OE ZCP Suspension Info

[derbo]

Originally Posted by wyatth

To retain EDC, you go B6 or B16.
B12, I think, is B8s (non-EDC) + Eibachs.
But, B6 and B8 are the same, except shaft length, and B8s are only recommended when dropping ~1''+. So you can make the equivalent of an EDC B12 with EDC B6s + mild springs.

A few are very happy with their EDC B6s with Eibachs (or Dinans, or Swifts) but others have admitted to being more satisfied with the OEM setup, especially if ZCP.

I think the Bilstein stuff is a worthwhile swap as you approach 50K, but probably not an upgrade worth doing any sooner.

To clarify my post above, the benefits of a ZCP car are the suspension and wheels (wheels easily changed). As cars approach 50K and need suspension overhauls, the fact that all parts are interchangeable makes the value of a ZCP car reduced (closer to a non-ZCP car). Unless it's a garage queen or collector, why would I pay much more for a ZCP car that needs a suspension refresh when I can get a non-ZCP car and get to the exact same point after a refresh, for less? Either throw ZCP hardware on the non-ZCP car, or go Bilstein under either scenario, whichever one wants to do, and after coding, the cars are identical.

Thanks for a summarization. B12 is indeed B8 + Eibachs. There is no EDC component to that. My personal plan is swift, B6D, vorshlag camber plates. This setup isn't cheap and close to a coilover setup as I want to retain EDC.

Back on topic,

The point of this thread is to confirm ZCP parts and what is exactly different between the variations. It is up to the reader if they want to use this information and build their own ZCP or if they want to go aftermarket. If I had ZCP, I would probably not touch my setup. Since I have a non-ZCP, I was curious what the difference between the ZCP parts were and if it was feasible to do all that work.

Personally, I think it isn't enough of a drop for me and I think I will be happy with my proposed setup.

[SYT_Shadow]

Originally Posted by SeattleLSB

Are you thinking B12 with the EDC delete? I can only find the B6 and Damptronic for cars that want to retain the EDC.

I'm at 51K miles and looking to upgrade soon!

One option would be B12 plus edc delete for a zcp car

Another is to just use the b6 or b8 edc shocks and pair them either with stock zcp springs or with the eibachs

[BOOF-M3]

Originally Posted by SYT_Shadow

One option would be B12 plus edc delete for a zcp car

Another is to just use the b6 or b8 edc shocks and pair them either with stock zcp springs or with the eibachs

What about stock ZCP springs and rear ZCP struts mismatched with B6 or B8? Can you mismatch items or must you keep them all one brand?

[SYT_Shadow]

Originally Posted by BOOF-M3

What about stock ZCP springs and rear ZCP struts mismatched with B6 or B8? Can you mismatch items or must you keep them all one brand?

Someone here has rear B6 or B8 and stock front struts and is happy

Personally I'd probably swap all 4 at the same time but that's just me

[wyatth]

I’d match shocks and struts as well.
Also can’t imagine deleting EDC in a ZCP car.

[SYT_Shadow]

Originally Posted by wyatth

I’d match shocks and struts as well.
Also can’t imagine deleting EDC in a ZCP car.

Wyatt, it's good to see you in this forum! Are you thinking of an E9X?

I wouldn't delete edc on a zcp car. I really like the edc system and unless i'm swapping to MCS I would keep edc shocks, either oem or the Bilsteins

On a side note, i just removed the mcs 2wnr system from my E92 which is supposed to be my nice street car and went back to oem zcp edc.

[wyatth]

Hey bud! Indeed I am on the hunt for an E90M! And through the process I’ve appreciated your input on these boards. Growing family, growing door count...

I want EDC, too. I’d like a ZCP car but considering whatever it is will have ~50K miles, the shocks will be swapped soon after purchase anyway (also OE or Bilstein shocks with ZCP or Dinan Springs, ZCP software). Then the starting point doesn’t matter so much.

[derbo]

Originally Posted by wyatth

Hey bud! Indeed I am on the hunt for an E90M! And through the process I’ve appreciated your input on these boards. Growing family, growing door count...

I want EDC, too. I’d like a ZCP car but considering whatever it is will have ~50K miles, the shocks will be swapped soon after purchase anyway (also OE or Bilstein shocks with ZCP or Dinan Springs, ZCP software). Then the starting point doesn’t matter so much.

Wyatt,

I ended up with a non-ZCP with goodies cause it was too hard to pass up an alpine white E90 Slicktop 6MT.

[SYT_Shadow]

Originally Posted by wyatth

Hey bud! Indeed I am on the hunt for an E90M! And through the process I’ve appreciated your input on these boards. Growing family, growing door count...

I want EDC, too. I’d like a ZCP car but considering whatever it is will have ~50K miles, the shocks will be swapped soon after purchase anyway (also OE or Bilstein shocks with ZCP or Dinan Springs, ZCP software). Then the starting point doesn’t matter so much.

Awesome! I love my E90!

Let me know if i can help with anything

[wyatth]

Congrats, Derbo! Clean car you have for sure, congrats.

Feeling welcomed here already.

Final question on this topic:
So it seems like base EDC and ZCP EDC shocks are identical, despite different PNs, and thus the drop on a ZCP comes solely from the springs. Is that right? If so, If Bilstein were to make a B6 unique to the ZCP, it would end up being identical to the non-ZCP part, yeah? Perhaps B6 EDCs with ZCP springs/software is another approach.
Do we know the drop/rates of the springs when put on a non-ZCP car? Wonder how they compare to Dinan springs. I like the Eibach drop, especially with the stout Bilsteins, but would prefer a linear rate.

[SYT_Shadow]

Originally Posted by wyatth

Congrats, Derbo! Clean car you have for sure, congrats.

Feeling welcomed here already.

Final question on this topic:
So it seems like base EDC and ZCP EDC shocks are identical, despite different PNs, and thus the drop on a ZCP comes solely from the springs. Is that right? If so, If Bilstein were to make a B6 unique to the ZCP, it would end up being identical to the non-ZCP part, yeah? Perhaps B6 EDCs with ZCP springs/software is another approach.
Do we know the drop/rates of the springs when put on a non-ZCP car? Wonder how they compare to Dinan springs. I like the Eibach drop, especially with the stout Bilsteins, but would prefer a linear rate.

Once my ZCP EDC shocks are shot I'll replace with the B6/8 EDC. I'll probably keep the ZCP springs.

An interesting option for a more track ready suspension that still doesn't mess around with coilovers would be the B6/8 EDC shock paired with a harder spring, like the Swifts.

I'm fine with the ride height of the ZCP suspension although I wish the front were a little lower.

[derbo]

Originally Posted by wyatth

Congrats, Derbo! Clean car you have for sure, congrats.

Feeling welcomed here already.

Final question on this topic:
So it seems like base EDC and ZCP EDC shocks are identical, despite different PNs, and thus the drop on a ZCP comes solely from the springs. Is that right? If so, If Bilstein were to make a B6 unique to the ZCP, it would end up being identical to the non-ZCP part, yeah? Perhaps B6 EDCs with ZCP springs/software is another approach.
Do we know the drop/rates of the springs when put on a non-ZCP car? Wonder how they compare to Dinan springs. I like the Eibach drop, especially with the stout Bilsteins, but would prefer a linear rate.

SYT_Shadow noted in his comparison that ZCP EDC shaft is shorter than the non-ZCP EDC in post 67.

I definitely want B6 w/ Swifts but will entertain the Swift only with nonZCP EDC to see how it is.

[wyatth]

^ Ah, missed that. Thanks! I just remembered the perch was the same, so the springs were the cause of the drop. But indeed the shocks are shortened to match (perhaps a la B8). I can't find info on the drop/feel of ZCP springs on a non-ZCP EDC setup.

Swift sounds like a good match for a slightly stouter setup. I think it was Lufty that tried that but it was rough on DC roads, so he went back to Eibach.

I wonder if you can/should match Dinan F/R mounts with the Bilsteins for increased travel? Bilsteins had short travel on the E46s so it's common to match them to GC camber plates. But trimming the front mount (as Dinan does, but less the E36 bump stop since that is integrated in the Billy) and the Dinan rear mounts might be a good setup.

[derbo]

Originally Posted by wyatth

^ Ah, missed that. Thanks! I just remembered the perch was the same, so the springs were the cause of the drop. But indeed the shocks are shortened to match (perhaps a la B8). I can't find info on the drop/feel of ZCP springs on a non-ZCP EDC setup.

Swift sounds like a good match for a slightly stouter setup. I think it was Lufty that tried that but it was rough on DC roads, so he went back to Eibach.

I wonder if you can/should match Dinan F/R mounts with the Bilsteins for increased travel? Bilsteins had short travel on the E46s so it's common to match them to GC camber plates. But trimming the front mount (as Dinan does, but less the E36 bump stop since that is integrated in the Billy) and the Dinan rear mounts might be a good setup.

wyatth ,

Richbot posted a thread years ago of ZCP springs on his 08 E90. https://www.m3post.com/forums/showthread.php?t=1195714

The Bilsteins have internal bump stops up front and is inherently a different design than the factory OE Sachs hardware and I believe increases the travel problem.

[wyatth]

^ Agreed, no need for E36 bump stops. But what about top hats/mounts (front or rear)? Are those retained? The trimmed front mount/support is where Dinan gets half of the travel (other half from bump stops).
On the E46M, Bilsteins had limited travel. I am wondering how the travel of the B6s compares to OE Sachs for the E9xM.
It's hard to get much out of Richbot's post since he went from MCS to OE/ZCP, rather than OE non-ZCP to OE+ZCP springs. But, his height looks pretty good (regardless of tire optics).
Sounds like ZCP springs are a fine alternative to Eibach or Dinan for those non-ZCP cars that want Bilsteins and a slight drop.

Question - does anybody use different rear spring pads to fine tune the height? Common on other chassis, but I don't see it much here. Since the Bilsteins tend to raise the front slightly (and because I want to use the Dinan camber plates), it would be nice to elevate the rear a smidge, and thicker/fresh rear spring pads would do the trick if there are others thicknesses that fit.

[SYT_Shadow]

Originally Posted by wyatth

^ Agreed, no need for E36 bump stops. But what about top hats/mounts (front or rear)? Are those retained? The trimmed front mount/support is where Dinan gets half of the travel (other half from bump stops).
On the E46M, Bilsteins had limited travel. I am wondering how the travel of the B6s compares to OE Sachs for the E9xM.
It's hard to get much out of Richbot's post since he went from MCS to OE/ZCP, rather than OE non-ZCP to OE+ZCP springs. But, his height looks pretty good (regardless of tire optics).
Sounds like ZCP springs are a fine alternative to Eibach or Dinan for those non-ZCP cars that want Bilsteins and a slight drop.

Question - does anybody use different rear spring pads to fine tune the height? Common on other chassis, but I don't see it much here. Since the Bilsteins tend to raise the front slightly (and because I want to use the Dinan camber plates), it would be nice to elevate the rear a smidge, and thicker/fresh rear spring pads would do the trick if there are others thicknesses that fit.

You could easily use a fatter rear pad. Personally i think the rear of the zcp setup does not need to be lowered at all. It's the front that could use some TLC

[wyatth]

I completely agree. That’s why Eibach is the best drop, but I want linear rates. Bilsteins exacerbate the issue by raising the front a smidge, and Dinan plates would further compound the problem. So I thought maybe the rear pads could at least maintain the rake even if things were moving in the wrong direction. Sounds possible then.

[SYT_Shadow]

Originally Posted by wyatth

I completely agree. That’s why Eibach is the best drop, but I want linear rates. Bilsteins exacerbate the issue by raising the front a smidge, and Dinan plates would further compound the problem. So I thought maybe the rear pads could at least maintain the rake even if things were moving in the wrong direction. Sounds possible then.

Why linear rates? I thought you wanted comfy suspension on the E46 and got rid of your MCS due to that

Won't the GC plates return the travel you lose by going Bilstein?

I faintly recall someone, maybe EricSMG, getting his Bilstein worked on at a shop where they cut down the bump stops and revalved them for additional spiritual creaminess

[wyatth]

I just prefer linear to progressive. Never had MCS on E46, always had TCKs.
Not sure if GC plates work on the E90 B6 EDCs the same way, but that’s another option. But I don’t need the adjustability or expense. If I can get travel and good weekend camber with Dinan mounts/plates, that’d be ideal. Maybe there’s no travel issue on this chassis, I don’t know.
Eric indeed worked on the Bilsteins with Fat Cat Motorsports. Anxious to see what he does with his E90.

[dparm]

Originally Posted by wyatth

I think they will diminish equally starting around 50k, and will be looking at replacement soon depending on use and conditions.

It will vary wildly based on what kind of use the car has seen. 50k of crappy urban streets will do much more wear than 100k of smooth highway driving.

Just check periodically for proper rebound. No need to throw out perfectly good shocks or whatever just because you think they're worn out.

[BOOF-M3]

Originally Posted by dparm

It will vary wildly based on what kind of use the car has seen. 50k of crappy urban streets will do much more wear than 100k of smooth highway driving.

Just check periodically for proper rebound. No need to throw out perfectly good shocks or whatever just because you think they're worn out.

I bent one of my 100k struts. Replaced it with one with 7k. My suspension guy said the rest of my struts/shocks/springs are working like new and are holding their height perfectly. But I do baby my car and have rarely driven over 40mph

Yea that's me above slapping myself.

[EricSMG]

Yeah, I had Fat Cat shorten the (front) internal bumpstops on the 46M Billy HD struts. I tried two different lengths with varying results. But it did totally resolve the travel issues for that particular strut/chassis. But note that the Billy internal bumps are very different than the standard external OE bumps and so trimming the former plays out differently than trimming the later. I would almost never ever recommend trimming an OE foam front bumpstop as they are very soft and designed to compress a great deal - too short and the bump will fully compress much too soon (been there done that). If you want to go shorter the trick is to start with a firmer stop so that energy capacity isn't lost. The Billy bumps are super firm and way too long so trimming then (a bit) is acceptable since capacity isn't lost (from my first experience, second I went too short).

I would fully expect the same limited travel on this chassis as well since that seems to be a Billy trait and a carefully trimmed bumpstop should work well here, too, I'd think.

Now - I haven't even unbolted the E90's suspension yet and measured the factory non-ZCP bumptravel so I really have no first hand knowledge of what's going on under there.

It will happen soon enough