 2000 11:33 PM
Your not too far off. If the track has a decent banking, I dont see a reason to clamp a car. Centrifigal force pushes you toward banking on a steeper track, you wont need as much left rear. If it gets dry slick and you want to try to clamp the car, do it, but only on the left side. Clamping a 4 link on the right side will kill you. I see clamping a measure of when a car is running a relatively flat track and needs to keep the left rear on the ground when trying to set the right side tires with roll. That is the only advantage I can see with it. Your just basically getting more wedge into your car. Thats what it basically does. You can do that by manipulating other things on your car.

The way we square our car is to block the tires in the front so it wont move, then, use a plumb bob and shoot the center of both front ball joints, shoot a straight line back and drop the bob behind the rearend tubing, mark them on the floor and measure them, make your dedisions with those measurements. You can move the rear back and forth, as long as the front wheels wont move.



A2KY2K88
Member
posted February 28, 2000 11:36 PM
THAT IS HOW I SQUARE MY CAR. I RUN BOTH SPRINGS BEHIND THE AXLE, AND I DONT KNOW A WHOLE LOT ABOUT INDEXING. ANY HELP ON THIS??


jammin
Administrator
posted February 29, 2000 05:47 AM
Are your spring mounts directly on the bird cages?


A2KY2K88
Member
posted February 29, 2000 10:35 AM
YES. MY SHOCKS ARE IN FRONT AND SPRINGS IN REAR. BOTH ON BIRD CAGES


jammin
Administrator
posted February 29, 2000 10:51 AM
Is there a way you can put your LR spring in front of the housing off of the housing, instead of having it on the birdcage?

This can be very important.

[This message has been edited by jammin (edited 02-29-2000).]

A2KY2K88
Member
posted February 29, 2000 09:06 PM
THERE IS NO WAY TO PUT THE SPRING ANYWHERE EXCEPT THE BIRDCAGE. I CAN PUT IT IN FRONT OR REAR, BUT THE ONLY WAY IT WILL BE EFFECTIVE IN FRONT OF THE HOUSING, IS IF I CLAMP THE LEFT REAR. OTHERWISE, IT WOULD BE BENEFICIAL TO KEEP IT BEHIND THE HOUSING SO IT INDEXES WHEN I ROLL INTO THE TURNS


jammin
Administrator
posted March 01, 2000 05:43 AM
This is one thing that I see that is lost when using a 4-Link. When the pinion raises under acceleration, the rotation of the housing can be used to manipulate the weight on the car. You can do this somewhat with a birdcage, but not as much. On a 4-Link, it still depends on the geometry of the arms. You can put the LR spring in front of the birdcage in some situations and get more LR bite off the turns.

[This message has been edited by jammin (edited 03-01-2000).]

A2KY2K88
Member
posted March 01, 2000 10:30 AM
SHOULD I MOVE THE RR AHEAD OR BACK, AND HOW MUCH EITHER WAY?


jammin
Administrator
posted March 06, 2000 08:08 AM
To start, you want to try to go square. See where your at. Then the rearend needs to go forward in the turns unless your trying to loosen the car, then it can go backwards with the geometry of the arms steering it. Then, if the car skates to the wall, then take it up some, bring it forward an 1/8 at a time. It will make a huge difference and will tighten the car up.

[This message has been edited by jammin (edited 03-06-2000).]

A2KY2K88
Member
posted March 13, 2000 12:05 AM
ANY OTHER TIPS OR SECRETS??


jammin
Administrator
posted March 13, 2000 07:16 AM
Personally, I prefer a Panhard bar over a J-bar. The J-bar (under acceleration) tends to lose sidebite. The panhard bar increases sidebite depending on where its located. I want more sidebite so I can set the car in the turns and accelerate through the turns more. It seems to help us.


donnie
Member
posted March 13, 2000 06:58 PM
Jammin should you use a full length panhard bar or a short one? Doesn't the length affect roll center placement as far as left to right is concerned?


jammin
Administrator
posted March 14, 2000 06:37 AM
I like the shorter ones. I think it helps weight transfer to the right.


roostertail
Member
posted March 14, 2000 07:31 PM
Just wondering, what tires are you all on? We found that running the american racer tire with the 4 link we just couldn't get or stay hooked up. Even with well over 60% rear. But when we ran a tire like the mcreary 82.8 we could run the car with no lead and fly. never really understood other than the softer sidewall, went back to a 2 link, and really haveing good luck, but still think the 4 link should have performed better.



A2KY2K88
Member
posted March 15, 2000 12:58 AM
I RUN THE AMERICAN RACER AS WELL. HAVE NOT RAN THE CAR YET


jammin
Administrator
posted March 15, 2000 10:09 AM
Make sure you take a look at your fifth coil travel when you first run it, if the spring is too stiff, the car will want to spin alot on the Americans


roostertail
Member
posted March 15, 2000 03:52 PM
We ran the 150# fifth coil spring the most. At least thats where it seemed to work the best. We did try the progressive spring, didn't seem to be any better, unless we ran the 82.8's. We did not try the clamp bracket on the left rear, think I would have liked it, Love it on the late model.



A2KY2K88
Member
posted March 15, 2000 09:37 PM
HEY ROOSTER, IS IT IMPORTANT TO CLAMP UP THE LEFT REAR OR NOT. WHAT SIZE AND SHAPE OF TRACK WOULD THIS BE BENENFICIAL FOR??


roostertail
Member
posted March 16, 2000 04:49 PM
Can't say for sure on the mod, I feel it would work well but didn't try it. Late model for sure, I like it the most when its dry, really plants the left rear, it can create a push at times but shouldn't be as bad on the mod. Best on short tracks with tight turns, you know on and off the gas type. I have only played with it for one year but I like it, Hope that helps.



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