98trans/am

iTrader: (1)

Just seeing if anyone has used any of the adjustable sway bars on the market for 93-02 4th gen fbodies. I know Hellwig makes a rear adjustable sway bar and Detroit speed recently released a front adjustable sway bar. My car currently tends to oversteer and im looking to try and fix that maybe with an adjustable sway bar. Any feed back is appreciated. Thanks

JD_AMG

What is your current setup now? If your car oversteers now and you have the stock swaybars then you would want to get a larger (35mm) front swaybar. Tell us what your whole setup is, shocks, springs,swaybars, torque arm, LCAs, etc.

98trans/am

iTrader: (1)

Current set up is adjustable koni shocks with bmw lowering springs, umi 35mm front sway bar and 23mm rear sway bar, umi lca's with lca relocation brackets and an adjustable umi panhard bar

JD_AMG

Im guessing you installed everything all at once and not one at a time to see the difference each part made?

Alright don't buy anything yet, lets go through a checklist.
Are you running the same tire front and rear? Not running some cheapo no traction all season tire in the rear?
You don't have the tire pressure jacked up in the rear right? No more than 30psi all around?
Are your rear shocks set at or near full soft and not full hard?

Are the LCA's poly bushings on both ends? (Poly can stick and bind which can cause oversteer) If so try putting your stock LCAs back on without the relocation brackets and go for a drive and see if you are still getting oversteer like you were before. If that does solve the issue but you still want to run aftermarket LCAs then get roto-joints on each end. If that doesn't solve the issue then put on your stock rear swaybar (which is 19mm) and go back out for a drive and try again, get back to us on here and tell us the results, it should be one of those two I would guess, assuming the check list didn't fix it above.

The problem with adjustable rear swaybars is some might start out at the stiffness you already have right now and only get stiffer with adjustment, which would cause more oversteer. Some may not be like that though, you will have to ask the manufacturer how they compare stiffness-wise with each adjustment. Plus you can run your stock 19mm rear bar for free or find a used stock 21mm rear bar off a 3rd gen for cheap, then the next step up would be roughly what you have now, a 22mm rear bar, and you don't want to go stiffer than that if you are already having oversteer issues.

00PewterSS

iTrader: (3)

Under what condition does the car oversteer? At the cars limit under trail braking or power it is normal (and desirable) to have some oversteer.

98trans/am

iTrader: (1)

Alright i decided to wait until i had some autocross time to update my findings with the current set up before changing things. Car had lots of oversteer on the tight course coming out of turns. The car was very planted on entry but could use more front camber. Through the turn it was the same but on exit the car loved to oversteer even with the slightest throttle input. Whats the first thing i should look to do?

00PewterSS

iTrader: (3)

Oversteer on power could be your diff, rear roll center (is your UMI bar adjustable roll center?), rear stiffness (springs, bar, shocks, bumpers). I think you mean you have BMR springs. If you bottom the rear suspension on acceleration that will suddenly cause oversteer as well. You could be getting into the jounce bumpers. I've never had any significant issue with power oversteer. I had issues with brake oversteer though.

JD_AMG

Answer these first:

Alright don't buy anything yet, lets go through a checklist.
Are you running the same tire front and rear? Not running some cheapo no traction all season tire in the rear?
You don't have the tire pressure jacked up in the rear right? No more than 30psi all around?
Are your rear shocks set at or near full soft and not full hard?

Do the free stuff first, like if you still have your stock rear swaybar laying around try putting that back on and see how it feels.

Sam Strano

iTrader: (41)

Let's start with the fact the rear bar is 22mm not 23. Is it a solid bar, or a hollow one? They made both. And a solid 22 is stiffer than I like for sure.

However, I want to focus on the fact it's loose on power down. That is pretty typical of a car with a lot of power and not a lot of grip. Anytime you spin the tires, you will get oversteer. It's worst with a stock, weak, limited slip. If the balance of the car is ok mid corner, then a smaller bar will hurt that, and you already state you lack front camber, so I think the issue here is that it's time to look into a better diff, better tires, etc.

98trans/am

iTrader: (1)

Last time I ran the car i ran the front tire pressures around 30-32 psi and the rears around 28 psi. The tires are a square set up 295/35r18 michelin pilot super sports. The shocks are set about the middle of soft and hard. I dont have my stock sway bar.

Sam Strano

iTrader: (41)

Have you tried softer rear shocks? Have you tried a full tank of fuel? Both? You might even be able to run a little less rear air (maybe, maybe not).

98trans/am

iTrader: (1)

First time i ran about an 1/8 of a tank and did notice a difference when i ran a 1/2 tank at my last event. Car still feels very loose mid corner sometimes and other times its planted. Going below 28psi I lost a lot of traction. How much would hollow sway bars help whether I do one in the rear or the front of the car? I also know I need more front camber but upper and lower a arms are a little out of my price range currently.

00PewterSS

iTrader: (3)

My experience with PSS is that they need more pressure or they feel sloppy. I experienced oversteer as well with 30psi in them. I would try a much higher pressure with those, like 35psi hot square and see how it feels. I think their sidewall stiffness isn't so great so they need more pressure. They aren't the best AutoX tires even though they are a very good tire overall.

Hollow vs solid bar stiffness isn't much because the rate of the bar is from the outside of the bar.

Sam Strano

iTrader: (41)

First, you need to confirm if you have a hollow bar now, or not. That is kind of important. As for will a hollow make a difference from a solid. Yes, saying otherwise ignores the variable of wall thickness, and I don't use a super thick wall tube. A solid piece of steel is harder to bend than a hollow one. It's true because of how a torsion bar works that you get MORE effect from the outside of the bar, which is why you start figuring bars as diameter to the 4th power, but there is more to it than just the diameter.

00PewterSS

iTrader: (3)

Sam, you ever checked the rate between a solid 35 and a hollow? I have a solid bar now, and considered a hollow bar, but if you are saying the tubing isn't that thick it would make quite a difference in the rate.

pdxmotorhead

Lowing a car doesn't always make it drive better if the whole package isn't sorted,
My old road race car I had 12 full sets of springs, wet/Dry for 3 tracks, plus the ones that didn't work..
You can only dial out so much oversteer with tire pressure..
Stiff springs will do as much as a stiff bar to let the rear get loose.
Stiff flex joints(LCA's as noted above) can raise hell...
Are you lifting the inside rear when it lets go? Sometimes if you have too much quick roll it will
plant the outside tire too hard then inside rear lifts and you don't gain as
much traction on the outside as you lost on the inside and around she goes..
How old are the tires and how many times have they been run? (If you've already scuffed the outside edges off ... they may give up early.)
Was the surface prepped by being swept and vacuumed or just swept? (It matters.. )
The Alloy of the bars matters too..


Good luck..

98trans/am

iTrader: (1)

Yea I know the pss arent the best tire but they were the best for everything all around since he car is my daily and I dont have another set of wheels yet. Running around 28psi was when the car was its fastest. I started around 36psi and the lower i went the faster my times got and the more planted the rear end felt.

98trans/am

iTrader: (1)

Its a 22mm solid rear sway bar from umi. What are your thoughts on getting a watts link to help out with the overtsteer? The autox course im on isnt the nicest pavement and isn't flat, its also very sandy and dirty which could be causing this problem as well. I was thinking the adjustable sway bars so I can have more adjustment with the car once I can really have to become a track/autocross focused build.

98trans/am

iTrader: (1)

Speaking of springs my spring rates are most likely off. Im running 550lb springs front and 150lb springs rear. The inside wheel is lifting up on turns but it isnt close to three wheeling. Theres a lot left I want to do with the car once it can become a more autocross/track focused build. Just trying to figure out how to get the car really dialed until I can really build it up.

Sam Strano

iTrader: (41)

it's softer, it just isn't a lot softer. My front bars use a quite thick wall tube, to maximize the stiffness for the size. But it isn't solid, and that does have an effect. I said the tubing in I use on the rear isn't super heavy, the front is much more thick wall.