Sway bars

[macdude357]

Originally Posted by E90Dave

I have camber plates on the car with my TCK DA coils!

Ah, of course. So it's just a matter of getting them setup with a street and track setting.

[FogCityM3]

Thanks all, really helpful.

[E90Dave]

Excellent info.

I have read of some users reporting more under steer and higher lap times with a front bar.

[G-Lo408]

Originally Posted by E90Dave

Exactly. How would someone think that a thicker front bar beats under steer lol!?

255/35/19 and 285/35/19 Potenza RE-11

-2* camber!

I think this has been explained already. My other suggestion is to go with 18x10's. 18' are lighter and tires are cheaper too. Try the Re71R's. Great tire!

[MFL]

I would say that if you plan on doing solid rear differential bushings, that is when you should consider swaybars if at all while you have the rear subframe out. FWIW I'm opting to stick with my stock sway bars and just doing Powerflex rear swaybar bushings while my subframe is off the car.

[bigjae1976]

Originally Posted by E90Dave

Exactly. How would someone think that a thicker front bar beats under steer lol!?

255/35/19 and 285/35/19 Potenza RE-11

-2* camber!

On most cars that is right. On a non-double A arm front suspension BMW...that is wrong.

A front sway reduces understeer by increasing front roll stiffness. Front roll stiffness reduces the dynamic camber change and improves the contact patch on the front tires during cornering. Since you're no longer driving through the corners on the sidewall...which is not designed for max grip...you get more grip.

Turner used to sell a 40mm front sway bar for E46s which they paired with no sway bar on their 325i.

I definitely drive my E90 through quick switchbacks differently than my E46. You really need to be on throttle (at least maintenance throttle) to settle the rear end with the E90. The only reason I trailbrake in my E90 is because its by accident and I feel like I really needed to slow the car more. Which is why my E90 was soooo fun on track. Just begs for throttle through the corners.

The stock E90 is super easy to control with the throttle...not sure swapping in more aftermarket parts will help.

[///Mobbin]

Eibach also makes an adjustable front sway for our cars.

Eibach Adjustable Sway Bars

Curious to hear thoughts on the Dinan bar vs the Eibach.

[Richbot]

I am not a fan of the way their adjustment works, without proof/info to the contrary. The way the bar ends drop down and the three holes move the endlink attachment in such a way that it seems like it relies on putting progressively more bending moment on the swaybar to get additional stiffness, which means bushing bind when the bar tries to lift up against the mounts. By contrast the Dinan and RD bars have their holes oriented roughly parallel to the ground so that you'r twisting the bar primarily about the long straight center section, which is how a swaybar is supposed to work and how the OE bar is designed. Eibach appears to have foregone the spaghetti bends the stock and Dinan/RD bars have in favor of...whatever that is. Maybe it works great, no idea, but it doesn't pass the eyeball test without knowing more

[///Mobbin]

Originally Posted by Richbot

I am not a fan of the way their adjustment works, without proof/info to the contrary. The way the bar ends drop down and the three holes move the endlink attachment in such a way that it seems like it relies on putting progressively more bending moment on the swaybar to get additional stiffness, which means bushing bind when the bar tries to lift up against the mounts. By contrast the Dinan and RD bars have their holes oriented roughly parallel to the ground so that you'r twisting the bar primarily about the long straight center section, which is how a swaybar is supposed to work and how the OE bar is designed. Eibach appears to have foregone the spaghetti bends the stock and Dinan/RD bars have in favor of...whatever that is. Maybe it works great, no idea, but it doesn't pass the eyeball test without knowing more

Good to know, thanks for the thoughts! With the Dinan bar going for a premium I have a decision to make ... May actually try the H&R first and sell it if I want the adjust-ability later.

[CSBM5]

Originally Posted by ///Mobbin

Good to know, thanks for the thoughts! With the Dinan bar going for a premium I have a decision to make ... May actually try the H&R first and sell it if I want the adjust-ability later.

I have the older Dinan non-adjustable front sway bar. It's 28.5mm and solid. My calculations showed that it is 64% stiffer than the stock bar. Their current 32mm hollow bar is 50-90% stiffer than stock. I've been happy with it and haven't missed being able to adjust it when driving autocross events in F-street and CCA time trail/autox events at the PerfCenter track. I can see why the E92 M3 that won 1st place last year at Nationals was using the softest adjustment (50%) I think. Anything stiffer than this one (64%) would be too much I'm guessing.

Running square 275s and pins-out-max-camber up front, the car is very well balanced; however, if I was doing track events with this car, I'd likely want an adjustable rear bar to complement it -- something that isn't allowed in SCCA autox.

[Richbot]

The 60-70% stiffer range is where I landed with my RD Sport bar for best fun times on street tires (either middle setting both sides or one middle/one stiff) On Hoosiers, the car wanted all the bar had to offer and more

[lutfy]

Originally Posted by ///Mobbin

Eibach also makes an adjustable front sway for our cars.

Eibach Adjustable Sway Bars

Curious to hear thoughts on the Dinan bar vs the Eibach.

I am going to tinker with Eibach bar and report back.

All others, Listed my H&R front bar if anyone wants to experiment with:

http://www.m3post.com/forums/showthread.php?p=20573207#post20573207

Lutfy

[Datka]

Interesting thread.
So as i understand, the consensus here is, stiffer front bar will improve our cars performance at the autocross.
But what about stock suspension that has very soft spring rate with front camber set to -2.8 and r-compound tires?
Will it improve performance on the road course?

[bigjae1976]

Originally Posted by Datka

Interesting thread.
So as i understand, the consensus here is, stiffer front bar will improve our cars performance at the autocross.
But what about stock suspension that has very soft spring rate with front camber set to -2.8 and r-compound tires?
Will it improve performance on the road course?

I would think a stiffer front bar would not help in autocross. Might help in on the road course but probably won't be a drastic improvement.

[CSBM5]

Originally Posted by bigjae1976

I would think a stiffer front bar would not help in autocross. Might help in on the road course but probably won't be a drastic improvement.

...well, one can't win a 1st place at Nationals without the larger front bar, so it likely matters. Everything about the car's handling is enhanced with a larger front bar on course as has been covered ad infinitum in the forum here by National level trophy winning drivers.

[lutfy]

Originally Posted by lutfy

I am going to tinker with Eibach bar and report back.

All others, Listed my H&R front bar if anyone wants to experiment with:

http://www.m3post.com/forums/showthr...7#post20573207

Lutfy

Eibach bar installed. On full stiff setting is it stiffer than the HR bar? Yes. Can I feel the difference, very little. It's hard to tell much on the street. The HR bar was solid and noticibly heavier. It was built with Input from Turner.....

If I had to do it again (swap); hmmm.

If I had to do it first time, Eibach, only given the adjustability.

Separate note, the endlinks looked pretty much overworked with the ends almost at their max. Let's see if they can take the load.

Cheers,

Lutfy

[z3papa]

Originally Posted by E90Dave

I have camber plates on the car with my TCK DA coils!

Don't take this wrong but it's like you spent decent $$ to buy suspension parts you don't understand how to use. The whole point of camber plates is to have easy means to swap settings from street daily driving, and then separate track/autocross or spirited driving. All it takes is unweighting the car, loosening three top nuts a little on each side, slide the plates in to the settings marked and tightening. I personally had my previous car aligned to autocross/track alignment settings I wanted (typically a very little toe out - yes I it was a bit twitchy on the track - then marked) and lived with the alignment when the plates where placed in daily (toe moved in).

[GeorgeA]

Originally Posted by lutfy

Eibach bar installed. On full stiff setting is it stiffer than the HR bar? Yes. Can I feel the difference, very little. It's hard to tell much on the street. The HR bar was solid and noticibly heavier. It was built with Input from Turner.....

If I had to do it again (swap); hmmm.

If I had to do it first time, Eibach, only given the adjustability.

Separate note, the endlinks looked pretty much overworked with the ends almost at their max. Let's see if they can take the load.

Cheers,

Lutfy

I'm actually considering getting a front bar and I'm stuck between the two. My question is if the stiffness difference between the H&R and the Eibach actually helps anything or if its overkill since too stiff might not be ideal either. Also, do they make any noise? I had Eibach bars on my G37s and those made a bit of noise even with lubricant.

[lutfy]

Originally Posted by GeorgeA

I'm actually considering getting a front bar and I'm stuck between the two. My question is if the stiffness difference between the H&R and the Eibach actually helps anything or if its overkill since too stiff might not be ideal either. Also, do they make any noise? I had Eibach bars on my G37s and those made a bit of noise even with lubricant.

Get the Eibach. They can be made as stiff as HR and more. No noise what so ever. Also the Eibach bar is slightly lighter (3lbs or so).

Lutfy

[GeorgeA]

Originally Posted by lutfy

Get the Eibach. They can be made as stiff as HR and more. No noise what so ever. Also the Eibach bar is slightly lighter (3lbs or so).

Lutfy

Sounds good, thanks for the feedback, I wasn't aware of the weight savings.

[lutfy]

Originally Posted by GeorgeA

Sounds good, thanks for the feedback, I wasn't aware of the weight savings.

Hollow vs solid (HR)

Lutfy

[Datka]

After some research, sounds like Dinan front bar is the best for our cars but is pricey.