Ridetech triangulated 4 link modification

[exwestracer]

IMO, if you try to get over 100% AS (with LCA level), you are seriously compromising the handling and braking on a street car. Like Bret said, avoid having the UCA lower at the axle end. You are asking for wheel hop. Since you are trying to get it right, consider weighing the car, finding the actual neutral line, and shooting for that. Your LCA is locked in as you've modified it, so your only tuning option is the UCA mount on the axle end.

[DRJDVM's '69]

Started wondering about how everything was set up with the AirBar "out of the box"....dug some old pix of everything before I started to screw with it to get it lower...




Looks like the LCa is pretty horizontal.....UCA angled up a few degrees to axle

[DRJDVM's '69]

I read all the instructions for the "generic" weld in ridetech 4 link systems...both triangulated and parallel.......their instructions for both are to position the LCA and UCA so that they are level.

My other option is to have the LCA axle bracket made again with another hole at the bottom...that would drop the rear LCA mount, so the bar would be angled down front to back.

[DRJDVM's '69]

I'm going to bite the bullet and have the axle LCA mount re-done...drop the lower bolt hole.... I guess the big question is what angle on the LCA am I shooting for?

[bret]

I'm going to bite the bullet and have the axle LCA mount re-done...drop the lower bolt hole.... I guess the big question is what angle on the LCA am I shooting for?

We have a multi hole lower axle bracket that will drop your lower bar by 1inch. Call and talk to Rodney.

[DRJDVM's '69]

Hey Bret
I actually bought that bracket... But when I got it, the shock mounts weren't in the same location relative to the axle centerline and the holes were smaller... So I would have had to drill out the holes and change some other stuff to get it to work with the way I have stuff set up now

Would have been great if I had started with it at the beginning, but won't really work now

[onair]

Ned,

We can do the bolt in lower bracket with the multiple hole setup also to replace your existing one. With it you could lower the rear of your bar by 1" without any modifications to anything else. Give me a call here at the shop and we can work it out.

[bret]

Hey Bret
I actually bought that bracket... But when I got it, the shock mounts weren't in the same location relative to the axle centerline and the holes were smaller... So I would have had to drill out the holes and change some other stuff to get it to work with the way I have stuff set up now

Would have been great if I had started with it at the beginning, but won't really work now

With the level of modifications that you have done / are doing, you're likely better off fabricating a lower bracket from scratch. What you want to end up with is [at ride height] the lower bar to be parallel to the ground [assuming the chassis of the car is parallel to the ground]. If a variation is to be made, it is acceptable for the lower bar to run slightly higher in front than at the axle. That would move your instant center up but won't be a factor except in forward traction [drag racing]. Having the lower bar higher in front will also serve to give you a slight bit of "roll oversteer" and will help the car rotate a bit through the turns. As with anything mechanical, the "best" solution is still the one that sucks the least. I sometimes use lower bar angles to fine tune a rear suspension. Sometimes you can resolve an understeer problem by "rear steering" the car.
The upper bar [again, at ride height] should be about 2 degrees nose down [lower at the front]. With that configuration the theroretical intersection point of the bars [from a side view] would be around the center of the flywheel. While there are mathmatical formulas that seem to dictate the "best" location for the instant center, I have found that on anything less than a finely tuned race car you actually have quite a bit of latitude on the exact instant center point.

Here is what you DON'T want:

1. If the lower bar is "nose down" [lower at the front than the back], the instant center ends up somewhere in infinity [or at least in an incalculable and unknown area] and you can experiece tire shake on acceleration. It also induces a lot of pinion angle migration becuse as the suspension compresses, the bottom of the rearend housing is pulled forward at an increasingly quicker rate. Another secondary effect is "roll understeer"...a condition that few cars benefit from.
2. If the upper bar is "nose up" [higher in front than in back] you get the same results as above...an instant center that is ugly, excessive pinion angle migration, and tire shake on acceleration.

I think the point here is the car can be built to any ride height you choose...BUT, that ride height should be determined and accommodated for from the beginning. To change the foundation of the car in mid build, while possible, becomes really difficult. Beleive me...I've been where your are My typical path to making things work is to find out a few ways that DON'T work!

Looks like you're on the right track. Keep in mind that I am NOT criticizing your decisions or your work...just trying to explain to everyone else viewing what is important and what has some latitude.

Good luck with the build...keep us informed of your progress!

[DRJDVM's '69]

Thanks Bret
Had a talk with Rodney yesterday to help me think things out

I'm having a new LCA bracket made that will drop the mount another inch which should put me level to a degree down in the rear..... Rodney is trying to find me some a
Pre made axle brackets to work with or I'll make my own to get the UCA down about 2 degrees in front....

This snowball all started when we shortened the upper shock mount to get the car lower.... Price I have t pay to be cool

Bottomline is that I'm trying to get this dialed in now while the car is still bare metal in million pieces... Now is the time. It's taking me alot of "well that ain't going to work" moments but now I know what my goal really is, I'll make it happen... Just more work and time... But I want it to be right

[l_and_t_reproductions]

I totally agree. That is awsome!

That's what I love about this forum, you didn't even have to call the manufacturer, he's right here.