[justpete]

Originally Posted by dicostal

That is another great point. I have the sport package with sport springs if I get the m3 sway bars (bmw or H&R) should I be changing springs or are stock springs ok? (I will reach out to Turner Motorsport for their advise and report back )

I originally had the sport package and upgraded to the Performance Suspension at 897mi, huge difference. After upgrading to a race suspension the Performance Suspension front ARB and rear upper shock mounts are still there although I did upgrade the front ARB bushings to BMW Motorsports Group N parts. The springs were chosen by the suspension shop based on the ARB with little to no need to ever readdress it in the future. So really it's possible to upgrade springs, front and rear, from the sport pkg to pretty much anything without addressing the ARB at all as long as the spring rate provides equivalent roll rate. But the price of this is a harsher ride. If you can tolerate it then the ARB is pretty much meaningless unless pushing the car to the limit on the track. Otherwise go for the M3 bar and leaves the springs alone for the time being to see if it provides the roll resistance you want and the ride comfort you're looking for. You haven't really said what your goals are but I'm guessing it's to minimize roll while maintaining streetability, correct?

[dicostal]

Originally Posted by justpete

I originally had the sport package and upgraded to the Performance Suspension at 897mi, huge difference. After upgrading to a race suspension the Performance Suspension front ARB and rear upper shock mounts are still there although I did upgrade the front ARB bushings to BMW Motorsports Group N parts. The springs were chosen by the suspension shop based on the ARB with little to no need to ever readdress it in the future. So really it's possible to upgrade springs, front and rear, from the sport pkg to pretty much anything without addressing the ARB at all as long as the spring rate provides equivalent roll rate. But the price of this is a harsher ride. If you can tolerate it then the ARB is pretty much meaningless unless pushing the car to the limit on the track. Otherwise go for the M3 bar and leaves the springs alone for the time being to see if it provides the roll resistance you want and the ride comfort you're looking for. You haven't really said what your goals are but I'm guessing it's to minimize roll while maintaining streetability, correct?

Correct. my car has 110k miles, it is not a track car, its my daily driver but I like a car that can handle, always did and always will
I do like to push the car to the limits every now and then and I like it a lot when the car feels like its on rails, and when I am cruising above the speed limit and it feels planted and safe.

[justpete]

Originally Posted by dicostal

Correct. my car has 110k miles, it is not a track car, its my daily driver but I like a car that can handle, always did and always will
I do like to push the car to the limits every now and then and I like it a lot when the car feels like its on rails, and when I am cruising above the speed limit and it feels planted and safe.

Honestly, the best thing you can do is go to a square set up with the rear track slightly narrower than the front. This and an M3 ARB up front might be sufficient although I'd recommend M3 control arms as well as more rigid rear subframe mounts to get a more balanced chassis. Not cheap though.

[brocklanders]

I've had three of these cars so far, and the first thing I do is shocks springs front control arm bushes rear subframe bushes and sway bars. I've had a few different combinations. On my current e82 I went with Swift springs, bilsteins, whiteline poly bushings and eibach swaybars. The one constant through two e90's and an e82 has been the swaybars, I think 28mm front and 15mm back is a good upgrade without losing too much performance which I never bring it to the limit on the street anyway.

[dicostal]

Found a very good article at Turner motorsport

Originally Posted by TurnerMotorsport

E82, E90, E92, E93 Front Sway Bar Upgrade Comparisons

BMW made a lot of changes in the front suspension for the E82 1-series and E9X 3-series. One area where they improved on past suspensions is by using hollow sway bars to reduce weight. And to further tune the handling the bar, sizes were varied among each model. We have collected the various stock sizes along with an H&R M3 bar and gave it all to one of our suspension engineers to draw some direct comparisons.

All of the E9X front sway bars are interchangeable so you can pick and choose which bar will work best for your particular application. The E93 M3 cabrio bar is the largest outside diameter - BUT it narrows down to 24mm in the middle and it's hollow. Both will reduce it's effectiveness. You can see that the stock E90/E92 M3 front bar is a straight 26.5mm throughout it's entire length. So the difference between the two is pretty small on paper. Either one would be an upgrade over the stock non-M E9X bar. But if you want the stiffest, the H&R is clearly superior because A) it's a straight 27.0mm diameter across its length, and B) it's a solid bar, not hollow, so it resists twisting a lot more.

Sway bars contribute to the overall spring rate of the suspension. Going with too large/stiff of a bar will impact the handling balance and ride, especially with stock or mild sport springs. So you don't always want to install the biggest and stiffest bar out there. Careful consideration of the rest of your suspension and even your tires is recommended. For a E9X non-M street car, with stock or sport springs, we would probably recommend a stock M3 or the E93 M3 front bar because we know it works well in this application and it's guaranteed to be an improvement with minimal downsides. If you use the H&R M3 bar on the street, you should balance it with the H&R M3 rear bar. And if you're building a track car with stiff springs, or already have an M3, the H&R bar is clearly the best choice.

Here are the specs on the individual bars:

Model Part
Number Diameter Core % Over
Stock E9X % Over
Stock E90 M3
E9X non-M 31 35 6 796 302 26.5-23.0mm Hollow n/a -6.51%
E90/E92 M3 31 35 2 283 515 26.5mm Hollow +6.96% n/a
E93 M3 31 35 2 283 965 28.0-24.0mm Hollow +13.12% +5.75%
H&R E9X 70053 27.0mm Solid +52.44% +42.52%

[lutfy]

Originally Posted by dicostal

Found a very good article at Turner motorsport

Hey folks,

I have a reverse problem. I have a non M3 FSB which we tried to intall on an M3 and it wouldnt fit the bracket (bushing is too wide).

Appears I'd need a non M (or a 335i) swaybar brakcet to make it work since all the FSB seem to be same (fitting the endlinks)?

Went with the solid non adjustable e9x bar (1mm smaller) as the larger adjustable one broke the endlink twice even on the softest setting. Suspension wise Bilstein and Eibach. Nothing crazy (rest all stock).

TIA

Lutfy