B4 Vs B6 Vs B12 Or Equivalent???

Buug959 · 08-07-2020, 03:09 PM

I am new to BMW ownership and I need some informed advice on which way to go with my suspension. I have a 2008 335xi e90 , that I just bought, that has two completely useless rear shocks. The drivers side is probably working at about 40-50% and the passengers side is about as helpful as a hockey stick in a garbage can at damping the ride. Needless to say when I hit a bump in any kind of corner it is quite a butt-puckering experience. Now as near as I can figure out the stock shocks ( which I'm sure these are the original that were installed by the factory) are equivalent to Bilstein B4. I want to use the car for the occasional track day but mostly for long(ish) road trips ( if the current Covid 19 situation eases ) so I want better handling without sacrificing too much comfort. The next problem I have is that my driveway is quite steep so I am not able to lower the car very much, if any, and still be able to get off the street without scraping the chin. See Attached photo.
Now we get to to point. What should I do and why? Take one step up to B6 shocks and struts, change to the B12 system and keep it as high as possible or do you have other options bearing in mind that I don't have an unlimited budget. Or do I just stay with the factory setup?
If you need any more details, just ask and I'll do my best to answer.

Cheers

colorado.e9x · 08-07-2020, 03:27 PM

Go with B6 and upgraded top mounts (Monroe) in the rear. Replace all other mounting hardware as well.

The B12 lowers it to about stock sport height, which judging by your driveway is a little too low.

Someone correct me if I'm wrong but B4 is an OE equivalent, B6 is more performance oriented, and B8 is just a lower version of the B6

Edit: With the money saved keeping your stock springs you can get subframe bushing inserts so your car won't shimmy side to side when you hit bumps while cornering. The upgraded top mounts help with the lateral shimmy

mweisdorfer · 08-07-2020, 07:15 PM

Quote:

Originally Posted by colorado.e9x

Go with B6 and upgraded top mounts (Monroe) in the rear. Replace all other mounting hardware as well.

The B12 lowers it to about stock sport height, which judging by your driveway is a little too low.

Someone correct me if I'm wrong but B4 is an OE equivalent, B6 is more performance oriented, and B8 is just a lower version of the B6

Edit: With the money saved keeping your stock springs you can get subframe bushing inserts so your car won't shimmy side to side when you hit bumps while cornering. The upgraded top mounts help with the lateral shimmy

I think B8's are an upgrade over the B6. Yes, B8's are for lowering the car.

B12 Kit coupled with M3 control arms is better than the m-sport suspension

Buug959 · 08-07-2020, 07:35 PM

Quote:

Originally Posted by colorado.e9x

Go with B6 and upgraded top mounts (Monroe) in the rear. Replace all other mounting hardware as well.

The B12 lowers it to about stock sport height, which judging by your driveway is a little too low.

Someone correct me if I'm wrong but B4 is an OE equivalent, B6 is more performance oriented, and B8 is just a lower version of the B6

Edit: With the money saved keeping your stock springs you can get subframe bushing inserts so your car won't shimmy side to side when you hit bumps while cornering. The upgraded top mounts help with the lateral shimmy

I found this kit at FCP Euro - BMW Subframe Bushing Insert Kit - Whiteline KDT918. Is this what you are talking about?

Buug959 · 08-07-2020, 07:39 PM

Quote:

Originally Posted by mweisdorfer

I think B8's are an upgrade over the B6. Yes, B8's are for lowering the car.

B12 Kit coupled with M3 control arms is better than the m-sport suspension

Will the M3 control arms work on an xdrive? Even if they do I think it will lower the car too much for my driveway. What do you think? I don't have very much clearance now.

colorado.e9x · 08-07-2020, 07:40 PM

Quote:

Originally Posted by LemansE90335xi

Quote:

Originally Posted by colorado.e9x

Go with B6 and upgraded top mounts (Monroe) in the rear. Replace all other mounting hardware as well.

The B12 lowers it to about stock sport height, which judging by your driveway is a little too low.

Someone correct me if I'm wrong but B4 is an OE equivalent, B6 is more performance oriented, and B8 is just a lower version of the B6

Edit: With the money saved keeping your stock springs you can get subframe bushing inserts so your car won't shimmy side to side when you hit bumps while cornering. The upgraded top mounts help with the lateral shimmy

I found this kit at FCP Euro - BMW Subframe Bushing Insert Kit - Whiteline KDT918. Is this what you are talking about?

That sounds like the one, there's a few out there but if that ones made out of poly then yes that's it

Front M3 control arms won't work on xdrive unfortunately.. I really wish they did. The rear for xdrives are the same as rwd though.

If you're curious on the drop, I'm xdrive on the B12 kit. My IG handle is the same as my username on here

Buug959 · 08-07-2020, 07:53 PM

I just went back to FCP Euro to check but it doesn't say what material these are made from. I get the idea though so I'm sure I'll find something suitable.

tlow98 · 08-07-2020, 08:43 PM

How sensitive to ride quality are you? If you like a stock sporty ride then go with b4. If you don’t mind a rough ride the go with b6/8. Increased handling with the b6/8 tho.

Buug959 · 08-07-2020, 08:52 PM

Quote:

Originally Posted by tlow98

How sensitive to ride quality are you? If you like a stock sporty ride then go with b4. If you don’t mind a rough ride the go with b6/8. Increased handling with the b6/8 tho.

I'm thinking I'll probably go with the B6 setup. I really like to throw the car into the corners hard. Oh, and make it out the other side too. Always a bonus.

colorado.e9x · 08-07-2020, 09:25 PM

If you like that you should definitely invest in xDelete if you haven't already. Removes a lot of the understeer, making it easier to hit corners.. Faster

Buug959 · 08-07-2020, 09:36 PM

Faster is always better but c'mon, I need to take baby steps here. So far I haven't even driven the car with a complete, working suspension. Let me fix that first and then maybe I'll entertain the idea of the xDelete. LOL

mweisdorfer · 08-07-2020, 09:38 PM

Quote:

Originally Posted by LemansE90335xi

Quote:

Originally Posted by mweisdorfer

I think B8's are an upgrade over the B6. Yes, B8's are for lowering the car.

B12 Kit coupled with M3 control arms is better than the m-sport suspension

Will the M3 control arms work on an xdrive? Even if they do I think it will lower the car too much for my driveway. What do you think? I don't have very much clearance now.

No, but you could almost do the same thing by changing the bushings out of your current set of control arms. You won't get the .75 negative camber, but you will get a much stiffer steering feel that hugs the road.

Buug959 · 08-07-2020, 10:17 PM

Quote:

Originally Posted by mweisdorfer

No, but you could almost do the same thing by changing the bushings out of your current set of control arms. You won't get the .75 negative camber, but you will get a much stiffer steering feel that hugs the road.

Ok so I'm going to sound like a complete noobie here because, well, I am. What you're saying is the M3 bushings will fit in place of my stock bushings in my stock control arms with the major difference being that I don't get the negative camber. What I do get is stiffer bushings, which means less deflection under load, and therefore a tighter steering feel, correct?
This is all in conjunction with which shock/strut setup, B6 or B12? I'm pretty sure the B8s are out of the question because they're basically just shorter B6s.

mweisdorfer · 08-08-2020, 10:21 AM

Quote:

Originally Posted by LemansE90335xi

Quote:

Originally Posted by mweisdorfer

No, but you could almost do the same thing by changing the bushings out of your current set of control arms. You won't get the .75 negative camber, but you will get a much stiffer steering feel that hugs the road.

Ok so I'm going to sound like a complete noobie here because, well, I am. What you're saying is the M3 bushings will fit in place of my stock bushings in my stock control arms with the major difference being that I don't get the negative camber. What I do get is stiffer bushings, which means less deflection under load, and therefore a tighter steering feel, correct?
This is all in conjunction with which shock/strut setup, B6 or B12? I'm pretty sure the B8s are out of the question because they're basically just shorter B6s.

If it were me and I was creating a semi track car, I would :

Springs -

https://www.ecstuning.com/b-dinan-pa.../d100-0925~din

Shocks & Struts -

https://www.fcpeuro.com/products/bmw...2478kt#fitment

Control arm bushings (Front) -

https://www.ecstuning.com/BMW-E90-33...rol_Arm/Front/

Consider some items on this page -

Rear Subframe -

https://www.ecstuning.com/b-trw-part...3322283547kt4/

You are going to want to upgrade the sway bars, differential & subframe bushings.

Motor mounts - go with Turner 60a

Trans mounts - rogue engineering

08-07-2020, 03:09 PM	#1
Buug959 Captain 17177 Rep 873 Posts Drives: 335xi E90, GMC Sierra, VW Golf Join Date: Jun 2020 Location: Nova Scotia iTrader: (0)	B4 Vs B6 Vs B12 Or Equivalent??? I am new to BMW ownership and I need some informed advice on which way to go with my suspension. I have a 2008 335xi e90 , that I just bought, that has two completely useless rear shocks. The drivers side is probably working at about 40-50% and the passengers side is about as helpful as a hockey stick in a garbage can at damping the ride. Needless to say when I hit a bump in any kind of corner it is quite a butt-puckering experience. Now as near as I can figure out the stock shocks ( which I'm sure these are the original that were installed by the factory) are equivalent to Bilstein B4. I want to use the car for the occasional track day but mostly for long(ish) road trips ( if the current Covid 19 situation eases ) so I want better handling without sacrificing too much comfort. The next problem I have is that my driveway is quite steep so I am not able to lower the car very much, if any, and still be able to get off the street without scraping the chin. See Attached photo. Now we get to to point. What should I do and why? Take one step up to B6 shocks and struts, change to the B12 system and keep it as high as possible or do you have other options bearing in mind that I don't have an unlimited budget. Or do I just stay with the factory setup? If you need any more details, just ask and I'll do my best to answer. Cheers Attached Images Last edited by Buug959; 08-07-2020 at 07:58 PM..
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08-07-2020, 03:27 PM	#2
colorado.e9x eBay Special 3066 Rep 3,028 Posts Drives: E90 330xi Join Date: Feb 2018 Location: Western Slope, Colorado iTrader: (1) Garage List 2007 BMW 328xi [9.50] 2006 BMW 330xi [10.00]	Go with B6 and upgraded top mounts (Monroe) in the rear. Replace all other mounting hardware as well. The B12 lowers it to about stock sport height, which judging by your driveway is a little too low. Someone correct me if I'm wrong but B4 is an OE equivalent, B6 is more performance oriented, and B8 is just a lower version of the B6 Edit: With the money saved keeping your stock springs you can get subframe bushing inserts so your car won't shimmy side to side when you hit bumps while cornering. The upgraded top mounts help with the lateral shimmy __________________ Common sense is a flower that does not bloom in everyone's garden
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08-07-2020, 07:53 PM	#7
Buug959 Captain 17177 Rep 873 Posts Drives: 335xi E90, GMC Sierra, VW Golf Join Date: Jun 2020 Location: Nova Scotia iTrader: (0)	I just went back to FCP Euro to check but it doesn't say what material these are made from. I get the idea though so I'm sure I'll find something suitable. __________________ Wha' da ya mean? No brakes never stopped anyone before!
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08-07-2020, 08:43 PM	#8
tlow98 Brigadier General 2173 Rep 4,989 Posts Drives: 2009 E91, 2014 F15 x35i Join Date: Aug 2011 Location: Bay Area iTrader: (2)	How sensitive to ride quality are you? If you like a stock sporty ride then go with b4. If you don’t mind a rough ride the go with b6/8. Increased handling with the b6/8 tho.
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08-07-2020, 09:25 PM	#10
colorado.e9x eBay Special 3066 Rep 3,028 Posts Drives: E90 330xi Join Date: Feb 2018 Location: Western Slope, Colorado iTrader: (1) Garage List 2007 BMW 328xi [9.50] 2006 BMW 330xi [10.00]	If you like that you should definitely invest in xDelete if you haven't already. Removes a lot of the understeer, making it easier to hit corners.. Faster __________________ Common sense is a flower that does not bloom in everyone's garden
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08-07-2020, 09:36 PM	#11
Buug959 Captain 17177 Rep 873 Posts Drives: 335xi E90, GMC Sierra, VW Golf Join Date: Jun 2020 Location: Nova Scotia iTrader: (0)	Faster is always better but c'mon, I need to take baby steps here. So far I haven't even driven the car with a complete, working suspension. Let me fix that first and then maybe I'll entertain the idea of the xDelete. LOL __________________ Wha' da ya mean? No brakes never stopped anyone before!
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