adjusting corner weights w/ heim joint front sway bar links?
#1
Race Director
Thread Starter
adjusting corner weights w/ heim joint front sway bar links?
I bought some adjustabl solide heim joint sway bar links to replace the deteriorated rubber links of my 93 vert w/ 32 mm solid bar.
I got these from exotic muscle. They said that I could adjust corner weights with these?
How do you do this? I do have some scales.
I imagine you do thhis with an assistant and yourself seated in the car.
Also, are you supposed to do this on the rear also? Or just front?
Any help is appreciated
I got these from exotic muscle. They said that I could adjust corner weights with these?
How do you do this? I do have some scales.
I imagine you do thhis with an assistant and yourself seated in the car.
Also, are you supposed to do this on the rear also? Or just front?
Any help is appreciated
#2
Drifting
I've never used the adjustable heim joints to assist in achieving a certain corner weight or corner balance. They are useful in making sure that once you have the weights set, there's no preload in the bar that skews the weights.
The way I've always done it is to scale the car with the bars disconnected, then use the adjustment to insure that when the links are installed the bolts go smoothly through the rod end and the bar (i.e.: you don't have to force the bolt through the hole in the bar, because that's what puts the pre-load into the sway bar, affecting the corner weight). You can scale the car with one side connected, and adjust the other side to achieve no pre-load.
That means when you reconnect the bar the car should be sitting at the desired static ride height.
If you can do both the front and rear, that's desireable.
The way I've always done it is to scale the car with the bars disconnected, then use the adjustment to insure that when the links are installed the bolts go smoothly through the rod end and the bar (i.e.: you don't have to force the bolt through the hole in the bar, because that's what puts the pre-load into the sway bar, affecting the corner weight). You can scale the car with one side connected, and adjust the other side to achieve no pre-load.
That means when you reconnect the bar the car should be sitting at the desired static ride height.
If you can do both the front and rear, that's desireable.
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jcriner (09-16-2018)
#3
Race Director
what they mean is by using heims, you can properly adjust your corner balance at the spring and reset the bars to neutral when you are done. Adjusting the corner balance, to then only jack things up with misaligned bars, is nearly useless.
You adjust the balance using the OEM spring adjusters, and yes you balance the entire car, by simultaneously trying to get a 50/50 crossweight and dialing in your ride height/rake.
You adjust the balance using the OEM spring adjusters, and yes you balance the entire car, by simultaneously trying to get a 50/50 crossweight and dialing in your ride height/rake.
#4
Tech Contributor
David,
Al just wrote it all! The only thing that we would stress is for you to have the scales PERFECTLY LEVEL, each individually, and all four as a group, before weighing. Changing corner weights involves adjustments to the SPRING connectors or mounts, NEVER to the anti-roll bars, which should be disconnected.
Once the corner weights are satisfactory, then WHILE THE CAR IS STILL SITTING PERFECTLY LEVEL, reconnect the anti-roll bars, just as Al instructs.
There are several other threads here concerning adjusting corner weights.
Ed LoPresti
Al just wrote it all! The only thing that we would stress is for you to have the scales PERFECTLY LEVEL, each individually, and all four as a group, before weighing. Changing corner weights involves adjustments to the SPRING connectors or mounts, NEVER to the anti-roll bars, which should be disconnected.
Once the corner weights are satisfactory, then WHILE THE CAR IS STILL SITTING PERFECTLY LEVEL, reconnect the anti-roll bars, just as Al instructs.
There are several other threads here concerning adjusting corner weights.
Ed LoPresti
#8
Le Mans Master
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St. Jude Donor '09-'10-'11
Unless he has a VBP adjustable spring, or I mounted my OEM spring UNDER the control arms and used bolts through the arm to hold the spring up. Now both front and rear of my car are height and weight adjustable. I havnt had it on track yet because I need to finish the engine first.
#9
Drifting
I can see adjusting the rear on a C4 with the spring connectors, but then you are probably preloading the rear bar, right? So I assume to do a C4 you need heims at both front and rear bars? Adjust corner weights with the rear spring and then install both heimed bars with no preload?
#10
Tech Contributor
Mike and Bill,
(With due apologies to David for a temporaty hijack of his thread.)
Whenever one attempts to prep a street car for the track, there are a whole raft of compromises, and you are both RIGHT ON THE MONEY -- the front end of a C4 is a real PIA! However, making the best choices of the available compromises is what seperates an incredibly handling car from one that is difficult to drive fast.
While David made a big step forward in ADJUSTABILITY with his anti-roll bar, we are still using non-adjustable bars on our C4 racer, so here is how we attack the problem:
[1] Loosen the attachments to both F and R anti-roll bars.
[2] Roll car onto a perfectly flat surface.
[3] Settle suspension by compressing and releasing F and R.
[4] Securely tighten all attachments to both F and R anti-roll bars.
[NOTE] We have now effectively removed static pre-load from the anti-roll bars. From this point forward, since our bars are non-adjustable, we treat them just like any other solidly mounted suspension member. If we were to make any GEOMETRY changes to our suspension (not alignment), we would need to repeat this process.
From this point, we now proceed with setting ride height, doing the alignment, and adjusting corner weights.
Returning to the front of the car, if the ride height from side-to-side is
equal, as measured from fixed reference points ON THE FRAME, to the perfectly level horizon, then we will not need any wedging of either side of the spring. So, if front ride height needs changing, all changes can be handled at the center where the spring clamps to the chassis.
If, on the other hand, the ride height varies from side-to-side, and in the absence of a VBP-style adjustable spring connector, one will need to attach an appropriate thickness shim to the spring on the lower side of the front.
With front ride height satisfactory, and set equal from side-to-side, we now proceed to set rake by adjusting the connecting bolts on the rear springs, again shooting for equal ride height from side-to-side.
Without calling out all the excruciating details of alignment and corner weights, we next do:
[1] Caster
[2] Camber
[3] Toe
[4] Corner weights, adjusting now from the rear spring connecting bolts.
[5] Repeat as necessary . . . .
It is a lengthy, and pains-taking process, where short-cuts do not reward. And, like all things in racing, it is a cluster of compromises. Done carefully, the results can be stunning.
Ed
(With due apologies to David for a temporaty hijack of his thread.)
Whenever one attempts to prep a street car for the track, there are a whole raft of compromises, and you are both RIGHT ON THE MONEY -- the front end of a C4 is a real PIA! However, making the best choices of the available compromises is what seperates an incredibly handling car from one that is difficult to drive fast.
While David made a big step forward in ADJUSTABILITY with his anti-roll bar, we are still using non-adjustable bars on our C4 racer, so here is how we attack the problem:
[1] Loosen the attachments to both F and R anti-roll bars.
[2] Roll car onto a perfectly flat surface.
[3] Settle suspension by compressing and releasing F and R.
[4] Securely tighten all attachments to both F and R anti-roll bars.
[NOTE] We have now effectively removed static pre-load from the anti-roll bars. From this point forward, since our bars are non-adjustable, we treat them just like any other solidly mounted suspension member. If we were to make any GEOMETRY changes to our suspension (not alignment), we would need to repeat this process.
From this point, we now proceed with setting ride height, doing the alignment, and adjusting corner weights.
Returning to the front of the car, if the ride height from side-to-side is
equal, as measured from fixed reference points ON THE FRAME, to the perfectly level horizon, then we will not need any wedging of either side of the spring. So, if front ride height needs changing, all changes can be handled at the center where the spring clamps to the chassis.
If, on the other hand, the ride height varies from side-to-side, and in the absence of a VBP-style adjustable spring connector, one will need to attach an appropriate thickness shim to the spring on the lower side of the front.
With front ride height satisfactory, and set equal from side-to-side, we now proceed to set rake by adjusting the connecting bolts on the rear springs, again shooting for equal ride height from side-to-side.
Without calling out all the excruciating details of alignment and corner weights, we next do:
[1] Caster
[2] Camber
[3] Toe
[4] Corner weights, adjusting now from the rear spring connecting bolts.
[5] Repeat as necessary . . . .
It is a lengthy, and pains-taking process, where short-cuts do not reward. And, like all things in racing, it is a cluster of compromises. Done carefully, the results can be stunning.
Ed
Last edited by RacePro Engineering; 11-03-2011 at 08:28 PM. Reason: Elaboration
#11
Melting Slicks
OK. I've never adjusted corner weights.
I can see adjusting the rear on a C4 with the spring connectors, but then you are probably preloading the rear bar, right? So I assume to do a C4 you need heims at both front and rear bars? Adjust corner weights with the rear spring and then install both heimed bars with no preload?
I can see adjusting the rear on a C4 with the spring connectors, but then you are probably preloading the rear bar, right? So I assume to do a C4 you need heims at both front and rear bars? Adjust corner weights with the rear spring and then install both heimed bars with no preload?
And in a perfect world you'd take off the rear bar too. But the rear bar is a lot smaller than the front bar so you won't be jacking nearly as much weight back there. Also in SCCA solo stock classes you can't dink with the rear bar so it is just left alone.
Another reason to disconnect the front bar is that on lots of cars (like on a C5) if the front bar is preloaded, it will often walk from side to side since it can slip in the bushings and that can screw things up.
In a C4 the front bar is mounted in rubber and it won't walk to one side if it is preloaded. As a result, you can, and I have, at times preloaded the front bar on a C4 to get the corner weights to where I wanted them and it worked fine.
Sometimes you do what you gotta do..... I always felt that getting corner weights right was more important than unloading the front bar.
#12
Drifting
Some great info here! But, keep in mind the reason for adjusting corner weight, rake, ride hieght, ect..., is for one goal......
Make the car comfortable and perdictable to drive at high speeds while aggressivly cornering, braking hard, and accelerating. With a perdictable handling car you are comfortable driving, your speeds will increase and times will decrease.
Make the car comfortable and perdictable to drive at high speeds while aggressivly cornering, braking hard, and accelerating. With a perdictable handling car you are comfortable driving, your speeds will increase and times will decrease.