I'll bite. I run STU (05'-06') and use a 25mm solid Progress rear sway bar (stock front). I have the bar set up on the softest setting. I actually fine tune the suspension with spring rates rather than sway bar settings or thickness. Although the rear sway bar can help determine your cars response to corner turn in and exit, where it really defines your needs is mid corner or steady state cornering. If you like to brake late or trail brake, a simple click or two on your dampening can reduce oversteer on corner entry. Autocross is all about smooth, controlled, and quick transitions. A lot of guys I know run the stock rear bar and stiffen the rear spring rates.

I don't believe one bar is that much more improvement over the next when your talking brand names. There is also a point that big is too big. Also, IMO, I personally would not use a hollow bar on my car.

Dave

 

I've got a perrin 25mm rear sway bar. Performs great and gives the car a balanced, neutral feel through corners. I use the middle setting for even balance (eliminating any stock understeer issues) but you can also use the softest setting which may help your driving style. 27mm is just huge, thats str8 drift style

 

Within a tolerance of about 5%, all spring steels have the same modulus of elasticity which is what sets their intrinsic flexibility of a steel for use as a swaybar. The yield strength of the material will affect how far the bar can twist before it takes a permanent set. Assuming that there are no swaybars out there made from dirt cheap material that takes a permanent set at relatively low strains, any 27 mm bar is going to be way stiffer than any 24 mm bar (even if the 24 mm bar has shorter arms).

 

Why wouldn't you use a hollow bar? Of the top of my head, I can't think of any drawbacks to using a hollow bar.

 

Wow I cannot believe that I put oversteer. What I should have typed was understeer.

Silencer~ I'm not for sure on why you wouldn't use a hollow bar. Being that the bar is hollow doesn't make it weaker it just makes it lighter. I can prove that to you if you would like.

I think that I am just going to go with a 24 or 25mm bar. I think any bigger than that would just be too much for street tires.


Thanks for the input everyone.

 

I have the works 24mm sway bar set on medium. It's an excellent mod for the money

 

why wouldn't you run a hollow bar? Simple - given enough torque, they can bend. On paper a light swaybar sounds great, but if you are going to add weight to a car, the swaybar is one of the areas, given its low location on the car, where the weight can be a good thing

 

Not significantly more than a solid bar. The central region of a sway bar contributes only a minor amount to the torsional rigidity and strength of a sway bar. This is because the central region undergoes the least amount of strain, and because there actually isn't that much material there.

 

I have the Cusco 23mm 3-way adjustable rear sway bar I love it. I can set up the car every type of Autocross track if needed. And if I need to adjust it well thats about 5 minutes and two wrenches away. My set up also has just about every part Cusco makes for the car as well so I guess that might make it perform better. Great parts excellent performing as well on the street or the track.

 

From all my research, I have found that most people recommend running a 25mm solid rear swaybar and better endlinks for a budget setup. I don't want coilovers etc etc coz its a hassle FOR ME! (no flaming, please)

So, I chose to go with the progress rear 25mm swaybar (robispec approved), perrin end links and the swift MR specific springs. I will do the robispec toe kit and bushings as well some sort of camber correction for the front (plates up top maybe). I may replace the front swaybar bushings with poly ones. Thats about all my suspension setup will consist of. I will add all the cusco bars onoe by one to help firm the car up. Thats all my Evo needs IMHO.

 

i am currently running:

Agency Power 27mm Adjustable Rear Sway on SOFT setting (25mm)

and WORKS/Ohlins stage 3 coilovers

i have a cusco 25mm front that i havent installed yet

handle great

super balance

 

it should definately take care of that understeer of yours....I got major oversteer right now, but I can handle it....although, I still need to upgrade my front swaybar to balance it....

 

Who said anything about the center region? Do you think a hollow bar is only hollow in the center region? Hollow bars may be rigid or strong enough for street duty, but there is a point reached that the hollow bar starts to repeatedly distort enough to fatigue the metal. Ultimately bending. I have seen the remnants of 2 bent hollow bars on a 3200 lb car (race only).

Benefits? Can't say for sure, but does any factory (GM, Ford, Mitsu, Subaru, etc.) use hollow bars on their sports cars? All of the Speed GT/Touring car teams that I've followed use solid bars. Like I stated, it's just my humble opinion.

Dave

 

problem is that a hollow ball is hollow all the way through, except at the mounting tabs

Having seen quite a number of hollow bars bend at the track, for my money, on a car that sees the track, solid is the way to go. Plus like I mentioned, if you are going to add weight to a car, what better place than at one of the lowest points.

 

I just installed my Agency Power 27 mm rear sway bar. This thing is awesome. I can definitley tell a difference as far as stiffening up the rear end. Its been raining here the last few days so I havent really been able to test it out, but taking turns really feels good. its hard to describe, but I am definintely glad I went with that one. I have it set at the softest setting, which I'll probabaly leave at until I do more suspension mods.