[W37V]

Originally Posted by feuer

I'm Koni user but would would like to know for what suspension B4 is built for?
B4-
B6-non sport
B8-sport & aftermarket lower

From my research, b4s are supposed to replace stock shocks. They are about 10% stiffer than OE shocks.

B6 and B8 have same valving, which B8 having shorter shaft. Someone mentioned that B6 and B8s are about 30% stiffer than OE.

[feuer]

Originally Posted by W37V

From my research, b4s are supposed to replace stock shocks. They are about 10% stiffer than OE shocks.

B6 and B8 have same valving, which B8 having shorter shaft. Someone mentioned that B6 and B8s are about 30% stiffer than OE.

That doesn't really answer my question. You say B4 replaces stock shock? All shocks that came on a car from the factory are stock. Non sport is stock. Sport is stock too. Are they firmer 10% from non sport? Or from sport? Are they same lenght as B6 ?

[W37V]

Originally Posted by feuer

That doesn't really answer my question. You say B4 replaces stock shock? All shocks that came on a car from the factory are stock. Non sport is stock. Sport is stock too. Are they firmer 10% from non sport? Or from sport? Are they same lenght as B6 ?

B4 comes in two lengths regular and sport. Sport is shorter. I think B4 sport would be same size as B8, while regular one should be equivalent to B6.

When I say B4 replaces stock shock, I meant that driving characteristics are very similar to stock ride ( how it came from factory).

Per various threads (Audi, Porsche, VW, etc. forums), b4 should be about 10% stiffer than OE shock. im not sure if sport is firmer than regular. I would assume valving is the same, with difference in shaft.

[techwhiz]

Originally Posted by W37V

B4 comes in two lengths regular and sport. Sport is shorter. I think B4 sport would be same size as B8, while regular one should be equivalent to B6.

When I say B4 replaces stock shock, I meant that driving characteristics are very similar to stock ride ( how it came from factory).

Per various threads (Audi, Porsche, VW, etc. forums), b4 should be about 10% stiffer than OE shock. im not sure if sport is firmer than regular. I would assume valving is the same, with difference in shaft.

Correct.
There is a B4 for both regular and sport suspension on E90.
The B6 is the HD version for regular suspension and the B8 is the shorter sport shock.

The B4 will be marginally stiffer than stock with similar ride.
The B6 or B8 will be stiffer.

[Spitfire007]

Originally Posted by techwhiz

The dealer/company that sold you B6 shocks to go on a sport package car didn't RTFM from Bilstein where it clearly states what is what. I'd go back and scream at them. But that's me.

The reason I know the difference is from experience.
I had an E36 M3 and the suspension difference between it and a regular E36 was the M3 took B8 along with M-Sport suspension cars while the regular E36 took B6.

I don't understand the confusion people have.
The B8 is a shorter shock.
The sport suspension cars have a shorter spring.
Short shocks go with short springs, aftermarket OR factory.

The shocks on sport suspension cars is not the same shock on regular cars.
So why would the aftermarket replacement use the same shock when it is a clearly different application?

People don't believe what a sales guy on the phone tells you ->
The manufacturer knows.

Yeah, but when the manufacturer (in this case Bilstein themselves) tells you over the phone to go B6....then....guess what: you go B6.

[W37V]

Originally Posted by Spitfire007

Yeah, but when the manufacturer (in this case Bilstein themselves) tells you over the phone to go B6....then....guess what: you go B6.

Just don't!

Dude, click on the link to see the picture? Did you see the height difference? And you are still claiming that B6 is right for sport suspension?

I don't know who told you what, but they were wrong, as their website states that B8s are for sport suspension. Btw. Not all e92 have sport suspension.

[Spitfire007]

Originally Posted by W37V

Just don't!

Dude, click on the link to see the picture? Did you see the height difference? And you are still claiming that B6 is right for sport suspension?

I don't know who told you what, but they were wrong, as their website states that B8s are for sport suspension. Btw. Not all e92 have sport suspension.

I've had Turner, Bilstein themselves, and an Indy tell me...I don't know what else to tell you.
They recommended B8 for aftermarket lowering spring solutions.

How can all three be wrong?

[rothwem]

So, the shaft is shorter on B8 vs B6...is the strut housing any shorter on the B8s?

[techwhiz]

Originally Posted by Spitfire007

I've had Turner, Bilstein themselves, and an Indy tell me...I don't know what else to tell you.
They recommended B8 for aftermarket lowering spring solutions.

How can all three be wrong?

Because the manual says they are?
How many times have you and everyone else gotten bad information over the phone? I have a copy of the application manual and it explicitly states that the B6 is not for M-Sport/M-Technic suspension. I don't know what else to say.
B8 says for cars with M-Sport/M-Technic suspension.

I believe what the manual says.
The actual valving of the B8 is the same as the B6, the unit is just shorter so as not to preload the shock. I don't know if it's just the rod or the body since I don't have anything to compare.

This is also why there are two B4 variants. One for M-Technic/M-Sport and one not. Different lengths, same valving.

Yeah, it appears that Bilstein changed their wording on which shocks to get for sport suspension vehicles. Originally they stated the B6 was for non-sport AND sport suspension; this has since changed now referencing that B8 is for sport suspension and lower.

[E30_335i]

I run the B6 with the sport suspension. Its about perfect. They work really well on track, not too bad on road.

[jwong77]

I run B8's on the Yellow BMW Performance springs, perhaps this is where the confusion is coming from. These springs are shorter/stiffer than the OEM sport suspension. Btw, the ride is brilliant and has gotten better over time, I've had them since January. A bit stiff when you're driving slow, but absorbs impacts great at high speeds.

[techwhiz]

Originally Posted by FCobra94

Yeah, it appears that Bilstein changed their wording on which shocks to get for sport suspension vehicles. Originally they stated the B6 was for non-sport AND sport suspension; this has since changed now referencing that B8 is for sport suspension and lower.

It's been that way for at least two years.
The catalog and application guide I have is dated 2014.
I've had my B8's for that long.

[W37V]

Originally Posted by rothwem

So, the shaft is shorter on B8 vs B6...is the strut housing any shorter on the B8s?

I don't think so. It should be the same.

[rothwem]

Originally Posted by W37V

I don't think so. It should be the same.

Well that's just frustrating then. It sounds like they don't add any bump travel, thy just take away droop so the springs don't get loose while the vehicle is unloaded.

Ugh, you with the "droop travel" again...that's not how it works in the rear on these cars. Please re-read the thread you started a couple weeks back; some good info was posted in there that you probably glossed over.

[CSBM5]

Originally Posted by FCobra94

Yeah, it appears that Bilstein changed their wording on which shocks to get for sport suspension vehicles. Originally they stated the B6 was for non-sport AND sport suspension; this has since changed now referencing that B8 is for sport suspension and lower.

This is exactly what happened. On the 330i I went with the B6 due to the guide from both Bilstein and TireRack at the time (car has ZSP) which was about two years ago. We bought the car new and it had ~130k on it, and the stock shocks were wasted, rear bump stops crumbled, etc. While the ride is much better over abrupt transitions (as you'd expect with Bilstein), it is too choppy over minor pavement undulations. If feels like the rear compression damping is too stiff in the mid-range shock velocity region. Ride height was raised almost 1/2" but I attributed that to the stock struts/shocks being shot coupled with the always slightly added spring rate a Bilstein provides.

If I had to do it over, I would either get the B8 or simply go with Konis.

[rothwem]

Originally Posted by CSBM5

This is exactly what happened. On the 330i I went with the B6 due to the guide from both Bilstein and TireRack at the time (car has ZSP) which was about two years ago. We bought the car new and it had ~130k on it, and the stock shocks were wasted, rear bump stops crumbled, etc. While the ride is much better over abrupt transitions (as you'd expect with Bilstein), it is too choppy over minor pavement undulations. If feels like the rear compression damping is too stiff in the mid-range shock velocity region. Ride height was raised almost 1/2" but I attributed that to the stock struts/shocks being shot coupled with the always slightly added spring rate a Bilstein provides.

If I had to do it over, I would either get the B8 or simply go with Konis.

The Bilsteins do loosen up a bit as they break in, but I'm thinking that a small amount of bleed would make the ride a bit better.

Supposedly Shaikh from Fatcat motorsports has a way to modify the Bilstein HDs and other Bilstein monotubes to make them ride a little better, they call it a "ripple reducer". I think he just drills holes in the spool valve to let it bleed a little bit so that really small displacement movements are allowed by the shock.

http://www.fatcatmotorsports.com/index.htm#page-top

There was a thread on Bimmerforums somewhere where they mentioned it:

http://www.m3forum.net/m3forum/showthread.php?t=534318

lots of good stuff there.

[CSBM5]

Originally Posted by rothwem

The Bilsteins do loosen up a bit as they break in, but I'm thinking that a small amount of bleed would make the ride a bit better.

Supposedly Shaikh from Fatcat motorsports has a way to modify the Bilstein HDs and other Bilstein monotubes to make them ride a little better, they call it a "ripple reducer". I think he just drills holes in the spool valve to let it bleed a little bit so that really small displacement movements are allowed by the shock.

http://www.fatcatmotorsports.com/index.htm#page-top

There was a thread on Bimmerforums somewhere where they mentioned it:

http://www.m3forum.net/m3forum/showthread.php?t=534318

lots of good stuff there.

Thanks for the link -- good stuff. Ages ago I studied shock dyno data, etc, a good bit after attending a seminar on the subject, so those comparisons are very interesting and nice to see posted up. The range of piston velocity between -2 to 2 in/sec is what a driver can impart on them through the steering wheel, brakes and accelerator inputs, so it's nice to see the comparison in the first chart with the expanded x-axis. It easily shows why in this comparison the Koni would be more responsive to driver inputs and then softer riding over large road-induced inputs at the same time. Neat stuff, thanks.

On my daughters E46 ZHP, she installed coilovers and camber plates with custom selected spring rates 4-5 years back now and ran into a major ride quality issue with the rear Konis this particular kit came with -- compression damping was way too stiff (these are SA Konis adjustable for rebound only) such that everyone riding in the car was constantly jiggling (i.e. feel your internal organs moving even) on even smooth pavement. No setting of rebound from full soft to full hard had hardly any effect. The vendor dyno tested the returned shocks and stated they were operating as designed, but fortunately refunded their cost when she found a solution elsewhere.

The solution she found was to use the TC Kline rear SA Konis in place of the original company's Koni/valving -- immediately the ride was *dramatically* improved and there was no sacrifice in handling performance. I came away from that experience sort of shaking my head at this entire industry in a way...

Her car is a blast to drive now -- 440/550 rates, Konis with TCK Koni in rear, Turner front and rear sway bars, 8.5/255s all around, and the lightest ZHP sedan config (no sunroof, 6MT, no fold-down seats). It rides "firm" but supple, and the transient response of the chassis is phenomenal.

[Washington335i]

You got me curious, so I called bilstein and they told me B6 for stock springs, incl sport springs. Funny, I still do not believe it...

Originally Posted by Spitfire007

Yeah, but when the manufacturer (in this case Bilstein themselves) tells you over the phone to go B6....then....guess what: you go B6.

[Spitfire007]

Originally Posted by Washington335i

You got me curious, so I called bilstein and they told me B6 for stock springs, incl sport springs. Funny, I still do not believe it...

They told me the stock sport springs were not a big enough drop for B8

[ednyc2nc]

Originally Posted by Spitfire007

They told me the stock sport springs were not a big enough drop for B8

I called bilstein and they told me that if I have sports package on my bmw 335i, I need the B8, but now I'm in doubt because I have sports package but no M package, I guess I will call them again to clarify.