[rubicon1976]

Hi all,
I just picked up this 2009 e92 335i with the M Sport. The front struts were replaced about 10K miles ago with B4s. I don't think the rear shocks have been replaced (113K on the car). I am thinking about taking the car to the track, maybe 2 or 3 times a year (High Planes raceway outside of Denver). I am happy with the ride height but I would like to upgrade the handling a little. I was thinking maybe the Bilstein B6 shocks and struts or B8s. Any thoughts here? Seems like maybe the B8s are for lowered cars or am I getting bad info? What do you guys recommend? Given 97% of the time, the car will be spiritedly daily driven and not at the track, is this a good plan? On a scale of 1 to 5 where 1 is the slushy stock suspension and 5 is race car, I'd like to be somewhere around a 2.5-3 if that makes sense.

Second, I see that Turner has M3 control arm kits by TRW for the front and rear that upgrade the joints for a tighter feel, better feedback. Is this worth the price ~340 for the front kit and ~ 520 for the rear kit? Or should I be looking at something else? I figure with 113K, the joints are probably toward the end of their service life.

Am I going to be happy with this setup or should I just go full coilover kit now? Any other options for the control arms?

I do plan to replace the strut and shock mounting hardware when I do shocks and struts too.

Any feedback is appreciated.

[ky0u]

Would look into the b12 kit which are the bilstein b8 struts and eibach pro springs

It’s a pretty popular plug and play set up for our cars. Tightens up in every aspect without shocking your spine whenever you hit a crack in the road. I have it paired with the m3 control arms and it makes for a well handling Daily. If you’re already about to refresh the stock arms, you might as well do the conversion.

(Although there was some issue relatively recently with TRW quality diff due to switching manufacturing locations. Unsure what became of it, would double check)

Unsure what your tolerance for a DD is but I would say it’s about a 2-2.25 on your scale.

(I am still on my stock e92 sways though, so the car does feel like it leans a bit more than I’d like it to, im sure that also plays a big part)

[Malteser_wfj]

Originally Posted by ky0u

Would look into the b12 kit which are the bilstein b8 struts and eibach pro springs

It’s a pretty popular plug and play set up for our cars. Tightens up in every aspect without shocking your spine whenever you hit a crack in the road. I have it paired with the m3 control arms and it makes for a well handling Daily. If you’re already about to refresh the stock arms, you might as well do the conversion.

(I am still on my stock e92 sways though, so the car does feel like it leans a bit more than I’d like it to, im sure that also plays a big part)

Does the B12 kit lower m sport suspension cars at all?

I've got 120k miles on my stock suspension and want to refresh it but I can't afford to go any lower than the stock height (which albeit may have sagged a bit over time anyway with worn mounts etc) because of speed bumps where I live.

[Tambohamilton]

No point in going to pro kit; the springs are lower than m-sport and barely any stiffer. If you want to go in that direction, the first step is to use BMW performance springs - these are markedly stiffer than the stock springs...and a bit lower than m-sport.

If you want to keep m-sport ride height but run stiffer suspension, you may need to go for height-adjustable coilovers.

[rubicon1976]

Tambohamilton do you have a link or PN for those BMW Performance springs you speak of?

Thanks!

[Tambohamilton]

Not handy, sorry. There are different springs though, depending on which model your car is. And I can't remember which parts are discontinued etc... I think the springs are still available though, so you may be able to ask a dealer for the correct part numbers for your car.

[ky0u]

Originally Posted by Tambohamilton

Not handy, sorry. There are different springs though, depending on which model your car is. And I can't remember which parts are discontinued etc... I think the springs are still available though, so you may be able to ask a dealer for the correct part numbers for your car.

Are you talking about the yellow springs? I’ve been curious about these too. I wonder if they’ll solve the mush/leaning behaviour of the b12 set up

Aside from stiffness, how do they sit height wise compared to the eibach pros?

[vester86]

if you’re happy with the height i wouldn’t drop lots of $$$ in new coilovers, but just replace the B4s with B8. B6 is for standard ride height which yours isn’t.

for M3 arms: the front is worth it, the rear not so unless it’s all tired and needs replacing anyway.

[Tambohamilton]

Yeah, yellow springs. Can't find the thread now that discusses them. Pretty sure it's another Mr. 5 thread...
Edit - found it:
https://www.e90post.com/forums/showthread.php?t=237309

Here's one that covers the spring rates:
https://www.e90post.com/forums/showthread.php?t=235797

I think the drop is about 0.6" from m-sport. Though bear in mind that if you refresh the top mounts etc, it'll be less than 0.6" lower than you are now. You can raise it a bit with spring pads or camber fix plates, etc.

They're definitely a lot stiffer than eibach pro kit; ~148 Vs ~195lb/in. Stock is ~135. Remember bump stops are super important too, and way more difficult to quantify.

[mattanderson]

If you're happy with the ride, I'd consider just refreshing your rear shocks w/ the correct B4's, and focus on tightening up other areas (swaybar links, subframe bushings/inserts, camber plates, to mention a few ideas in addition to the M3 arms).

I'm running M3 arms and Eibach Pro-Kit + Koni yellows. My car came with non-sport suspension; otherwise I would have re-used the stock sport springs.

The Pro-Kit alone gave me even fender gaps front + rear (ie., quite a bit of rake). From all the threads I've browsed, the Pro-Kit drop seems to vary depending on the car. I raised the front back up a bit with E30 strut mounts and Dinan camber plates, after which I'm about a half inch lower than OE sport ride height all around.

As much as I like the idea of the "BMW Performance" springs, I didn't opt for them due to the relatively high [presumed?] front vs. rear spring rate. That said, I wonder how accurate the spring rate info is that we all use as a reference.

[mattanderson]

Originally Posted by Malteser_wfj

Does the B12 kit lower m sport suspension cars at all?

I've got 120k miles on my stock suspension and want to refresh it but I can't afford to go any lower than the stock height (which albeit may have sagged a bit over time anyway with worn mounts etc) because of speed bumps where I live.

The Pro-Kit will lower more than OE sport.

In my experience (on my stripper E92 328i) and estimation, it dropped my front about 1" beyond OE sport height, and the rear ~0.5" [with OE sport height being 0.6" lower than non-sport, I believe].

If you like your ride height, I'd just upgrade the shocks and struts + all the mounts/hardware and re-use your stock sport springs.

[StradaRedlands]

Originally Posted by vester86

for M3 arms: the front is worth it, the rear not so unless it’s all tired and needs replacing anyway.

I agree that the M3 arms are the way to go in front. Pretty much a no-brainer when you need them.

[Tambohamilton]

Originally Posted by mattanderson

If you're happy with the ride, I'd consider just refreshing your rear shocks w/ the correct B4's, and focus on tightening up other areas (swaybar links, subframe bushings/inserts, camber plates, to mention a few ideas in addition to the M3 arms).

I'm running M3 arms and Eibach Pro-Kit + Koni yellows. My car came with non-sport suspension; otherwise I would have re-used the stock sport springs.

The Pro-Kit alone gave me even fender gaps front + rear (ie., quite a bit of rake). From all the threads I've browsed, the Pro-Kit drop seems to vary depending on the car. I raised the front back up a bit with E30 strut mounts and Dinan camber plates, after which I'm about a half inch lower than OE sport ride height all around.

As much as I like the idea of the "BMW Performance" springs, I didn't opt for them due to the relatively high [presumed?] front vs. rear spring rate. That said, I wonder how accurate the spring rate info is that we all use as a reference.

Yeah, the rates we're working from aren't 100%, but they're a perfectly good indicator for what we're capable of feeling. I use front bmwp and rear m-sport springs from another model to hit the right spring rates and ride height...but then they also never made performance suspension for the e91.

[Malteser_wfj]

Originally Posted by mattanderson

The Pro-Kit will lower more than OE sport.

In my experience (on my stripper E92 328i) and estimation, it dropped my front about 1" beyond OE sport height, and the rear ~0.5" [with OE sport height being 0.6" lower than non-sport, I believe].

If you like your ride height, I'd just upgrade the shocks and struts + all the mounts/hardware and re-use your stock sport springs.

Okay perfect, thank you for all the info!! Super helpful

When it comes time I'll just do shocks and the mounts.

[rubicon1976]

Sounds like the front M3 control arm upgrade is worth it. I think I'll stick with the stock M Sport springs and do the B8 shocks and struts.

What about sway bars? Any recommendations there? How hard are they to change?

[Tambohamilton]

Front is a half hour job. Rear is a few hours (need to drop the rear subframe).

Most people recommend going for a very stiff front sway bar, though I disagree slightly (I'd rather have better mid corner balance than prioritise being able to put the power down on exit). With 335i power and the open diff you probably want to leave the rear quite soft though. I think a decent balance for stock springs could be an e93 M3 front bar, and a 14mm rear bar from an XD. Or I seem to remember eibach have a reasonably balanced set of bars available...

[Shoooter_j]

FWIW, I’ve had the B12 Prokit on for about 7 yrs, 36k miles and its always been 1/4in lower in the front, and was about 1/2in lower before getting Dinan camber plates. Going with e30 spring perches soon to hopefully even out the fender gap and raise the front another 1/4in from what I’ve been reading. Good setup for the street but probably would go coilovers if tracking.

[Andy198712]

There’s also the e30 I think upper spring pad that can be had thicker if needs be too.

I did the e30 upper and the pad as the pro kit left my B4 sports sat on the bump stops at rest.

[Andy198712]

Those bump stops are off a bmw mini

[Shoooter_j]

Originally Posted by Andy198712

There’s also the e30 I think upper spring pad that can be had thicker if needs be too.

I did the e30 upper and the pad as the pro kit left my B4 sports sat on the bump stops at rest.

Thanks! I read that the spring pad was also an option but don’t want to potentially end up with the front now sitting higher than the rear. I’ve read a 12mm gain with the perches and another 9mm with the pads. How did the height change work out for you?

[Andy198712]

Originally Posted by Shoooter_j

Thanks! I read that the spring pad was also an option but don’t want to potentially end up with the front now sitting higher than the rear. I’ve read a 12mm gain with the perches and another 9mm with the pads. How did the height change work out for you?

In terms of?

Wheel gap, yes it does raise it up. I wouldn’t say it raises the gap that much though, I’ll measure it for you, I have an a before measurement of wheel centre to wing lip, will take an after now it has a few thousand miles on it.
Now doesn’t scrape on speed bumps

In terms of comfort….. hugely as it actually gave me some shock travel and not sat on bump stops.

It’s oem fit well….. compatable so it works nice


I just wish I didn’t go eibach pro springs, or the b4s’s tbh. Wish I went Sachs and stock springs for the comfort and I wouldn’t have needed to do all the parts listed above to get a setup that even remotely works

[Shoooter_j]

Originally Posted by Andy198712

In terms of?

Wheel gap, yes it does raise it up. I wouldn’t say it raises the gap that much though, I’ll measure it for you, I have an a before measurement of wheel centre to wing lip, will take an after now it has a few thousand miles on it.
Now doesn’t scrape on speed bumps

In terms of comfort….. hugely as it actually gave me some shock travel and not sat on bump stops.

It’s oem fit well….. compatable so it works nice


I just wish I didn’t go eibach pro springs, or the b4s’s tbh. Wish I went Sachs and stock springs for the comfort and I wouldn’t have needed to do all the parts listed above to get a setup that even remotely works

Thanks for the detail and would be great whenever you can get to the measurements! I ended up going with both the spring perch and pads, and to top it off fresh strut mounts so will be great to see how gaining 1in of height feels (before it settles to a ~0.75in gain after the strut mounts wear down again).