Coilover Recommendation

[Obioban]

Just started one.

I might move some of my journal to that thread 🤔

[duracellttu]

One of you guys should start a FCM setup thread so we can hear your experiences and what options/stage you went with. Plus then I could keep track of the scattered discussions about it 😂

Just started one.

[r4dr]

One of you guys should start a FCM setup thread so we can hear your experiences and what options/stage you went with. Plus then I could keep track of the scattered discussions about it 😂

[duracellttu]

I spoke with him too, I forgot to ask if there is a stage1

He told me he no longer offers a stage 1, just 2 and 3 .

[maupineda]

Yeah guys. So I did too much research yesterday (still hungover). After looking at every option it really does seem like FCM has the best option suspension wise. I’ll certainly be going to him for my suspension. I know I mentioned a budget earlier but I hate cutting corners. I just end up regretting the decision later and spending even more money. I’ll just wait until I’m comfortable to drop that kind of cash. The college life kills 😅

Wether I go stage 2 or 3 will probably be dependent on the feedback that the forum members that are getting stage 3 provide. For those that don’t know, stage 2 ($2500 service on top of H+R coils) gets you the custom everything. The whole package. What stage 3 ($4500 service on top of H+R coils) adds is his “KBO” or kerb blow off. Honestly I couldn’t accurately repeat what he told me about this but it sounded like good stuff. I just wish I could feel the difference between non KBO and KBO.

I spoke with Shaik for a long time yesterday and his knowledge on the whole topic was pretty impressive. I’d highly recommend giving him a call if you’re uncertain about something. He’s easy to talk to and will answer your millions of questions.

I spoke with him too, I forgot to ask if there is a stage1

[Obioban]

Obioban Side question did you understand Shaiks KBO stuff? Or understand it well enough to school me on it?

It's a high velocity blow off valve-- so when you hit a bump the shock just opens up and lets the spring absorb it and rebound.

Similar, but hopefully superior, to Ohlins

Figure 1: (Compression flow) At low shaft speeds, oil flows mostly through the shaft jet bleed (lower dotted arrow). At higher shaft speeds, oil flows mostly through the compression ports in the piston (upper dotted arrow). At very high shaft speeds, or during sudden shaft accelerations, oil can also escape through the compression ports in the DFV, increasing comfort.

Figure 2: (Rebound flow) At low shaft speeds, oil flows mostly through the shaft jet bleed (lower dotted arrow). At higher shaft speeds, oil flows mostly through the rebound ports in the piston (upper dotted arrow). At very high shaft speeds, or during sudden shaft accelerations, oil can also escape through the rebound ports in the DFV, maintaining tyre contact with the road.



Figure 3: (Vehicle – no DFV) Without DFV the oil can not flow through the piston quickly enough on the rebound stroke after hitting a bump, so the tyre is not able to stay in contact with the road.



Figure 4: (Vehicle – DFV technique) The DFV valve opens, letting the oil flow quicker through the piston on the rebound stroke after hitting a bump, enabling the tyre to stay in contact with the road.

[SteelGreyM]

Obioban Side question did you understand Shaiks KBO stuff? Or understand it well enough to school me on it?

[Obioban]

^ that certainly looks like it'll ride and handle well-- if the shocks have enough bump travel to function.
(to be clear, I'm not saying they don't-- I'm saying I don't know. The TCK Z4M setup I installed really didn't at anything lower than ~stock ride height)

[maupineda]

Yeah, but are they any good... or are they half assed. Bilstein has a lot of half assed damper offerings out there, every for high production volume chassis.

Who knows, the benefit they have is the ability to be rebuilt, that is why I am looking at them. They seem to work out of the box according to the EU community, but the plan is to have them valved to my setup. Down below is what I have in mind for a fast road setup. Thoughts?

The Z4M comes with the CSL rear bar and a 27mm front bar. I could upgrade the front but since I don't track the car I may be fine with the stock bars. the CSL front bar would leave me right at CSL numbers for FRC should I see the need to upgrade. Z4M and M3 bars are interchangeable.

The below numbers consider:

stock front springs
linear TCK 500# rear springs
Bilstein B6 (ideally re-valved by FCM)

Fronts spring rates were measured by someone in a spring tester, so they should be accurate.

Since I am fine with the stock ride height I see no detriment there, in fact, my current H&R coils are set almost at stock ride heigh values

Current RH (606mm front, 600mm rear) - 14.85in front, 14.6in rear in US Speak
Stock RH (607mm front, 594mm rear) -

[SteelGreyM]

Yeah guys. So I did too much research yesterday (still hungover). After looking at every option it really does seem like FCM has the best option suspension wise. I’ll certainly be going to him for my suspension. I know I mentioned a budget earlier but I hate cutting corners. I just end up regretting the decision later and spending even more money. I’ll just wait until I’m comfortable to drop that kind of cash. The college life kills 😅

Wether I go stage 2 or 3 will probably be dependent on the feedback that the forum members that are getting stage 3 provide. For those that don’t know, stage 2 ($2500 service on top of H+R coils) gets you the custom everything. The whole package. What stage 3 ($4500 service on top of H+R coils) adds is his “KBO” or kerb blow off. Honestly I couldn’t accurately repeat what he told me about this but it sounded like good stuff. I just wish I could feel the difference between non KBO and KBO.

I spoke with Shaik for a long time yesterday and his knowledge on the whole topic was pretty impressive. I’d highly recommend giving him a call if you’re uncertain about something. He’s easy to talk to and will answer your millions of questions.

[Obioban]

Bilstein has Z4M specific B6/HD shocks.

Yeah, but are they any good... or are they half assed. Bilstein has a lot of half assed damper offerings out there, every for high production volume chassis.

[jvit27]

I already have turner sways. Don’t TCK come with camber plates?

Why do you say that these have better dampers than the other options?

Even better. TCK do come with camber plates (although these can be removed from order as a line item if you have your own set, or want to use the E36 hats as Ian mentioned), but since you mentioned the DA were out of your budget and the SA are still 800-1000 more than what you can sometimes find PSS10's for on sale etc..

The Bilstein B16 Monotube damper kicks the shit out of anything KW V1/2/3. It's quite comparable to the Ohlins in design, and has better valving IMO. Great setup for the $

[maupineda]

The overwhelming majority of Z4M setups are compromised by the car being very low production and kinda sorta similar to e36 up front. Most setups sold for the Z4M are e36 setups... and not at all optimized for the car as a result.

If KW actually developed a bespoke setup for the Z4M in the V3s, I could easily see it actually being better than a half assed e36 setup from one of the other companies,
(I'm not saying this is the case, just giving a possible explanation).

If you can get a Bilstein that fits the chassis and has sufficient bump and droop travel, FCM could certainly valve it to match whatever spring rates you want and not ride like crap. If such a bilstein exists, I don't know. If they're using e36 parts, the e36 Bilsteins were already severely limited on bump travel, and it'll only be worse in the Z4M...

Bilstein has Z4M specific B6/HD shocks.

[Obioban]

Holy...

Sticker shock. Just curious as to what more you’re getting from FCM instead of doing the math and doing it all yourself. Haven’t you already done that with your Öhlins?

Custom built shocks, with all of his extras. And camber plates, rsms, etc again.

[Obioban]

This is very interesting, the V3 is praised as being the best of the best for the Z4M platform, and here I find conflicting comments. I say interesting because despite being different cars, the suspension geometry is very similar (the rear is actually the same and the front is a very similar architecture). Now the Z4M is "known" to ride like crap (mine at least does, and is on H&R coil overs) and I am advised to migrate to KW V3.

So this time I plan to perhaps do a more thoughtful move and pay for a consultancy call with FCM and see what they say about my plan of using stock springs front (linear for the matter of the actual travel once installed) and linear rear TCK springs, stock height and stock bump stops. I should be able to match the front using 400 or 500# springs. for the dampers my idea is to get a set of B6 Bilsteins shocks and have FMC tune them to my application; a fast road setup that rides well and does not knock my teeth off every bump!!!!

Thoughts on this approach?

The overwhelming majority of Z4M setups are compromised by the car being very low production and kinda sorta similar to e36 up front. Most setups sold for the Z4M are e36 setups... and not at all optimized for the car as a result.

If KW actually developed a bespoke setup for the Z4M in the V3s, I could easily see it actually being better than a half assed e36 setup from one of the other companies,
(I'm not saying this is the case, just giving a possible explanation).

If you can get a Bilstein that fits the chassis and has sufficient bump and droop travel, FCM could certainly valve it to match whatever spring rates you want and not ride like crap. If such a bilstein exists, I don't know. If they're using e36 parts, the e36 Bilsteins were already severely limited on bump travel, and it'll only be worse in the Z4M...