Bilstein B6 (SP) or Bilstein B8 (HD)?

[aritala]

So I am currently doing a suspension upgrade on my 2008 135i with M sport package. I just ordered and am about to install a M3 Front Control Arm Upgrade Kit and an M3 Sway Bar. I live in NJ and my car is a daily driver and potholes here are a problem, however, I want to benefit from a tighter and sportier suspension. Given the suspension mods I've mentioned above, would going with Bilstein Sport Performance shocks/struts be too unforgiving or should I go with Bilstein Heavy Duty?

I had previously considered Koni Adjustable Yellows but they tend to wear out by 70k miles or so and from what I hear Bilsteins last forever. I will not be adding lowering springs because I think the difference in performance is negligible and I think the car is low enough as is stock.

[asbrr]

Originally Posted by aritala

So I am currently doing a suspension upgrade on my 2008 135i with M sport package. I just ordered and am about to install a M3 Front Control Arm Upgrade Kit and an M3 Sway Bar. I live in NJ and my car is a daily driver and potholes here are a problem, however, I want to benefit from a tighter and sportier suspension. Given the suspension mods I've mentioned above, would going with Bilstein Sport Performance shocks/struts be too unforgiving or should I go with Bilstein Heavy Duty?

I had previously considered Koni Adjustable Yellows but they tend to wear out by 70k miles or so and from what I hear Bilsteins last forever. I will not be adding lowering springs because I think the difference in performance is negligible and I think the car is low enough as is stock.

If you are not changing the springs, go with Bilstein HD (B6) shocks. The difference between the two is not so much dampening force/profile, but rather the shock length. The B8s are made for lowering springs beyond 15 mm or so of lowering, so with stock springs B6 is the way to go.

I'm interested in your opinions if you go with Bilsteins, and how they compare to your previous Koni experience. I had Bilsteins on an Audi a few years back, they were good, but found them to be harsh in that application. I heard the Konis vs the high pressure gas Bilsteins were a bit smoother/more forgiving.....

I'm torn between doing a Bilstein setup (with some spring, not sure which yet) or Koni sports or custom valved Konis (TC Kline or Dinan maybe).

Edit: You should really consider upgrading the rear subframe bushings as well, they will be exposed even further with a modified suspension.

Good luck
Ash

[Suhb]

I have the B12 kit and I'm already wishing I had a stiffer set up. OP, to answer your question, I have the B8 schocks on mine and despite the stiffer ride, they handle potholes A LOT better than stock. With the stock set up, if I knew a bad patch of road was ahead, I would have to brace for it. Now I don't worry because the shocks react really quickly. You won't regret going with the B8, but if you're not changing springs, get the B6. Also keep in mind, I am on 17's.

[aritala]

Originally Posted by Suhb

I have the B12 kit and I'm already wishing I had a stiffer set up. OP, to answer your question, I have the B8 schocks on mine and despite the stiffer ride, they handle potholes A LOT better than stock. With the stock set up, if I knew a bad patch of road was ahead, I would have to brace for it. Now I don't worry because the shocks react really quickly. You won't regret going with the B8, but if you're not changing springs, get the B6. Also keep in mind, I am on 17's.

So I spoke with technical specialist at turnermotorsports.com and it seems like the B6 and B8 are identical except for the fact that the B8 can be used with a spring but not required. Did you find the car too close too the ground/bottoming out too easily or was it manageable? Also, did you notice an improvement in handling by having the springs?

[houtan]

I will have a lightly used set of bilstein b8 with swift spec r springs and Dinah rear upper shock mounts if you are interested. Like the b12, this combo is an excellent balance of comfort and better handling.

[Nicklv_m3]

I rock a B12 pro kit and it's absolutely perfect! I also paired it with ECSTuning solid 28MM front sway bar and I also did Whiteline Rear Subframe Bushing Inserts which really helped stiffen up the rear a bit... Helps with launching a lot.
Car rides perfect! Especially with proper wheel/tire setup also.

[aritala]

Originally Posted by Vegas135i

I rock a B12 pro kit and it's absolutely perfect! I also paired it with ECSTuning solid 28MM front sway bar and I also did Whiteline Rear Subframe Bushing Inserts which really helped stiffen up the rear a bit... Helps with launching a lot.
Car rides perfect! Especially with proper wheel/tire setup also.

I also plan on adding M3 bushings and an M3 sway bar. Did you find the B12 sport kit to drop your car a little too much? The 135i's are already pretty low so did you find yourself bottoming out more? I am leaning toward the B12 kit too but Im concerned about scraping on potholes, driveways, and certain roads

[Nicklv_m3]

Doesn't bottom out at all or rub and I'm running APEX EC-7's, 18x8.5 ET45 Front, 18x9.5 ET58 Rears and running 225/40 fronts, 265/35 Michelin PSS which run wider and taller than most tires and I don't ever rub or anything. It's perfect amount of low! Looks great too

[Esteban]

Originally Posted by aritala

I also plan on adding M3 bushings and an M3 sway bar. Did you find the B12 sport kit to drop your car a little too much? The 135i's are already pretty low so did you find yourself bottoming out more? I am leaning toward the B12 kit too but Im concerned about scraping on potholes, driveways, and certain roads

The Bilstein B12 Pro-Kit (part #46-180537) provides about a 1.2" drop in front and rear from Eibach's Pro-Kit springs (according to Eibach's website), which are included in the kit.

Edit: something worth mentioning is that I noticed that some of the different sellers of the B12 Pro-Kit for the 1 series quoting different numbers for the drop. That might be confusing but I would go with what Eibach states the drop is since they make the springs.

[ShocknAwe]

B6 is the HD and B8 are the sport. Their valving is the same, but stroke is slightly different for the B8 to accommodate lowering springs of somewhere around 15-50mm difference from stock.

All shocks require springs FYI.

Would recommend getting new top hats, spring seats, and replace the upper RSMs with the Dinan part. B6 and B8 damper is compatible with the 10mm kit. Very high quality.

If you have any questions feel free to send me a PM.

[dojk]

Originally Posted by houtan

I will have a lightly used set of bilstein b8 with swift spec r springs and Dinah rear upper shock mounts if you are interested. Like the b12, this combo is an excellent balance of comfort and better handling.

Hi,

Would you be interested in just selling the Dinan rear top shock mounts?