Let me ask you this question.......when the left rear is up on the bars and the right front is over on the bump as far as it can be (which is always).....what is your thoughts on camber ? ......would you say it is what it is and start thinking about what happens over all next ? when the car is in attitude like I just described where does the weight go on corner entry ?...remember my user name......I'm not to enlightened with 4 links
I did stay at a Holiday Inn the last few days in Charlotte so with just a quick read about 3/4 links I can answer you. It won't be correct especially since I have no talent for correct answers since dumb questions are my thing. So I only took a quick 2 minutes to scan up on it.
I'm not into knowing exactly what parts are involved with each and everything on anything I try to only get involved first with what needs done and second how you may need to alter the machine which in this case is a race car, to do what you need done.
Movement wise all you need to do with a rear end is cause the chassis to move up and down around it and to control how the chassis rotates or doesn't rotate around the axle. First off it doesn't make any sense to me to think about rear end movement in terms of how it moves in the chassis. That is because the rear end has axles extending from each side of it with tires mounted on each end. It's the tire axle assembly which determines the definition of what is going straight on the track not the chassis and attached sheet metal. If you really want to understand how a chassis is working out on the track you must have a reference. I am convinced there is only one valid reference of control for of anything your racing on the track, whether it's axle's tires are non staggered, staggered or reverse staggered. The only valid baseline reference is the direction your axle assemble wants to roll without any input from your chassis. For a staggered or non staggered race car going or rolling "Straight" is the direction your axle naturally wants to roll.
Everything you do setting up a chassis, weight positioning and weight movement both mechanical and dynamic along with your tire preparation is about making your axle want to roll in the direction you want to roll. If you can't your only option is to force the axle to roll via turning your front tires or reducing grip at one or both rear tires. Fast is about your skill off the track and the drivers skill on the track to make the axle roll in the direction needed for racing. Any input from the front tires to turn the car creates a conflict between tires which eats both hp and grip which sets up potential to reduce your ability to accelerate in any direction. It's that simple.
What's not so simple is every kind of car your racing has built in per rules reductions in its ability to use your chassis, hp and grip to cause your rear end/axle assemble to roll in the direction you want to go.
All that BS which i'm not sure is in anyway correct to say my quick scan tells me the few difference between 3 and 4 link besides the parts is that if you have the room or need for additional movement of the chassis around the axle in any way a 4 link will accommodate additional movement. The 3 link per design and the need panhard bar constricts your ability to move the chassis up and down and around the axle. I think a 3 link or even a 4 link needing a panhard bar would be easier to think about or get a grip on how forces are applied to the back of the car. I think the difference is between forces being applied through triangulation points as opposed to mainly through a panhard bar. That's especially telling to me when I think about super modifieds. And how one builder will chose to place the up and down directional adjustment of force applied to the rear tires on the right and another have it on the left. If you ever look at one of Ray Bodnar's current chassis and how his chassis preform at the end of the straight the importance of how rear weight is directed will become obvious. And it's not all about the lateral projection of weight because of his positioning of the panhard bar.
The above though I don't know it's correct was to lead me into another though about the difference between use of a 3 link verses a 4 link. I think because so much force is associated with the panhard bar it becomes very hare with a panhard bar to sort of ease the movement of dynamic forces around the back of the car. Because of that and with the writing of these thoughts on it, I think a 4 link would be easier for the driver to ease into turn in as opposed to having to have a more abrupt turn entry. All in all with the huge use of chassis movement on a late model I think a 4 link would suit it better. On the other end of the spectrum with it's unique weight distribution and lesser chassis movement, I think a panhard bar would be a must for a super modified.
Well that was fun to write. I don't have a clue if any of it is ok or correct but right or wrong it does seem to flow ok.
3link, did I do ok or even half ok? I figure you read this far so thanks for listening to my dumb thoughts trying to throw an answer to your question.
Edited by dirtstudent2, 11 November 2019 - 09:45 AM.