Eibach/Koni vs. Bilstein PSS10 for a street setup

[Tbonem3]

Member DAL, years ago, made a nice comparison between Sachs, Koni & Billys:

"In my opinion, comparing most of OE replacement dampers for the 46M goes like this:

Most comfort = OEM
Similar comfort = Koni
Best performance = Bilstein
Best quality = Bilstein
Least bump travel = Bilstein (same for their coilovers)
Worst comfort = Bilstein (N/A for Bilstein Coilovers - they are ok here)


Bilstein B6
The Bilstein B6 is a fantastic monotube damper. It's robust, long lasting and high performance orientated and great value. There are some things that let it down though. There is long internal bump stop meaning the bump travel isn't great.

This is made worse by lowering springs which reduce the travel even more... go too low and you'll be riding on the bumpstop constantly.... not pleasant!

Eibachs are the only lowering spring I would consider with them, due to a small drop. You can do clever things and regain lost damper travel with the use of GC plates - see my build thread for more info on them. Otherwise stick to OEM springs for maximum travel. For poor UK roads we want all the travel we can get.

Finally, the dampers seem to have a ''always ready to attack" nature. This is superb for weekend drives, but in the city things can become a little busy. To be expected I suppose given its construction (high pressure gas / monotube design).


Koni
I haven't had these on the car yet - every time I'm ready to buy vendors are out of stock. However I have read data charts on them that represent the views of owners I trust - so I have some bearing on them.

They are twin tube in design like OE, so more comfortable than the B6. They are rebound adjustable which makes them great for use with lowering springs. One annoyance is the method of adjusting the rears... the dampers have to be taken off the car. That said, there is a lot of information out here on the ideal damping adjustment vs spring used. So you are likely to get the adjustment right first time.

I do hear reports about Koni shocks leaking after a while for some. But if I was to run something like a H&R spring I'd be more inclined to use the Koni as above. Do remember though you're still eating into your travel when using a lowering spring.


OEM
OEM Sachs are cheap and cheerful. You're not going to get the best handling, nor build quality.... but they get the job done at low cost - a comfortable ride for everyday driving. I'm running a modified OEM setup with eibach springs that gives me lowering without any penalty on damper travel. Review inbound soon"

I'm adding:

Monotubes don't tire as quickly as OE/Koni twin tubes.

Also, since I still see the misconception - Koni's (and many coilovers) are only REBOUND adjustable. That has nothing to do with stiffness. Rebound it the speed at which the damper controls the release of the springs' contained energy from having been compressed. You match rebound to the spring rate which is also partly determined by variances in vehicle weight between our cars. Though it is a neat trick to extend Konis' lifespan by slowing the rebound as they age to keep up with the springs.

Billys are stiffer and more robust, and have much better control at speed. Konis are prety comfy esp if you do slower city driving.

[Tbonem3]

This is my current ride height with stockish shocks and eibach springs. You think it would ride higher than this or similar? Hopefully the picture shows it well.

Due to your car's and tires' black color, I can't quite see. What are "stockish shocks"?

[GreyM340i]

Due to your car's and tires' black color, I can't quite see. What are "stockish shocks"?

As far I can tell from previous receipts they might be B4 shocks.

[Tbonem3]

As far I can tell from previous receipts they might be B4 shocks.

Which are twin tube, and will not raise the height. So you should truly be -.6" front and -.9" rear from stock.

[GreyM340i]

Which are twin tube, and will not raise the height. So you should truly be -.6" front and -.9" rear from stock.

Thanks. So the B6 will raise the car from its current position.

[Tbonem3]

Yes, a bit. I don't think it goes right back up to fresh stock height. I had a car with new B6/Eibachs in my garage yesterday and it still looked a bit lower than factory. Maybe I'm getting a little older, but it looked great. Gonna be raising my car a little soon too.

[bullet0770]

Lighter overall (fewer options, no sunroof, components removed, light mods like battery, cf airbox, cf trunki, etc), talking about sprung weight, which increases spring rate, effectively, so that you get less body roll, though you can also install swaybars too.

Best price will depend on your patience - I find best price by searching by part #s, then comparing vendors as some do or don't charge shipping and/or tax (despite the law changing to require sales tax; some still don't).

My latest bilstein purchase (November, for E90, B8s) was via Autozone because they had a 20% sale that I couldn't believe applied to bilstein suspension! Other vendors that have low prices on bilstein are shock surplus, throtl, bimmerworld depends on what coupon codes you can find and sales. If you don't want to work too hard, it looked like Bimmerworld's price was about the best, though FCP wasn't much more and you can get another set for almost free in the future, presumably.

Though I think bilsteins have lifetime warranty for original owner, should something go wrong, prematurely.

My car is OEM, has a sunroof, and added weight of music system....so it is not light :P. Reading from the posts it looks like KONI are the best for comfort. But, you buy rear shocks from TCK and then tweak if needed (PITA). Also they are not the best quality. I like to buy once and be done with it. I buy most of my stuff from FCPEuro, I have seen tirerack has sale some times. I would keep an eye out as I have some time to tackle this.

So, technically B6 would be at least as comfortable as my OEM setup which is on 80k miles I don't want the ride to be harsh, my concern.

Thanks for your help, much appreciated.

[Tbonem3]

You're welcome, but in my opinion, there's little need for the special tck konis that are top adjustable unless you're going to be testing different springs. The factory springs or common lowering springs don't need any more rebound than the lowest setting (since konis are already "sportier" than stock sachs) esp if your car is a little heavier than average, which lowers effective spring rate thus needing even less rebound.

Maybe people have done a quarter turn or something, but I don't see how you'd need much at all unless you're putting in linear spings like GC kit something like 600lb.

Member Cobra touched on this as well, with actualy shock dyno data:

"I tested my Koni Sport on a dyno and was amazed by the rebound range. With stock or stock-ish springs, you pretty much want full soft. Maybe a TOUCH more in back (like 1/2-3/4 as Tbone mentioned) to balance the handling."

[liam821]

I shouldn’t have opened this thread. Now I’m looking at replacing my PSS10s with B6s or Koni Yellows + Eibach springs.

As long as your car isn't slammed, the PSS10s are great. They're a bit soft, IMHO, so ride height is needed to keep out of the pump stops. But other than that, they ride really well.

[SQ13]

Anyone with B6s, Eibach springs, and TMS street camber plates willing to share a photo of their car? Just wanna see what the ride height is like. I imagine this setup won’t be as harsh as the PSS10s?

[SQ13]

As long as your car isn't slammed, the PSS10s are great. They're a bit soft, IMHO, so ride height is needed to keep out of the pump stops. But other than that, they ride really well.

So I actually have the fronts maxed out on ride height, and I still can’t get to 13.5”. The ride feels very complaint, but I don’t have anything to compare it to except the MCS 2WNR setup on my other car, which rides pretty harshly. The ride height is what annoys me the most.

[Tbonem3]

SQ13 Wow I'm surprised. It must be to how thin the TMS camber plates are (you have TMS plates now SQ?). You could easly shim them. Did you install the TMS plates with the thick spacer that TMS includes?

[liam821]

So I actually have the fronts maxed out on ride height, and I still can’t get to 13.5”. The ride feels very complaint, but I don’t have anything to compare it to except the MCS 2WNR setup on my other car, which rides pretty harshly. The ride height is what annoys me the most.

That's about how my car looked with my old PSSs. Yeah, even maxed out it's still a bit low, I had the same problem. You could try using an energy suspension coil spring isolator, you can get them in a bunch of different sizes (thicknesses). You can slap it on the top or bottom of the spring and it will give you more ride height. I use one on my car and they work good.

https://www.energysuspensionparts.com/9.6103

[SQ13]

SQ13 Wow I'm surprised. It must be to how thin the TMS camber plates are (you have TMS plates now SQ?). You could easly shim them. Did you install the TMS plates with the thick spacer that TMS includes?

Yes, have TMS street plates. This is the only photo I have of them off the car. Not sure what spacer you’re talking about. Re shims, could I add a shim in between the camber plates and upper spring perches?

[SQ13]

That's about how my car looked with my old PSSs. Yeah, even maxed out it's still a bit low, I had the same problem. You could try using an energy suspension coil spring isolator, you can get them in a bunch of different sizes (thicknesses). You can slap it on the top or bottom of the spring and it will give you more ride height. I use one on my car and they work good.

https://www.energysuspensionparts.com/9.6103

Could I also do the same thing with helper springs? I have a set of Hyperco helper springs sitting in a box. I think the compressed height is around 0.5”, so that should help me get the ride height I’m wanting.