BMW Performance Coils + Bilstein HDs (B6s)

[Rainier42]

Greetings all! Acquired a 2011 BMW 128i with sport suspension in early March and am new to the forum. Auto is a DD but also doing some track days. To date have have installed M3 rear subframe bushings and Michelin PSS square tire set-up. Am looking to firm up the suspension just a little to improve handling and am considering BMW Performance coils with Bilstein HDs (B6 variant). Some information about this on this site but not too much. Anyone running this setup and, if so, what's the good, bad, etc?

[1forI]

The HDs with Swift spec R springs (slightly higher rate than your option) and rsfb inserts were my first suspension mods. It's a really great setup for the street.

Much more compliant.
Much less body roll.
Noticeably stiffer ride but definitely not uncomfortable.
Much less rear wiggle (tho that's mostly from the rsfb inserts.

On the track it also made a huge difference, although there is still a bit more body roll than I'd like, so would have to eventually switch to coilovers but will add an e92 fsb in the meantime.

If you want to maintain some street comfort and still stiffen up then you're on the right path...I actually had the HDs on first and they made the car feel much more stable, then I added the springs which stiffened and planted the car.

It's a good option unless you plan to do some aggressive tracking later on, in which case spring for good coilovers now.

[david in germany]

With the performance springs I would step past the B6 and get the B8 dampers. This is the same thing I did. Keep in mind Bilstien b4s are for stock suspension, b6s are for slight lowering like the M-sport and the B8 are for a lower drop like the bmw performance springs or others with a similar ride height. I can tell you that the B8s with the performance springs not only look awesome but there are not many cars that can handle like my little e87 118i. Even my 335i with full BMW Performance suspension feels a little floaty after driving my 118i.

David

[John_01]

BMW performance springs are intended to be used with the matching bump stops. In the case of Bilstiens, the bump stops for the Front struts are internal so you won't be able to use the matching bump stops from BMW. The alternative is Koni yellow struts and shocks which are closer in design to the stock M-sport items. I don't know if there is any difference in the ride height due to Konis internal gas pressure. Konis are adjustable which may be an advantage.

[ShocknAwe]

Originally Posted by John_01

BMW performance springs are intended to be used with the matching bump stops. In the case of Bilstiens, the bump stops are internal so you won't be able to use the matching bump stops from BMW. The alternative is Koni yellow struts and shocks which are closer in design to the stock M-sport items. I don't know if there is any difference in the ride height due to Konis internal gas pressure. Konis are adjustable which may be an advantage.

Front bump stops are internal. The rears still have an external bump stop.

[Rainier42]

Thanks all for your response. Reason why have considered the Billy B6s instead of the B8s is a conversation I had with Bilstein. Their recommendation was to use B6s with coils that drop 30mm or less and B8s with coils that drop greater than 30mm. The BMW performance coils drop 25mm from stock (not sport) coils.

[Pyrat 2]

My setup is similar to what you are looking to do. Current setup is:

• MPSS 245/35
• M3 RSFB
• Bilstein B8 Sports
• BMWP Springs
• Eibach Sway Bars
• Dinan Camber Plates with alignment at -1.5 camber

I'm very pleased with the setup and would do it again in a second with no changes. Car is extremely responsive. The camber plus square setup gives very fast turn-in. The ride is firm as you would expect from the Bilsteins. Not overly so though. Very tight at the track.

[ShocknAwe]

Originally Posted by Rainier42

Thanks all for your response. Reason why have considered the Billy B6s instead of the B8s is a conversation I had with Bilstein. Their recommendation was to use B6s with coils that drop 30mm or less and B8s with coils that drop greater than 30mm. The BMW performance coils drop 25mm from stock (not sport) coils.

This is correct. They told me the same thing. Using the B6 with Swift Spec-R and no regrets.

25mm ~~ 1 inch

[dojk]

I am a bit confused here. There are THREE susp variants from BMW?

1) stock
2) M-sport
3) BMW Performance

Mine is a 135 so i assume the stock susp is not applicable. I was under the assumption that the M-sport came witht he car from factory, and the BMW Performance items are accessories purchased from BMW as aftermarket items, hence the yellow gold colour. Other than the colour change, there is no difference.

Please help shine some light on this as I am about to pull the triggier on the B8, but now i am unsure if the B6 would be the better match with the factory (M-sport?) springs?

[Rainier42]

BMW Performance is not equivalent to the M-sport/sport suspension. M-sport/sport coils lower the auto by ~10mm; Performance coils lower the auto by an additional 15mm for a total of 25mm plus they are stiffer. Shocks and sway bar are also beefier. If you are not swapping out your M-sport springs, B6s are definitely the way to go.

[ShocknAwe]

Originally Posted by dojk

I am a bit confused here. There are THREE susp variants from BMW?

1) stock
2) M-sport
3) BMW Performance

Mine is a 135 so i assume the stock susp is not applicable. I was under the assumption that the M-sport came witht he car from factory, and the BMW Performance items are accessories purchased from BMW as aftermarket items, hence the yellow gold colour. Other than the colour change, there is no difference.

Please help shine some light on this as I am about to pull the triggier on the B8, but now i am unsure if the B6 would be the better match with the factory (M-sport?) springs?

Those three would apply if you were talking about the 128i. The Stock suspension on the 135i is the M-Sport. So the "Non-Sport" reference you are hearing about is the base 128i suspension, which is separate.

Then the BMWP suspension is actually physically different from the M-Sport as well.

[andrey_gta]

Someone did it here( BMW Perf Spring+ bil hd) along with Myele hd front bushings and loves it

I myself plan to use B8's with an HR or Swift springs because I am doing m3 rear carrier arm conversion and b8 or hd is one of the few choices and the prices seem to favour b8.
Also of note 1 series vs 3 series bilstiens. The 1 series are sometimes cheaper for the front shocks

[dojk]

Out of curiosity then, the B8 would have slightly higher damping and rebound rates than the B6?

Which leads to which damping and rebound rates would be better overall with M-sport springs?

[Rainier42]

Originally Posted by dojk

Out of curiosity then, the B8 would have slightly higher damping and rebound rates than the B6?

Which leads to which damping and rebound rates would be better overall with M-sport springs?

I don't think so. Valving on B8 and B6 are supposed to be the same. B8 is just for shorter springs.

[Solo_M_Tech]

Why not the Koni Yellows? I hear they are very similar to the B6's but with adjustable dampening? Just my thoughts. Bilsteins are a good choice too.

[Rainier42]

AR ... yes, that is an option I've been considering as well. Have some experience with Bilsteins in other autos and that is why I'm considering them.

[ShocknAwe]

Originally Posted by ApexResistance

Why not the Koni Yellows? I hear they are very similar to the B6's but with adjustable dampening? Just my thoughts. Bilsteins are a good choice too.

They are similar in that they are both dampers. That's about it.

Bilstein:
Monotube construction
Lighter (good for reducing unsprung weight)
Greater damper body diameter
Highly damped non-adjustable

Koni
traditional 2 piece
Thinner (helps with fitting bigger wheels and tires without spacers)
adjustable damping

B8 and B6 have identical valving. The piston stroke is physically shorter on the B8 to accommodate springs that lower the car 30mm or more.

[Lmw160]

Has anyone used Bilstein with the stock m springs?

[andrey_gta]

Originally Posted by dojk

Out of curiosity then, the B8 would have slightly higher damping and rebound rates than the B6?

Which leads to which damping and rebound rates would be better overall with M-sport springs?

B8 have a slight bump in rates to compensate for less shock travel, hardly noticeable form what I read. That is why I am looking at prices.

What will have an impact is using 3 series part numbers on the 1 series. I don't know how much or if it is into the desired direction.

[dojk]

Originally Posted by ApexResistance

Why not the Koni Yellows? I hear they are very similar to the B6's but with adjustable dampening? Just my thoughts. Bilsteins are a good choice too.

To be honest, I can't be bothered to fiddle with the adjustments.

[dojk]

Originally Posted by ShocknAwe

They are similar in that they are both dampers. That's about it.

Bilstein:
Monotube construction
Lighter (good for reducing unsprung weight)
Greater damper body diameter
Highly damped non-adjustable

Koni
traditional 2 piece
Thinner (helps with fitting bigger wheels and tires without spacers)
adjustable damping

B8 and B6 have identical valving. The piston stroke is physically shorter on the B8 to accommodate springs that lower the car 30mm or more.

mmmmm strange how this works.

Bilstein is selling the B6 and B8 with the same valving, but the B6 is suited for the M-Sport springs and the B8 for the M performance springs which are shorter and higher spring rate.

So will that mean the Bilsteins are a compromise between the 2 different springs?

Over damped for the M-sport and under damped for the M performance.

[Iron Man]

Originally Posted by dojk

mmmmm strange how this works.

Bilstein is selling the B6 and B8 with the same valving, but the B6 is suited for the M-Sport springs and the B8 for the M performance springs which are shorter and higher spring rate.

So will that mean the Bilsteins are a compromise between the 2 different springs?

Over damped for the M-sport and under damped for the M performance.

I believe some forum members on here have used the B6 for the BMW Performance springs.