anyone run MCS shocks yet?
 

anyone run MCS on rx8 yet? i'm in the market for double adjustable shocks. was looking at ohlins ttx before but they are quite pricey. mcs 2 ways none remote are $3500. they are very popular in the BMW community. i have ohlins RT custom valved now.

They generally work well but their valving is very wide because they build the same valving into the shocks for multiple different applications. So each click of adjustment is a big change, which is not really what you want.

I'd recommend a set of Penskes instead.

I autocross and I've moved from non-adjustable Fatcat revalves to MSC single adjustables this season. Profound positive difference in control.

I have not run them on an RX-8, but as an instructor for BMW CCA, I drive and ride in a lot of MCS-equipped Bimmers and have been impressed with them. If my budget were that high, they would be on my short list.

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If they did an inverted rear with both adjustments at the bottom like the Koni 2812 I’d definitely consider a set, but I seem to recall that their design doesn’t permit doing it that way.

maybe you can invert mount them in the rear like for bmw e36/46?

https://cimg0.ibsrv.net/gimg/www.rx8...2caf8d8114.jpg

If you happen to have the hookup on valving/rebuilding my suggestion is find a used set of the Penske's from a NC chassis MX5 cup car like I did... I'd say I probably have the cheapest setup of Gucci shocks anyone has on an RX8, and that even includes the consulting/tooling/parts to do the work myself. I found mine with all the mounting already sorted out, spherical front top hats, etc.

I have the same set of shocks. There are a bunch of sets of those floating around. I am willing to bet the spherical front uppers are the same as what you have as well, and while they're designed for an MX-5 they fit my RX-8 perfectly. One thing about them (at least mine), the rear shafts are a different diameter than what is generally sold now. It means it's a little harder to source a shaft if you end up needing one.

I made spherical rear upper mounts similar to what Tamra and Drew did on their car.

Yeah, I didn’t understand why you didn’t just take the aluminum MX5 rear hats and weld a spherical bearing cup into the top of it rather than modify the steel RX8 rear mounts?

Because I wanted to retain the shock tower braces, and it's easy to weld stainless steel bearing cups into steel.

Different size meaning length? All my shocks were the same diameter on the shafts and the rears were shorter iirc but all parts were available through Penske and RESuspension. I need to do the rear hats at some point, actually have a set sitting on the shelf ready for surgery, I am running the MX5 aluminum ones currently and haven't noticed anything, good or bad, about it.

yeah, I’d just weld some aluminum brackets on to make all that happen, but that’s probably part of why yours is done and mine is still sitting on jack stands 5 years later :dunce:

shaft diameter and threads are different than the ots stuff.

Interesting... have any numbers by chance? Part numbers or measurements...

The set I picked up do not seem to have any variation from OTS Penskes. I rebuilt them myself, swapped pistons, set valving, etc and ordered all the 'normal' parts for an 8300 in the process, including shaft wipers, ring nuts, etc.

My ability to fabricate stuff is quite novice and rudimentary compared to yours, and if I want to do anything interesting in Aluminum I have to go somewhere else. Eventually I'll pick up a TIG welder but for now I'm hacking away with a MIG

I should have been more clear. The shafts themselves are standard but the stepped portion of the shaft to mount to the top hat is a different diameter with a metric thread. Maybe yours are not set up this way but I know from talking to the Penske guys in Reading that the MX-5 cup stuff was all custom, so ordering new shafts to replace them as they come in needing repair means a new batch has to be run. I don't have the part numbers with me. It sounds like you have all your stuff figured out.

are all penske double adjustable for NC or RX8 use external reservoir? i need it to be non external reservoir to avoid taking additional mod points.

No, you can buy DA Penskes that are all internally adjustable. That's the 7500 series. The tradeoff is that the shock body needs to be long enough (really not a problem on the RX-8/NC) to fit the adjusters and get enough shock travel. Penske also recently came out with a double bleed adjuster that contains compression/rebound adjustment on the shock shaft, but the target application for that is for struts.

Let me rephrase that, I’m fairly certain that they can’t offer a non-remote DA that can be mounted with both adjusters easily accessible at the bottom. All non-remote DA monotube shocks have a potential length issue because the gas chamber and separator piston along with the oil/shaft travel all have to fit within the same body housing.

The Koni 2812 has been the only real option, but maybe MCS can offer something if they’ll make an adjuster end with an 18mm spherical eye needed at the RX8 rear upright end. For some reason the last year or two I raced mine kept having issues blowing out, leaking, etc. and nobody seems to be able to figure out why including Koni. Nothing more frustratng than chasing your own butt in this situation. So I’m just about ready to try something different if the situation continues.


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Well one thing I would add, if you went with the short NC MX5 rear shock setup, which uses the shorter aluminum rear hats, you could probably have both adjusters at the top and still access them. You just have to weld an aluminum spherical bearing cup into the top of OE aluminum MX5 rear hats.

You also lose the chassis tie-in point, which is also the mounting point for a rear strut tower bar. In theory you can add brackets to retain those, but it’s debatable if they’re really necessary with the shorter hats not having the same leverage arm as the tall RX8 rear hats. The only real issue, or thing I don’t like about doing it that way, is you have to use the delrin spring adapter at the bottom of the hat. All do-able though...

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I'd say you should ask your friendly neighborhood Penske builder to see if they can do an inverted shock with an eyelet at one end (hopefully they can fit one that's big enough) and a pin/stud mount at the other with a double bleed shaft. Otherwise, you're correct in that the Penske setups I've seen thus far for the RX-8 can't be done up like the 2812.

https://www.penskeshocks.com/wp-cont...eed%20tech.pdf

You’d need that with an 18mm or 19mm spherical end for the upright mount though; can’t recall exactly since it’s been several years since I last messed around with them. It’s fairy easy to do on the 2812 because they offer a blank steel top and you can cut down the proper size heim joint and weld it on easily. When it’s aluminum it’s hard to do that and have it be strong enough. It would need to be machined from billet or forged. Maybe they offer something similar though.

Well I sent a message to MCS asking if they’d be interested in exploring it. Not expecting a positive answer.


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Just remembered that Guy Ankeny has an inverted Penske for the rear of his and Steve's car, so Penske probably makes something that can fit the upright mount in the RX-8. It doesn't seem like much of a step from there to do a stud at the other end, if Penske makes such a thing.
https://cimg7.ibsrv.net/gimg/www.rx8...bb99ec5c69.jpg
PC: Guy Ankeny

Yeah, except the red knob there is rebound and the compression is probably on the other end up inside the shock tower.

The DB eyelet with that size heim might be an issue, but I’m no Penske expert. A lot of this stuff is kind of newish since the last time I gave then a serious look. I might ask if they can whip up some blank steel tops like the Koni.

On Guy's inverted setup as shown, he uses the NC top hat with the top cut. The remote canister with the compression stack lives in the trunk. The shock mounts to a custom-machined aluminum boss which forms the "cap" for the end of the aluminum shock hat. That boss / cap is then bolted to the NC top hat.

It's a very neat arrangement and Guy can put a setup together for you. Doesn't solve the OP's problem as it's still a shock with a remote reservoir. It's also, um, not cheap.

Ok, now I remember seeing the cut top a year or two ago now that you mention it. Be put way too much time into it imo

https://cimg9.ibsrv.net/gimg/www.rx8...211658d9b.jpeg