steve40th

Okay, can someone explain to me the proper way to adjust a sway bar with adjustable links. And how do you make it , via adjusting, to corect understeer, oversteer and to make things nuetral?
I have Fred Puhns book, but, I need a visual or a sailor proof answer as to how to adjust front and rear, particualry toa C4 if possible,.
Thanks, Joe the Sailor

Nimo

I'm not an expert, but always believed that you would set the car neutral with your weight in the drivers seat.
- Except if you are on velodrome type track.
Yes/No ?


/Nik

steve40th

I want to know how to though. Just disconnect and reconnect it so its level? no stress? etc etc

Nimo

When the bar is neutral, there should be no binding and the end links should be possible to insert in to the control arm mounting hole without force.
- Normally that is also when they are the same length and you can set them before you mount them. The actual length depends on what the bar looks like and may need to be adjusted to clear draglinks etc.

I have always just set mine at the same length as the stock ones as a starting point.


/Nik

Solofast

First of all, you want to make sure that the car is corner weighted correctly with the bar or bars disconnected. Then you want to make sure the car is on a level surface and connect the bars so that there is no preload on them. That means that the bolts that attach the bars to the suspension don't create any load in the bars when the car is sitting on a flat surface.

The end links of standard bars don't have an effect on the understeer/oversteer relationship. That is controlled by the stiffness of the bars. You can change the stiffness of the bar by increasing the diameter, changing the mount stiffness (going from rubber to poly bushings) or, you can adjust the length of the arm of the bar. This is how most adjustable bars work. If you shorten the arm, the bar becomes stiffer and that will reduce grip at that end of the car. If you lengthen the arm, the suspension will have more leverage on the bar and it will be less stiff and that will give you more grip.

So, for a front bar if you want less understeer, you want to make the arms longer, if you want more understeer, you want to make the arms shorter.

Bill Hetzel

Yep what Solofast said. There is no adjustement on almost all swaybars on production Corvettes. The adjustable links are there only to prevent preload on the bars. And what he said about "corner weighted correctly" is important.
I'd only add that " corner weighted correctly" is with the driver (or simulated weight) in the car so when adjusting the links to neutral, that weight needs to be in the car.

TedDBere

What the others said. An adjustable bar and an adjustable endlink are two different things.

An adjustable bar will either have holes in the arms of the bar for the endlink to be moved either in or out to increase or decrease the bar's flex, or it will have different arm lengths that can be used with the bar. Shortening the arms increases stiffness and lengthing them will make the bar softer.

An adjustable endlink will have helm joints connected together with a screw mechanism that can extend or shorten the length of the endlink.

To adjust the endlinks you attach the bar to one side with an endlink set to a position that puts the bar where you want it so it is not rubbing anything (the actual position does not seem to effect the performance of the bar). Once you've tightened the first endlink, with the suspension loaded but not compressed (sitting on the ground/lift), you adjust the second endlink by attaching one of the ends of the link and then screwing in the other end until it can pass easily, without binding, in and out of the second attachment point. When you get it right it's fairly obvious. Torque everything down! If you hear popping from the suspension then the endlinks are most likely not tight enough.

It's a fairly easy job, good luck.

argonaut

Thanks "Joe the Sailor" for posing this question.

I understand you adjust the bar stiffness by changing the length of the arms. But I don't understand the importance of the adjustable end links yet. Solofast mentions that you adjust the endlinks so that there is no "preload". Forgive my ignorance but why is this important? Or to put it in more parctical terms - what effect does this have on the car's handling. Thanks.

beerkat

gkmccready

If there's load on the bar when the car is neutral the bar is already starting to play its role in the suspension. Meaning it's already applying forces when it should be doing nothing at all.

What effect that has will be determined by positive or negative pre-loading and if the pre-load is even side to side or not. A bit of a crap shoot.

A big reason for adjustable end-links with adjustable swaybars is because you often can't actually get stock length end-links to reach all the possible adjustment locations in the arms.

froggy47

subscribe.

C66 Racing

In general, you want the cross corner weights to be equal (RF+LR=LF+RR). Grassroots Motorsports website has a pretty good explantation of why in their online aritcles tab (article titled "understanding corner weights").

As was mentioned above, to set corner weights, the sway bars are disconnected so they don't impact the corner weights and minor changes to ride height are made to increase/decrease the weight on on the cross corners. If you raise the RF, the weight on the RF and LR will go up as will the total of that cross. So to change the cross weights you really have four options (raise one of two corners or lower one of the two others - or any combination thereof). It's thus pretty easy to get to a 50-50 cross weight without really changing the ride height significantly.

When you are done, the sway bars need to be reconnected. Usually, my ride height adjustments are so minor that the endlink bolt I disconnected just slides right into its hole. If it doesn't, I adust the length of that endlink as required.

If the sway bar end link is too short or too long, it will impose a torque to the sway bar thus increasing effective weight on one side and lowering it on the other, which effectively changes the corner weight and cross weights. This will cause the car to handle differently when turning left than right. For most road courses, this isn't beneficial, though in circle track I believe that this technique may be used to modify the cars handling since it always turns in the same direction.

Although this is fairly complicated, I think that by increasing the weight on a tire, say the RF, you improve that tires grip. So, if my car understeered to the left, I think that if I increased pre-load on the RF (outside front) I could reduce that understeer. Note that this would cause the weight on the LF to go down so the car would understeer more in right hand corners.

Road courses are predominantly CW or CCW and theorhetically you could use pre-load to your advantage, but that would take a lot more knowledge than I have and a lot of testing time to see how much of an impact changes have on overall lap time. Gaining in one place will hurt in another...

trackboss

Subdriver I am pretty sure you meant to say that if the car understeered you would soften the outside front tire(and its diagonal rear). When boiling it down it does go both ways. If a corner is too soft it will understeer and will do the same if it is to firm. However, in general its best to go in the direction of soft for understeer unless the spring rates are way too soft. I always use RF/LR for cross weight percentage(circle track standards). Here's an example: On paper a 55% cross will generally help the car turn IN right better. There's many variables to consider however. If the side to side weight is biased towards one side considerably you may find that a 50% cross is not neutral. Also, on high hp cars you may tune for corner exit so you can put the power down and sacrifice turn in. You can make up for any understeer with the throttle. You will find that on cars with decent power you steer using the throttle and use less steering wheel input. Didn't mean to derail this topic. Just trying to help others understand. It took me years to understand this stuff and I continue to learn all the time. It can be very confusing for those with little experience.

-V

steve40th

Thanks, this all really helps. Basically with the bars disconnected, and car on ground, or on a lift with weight of body on the suspension, you want to disconnect bars and ensure (with me in it) that the bars go into their respective mounting eyelet with no force, to ensure the bar isnt pre loading already. The rear will be a little difficult due to getting to the bar end.
Now an adjustable sway bar will have multiple holes in it to adjust the stiffness of it, which in turn would allow you to fine tune the understeer/oversteer.

argonaut

After reading the responses and the artical on GRM (thanks Subdriver) I understand the purpose of adjustable endlinks and reasons you don't want preload. Excellent stuff, thank you much.

Any recommendations on performance shops that can do corner weighting in the Harrisburg, PA area?

steve40th

Okay, without actually doing the corner weighting, due to being a leaf spring non adjustable C4, can I just put a person of the same weight in drivers seat, disconnect the front sway bar on either side, and see if the bar goes up/down on one side. Then if it does, just make an adjustable link to compensate for the length change. Would that work for both sides?

varkwso

Thanks for the link info

C66 Racing

I'm partial to Phoenix Performance in Phoenixville. Tour Joe's shop once and you'll get sucked in.

Solofast

No, you should try to corner weight the car first, a C4 does have adjustment, it just isn't in the front.

With a C4 you do the corner weight jacking with the rear spring bolts. Even if you are in a stock class there is usually enough adjustment available in the rear to get the car pretty well corner weighted. In a street prepared class you can use longer bolts on one side and get plenty of adjustment to get it corner weighted. Most C4's were heavy on the drivers side front, so you could tighten up the drivers side rear spring bolt and loosen the passenger side one as much as you could and get a cotter key into it and you will be pretty close on corner weights. As I said, in a class with the allowance, you can use a longer bolt on the passenger side and get it right with no problem.

While we always say that it is best to have the front bar so that there is no preload, sometimes ya gotta do what ya gotta do. Sometimes you have to live with a little bit of front bar prelaod to get the corner weights right, and if you are in a stock class you might have to live with a little preload, if you are only putting 15 or 20 pounds into the front bar it isn't a big deal. In the C4 the stock rubber bushings are tight on the bar and the bushing rubber deflects in torsion when the bar moves. A little bit of preload in that case won't harm anything. On newer cars with lubricated bushings it is worse since sometimes bars with preload will move to one side or the other in repsonse to the preload, but with the jackscrews on the springs, the for C5's and later, preload can be eliminated so you should.

steve40th

Okay, so you can sorta corner weigh the C4. Here is my weights
W/Me in it 3480 LF 955, RF 880, LR 890, RR 755
What would you do. Now this is with bars attached, but for general purpose taining etc.