Hey all I have a question about 4 link preload and body roll. My 6.20 big block back half car has a pretty good twist to it after going to 3800 from 3000 launch. I needed to leave a little higher to be in my spot on the bottom.

The 4 link is neutral right now. Would lengthening or shortening my top right bar help combat the twist? An anti roll bar would be the best route I know but just trying to tune it okay right now.

Thanks in advance!

I have been at the track and forgotten which way it is before, and discovered if you support the third member and car, and simply give that bar a turn, it is visibly obvious which way it goes. It will push that side of the axle down that is getting the additional preload.

Lengthen the upper right side bar which results in more weight on the LF and RR tires.

Thank you. Tim’s videos are very good, I’ve watched most of them and a lot of Kevin Wilson’s videos.

I’m too stubborn to have someone else set it up so it’s time to learn. I’m replacing all the rod ends because they are very old and will put a couple flats of negative in and see how she does.

Buy or borrow a set of scales

quote:

Originally posted by 1320racer:
Lengthen the upper right side bar which results in more weight on the LF and RR tires.

Wrong
Shorten top right bar to add preload/weight to the RR/LF

scales will tell you which way to turn.

quote:

Originally posted by 1320racer:
scales will tell you which way to turn.

Cant argue that!

quote:

Originally posted by Jonesz:

quote:

Originally posted by 1320racer:
Lengthen the upper right side bar which results in more weight on the LF and RR tires.

Wrong
Shorten top right bar to add preload/weight to the RR/LF

I have seen videos where pro's have had it backwards and even one book that was reversed. From a fella I really respect too. Easy to mis speak or write it wrong and miss it in editing.

Hell I have even seen pro's get it wrong regarding pinion angle for that matter.

Dave Morgan is no pro and never was!

quote:

Originally posted by 1320racer:
Dave Morgan is no pro and never was!

We can agree there. Professional writer I guess would be correct.

quote:

Originally posted by Goob:

quote:

Originally posted by 1320racer:
Dave Morgan is no pro and never was!

We can agree there. Professional writer I guess would be correct.

This was a professional builder. And that's all I'm sayin about that.
Morgan just had a different way of looking at the picture. Not wrong IMO, but different. I like to look at all challenges in several ways. So I don't mind the view.

So which rear tire do I want to add weight to in order to combat body roll?

quote:

Originally posted by DragRacerJosh:
So which rear tire do I want to add weight to in order to combat body roll?

You want around 50 lbs more on the right rear with you sitting in the seat.

Shorten the top bar on the right side.

If you don't have scales, try 2 - 3 flats.

quote:

Originally posted by DragRacerJosh:
So which rear tire do I want to add weight to in order to combat body roll?

Look at what the car looks like at launch and it will answer your question. Although it is much harder to get a visual on a dragster. One tire is getting pushed away from the chassis, and one looks like it is getting sucked up into the chassis. You want the one that is sucking up to have more weight. If you adjust it on the ground, you can actually see or measure the car twist slightly and lean according to your adjustment.
If you can't see from a rear picture at launch or video, pay attention to what the front tires are doing. They tell the opposite story of the rear at launch. When I had my four link altered, a 2x4 under one front wheel, and adjust the bar til neutral was about right for that car.

quote:

Originally posted by Mike Rietow:

quote:

Originally posted by DragRacerJosh:
So which rear tire do I want to add weight to in order to combat body roll?

You want around 50 lbs more on the right rear with you sitting in the seat.

Shorten the top bar on the right side.

If you don't have scales, try 2 - 3 flats.

this.

i set mine with no one in the seat because no one is ever with me. i scale mine and make the right rear about 75 heavy. this again is with nobody in the seat. an anti roll would be a plus and something to do in the future.

ep-yes....shorten top right bar adds weight to right rear. if you think about it the top bar is running down hill. by shortening the top bar you are pulling the tire towards the ground. at least that is how my feeble mind remembers it.

I’ve been setting the RR 50 lbs. heavy as a baseline on all my cars for the past 15 years, even more if your LF isn’t at least 50 lbs. heavier than the RF on a door car.

My Firebird with driver

This message has been edited. Last edited by: 1320racer,

adding preload to reduce body roll is a bandaid at best. the amount of preload controls the direction the car goes not the amount of body roll. something is flexing in the chassis or the setup has the totally wrong springs for weight.

scales are a great place to start.