Bilstein B14 and B6 Strut Teardown & Comparison

Let's take a look at struts from Bilstein B14 and B6 kits for the BMW F2x/F3x chassis cars and see what the differences are.
Index:
0:00 Intro
0:13 B14/B6 descriptions
0:41 Strut body comparison/ride height
1:09 Droop comparison
1:45 Spring characteristics & functions
3:45 Strut components disassembled and compared
4:15 Inverted design explained
5:21 Bump stops' design
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[@CartubeCoIl]

Great Comparison, been looking for this one. Thanks a lot.

[@SuspensionTruth]

Great breakdown and information. I'll be referencing your vids in future comments to help people see pros / cons / features of various damper types. If you think of doing a visual / functional comparison with the factory non-inverted dampers, that might also be insightful (maybe bump travel differences?). At some point if we got a current source (I borrowed one years back examining Nissan GT-R Damptronics), we could do a dyno test of the Tenneco at various settings to see what they were doing.

[@pitbullbite5835]

Thx for video... Much appreciated!!

[@nesertema4583]

inverting the dampers helps reducing the unsprung weight as well

[@msmarshall854]

Farkle, I wonder if you ever weighed the strut-housing vs. the strut----this gives us an idea of how much unsprung weight is saved because this is an inverted monotube. Just based on 'feels' was the strut-housing much lighter compared to the damper itself?

[@MrUnicornsinmycereal]

I need to replace a b14 rear shock, what would be a good replacement? Cant seem to find a b14. Id like to replace a single shock but willing to buy two new rears to even things out

[@marcwang4830]

Thank you for putting this together. I am using B14s on a M135i and have been trying to understand them with what little information is provided online. On one of my front shocks, I get deep dead clunk / clack when the shock gets extended quickly, for example going over a speed bump on neutral throttle. But this does not happen under slight brakes over the same bumps. Any idea what could be it ? My dampers are less than 10K km old. You seem to also have experience owning both B8 and B14, could you share your views on their differences in ride/performance ? With my B14, despite the stiff springs, it bottoms out more often than expected, even with a relative small drop in height. Also, the rear continues to pogo on certain bump frequencies on the freeway. I am wondering if the B14s are underdamped for their spring rate. I wish for slower rebound and stiffer compression from a performance standpoint.

[@FaRKle0079]

I'm a bit surprised you have clunking on extension and not compression. I'd check the damper to top mount nut torque and the end links first. B14s have stiff front springs, but pretty soft rear springs. Some of the F2x/F3x chassis OE rear springs are stiffer than what comes with the B14s. The rocking sensation you get is likely due to the non-flat ride frequencies which makes the chassis take longer to settle. This is exacerbated when going over successive bumps/undulations in the road. Typically Bilstein doesn't underdamp their dampers, but tends to overdamp them. Regarding B8 vs B14, they're too different to compare since the B8 performance will vary depending on what springs you pair it with. B8s have decent damping curves in the front for stiffer springs, and in the rear, they are heavily overdamped, so you can go way up in spring rate (almost double OE) and still be controlled. The one thing to remember about Bilstein, is they spec the same damping curve/performance with the B8/14 and spring rate (B14) for a lightweight RWD 4cyl 2-series, and a heavy AWD 4-series convertible. Basically a 1000lb spread...

[@marcwang4830]

@@FaRKle0079 Thanks for your suggestion, I'll have a look again at the top mount to shock shaft bolt. My mechanic rounded one of the head when he was torquing the top mount to the shock shaft ! I suppose thats the end of that shock. Do you have any experience with the B12 Pro Kit then ? I've read many preferred its performance over the B14. And lastly, do you know if the B14 rear dampers are exactly the same as the rear B6 ? I am asking this because if my fronts are shot, I may have to buy a set of B6 upfronts and replace all 4 springs with Eibach Pro Kits which I already have. My local supplier do not sell individual B14 shocks unfortunately. Thank you so much for taking time to answer my queries.

[@FaRKle0079]

@@marcwang4830 Did he round the head of the nut, or strip the hex on damper piston shaft (the second one is much more likely). If he stripped the hex, he very well may not have applied the proper torque on the nut. The B12 kit is Bilstein B6/8 dampers paired with Eibach springs. It should have flat ride, but you can also go to stiffer springs than what's provided if you choose. I don't think B14 rear dampers are the same as B6 or B8. I know for this platform B6/8 have the same damping curve and the only difference is really the damper shaft length and bump stops. One thing you could do, is keep the B14 rear springs/adjuster assembly and just replace the dampers. You could also convert the B14 rear spring assembly by putting your own standard coilover spring on there, like the DIY HAS I made (kzbin.info/www/bejne/gnacYYKanr97g7M), and then just replace the dampers, and front spring. The B6/8 dampers pair pretty well with M3/4 competition pack front springs.

[@mattz38]

Thanks for the detailed comparison. Overall, would you recommend a b14 kit to fellow bmw enthusiasts? I have a higher mileage sport package e91 and at some point I’ll need to refresh the original shocks/struts. I was going to go with a b8 kit but the b14 kit for less then $50 more seems like a really compelling value.

[@FaRKle0079]

One thing I'd caution about the B14 is if Bilstein uses the same PN/kit across all models. They do this for the F2x/F3x series, which means that the rear spring rate and damping for the wagon is terrible. They also do this with the B6/8, however those tend to be more overdamped, so you need to run a very stiff spring with them. With your E91, running a stiffer spring in the rear is better since you have more weight, so if the B14 kit for the E9x is "one size fits all" I'd rather go with the B6/8 and picking your own springs. The E9x platform should be able to use the same rear springs as the F2x/F3x platform, and looking at Eibach drawings, some of their F2x/F3x springs are even labelled as being for E9x chassis cars.

[@mattz38]

FaRKle0079 It does look like the part number on the b14 kit is the same for all body styles, so maybe not such a great option after all. I mainly wanted to refresh the suspension on an 11 yo car, so maybe the best bet is to keep the oe sport springs and explore either the sport package specific B4, Sachs, or maybe Koni active. After all it’s just a budget daily for me. Thanks again, appreciate the info.

[@FaRKle0079]

@@mattz38 Konis or Sachs may be a better fit for OE springs than B6/8.

[@paganiluv9552]

How does comfort compare? I've been looking at a B12 pro kit for comfort and moderate lowering capabilities, but I would like the coil overs B14 kit for the adjustability, but I'm just put off by the harsher ride

[@FaRKle0079]

B12 will probably ride more smoothly than B14.

[@auTHORity0492]

Do you have any idea on where to get replacement bumper stops? I haven't had great luck with Bilstein support in the past on finding replacement parts, but may try them.

[@FaRKle0079]

I ordered them from Summit Racing. www.summitracing.com/parts/BSN-E4AP2Z118A00

[@VoxxerBae]

I am looking for an upgrade in my F30 320d. Is B6 With H&R Springs better Than B14 ? I want max better handling

[@FaRKle0079]

I'd probably prefer the H&R springs with B6 dampers over the B14 since they still maintain a similar spring balance to OE.

[@VoxxerBae]

@@FaRKle0079 Thanks Man. Can I have your Instagram Id ?

[@FaRKle0079]

@@VoxxerBae You can find me on IG at "farkle_tech"

[@AW.SO.M3]

Great info. Perhaps a b8 damper body can be used inside the b14 as I’m using softer front springs. I’d like to minimize down time so a replacement damper body seems to be the best route

[@FaRKle0079]

You can! I put my FCM modified B6 damper body into B14 strut bodies.

[@mohamad-q8s]

Bilstein has a lifetime warranty see if you can get it replaced. Also what mileage did yours last until?

[@icemen77]

Question, So are the bumpstops on the B14 on the inside of the damper cylinder... if I see this correctly?

[@FaRKle0079]

Close, all "inverted strut" designs have the bump stop inside the strut body. The damper cylinder/damper body is what moves in and out of the strut body.

[@JC-io8pv]

How did your take the b6 apart and where you can get o rings for replacement

[@FaRKle0079]

You can see the strut disassembly here: kzbin.info/www/bejne/r2jZpWiHa9iDrLs I'd call Bilstein for replacement parts/PNs. Then you can either buy from them or search those PNs to see who carries them.

[@Wachueu]

Hello! Do you know how much of milleage has took the B14 from the video?

[@FaRKle0079]

I don't recall exactly. I want it say it was in the 15k mile range.

[@Wachueu]

@@FaRKle0079 Thank you. I am waiting for my kit but i heard these shocks are not rust proof and i am a little bit worried. These from video looks good, i guess mine should be fine as well as we dont really have winters in our country and also i am making like 5k miles max per year so.

[@arkadiuszzauska4205]

theres a any shop to buy a bump stops for B8's ?

[@FaRKle0079]

I ordered mine from Summit Racing (www.summitracing.com/parts/BSN-E4AP2Z118A00). They direct order/drop ship them from Bilstein. PN is E4AP2Z118A00 if you want to search elsewhere.

[@diegotiziani4905]

Hi, I already have Eibach pro kit lowering springs on my 2018 GT86(-25mm front and -20mm back). Should I go for B6 or B8?

[@FaRKle0079]

I'd lean towards B8.

[@ricardoarriaga7595]

Hi which one would you recommend for a smoother ride on a 2008 328i E92 coupe, the B14 Coilovers or B6 Bilstein ? I'm looking into getting one or the other for My car and would like an opinion thanks .

[@FaRKle0079]

Probably B6 since you can get your own springs to pair with it and keep flat ride, which B14 won't have.

[@ricardoarriaga7595]

@@FaRKle0079 ok yeah thanks I'm gonna go with the B6 Bilstein I found a deal for 600$ thanks for your input .

[@Giannis6000]

@@FaRKle0079 Hallo i want the combination B6 with Eibach Pro kit.... is a gut idea or not?

[@FaRKle0079]

@@Giannis6000 It'll work fine. More damping than required for the springs in that kit, but it'll work.

[@Giannis6000]

@@ricardoarriaga7595 what have done finally what did you buy for you car. I'm asking because I have the same car and I want the Bilstein B6 with the Eibach Pro kit.

[@robertpurvis6106]

I have a 2011 135i. Was planning to upgrade koni yellows and lowing springs with the B14 per a recommendation of my current mechanic. Does the B14 kit use all the front and rear stock suspension pieces, shock mounts, plates, etc? There is no need for the front bump stop but the rear uses the oem one?

[@FaRKle0079]

It might be different for the E82 1-series. Bilstein's instructions (starting on page 21 media.carparts-cat.com/pdf/Einbau/186416/16/E4-WM4-Y733A00.PDF ) show you which OE parts to reuse.

[@robertpurvis6106]

@@FaRKle0079 yes very helpful! was planning on buying new oem parts to ensure no problems with the B14 kit. doesn't look like i need to buy a complete shock parts kit but just some of it. If it was only in English and had part numbers. lol. I can make out the shapes and compare to oem part pics. the rubber parts are fair priced. it's all the hardware, bolts, and locking nuts that add up quickly to hundreds. maybe overkill but i get how rubber gets old and bolts get rusted and stripped as the install takes place. makes sense to just spend the extra $200 to have them on hand and not have to have the mechanic wait for parts. thank you!

[@robertpurvis6106]

@@FaRKle0079 yes very helpful! was planning on buying new oem parts to ensure no problems with the B14 kit. doesn't look like i need to buy a complete shock parts kit but just some of it. If it was only in English and had part numbers. lol. I can make out the shapes and compare to oem part pics. the rubber parts are fair priced. it's all the hardware, bolts, and locking nuts that add up quickly to hundreds. maybe overkill but i get how rubber gets old and bolts get rusted and stripped as the install takes place. makes sense to just spend the extra $200 to have them on hand and not have to have the mechanic wait for parts. thank you!

[@FaRKle0079]

@@robertpurvis6106 I'm not sure if you've used this site before or not, but RealOEM (www.realoem.com/bmw/enUS/select ) will show you diagrams with the parts and part numbers. It's helpful for looking up what you might want to have on hand for the job.

[@robertpurvis6106]

@@FaRKle0079 again very helpful! i used that site to determine new brakes earlier this year but brain farted to look at it for my shocks. there is all the diagrams and part numbers. realoem diagram on the left screen and bilstein's german instructions diagram on the right screen is bringing the clarity. to complicate i am also looking at the Dinan upper rear shock mount kit to determine what oem parts they replace. figuring it out slowly but surely.

[@kenand10]

b6 for comfort

[@sr20dett1000]

Bilstein changed their e90 Bilstein B14 to a non inverted strut.

[@FaRKle0079]

That certainly makes it easier to make bump stop changes!