Thanks for all the input guys. I went with the 19mm H&R bar from Turner Motorsports.

 

Good choice, especially if you make more modifications later. I liked my 22mm bar with H-sport springs (back in 2003), but since going to camber plates and coil-overs, a 22mm bar plus 450 lb/inch rear springs was just too much.

 

Dude, once you've had it for a while, please share your impressions. I want to get the same bar myself eventually

 

I can give you my impression of the H&R 19mm.
I do only street driving and have mine on the firm setting.
It made my car neutral, which is what I wanted. I like a neutral feel in a front wheel drive car.

It is a very nice bar for the street.

 

Seems to be the consensus, thanks
I was planning to leave it on the "Soft" setting and move it up when AutoXing. How does the Soft setting compare to stock?

Thanks again

 

stabilizer bars are part of a car's suspension system. They are sometimes also called anti-sway bars or anti-roll bars. Their purpose in life is to try to keep the car's body from "rolling" in a sharp turn.

Think about what happens to a car in a sharp turn. If you are inside the car, you know that your body gets pulled toward the outside of the turn. The same thing is happening to all the parts of the car. So the part of the car on the outside of the turn gets pushed down toward the road and the part of the car on the inside of the turn rises up. In other words, the body of the car "rolls" 10 or 20 or 30 degrees toward the outside of the turn. If you take a turn fast enough, the tires on the inside of the turn actually rise off the road and the car flips over.

Roll is bad. It tends to put more weight on the outside tires and less weigh on the inside tires, reducing traction. It also messes up steering. What you would like is for the body of the car to remain flat through a turn so that the weight stays distributed evenly on all four tires.

A stabilizer bar tries to keep the car's body flat by moving force from one side of the body to another. To picture how a stabilizer bar works, imagine a metal rod that is an inch or two (2 to 5 cm) in diameter. If your front tires are 5 feet (1.6 meters) apart, make the rod about 4 feet long. Attach the rod to the frame of the car in front of the front tires, but attach it with bushings in such a way that it can rotate. Now attach arms from the rod to the front suspension member on both sides.

When you go into a turn now, the front suspension member of the outside of the turn gets pushed upward. The arm of the sway bar gets pushed upward, and this applies torsion to the rod. The torsion them moves the arm at the other end of the rod, and this causes the suspension on the other side of the car to compress as well. The car's body tends to stay flat in the turn.

If you don't have a stabilizer bar, you tend to have a lot of trouble with body roll in a turn. If you have too much stabilizer bar, you tend to lose independence between the suspension members on both sides of the car. When one wheel hits a bump, the stabilizer bar transmits the bump to the other side of the car as well, which is not what you want. The ideal is to find a setting that reduces body roll but does not hurt the independence of the tires

 

I concur. Hence my 450 lb/in springs in the rear, plus a 19mm bar on the weakest setting - and the car rotates NICELY but remains neutral mid-corner.

 

I've got Alta springs with stock struts and adjustable lower rear arms. Rear negative camber is set at 1.5%. Front negative camber is .5%. Rear toe in is .30 degrees. My front castor dipped below 4%. The car feels more stable at this ride height for sure when I push it with my et 37mm, 17 by 7 O.Z. Ultraleggeras.

The stock sway bar feels sufficient to me. Would it be worth it to go with a stiffer rear sway bar set up? I've autocrossed the car in stock configuration and plan to auto cross and do the odd track day with the car going forward. Thanks in advance!

 

That says it all right there. Motor on, and only buy a rear bar when you feel you have a problem to solve.

 

Two ways to think of this.

1- You feel your stock sway bar is OK. But this is based on what comparison? And also you have to consider your skill level. If you push your car really hard you might get to the level that your rear swaybar is at it's limit. Maybe you feel you don't really appreciate this.

What class do you autocross in? How are your doing locally within that class? If you are not at the top then keep working on getting steady improvement and no rush to upgrade the rear bar but if you are near the top then consider a modest upgrade.

2- You can do a few more suspension upgrades. Front camber could use more help. Either add fixed front Ireland camber plates or add adjustable front camber plates. This will allow for -2 to -2.4 degrees negative camber in front.

To balance more front neg camber you can then add an adjustable rear sway bar. Three holes is best and either 19 or 22mm will work. 19mm most likely usable for autocross while 22mm might work for track/ autocross.
Both still usuable for street. Softest settings probably a good place to start.

Depending on your class for autocross the front camber plates may be legal.

 

For those of you that are looking for just a little more rear sway bar I have a cheap fix for you. If you remove your drop link off the stock rear bar you will notice that their is enough room to drill another adjustment hole in the bar and still be able to clear the shoulder of the nut before the flattened area of the bar begins to grow. I do not know how much in percent that this would increase the bar's stiffness but it would be some.
Steve

 

Your math is right but the conclusion needs a little clarifying.

Going from a 17mm to a 19mm bar results in about 156% of the original stiffness, which is to say an increase of 56%.

Neil
05 MCS
96 M3

 

I recently put a 19mm bar on mine, its on the stiffer of two settings, and actually had to reduce my tire pressures (were in the high 30s) on the highway because the car was just too damn responsive and twitchy. I would say for a street car you don't need anything more than that.

I am switching mine to the softer setting, greasing the bushings, and taking off the s-lites for a set of holies (with the 175 conti all seasons) when I put my new exhaust on tomorrow. Should be fun.

 

There are endless factors that will contribute to what type of bar / other suspension mods you'll want to do. It just depends on what you want to accomplish with the mod. I personally have everything suspension-wise in my car, as stiff and rigid as can be. I just enjoy the way the ride feels like that.

 

I have the Alta 19" bar installed (middle of 3 settings) due to the stock sway bar causing too much desire on my cooper to feel rolly in a tight road rally curve. Now it drives much better, and feels much safer. My wife (as passenger) complained she felt unsafe on the curves and noticed the car ahead wasn't applying any braking as I had to, to feel safe. Now the car is great....I also learned I needed to reinitialize the Flat Tire Sensor after installing the sway bar! Thanks for all the education guys, I now know I picked the right one.

 

I was vacillating between the 19 and 22 for quite a while. Feedback form here, as well as from other sources, has convinced me to go with a 19mm bar.

Zip

 

Yes, for any MC owner the adjustable 19mm bar is a good place to start.
You can start with the softest setting and work up to the middle setting if you want.

For MCS owners the 19mm or 22mm bar is fine for most uses. The adjustable holes allow for customization enough.

I have an MCS used for the street and autocross set on the stiffest setting with a 22mm rear swaybar and it's fine for daily use as far as I'm concerned.