[Neuner]

@FaRKle! - do you have the original shock dyno data files for the Bilsteins? *.pvp files?

I suspect some of the overdamped feel of the B6/8 is from higher friction inherent to the inverted monotube design. The shock dyno software can calculate seal drag & you can see it in the F-V plots (not average F-V). Would be interesting to compare vs. Koni if anyone has test data for those too.

[FaRKle!]

Originally Posted by Neuner

@FaRKle! - do you have the original shock dyno data files for the Bilsteins? *.pvp files?

I suspect some of the overdamped feel of the B6/8 is from higher friction inherent to the inverted monotube design. The shock dyno software can calculate seal drag & you can see it in the F-V plots (not average F-V). Would be interesting to compare vs. Koni if anyone has test data for those too.

Yes, I do have the Bilstein B6 .pvp files. Unfortunately I haven't seen any Koni dyno data.

Additionally, I dyno'd the FCM tuned dampers again after 10k mi to see if seals breaking in had any affect on damping and it didn't. The curves still lay right on top of each other.

[Neuner]

Originally Posted by FaRKle!

Yes, I do have the Bilstein B6 .pvp files. Unfortunately I haven't seen any Koni dyno data.

Additionally, I dyno'd the FCM tuned dampers again after 10k mi to see if seals breaking in had any affect on damping and it didn't. The curves still lay right on top of each other.

Sent you a PM, could you send or upload the original (& modified?) shock dyno files? many thanks

[FaRKle!]

Thanks to ktw I got my hands on some OE passive damper data. To my knowledge this is the only OE passive damper dyno data out there and available for people to see freely.

ktw's vehicle is a F31 328ix wagon with the base suspension (although that's not the suspension he's running now).


Not surprisingly, the front OE base suspension damper has less damping force than all the others plotted here. This is what leads to the vague and floaty feeling where the car takes a good amount of time to settle. It also makes it feel like it has a lazy turn in. In particular, going to higher compression (left side of graph) will feel more responsive. The OE dampers do have low high velocity damping forces, which allows it to maintain comfort at higher speeds.


Looking at the rear dampers I was surprised to see the OE base suspension ones have higher compression than the Konis do. As expected, the Konis have a lot more rebound though. One thing that's not clear is what the Koni low-velocity forces are since they only supply data starting at 5in/sec. The low speed range generally dictates the sporty feeling. Looking at the Bilsteins, they have much higher low sped forces than the others, which is in line with their sportier feeling.

Another thing to note about the Bilsteins is how they manage to really taper off their high velocity forces. This is why they are known for feeling good at higher speeds, because the high velocity damping isn't very overdamped. Once again, the OE dampers also don't have high velocity forces here for cruising comfort.

It wouldn't surprise me if F30 base suspension rear dampers have lower forces than the F31 one. The F31 should have higher damping forces to deal with the higher rear weight and stiffer springs than the F30.

[Lancelot]

FaRKle! any thoughts about Bilstein B4 ? We saw good feedback in another thread, wondering if that’s not the compromise we’re looking for

[Solid67]

Originally Posted by Lancelot

FaRKle! any thoughts about Bilstein B4 ? We saw good feedback in another thread, wondering if that’s not the compromise we’re looking for

Yeah seems like from reading other forum members' posts, the Bilstein D4 is the way to go. I would pair them with MSS height-adjustable springs.

[FaRKle!]

Unfortunately I don't have any data on Bilstein B4 passive or adaptive dampers on the F2x/F3x platform.

I heard Enabled tried them on his F31, and didn't like them though, as if they were still much too underdamped.

[Lancelot]

Originally Posted by Lancelot

Quick feedback, i had decided on Koni SA but Koni advised against it on lowering springs and recommended Koni sport, which makes sense.

i'm settling for that, will report back in a couple of weeks when they are installed.

Months later, since confinement finally came to an end i've been able to get the Koni sport fitted and... wow!

What a difference from OEM adaptive shocks!

(I'm on lower and stiffer ST sport springs).

The Koni manage to both smooth out small imperfections that were making the oem dampers so busy, shrug off any bump in the road while keeping the car balance in check, i'm really impressed!

The car feels both more confident like on rails, as well as more comfortable, albeit remaining sporty by not giving in to weight, i'd express that as smoothing high frequencies, but following medium frequencies, if that makes sense!

[orangesquared]

Have the Koni Cup Kit on it's way (eibach pro kit and Koni Sports). What is the recommended settings to start with? Koni wasn't much help on this...

[Lancelot]

Originally Posted by orangesquared

Have the Koni Cup Kit on it's way (eibach pro kit and Koni Sports). What is the recommended settings to start with? Koni wasn't much help on this...

Well it's work in progress but i'd suggest to go the same way they propose here:


https://www.koni-na.com/en-US/NorthA...r-Under-Steer/

Set to low rebound damping force and adjust to increase;
On my side i like the front to almost full soft (so far), and haven't had a chance yet (because you need to unmount the dampers!) but i want to increase damping on the rear as i feel too much rebound and needs to be tamed a little.

Hope that helps

[orangesquared]

I appreciate the feedback! My main concern is installing...and removing and reinstalling the rears. I'm hoping for a happy medium in the rears.

[Lancelot]

You can check this video made by FaRKle!

but still a pain to adjust the rears indeed...haven't done it yet will probably ask the shop to do it cause I don't like to do it in my driveway

[orangesquared]

Originally Posted by Lancelot

You can check this video made by FaRKle!

but still a pain to adjust the rears indeed...haven't done it yet will probably ask the shop to do it cause I don't like to do it in my driveway

I really appreciate all the information you guys have provide (and continue to provide) to the community!

[orangesquared]

Installed the Eibach Pro Kit and Koni Sports last weekend. Set the Koni's to 1 full turn from soft and like it thus far. Car feels more planted and balanced. Front end dive under hard braking is gone, although car feels somewhat unsettled on small repetitive bumps. Planning to adjust a bit more to soft and see what that's like. Thanks Farkle! and Lancelot for your feedback.

[Torquey]

Found what I think is a pretty good deal on F3x Koni FSDs... which are the previous iteration of the Koni Special Actives (same technology). I was going to pick up a set myself, but these are ONLY for RWD models and the front shocks won't fit xDrives from what I understand. But thought I'd share if any of the RWD members want some quality shocks at a discount... whole set for $350!

https://www.ebay.com/itm/KONI-FSD-Sh...EAAOSwnpBdDCJ7

BTW... I'll be sure to follow the video from FaRKle! when it comes to my suspension install. It looks much easier for the fronts than the official BMW method!

[Z K]

Originally Posted by Torquey

Found what I think is a pretty good deal on F3x Koni FSDs... which are the previous iteration of the Koni Special Actives (same technology). I was going to pick up a set myself, but these are ONLY for RWD models and the front shocks won't fit xDrives from what I understand. But thought I'd share if any of the RWD members want some quality shocks at a discount... whole set for $350!

https://www.ebay.com/itm/KONI-FSD-Sh...EAAOSwnpBdDCJ7

BTW... I'll be sure to follow the video from FaRKle! when it comes to my suspension install. It looks much easier for the fronts than the official BMW method!

It's too bad they don't have them on clearance for cars with M sport suspension. This is for the base suspension and probably won't work well with anything other than the base springs.

[Torquey]

Originally Posted by Z K

It's too bad they don't have them on clearance for cars with M sport suspension. This is for the base suspension and probably won't work well with anything other than the base springs.

That's true... although if F30 M-Sports suspension only lowers the car by 10mm or so, I'd think the Konis should be able to manage that. I have the Koni Special Actives on my E60 with factory sports springs.

[Z K]

Originally Posted by Torquey

That's true... although if F30 M-Sports suspension only lowers the car by 10mm or so, I'd think the Konis should be able to manage that. I have the Koni Special Actives on my E60 with factory sports springs.

Koni makes a FSD that is specifically for M Sport springs - it has a different part number. I imagine those would be better suited. Maybe it's not that big a deal? No one would really know unless you test both FSD sets back to back.

Great price though!

[FaRKle!]

Originally Posted by Z K

Koni makes a FSD that is specifically for M Sport springs - it has a different part number. I imagine those would be better suited. Maybe it's not that big a deal? No one would really know unless you test both FSD sets back to back.

Great price though!

You probably missed my comment on the M-Sport vs Regular Koni SA dyno data:

One thing I found interesting is that it doesn't look like there's really any difference between the Koni SA M-Sport and Koni SA regular dampers. The mid-speed has a negligibly higher compression force, but that's it. It's possible the low-speed damping could differ a bit, but for now that's in the "unknown" region.

[Z K]

Originally Posted by FaRKle!

You probably missed my comment on the M-Sport vs Regular Koni SA dyno data:

The sport suspension is also lower than the standard suspension by about 10mm. Wouldn't that make a difference between sport and non sport applications? If you run a non-sport shock on a sport spring, the shock is not designed for that 10mm difference in static ride height?

[FaRKle!]

Originally Posted by Z K

The sport suspension is also lower than the standard suspension by about 10mm. Wouldn't that make a difference between sport and non sport applications? If you run a non-sport shock on a sport spring, the shock is not designed for that 10mm difference in static ride height?

Shocks aren't position sensitive. Unless you're hitting the ends of travel or they have internal springs that are engaged trying to force the piston to a certain position then where the piston starts at static ride height shouldn't matter.

If the shock is out of the car and unloaded if the shaft extends all the way to max (and you can't pull it out further) then there shouldn't be an internal spring in there. The ones I've seen that do have one you can pull the shock shaft out even more, and then it gets "sucked" back in.

It's possible the "sport" model has a slightly shorter shaft, but in either case you need to make sure your bump stop prevents the damper from bottoming out.

[Z K]

Originally Posted by FaRKle!

Shocks aren't position sensitive. Unless you're hitting the ends of travel or they have internal springs that are engaged trying to force the piston to a certain position then where the piston starts at static ride height shouldn't matter.

If the shock is out of the car and unloaded if the shaft extends all the way to max (and you can't pull it out further) then there shouldn't be an internal spring in there. The ones I've seen that do have one you can pull the shock shaft out even more, and then it gets "sucked" back in.

It's possible the "sport" model has a slightly shorter shaft, but in either case you need to make sure your bump stop prevents the damper from bottoming out.

Sounds good! I got a set of the FSD shocks from the ebay deal. I'll see how it is once I've installed it.

I had a set of Koni Special Active "sport" shocks before so I'm assuming these will be similar.