135i - Front M3 swaybar upgrade = TWO UNEXPECTED BENEFITS!

[yllwwgn]

So I'll keep this brief, and having swapped out sway bars on other cars in the past (330i, WRX, Fox-body 5.0, etc) yes the car is "tighter" and has "crisper" turn-in, etc, etc. etc. No need to go down the path of "increased understeer" discussion either... I don't drive Monza on the way to work in the morning

However, after the front M3 swaybar upgrade, I INSTANTLY noticed two things I was actually not expecting:

1. I used to have the dreaded passenger A-pillar rattle. Had tried to fix it with silicone spray, removing and tightening down the pillar cover, etc. In the past months I think I got rid of 80% of the rattle, but over certain pavement and/or under rapid steering inputs, it would rear its ugly head. Miraculously, after the sway bar install.... IT'S GONE!!!! Now I must admit I am not sure if the harder bushings, new torsional resistance, or what actually lead to this... but that inherent "chassis flex" that would creep up around the dash/A-pillar section... GONE!!!!

2. Our cars like to side-step over uneven pavement... yes the stock shock dampening sucks, RFT's suck, etc... but after the sway bar install, this was the other aspect of the 135's suspension that improved. I won't say it is completely gone, no; however driving over the same manhole covers and road imperfections that I do every morning, the improvement in straight-line stability was immediately obvious.

Anyway, for those of you with either of the 2 issues noted above, I would highly reccommend the upgrade to the E93 front bar. Even if you weren't looking for better steering feel, less body roll, etc... the benefits are well-worth the $$ for the improved dynamics.

[135ivert]

Good to know! Vert or coupe?

[yllwwgn]

135ivert, it's a coupe... but I imagine the added roll resistance and apperently overall (miraculously) reduced chassis flex could help a vert even more.

I only posted this as approaching it from a somewhat-engineering perspective, it seemed a bit counter-intuitive that adding roll resitance to the unsprung chassis components would stiffen the chassis itself. If anything I would think it would exacerbate the flex in the body itself.

If anyone else has had this experience or has a plausible explanation... by all means, please share.

[RimasRS]

wow .... and really wow did not expect that swaybar can fix rattle

[John_01]

Originally Posted by yllwwgn

I only posted this as approaching it from a somewhat-engineering perspective, it seemed a bit counter-intuitive that adding roll resitance to the unsprung chassis components would stiffen the chassis itself. If anything I would think it would exacerbate the flex in the body itself.

If anyone else has had this experience or has a plausible explanation... by all means, please share.

The sway bar transfers torsional loading directly to the sub-frame. Since the stock sway bar is weaker, a greater proportion of the load and vibrations transferred via the strut tower. The strut tower is typically where we hear most of the noise and harshness as its rigidity normally isn't perfect. Anyway I agree with your observation. I also noticed a bit less noise and vibration after upgrading the front sway bar.

[SteveAZ]

Hmmmm...my passenger side pillar is a creaky SOB, along with the glove box area..creaks like crazy...drives me nuts. M3 arms, -1.5 degrees of camber, E93 sway bar, rear subrame bushings....

Will check the strut tower bolts though...hadn't given it a lot of thought and since the car is currently on blocks...will double check the anti-sway bar is still tight.

[Kgolf31]

Adding a front bar on a BMW actually decreases understeer. It is kinda a weird thing that happens on our car that isn't typical on all RWD cars.

Enjoy!

[128Convertibleguy]

Originally Posted by Kgolf31

Adding a front bar on a BMW actually decreases understeer. It is kinda a weird thing that happens on our car that isn't typical on all RWD cars.

Enjoy!

Nothing weird about it, and it's common with any MacPherson strut front car, either FWD or RWD. The camber change due to roll, stock, is so unfavorable that reducing roll increases traction on the outside front tire more than enough to compensate for the increased weight transfer to that tire caused by the bar.

[Kgolf31]

Originally Posted by 128Convertibleguy

Nothing weird about it, and it's common with any MacPherson strut front car, either FWD or RWD. The camber change due to roll, stock, is so unfavorable that reducing roll increases traction on the outside front tire more than enough to compensate for the increased weight transfer to that tire caused by the bar.

People read the internets, and scream bloody murder when someone says throw a big bar up front and keep stock rear.

[dcaron9999]

OK. Was going to postpone the front sway bar upgrade until after I do my springs and dampers. You guys are convincing me to consider the E93/M3 bar first. Ive been attacking my understeer issue with camber plates, and M3 front control arms. My front RE-11 tires took a beating (especially outside edges) until I tamed the issue in the middle of my 2013 season.

I would not mind dialing the camber back a little, reducing body roll, and understeer even more, with a FSB worth $300 that is an easy DIY.

[Kgolf31]

Originally Posted by dcaron9999

OK. Was going to postpone the front sway bar upgrade until after I do my springs and dampers. You guys are convincing me to consider the E93/M3 bar first. Ive been attacking my understeer issue with camber plates, and M3 front control arms. My front RE-11 tires took a beating (especially outside edges) until I tamed the issue in the middle of my 2013 season.

I would not mind dialing the camber back a little, reducing body roll, and understeer even more, with a FSB worth $300 that is an easy DIY.

You'll need some serious camber to eliminate outside wear.

If you're going to bring back camber, go with a tire that had a stiffer sidewall...like ZII which can be used quite effectively on a camber challenged car.

[dcaron9999]

Originally Posted by Kgolf31

You'll need some serious camber to eliminate outside wear.

If you're going to bring back camber, go with a tire that had a stiffer sidewall...like ZII which can be used quite effectively on a camber challenged car.

I was set for -3.2 in the front, but did 3/4 of the season on stock camber, so hurt the fronts. Its still got some thread on them though, and hope they can last and wear somewhat evenly going forward. They are pretty sticky and good enough for my learning. I would like them to last at least for a year (bought them in July 2013).

On another note, I booked some lapping courses for late April, as investing in the driver is as critical as mods themselves.

[Kgolf31]

Originally Posted by dcaron9999

I was set for -3.2 in the front, but did 3/4 of the season on stock camber, so hurt the fronts. Its still got some thread on them though, and hope they can last and wear somewhat evenly going forward. They are pretty sticky and good enough for learning..

what I did with my Z4M is actually dismount and flip the tires to the other side in the off season to get even wear...worked pretty well and got 2 seasons on -2* camber before cording

[yllwwgn]

Originally Posted by John_01

The sway bar transfers torsional loading directly to the sub-frame. Since the stock sway bar is weaker, a greater proportion of the load and vibrations transferred via the strut tower. The strut tower is typically where we hear most of the noise and harshness as its rigidity normally isn't perfect. Anyway I agree with your observation. I also noticed a bit less noise and vibration after upgrading the front sway bar.

Thanks John_01, now that I think about it that actually makes sense... a greater amount of the forces are now transfered via the SB, as opposed to the strut towers. Now it makes me wonder if adding a strut brace (most of the time done for aesthetics vs. function) in addidtion to to the SB may remove any other inherent "flex". Guess it couldn't hurt

[yllwwgn]

Originally Posted by SteveAZ

Hmmmm...my passenger side pillar is a creaky SOB, along with the glove box area..creaks like crazy...drives me nuts. M3 arms, -1.5 degrees of camber, E93 sway bar, rear subrame bushings....

Will check the strut tower bolts though...hadn't given it a lot of thought and since the car is currently on blocks...will double check the anti-sway bar is still tight.

SteveAZ, I am in the valley as well... shoot me a PM and we can always meet up and compare squeaks/rattles... ha ha. According to your sig it looks like you're getting an LSD and I'd be really curious to see how that transforms your traction too!

[135ivert]

I think this just made it to my "next mod" list thanks to your write-up.

BTW, I was just in the Tempe area for 5 days. I saw zero 1-series. Either they're pretty rare there or just none in Tempe.

[Stupenal]

.

[135Pats]

Originally Posted by SteveAZ

Hmmmm...my passenger side pillar is a creaky SOB, along with the glove box area..creaks like crazy...drives me nuts. M3 arms, -1.5 degrees of camber, E93 sway bar, rear subrame bushings....

Will check the strut tower bolts though...hadn't given it a lot of thought and since the car is currently on blocks...will double check the anti-sway bar is still tight.

Lol that’s just that ‘vert life my friend. At this point when people ask what rattles, I just say “the cabin”.

[SteveAZ]

Originally Posted by yllwwgn

SteveAZ, I am in the valley as well... shoot me a PM and we can always meet up and compare squeaks/rattles... ha ha. According to your sig it looks like you're getting an LSD and I'd be really curious to see how that transforms your traction too!

Haha...funny. Yeah...the diff is done (I decided not to do the internals myself) and should be back on the car today. I sure hope it helps...may do a tire mod if not.

Originally Posted by 135ivert

I think this just made it to my "next mod" list thanks to your write-up.

BTW, I was just in the Tempe area for 5 days. I saw zero 1-series. Either they're pretty rare there or just none in Tempe.

Not a lot of them around here...not sure why...but they are around.

Originally Posted by 135Pats

Lol that’s just that ‘vert life my friend. At this point when people ask what rattles, I just say “the cabin”.

Funny...true...I just keep the top down and the stereo up, then it's not a problem

[1Pirate]

Originally Posted by yllwwgn

So I'll keep this brief, and having swapped out sway bars on other cars in the past (330i, WRX, Fox-body 5.0, etc) yes the car is "tighter" and has "crisper" turn-in, etc, etc. etc. No need to go down the path of "increased understeer" discussion either... I don't drive Monza on the way to work in the morning

However, after the front M3 swaybar upgrade, I INSTANTLY noticed two things I was actually not expecting:

1. I used to have the dreaded passenger A-pillar rattle. Had tried to fix it with silicone spray, removing and tightening down the pillar cover, etc. In the past months I think I got rid of 80% of the rattle, but over certain pavement and/or under rapid steering inputs, it would rear its ugly head. Miraculously, after the sway bar install.... IT'S GONE!!!! Now I must admit I am not sure if the harder bushings, new torsional resistance, or what actually lead to this... but that inherent "chassis flex" that would creep up around the dash/A-pillar section... GONE!!!!

2. Our cars like to side-step over uneven pavement... yes the stock shock dampening sucks, RFT's suck, etc... but after the sway bar install, this was the other aspect of the 135's suspension that improved. I won't say it is completely gone, no; however driving over the same manhole covers and road imperfections that I do every morning, the improvement in straight-line stability was immediately obvious.

Anyway, for those of you with either of the 2 issues noted above, I would highly reccommend the upgrade to the E93 front bar. Even if you weren't looking for better steering feel, less body roll, etc... the benefits are well-worth the $$ for the improved dynamics.

Interesting observations. The M3 E93 sway bar does make a difference in the way the car feels and handles. And the 1 gets even better if you ditch the run flats, install a good set of dampers and add a few more M3 suspension bits. I have upgraded my suspension piece meal since I have owned it (M3 E93 FSB, M3 control arms and tension rods, Koni Sport dampers, M3 sub frame bushings, M3 guide rods and upper links) and with each upgrade the handling and drivability of the car got incrementally better.

[dcaron9999]

Originally Posted by 1Pirate

Interesting observations. The M3 E93 sway bar does make a difference in the way the car feels and handles. And the 1 gets even better if you ditch the run flats, install a good set of dampers and add a few more M3 suspension bits. I have upgraded my suspension piece meal since I have owned it (M3 E93 FSB, M3 control arms and tension rods, Koni Sport dampers, M3 sub frame bushings, M3 guide rods and upper links) and with each upgrade the handling and drivability of the car got incrementally better.

Thanks for this feedback! Been thinking about sequence of optimal suspension tweaks for a while. Ive done M3 Front control arms, Ground Control Camber plates, and M3 rear subframe bushings so far.

The E92 or E93 FSB has been on my short term list, along with rear upper control arms.

I have read a couple of threads where members claimed that the E92 or E93 Front Sway bar should not be done until dampers and/or springs have been upgraded (slightly firmer). The reason being is that the cumulation of stiffer springs and stiffer bar might be too much, and create a negative effect (ie: increased understeer).

I notice you have done all of these piece meal.

What year is your 1 series (2011+ MY came with the linear springs)
Did you keep the stock M sport springs when you installed your Koni's?
Did you get the FSB before or after the Koni dampers?
Do you use your car on the track?
Any signs of understeer?

[128Convertibleguy]

Originally Posted by dcaron9999

I have read a couple of threads where members claimed that the E92 or E93 Front Sway bar should not be done until dampers and/or springs have been upgraded (slightly firmer). The reason being is that the cumulation of stiffer springs and stiffer bar might be too much, and create a negative effect (ie: increased understeer)

Are they experienced in doing using that particular combination, or just theorizing? My take is that you'd have to go pretty far on a 1 series before increased front roll stiffness is not a good thing. The increase in front grip due to more favorable camber should outweigh the decrease in front grip due to increased weight transfer. So, no increased understeer. This isn't a race car with good camber compensation at the front.

But, I'm just theorizing too. So don't trust me, either. Trust the guys who have been there and done that.