Cockroach Suspension Logs/Notes 10/14 MCS Tested

[fattycharged]

Sam, you got it correct. Needle valve is super common on a non remote setup. I've got a nitrogen setup at the house if you don't have access to one.


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[samthejam]

Sam, you got it correct. Needle valve is super common on a non remote setup. I've got a nitrogen setup at the house if you don't have access to one.


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Awesome, if I have any trouble with my aircooled friends setup I'm borrowing. I'll setup something with you

[cobra]

Nitrogen pressure should not really be used as a tuning tool. In a monotube setup like that with no base valve, you probably need to run 150-250psi depending on valving. If you want to play around with it, try to machine the hole for a schrader valve and fill it with a bicycle shock pump.

[samthejam]

Nitrogen pressure should not really be used as a tuning tool. In a monotube setup like that with no base valve, you probably need to run 150-250psi depending on valving. If you want to play around with it, try to machine the hole for a schrader valve and fill it with a bicycle shock pump.

A lot of remote reservoir shocks will give the user a nitrogen fill port (schrader) for servicing, if the reservoirs have to be disconnected. Some use it for tuning but it's intended purpose is for service.

Also targets to aim for he said

"AST . They run they kind of high, too high if you ask me. But 150psi front..."

Good to know it can go up to 250, I'm hoping I can get a reading from the other damper.

My nuclear plan is if something happens to the self healing membrane is to take it to my dad and figure out to add a Schrader with his machine shop tools.

Again mainly trying to refill it to by me some time while I save up for something else, since the shock doesn't look majorly damaged just seems like it is leaking the nitrogen very slowly. Ideally new MCS 1 ways or a set of used 2 ways.

[samthejam]

The Nitrogen filling went well, the shock was only at 60 psi. I filled it to 150psi, and it needed about a 100lbs of force to begin opening the shock on my scale. I didn't want to poke the other "good" shock as it was kindve a fiddly affair and I just didn't want to create more problems as myself.

So my only way to match it was using the gas force. I had both out of the car anyways so this was easy enough. The "good" shock was 50-55lbs to open. So I just kept bleeding off the nitrogen until I was able to get it within 5-10lbs of the "good shock". Which ended up being 55-60lbs of force for the damper to move. I used a corner weight scale t to measure the gas force for all of this.

Stole the idea from FCM

Thank You @fattycharged for the nitrogen tank, regulator and lines

[cobra]

There is a good chance if you had the nitrogen leak out, it will leak out again especially after being poked. Just a heads up!
Several companies have moved to a screw with an o-ring instead, but that requires an even more specialized tool. Or a schrader valve which is the easiest.

[samthejam]

On this episode of being a dumbass and on a shoestring budget and deprecated dampers. One of the rear ASTs called quits on my last roadtrip.

With my 784lb rear spring, this left me in a tough spot. This was my solution.

From the middle of the shock “eye” to the end of the shock body:
AST: 14"
911: 13.5”
911 w/ Spacer: 14.75”

Full length of shock from eye to the very end of the shaft
AST: 25"
911: 25"

But the measurement that really matters is the eye to the end of shiny part of the shaft as that merits the true “top” part of the shock as far as the car is concerned.
AST: 23.5
911 22.5"

Shock 911 / 930 1972-89 - BILSTEIN - REAR - B6 - Clubsport / Race (220/180)
Part Number: 24-009676
Series: B6 (HD)
Position: Rear
Descriptor: Club Sport Model

https://www.rockauto.com/en/moreinfo.php?pk=6603144&cc=0&pt=7556&jsn=329

M12: Rear Shock mount

https://www.bimmerworld.com/Ground-Control-Urethane-Alloy-RSM-Set-12MM.html

EDIT: The Bilsteins were M10, but I used the bushing the shocks came with and shoved them into the GC RSM Housing with their supplied washers.

Shocks
$383.15
RSM
$161.24
Amazon Sleeves for 14mm to 12mm for Shock Bolt
$8.43

https://www.bimmerforums.com/forum/showthread.php?2207929-Detailed-Information-on-E36-Struts-and-Shocks

https://www.bimmerforums.com/forum/showthread.php?2136006-Mounting-Koni-8210-1159-rear-sport-shocks

https://workshop.bilstein.com/wp-content/uploads/2020/08/4_BILSTEIN-Klassik-Katalog-2019.pdf

https://forums.pelicanparts.com/porsche-911-technical-forum/1111488-bilstein-shock-question.html#post11591117

$552.82



TC Klines sells the single and double adjustable rear indiv. E46 M3 Rear Koni Yellows would work but be underdamped and springs would fall out. The Koni 8210-1159 would also work, but were backordered from FCPEuro. Other sites were a little more than I wanted to spend and I think they'd work but me maxed out.


Untitled by Sam DaJam, on Flickr
Untitled by Sam DaJam, on Flickr
Untitled by Sam DaJam, on Flickr

Car doesn't seem as easy to thrown around, it was a little too playful arguably before. We'll see how I like it on track but It rides better. I have the front shocks on 4 now and it feels decent. 2 feels okay, but just can't throw the car around like in a slalom the way I like.

It used to be 2 and 3 for street. I'd turn it up to 5 and 6 for the track and loved it, but was bouncy and too rough for the street.

I'll play with it more at Road Atlanta

[samthejam]

Just wanted to see if I could repair it, just to do it.

Got it apart, thanks to some wisdom from Pavlo
You actually have to have gas in it to loosen the dust cap. I initially degassed and was stuck. The dust cap threads onto the shiny aluminum piece, and without the gas pressure they rotate together. All the sealing is done by the seal head, and it's all held in with a circlip.

Working through sourcing the seals at this moment. It looks like it uses a custom two piece seal for low drag, for the main shaft seal. Looks like that was a selling point for the 4150 way back. I should be able to get away with a regular u cup seal? At work right now need to grab some more measurements when I get home.

Some info: I found on the seal

https://www.vorshlag.com/forums/forum/board-rules-and-announcements/announcements/6771-ast-suspension-purchases-moton-suspension

https://www.vorshlag.com/forums/forum/board-rules-and-announcements/announcements/6851-ast-4150-series-damper-announced

Worst case, I am just where I started but figured I'd share if anyone wanted to see what the inside of it looked like.

[samthejam]

Seal head dimensions:
22x5x14

Seal Head oring: 33x4.5

[samthejam]

Good news!
I found a hydraulic seal—it came in Friday.

It’s a U-cup seal like the original, but made from urethane and in a single-piece design (unlike the two-piece original). Specs below:

• Max Speed: 3.0 ft/sec (1.0 m/sec)
• Temp Range: -50°F to +230°F (-45°C to +110°C)
• Max Pressure: 6,000 psi (400 bar)

---

A Bit About How the Shock Works


Untitled by Kurvenkamph Motorsport, on Flickr
Untitled by Kurvenkamph Motorsport, on Flickr

Part E is the shaft guide and main seal head. It originally sealed via Parts C and D, a special two-piece seal you can find in Vorshlag’s documentation. That seal’s no longer available, so I said screw it and went with a standard U-cup.

Now Parts C and D are replaced with the single-piece seal, which handles all the hydraulic sealing. It’s held in by Parts B and A—a washer and a circlip.

Part E also seals against the shock body with an O-ring, which holds both oil and nitrogen in. But this O-ring is a weird, obscure size—probably would’ve taken weeks to get from Europe. That would've killed my motivation, so I reused it.

The piston (anodized blue) also has an O-ring. It supports Part H, the wear band—a sort of hydraulic piston ring. VANOS fans will get it.

---

My Approach


A lot of people go by: “Do it right, or don’t do it at all.”
I lean more toward: “Get it running, even if it’s wrong.”

That usually means doing things twice—and probably spending more—but it keeps the project from stalling.

For example: Part G, the dust cap with the wiper seal. I couldn’t figure out how to get the seal out without destroying it. And since I couldn’t source a new one, I left it alone. It’s not critical—just keeps crap away from the seal head. Yeah, it’s beat up, but it’s better than risking not being able to replace it.

Untitled by Kurvenkamph Motorsport, on Flickr
Untitled by Kurvenkamph Motorsport, on Flickr

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Why the Shock Had to Come Apart


The shock was leaking oil and gas pretty bad on the car—but it was still holding pressure, about 50–60 psi when I took it apart.

So I just ordered the shaft seal. It was the most likely failure point, and I could get it fast enough that I wouldn’t lose steam or get distracted by another project.

I wasn’t even sure I could reassemble it. And I made a dumb mistake: I pulled the dividing piston without measuring it. Don’t do that. You’ll be sad.

Another unknown: how much oil it takes. I saved what came out, but since it had been leaking, I couldn’t rely on that to get the fill right.

I ended up using 3wt racing shock oil from Amazon. The original was probably a Motul—red and lower weight—but close enough for now.

---

Got it all assembled... then the nitrogen tank ran out. Luckily found a shop open Saturday that could fill it.

I matched gas force by feel, using the other (good) shock as reference—about 55 lbs of force. Both shocks rebounded at full soft in the same amount of time. Compression and rebound were smooth, no dead spots.

Reinstalled it, and have put 200 miles on it—still bone dry. I check by wiping the shaft with a clean paper towel. So far, so good.

Untitled by Kurvenkamph Motorsport, on Flickr


So I guess for Road Atlanta I'll be on ASTs, if it holds coming up to the weeks prior over Houston roads. I do enjoy having the adjustability for changing the cars handling balance.

[samthejam]

So I was able to find out what the internal issue in the shock that was creating an issue. It was the floating piston seal. Which was actually an xreal or a quad ring. I of course could not find one in that size but opted for an oring.
Untitled by Sam DaJam, on Flickr

Well the oring worked and that was the issue to seal the gas and oil from intermixing.

However the front shock shortly after me testing it on one of the worst roads I know had the same failure. At this point I realized the fragility of this whole endeavor. I can fix these items but at the end of the way was not satisfied with the valving even when they were working and they were one NLA component away from all my work meaning nothing and long down time.

So I started looking at the MCS options.

I initially wanted the 2WNR because I really wanted the second knob. However this is the conclusion and key note points that went into the mental gymnastics that lead to my final decision.

__________________________________________________ __________________________________________________ ________________________________

While used is an incredibly better value, if I am spending this much I want vendor and manufacturing support.

The price options are
1WNR: $3150
2WNR: $4200
2WR: $5100


The 2WR was the better of the options but that price is so astronomically high that just won't work. I would also like to add for all of these, these are all incredibly large amounts of moneys for me. It amazes me how many MCS equipped cars I see at the track. They're just a lot of money.


Because of that I was also considering TC Kline because for the 2 way it is currently cheaper. Also for the fact that those shocks would be better for longevity and replacements if in stock. I put 30k miles on the m3 last year and the recommended rebuild interval for MCS is 25k. I have seen many cars on Ground Control or TC Kline with 10+ years on a set so those shocks are tough and you can usually buy replacements.

Ultimately though, I really liked a lot of things about the ASTs, how light they were. The quality, and that they are a true race shock. I wanted that pain again, and also just wanted to try it so that left me again with MCS.

The ASTs were hugely digressive, enough to a fault. If I could get that with better ride/valving that'd be perfect and hell an extra knob. So know I am staring at the 2WNR, however I remember all of the FCM videos and for all of them except for one car, he was picking on the 2WNR. I was able to find one of his customers here complaining about them who switched from 2WNR to FCM and was happier.


I also found the 1WNR is a linear shock by default and can be valved to other options and the 2WNR cannot be valved to different options. Why? Also will linear be a downgrade? I have always been under the impression that digressive is always better. If you don't believe me that the 1WNR shock is linear.

https://www.motioncontrolsuspension.com/buyers-guide/1-way-non-remote/

Basically to do the magic of the 2WNR, there is no traditional shim stack.

https://forum.miata.net/vb/showthread.php?t=709634

"First, I have to correct a mis-statement.. The droop and compression travel for the MCS/Karcepts applications (1WNR, 2WNR, 2W, 3W) are all the same; no dimensional differences. We do not recommend bump stops in our coilover configurations no matter what MCS damper you run (as they generally create non desirable effects, and you will have more than enough spring rate to prevent any bottoming out). It is true that remotes have the ability to have more stroke per body length (this would be beneficial on say the rear of an NA/NB chassis); but on the ND application, the bodies are plenty long where no compromises have to be made for the non-remote variants.

As far as converting one damper to another, it can be done as MCS states, but there are still quite a number of differences between all the variants that the upgrade cost is often higher than selling your old dampers and buying new dampers. The very good resale value on used MCS makes this the smarter move if wishing to upgrade to a higher level.

Valving: D3lusions03 is mostly correct here. The 1WNR and 2W have conventional shim stacks so there are many valving options. The main thing to note is the 1WNR and 2W use linear pistons by default (but can also be made digressive if desired). The 2WNR is a totally different animal internally, does not have a shim stack, and is only digressive in nature. However, the 2WNR does has a very broad range of valving, and even without a shim stack, there are a couple of adjustments that can be done internally to manipulate its valving. There is an internal spring to change the overall range, and then the use of bleed plugs on the piston can be manipulated. Last year we tweaked the valving on this damper slightly with very positive results. For example, Mark Shrivastava was the Day 1 STR leader at Nats in 2019 with these changes. All 2WNR dampers sold since the middle of last year have our tweaks implemented with our Karcepts Spec setup.

All of MCS’s product line is amazing, which is the reason this is the only high end damper we desire to sell, support, and utilize in competition. In the case of MCS, you do get what you pay for. If you can swing the cost differential of the 2W over the 2WNR, I would recommend it. Likewise, between the 2WNR vs. the 1WNR. That still does not take away from the lower models. You just get a little more for your money as you progress through their product line.

To break it down, the 1WNR being linear in nature, has the trait that MCS does well, which is making higher sprung vehicles ride extremely nice. I have tested 3 nearly identically prepped chassis on the same course, same tire, and same day: 2x with Ohlins and 1x with MCS. The MCS 1WNR car had the highest spring rates, yet felt the most compliant over the bumps and turned the fastest times. That experience sold me on MCS. For a customer looking for a race capable damper, but not wanting to get confused with too many adjustments, the 1WNR will be excellent in both street and race trim.

For a little extra money, you can go with the 2WNR. Those who like to have more control over adjustments will appreciate this damper over a 1WNR. Being the 2WNR is digressive in nature, each click you make on either the rebound or compression side will be extremely noticeable in race trim. Digressive valving will typically be able to supply higher force outputs at lower shaft speeds than linear valving. When shock adjustments are made on digressive valving, the adjustments will feel extremely noticeable for a driver because that low speed shock movement is affected more significantly vs the high speed shock movements. To clarify low vs. high speed, high speed shock movements are observed when the car hits a sharp bump in the road (bridge seam, railroad tracks, etc.). Low speed shock movement are seen at the damper in response to your steering, throttle, and braking inputs. So while the 1WNR being linear valved will manipulate the compliance over bumps better, the adjuster won’t make huge effects on the roll/pitch control of the vehicle from driver inputs like the 2WNR will. For an autox car, the 2WNR really gives the racers a lot in regard to feedback and control of the chassis. These dampers are also extremely successful in NASA where guys get hit with points penalties for having remote reservoirs, so you will see a lot of track guys on the 2WNR’s as well. The only downside observed from having digressively valved dampers is if you run too high on the valving, those really fat low speed forces start influencing the ride quality where you will feel the bumps more than you would on linearly valved, which is where the 2W comes in.

The 2W damper MCS offers is really their flagship damper and worth every penny IMO (but yes, not within everyone’s budget). Being valved linear, you automatically get a very compliant ride, even with very high spring rates. The added large volume remote canister with internal blow off valve further aids in the bump compliance these dampers offer. If you are slamming into curbs on the race track or have a very bumpy autox surface, this is where these dampers shine. Other racers may complain of a bumpy section of a course affecting their car; but if on a 2W, you may not know what they are talking about. MCS is also one of the few to use very large diameter shafts. As the OP mentioned, the 2W uses 22mm diameter shafts vs. 16mm for the non-remote options. This is done to increase the response of the damper by pushing more volume of fluid through the piston for a specific increment of travel. Other brand dampers with remotes typically give 16mm or smaller shaft size, where you will have to pay another $1k+ for larger shaft options. What can be seen on the dyno graphs (and also observed behind the wheel) is this larger shaft results in more low speed damper forces (mainly on the compression side). What I feel is amazing about the 2W is you get that similar feel to having digressive valving like the 2WNR, where the damper adjustments control a lot of the pitch and roll of the vehicle that racers appreciate when trying to dial in their vehicles, but you still maintain the super compliance that linear pistons and remote reservoirs offer, keeping the tire stuck to the roughest of surfaces. "

Phil from BimmerWorld here - No, the MCS 2WNR is NOT being discontinued. I am not sure where that originated but if this information stemmed from us, then I believe there may have been a miscommunication somewhere along the way. We have been testing some different 2WNR designs with MCS for the F8X chassis that we are extremely excited about. The new designs are aimed to increase the control of the damper when used with spring rates that we would consider on the high side. The 2WNR damper in its current form is a fantastically capable damper, but just like your iPhone 11 was pretty sweet, there were some things that Apple could do to rub on it and make an iPhone 12 that is even sweeter (I know this example may not resonate with everyone but the improving technology principal remains).

The 2WNR really is a damper that was made to fit within a certain set of constraints or rules where two adjustments are allowed but no external reservoirs - what that means is that you are trying to package a lot into a little. In its crudest form, what you are doing with a damper system is moving around and displacing fluid. And MCS does this better than anyone else out there with a Non-Remote system. With the packaging constraints of a Non-Remote system you are limited on the volume/capacity available to be displaced. Move to a remote reservoir system and you more than double the volume of the fluid/gas which gains a lot of compliance and performance over a wider range of situations. If you are not trying to fit into a certain set of rules, and having two adjustments is of utmost importance to you, you will want the Remote Reservoir system due to this increased capacity. An analogy we use here often is that it's like trying to make 300 Hp out of a 2.3L S14 4-cylinder versus a 4L S65 V8 - the S65 does it with ease due to capacity.

So no - the 2WNR is not being discontinued, but we are working with MCS on an alternate version which may have led to a misunderstanding. And the current version is still being built, sold, and run on track very successfully.

I interpreted this as, this shock is made for racing classes where you get penalized for having remote reservoirs. It is still an incredibly well made, but it's intended use is for racing classes where rules restrict. Okay so I'll get the 1WNR but the

As of this point I was under the impression that digressive is always better, but the thing with the ASTs was with big bumps they were truly fine. However dips and slow speed variations in the road where the shock moves they were bad, horrific even. The low speed control was great when cornering. I also liked the easy to feel adjustments on turn in, the tied down feeling etc.

https://web.archive.org/web/20151129065359/http://www.nttyres.com/downloads/guide_to_dyno_graphs.pdf

Anyways watched a bunch of podcast, videos, forum post all that. I was a lot more comfortable with choosing linear damper, while digressive is better it seems harder to get right.

I called James Clay and he said yes the 2WNR just will not ride as nice as the 1WNR. It can of course be used on the street but it won't be what MCS is kin'dve renown for. It's market place is for competition. My fear was with the 1WNR just losing that turn in feel I really loved, with the car being so locked down and that shock control. However I use this car everyday, while obsessing over the car feels for 0.2 of a second is a mental illness I have. That would probably not be the choice for an expensive purchase.

So I got the 1WNR.


With Bimmerworld it came with the support, so the recommendations on clicks seems accurate and is very helpful. Based on spring rate, there is a limited range at which the rebound will work best in, so that info is fantastic to have.

Out of the box it was already very good 8/8 for the clicks, but pushy. I went to 7/8 and I did not like how the car took a wavy road, and some bumps. Just felt a bit too floaty. Very happy at 9/10, now no push very sharp front end and rotates on power. If I drive like a monkey can get rear out easily, which is how I like it. I will eventually switch to Spherical mounts in the rear.

The ride is not a Cadillac, but the car is composed over almost all road variations and I can attack a rough road at speed faster than a lot of people in normal cars. It's very similiar to my E28s homemade suspension which is a HUGE win, I don't have to slow down or care about the road. I can feel the difference in clicks and it communicates well. Overall very happy for first impressions.

[dreamdrivedrift]

Glad you're happy and thanks for teaching us about 1WNR v 2WNR v 2W. I didn't know that the piston design and shim stack was different between the 1WNR and 2WNR. What rates are you running?

Have fun dialing in. In case you need another baseline setup, I am running 400/650, 8F and 4R from full soft on my car. 4R helps the car rotate on brakes. You know my driving style, I find it to be balanced with a bit of float for the Norcal (terrible quality) roads, and works on track too.

[samthejam]

Saving swaybar notes here for quick reference on mobile

PoBoyR6 for my reference.

Hotchkis front bar at different settings with stock rear bar.

Last one is if I had an OE CSL front bar
I was comparing setup to someone that was really fast locally about a decade ago, as well as establish difference with sway bar settings.

https://www.youtube.com/watch?v=qBHJsJcneT8

I found spring rates and swaybars from comments of this video.

Yes yes, pitch is shit.

[bigjae46]

My TC Klines are 15 years and 60k miles old. They started falling off last fall.

The MCS route is probably the easiest to go fastest. Having support is worth a lot! Blowing up a motor is less costly than changing the suspension especially when you factor in testing and adjusting.

[samthejam]

After, playing with the bar. I want to play with a rear bar now, I will explain more if I find I like it.

Anyways, trying to document replacement parts I might need along the way and any documentation while it's in my head. Here is the swaybar instructions.

I want to also get the part #s for bushings and the endlinks. I have been using E28 swaybar links because I have them laying around. I bought Hotchkis links and they were too long.