[xpro]

Hi all,

Im looking for some advice regarding B8 shocks and various applicable springs.

Im currently running B12 with -06 spring set (the stiffest spring in f30 range 1095kg payload)

I also ran -05 spring before but I removed due to being to soft and due to car bottoming out ( 1060kg payload)

My opinion is that B12 kit is not great at all, Im really disappointed in Bilstein. Almost 1.5 years of driving and 30K miles now. They either didn't do enough testing, or this was just a generic upgrade.

My findings: For straight and level driving they are ok, the body roll is reduced and the stance is great.

But real world scenarios, bums on the road, undulations, etc they totally suck!
The inner bump stops have been completely disintegrated from continuous bottoming out.

It seem like Eibach springs are just too weak for the 335d drive.

I have tested the car on suspension tester and road dyno and this strut is continuously being compressed to its full travel which is not good at all!

So what I'm looking now is either return the car to standard OE spring but still use b8 shock, which in theory should again lift the car height but it will stop the bottoming out.

The second option is buy M4 Competition springs and use them instead.
Im hoping m4 springs would lift the car a tiny bit, but prevent the bottoming out.

Other then that is a complete suspension change to likes of B14 or B16

Any other advice there please?

Thanks

[alohasurftoad]

i have m-performance suspension so my advice is based on what i've read here.

i don't think B8 with OEM springs would work since the B8 damper is physically shorter, i'm not sure if they can be assembled. if they can i would think the combo would not perform optimally.

after farkle's extensive reviews on Bilstein's, i believe Koni makes better dampers. i'd do Koni Yellow Sport or SA dampers with your Eibach Pro-Kit -06 or M-Performance springs if you can obtain them.

If you're switching to coilovers, KW street comfort.

[Torquey]

What kind of roads are you mostly driving on?

I have the same combo on my F34 335i GT although with 05-22 springs; installed last weekend along with F80 rear bump stops. My initial impressions are very positive! The car feels more athletic and lot more willing to turn. The city streets near me are a mixed bag... but none of the bumps or pot-holes have upset the cabin yet and definitely no bottoming out. On the contrary I feel the car is now more composed and shrugging off the imperfections with ease. I've been intentionally driving the familiar routes so I can compare it with the stock non M suspension that was just taken off, with 51k on it. There is absolutely no comparison in my mind!

I do feel the road a lot more, specially the grooves on the highway... so on long road trips that may be a factor. If the highway is relatively smooth, the car just hunkers down and runs... I've "tested" it to 100

[FaRKle!]

Yeah the Eibach kit isn't very stiff for 6cyl diesel xDrive both front and rear.

You could consider looking at F33 OE springs (both regular and M-perf) since those are the stiffest BMW makes for the platform (since that car is the heaviest F3x). The F33 M-Perf front springs are about 240lbs/in (vs 195lbs/in for the Eibach kit). For the rear I recommend doing a DIY rear HAS setup so you can use standard coilover springs and have many spring rate options. Using my

The Bilsteins can handle the stronger springs no problem. The rear in particular you can go way high on spring like (like 1000lbs/in) and the damping will still be fine. I think for OE rates or a bit above, Konis are probably better, but when you get to higher spring rates and heavier platforms, the Bilsteins are better suited. Using my ride frequency calculator you'd probably want a rear spring in the 650-700lbs/in range with the F33 M-Perf front spring to get around a 10% flat ride ratio.

[Torquey]

Is the diesel an iron block, making that front end heavier than petrols with same displacement?