e46 M3 suspension setup, or how to not downgrade your car with suspension mods

[cobra]

Typical rebuild interval that I've seen is 10k-20k miles or 4-6 years. I'm not a damper expert to tell you why that is. I'm assuming higher pressures = higher wear? MCS and Moton aren't that different from JRZ for service intervals.

I remember reading somewhere that, in damper piston seals, there's typically a tradeoff between longevity and friction. You can make one that lasts a long time, or one that has low friction, but it's very hard to have both. Can't help but feel like that explains the difference between, say, a stock-replacement Bilstein damper (somewhat stiff ride relative to spring rates, lasts forever) and something like a Moton (moves like butter, needs constant rebuilds).

If this is true, it might help explain JRZ's short rebuild intervals.

It also makes me feel like Öhlins is doing something magic. IDK how else mine could have lasted this long, given the punishment they've seen...

This makes sense. Shaft seals generally are on a scale of high friction/high sealing ability to low friction/low sealing ability. The rest of the shock doesn't really follow the same logic so if the shock isn't leaking it's probably fine.

Ohlins is kind of notorious for needing rebuilds, at least in my experience. They use low tension seals in many places for ultra buttery smooth action but they don't last.

Vorshlag was the only BMW tuner that I could think of that was selling ASTs for BMWs. I think Vorshlag has not kept up with the newer cars so they kind of fell off the map.

I've learned its less about the actual damper and more about the vendor taking the time to setup and test the dampers for their intended use. There is value in knowledge.

Bimmerworld & MCS is a good example. You can buy MCS dampers, call Bimmerworld who has ran the damper on the track and be pretty much setup correctly out the box. You can get a JRZ damper which is probably just as good...maybe better...but you're going to spend more time and money getting the suspension dialed in unless there is a BMW tuner that supports JRZ that I don't know about.

Which is the same reason why I use and recommend TC Kline. In 2014, I saw TC at Road America in a new F82 M4 with his coilovers installed doing track and street testing. I used TC's recommendations for springs and damper adjustments. Made 1 adjustment to the dampers and didn't make another change until I removed 500 lbs and installed a rollcage. I swapped my TCKs from the 330 to the M3 back in 2013, he told me a little secret to keep the non-M plates for added negative camber. Works fantastic!

Now...since I've become aware of the flat ride concept I have changed my thinking a little bit especially when it comes to spring rates and compliance. Some advice I have received is not in total agreement with flat ride but it's not far off either.

You have some good points. You can have a really nice shock but if it isn't tuned properly it's going to function worse than a properly set up "budget" shock like a Koni.

I would hope these companies like jrz/moton/ast are putting effort into tuning each vehicle individually but maybe they aren't.

[elbert]

I remember reading somewhere that, in damper piston seals, there's typically a tradeoff between longevity and friction. You can make one that lasts a long time, or one that has low friction, but it's very hard to have both. Can't help but feel like that explains the difference between, say, a stock-replacement Bilstein damper (somewhat stiff ride relative to spring rates, lasts forever) and something like a Moton (moves like butter, needs constant rebuilds).

That's pretty much it -- stiction.

Why doesn't anyone use AST suspension on the E46 M3 chassis? I ran AST 5100's on my '95 M3 in the past and they were absolutely quality, looks like they're paired up with Moton now?

AST acquired Moton a few years ago. One of the founders of JRZ and one of the people from Moton (Lex) then went off to form MCS.

The reason you don't hear about AST anymore is because their most vocal backer (Vorshlag) stopped selling them and switched to MCS. AST had some "teething issues" to put it politely. Not sure how AST is now.

I'm teetering between MCS and AST

I would go with MCS in that case because you will probably get better tech support from your vendor, assuming you buy from someone who knows what they're talking about.

[CrisSilberGrau]

Why doesn't anyone use AST suspension on the E46 M3 chassis? I ran AST 5100's on my '95 M3 in the past and they were absolutely quality, looks like they're paired up with Moton now?

I personally went with ST XTA's (same as KW2's minus the shock body coating) for my E46 M3 build and thus far, I gotta say I'm pleasantly surprised. Ideally I'd like to get everything dialed in after finishing up some other work on the car.

From the local pool of guys that use AST on either the F87 or the E46 I've only heard good things. All of those accounts are mostly for the 5100s and nothing else.

I'm on TCK DAs, but they have been rebuilt once under me, and are not leaking pretty badly again and im looking at viable options for what my use case is. I've mentioned to some members here that I'd like a more "hardcore"/GTS spec style suspension, something that will see a decent amount of track duty but will still be daily at least 2 or 3 days a week in the summer.

Easiest option:
Buy new TCK DAs and maybe go from 400F/600R to 450/500F - 650/700R

OR
MCS 2way NR coilover rear
AST 5100/5200 coilover rear

I'm teetering between MCS and AST, looking to participate in a time attack competition. If anyone has some info on the above MCS/AST id appreciate it. Car is around 3280lbs without me and a full tank. Will either run 265 or 275 square.

[bigjae46]

Why doesn't anyone use AST suspension on the E46 M3 chassis? I ran AST 5100's on my '95 M3 in the past and they were absolutely quality, looks like they're paired up with Moton now?

Vorshlag was the only BMW tuner that I could think of that was selling ASTs for BMWs. I think Vorshlag has not kept up with the newer cars so they kind of fell off the map.

I've learned its less about the actual damper and more about the vendor taking the time to setup and test the dampers for their intended use. There is value in knowledge.

Bimmerworld & MCS is a good example. You can buy MCS dampers, call Bimmerworld who has ran the damper on the track and be pretty much setup correctly out the box. You can get a JRZ damper which is probably just as good...maybe better...but you're going to spend more time and money getting the suspension dialed in unless there is a BMW tuner that supports JRZ that I don't know about.

Which is the same reason why I use and recommend TC Kline. In 2014, I saw TC at Road America in a new F82 M4 with his coilovers installed doing track and street testing. I used TC's recommendations for springs and damper adjustments. Made 1 adjustment to the dampers and didn't make another change until I removed 500 lbs and installed a rollcage. I swapped my TCKs from the 330 to the M3 back in 2013, he told me a little secret to keep the non-M plates for added negative camber. Works fantastic!

Now...since I've become aware of the flat ride concept I have changed my thinking a little bit especially when it comes to spring rates and compliance. Some advice I have received is not in total agreement with flat ride but it's not far off either.

[IamFODI]

I remember reading somewhere that, in damper piston seals, there's typically a tradeoff between longevity and friction. You can make one that lasts a long time, or one that has low friction, but it's very hard to have both. Can't help but feel like that explains the difference between, say, a stock-replacement Bilstein damper (somewhat stiff ride relative to spring rates, lasts forever) and something like a Moton (moves like butter, needs constant rebuilds).

If this is true, it might help explain JRZ's short rebuild intervals.

It also makes me feel like Öhlins is doing something magic. IDK how else mine could have lasted this long, given the punishment they've seen...

[WestBankM4]

Why doesn't anyone use AST suspension on the E46 M3 chassis? I ran AST 5100's on my '95 M3 in the past and they were absolutely quality, looks like they're paired up with Moton now?

I personally went with ST XTA's (same as KW2's minus the shock body coating) for my E46 M3 build and thus far, I gotta say I'm pleasantly surprised. Ideally I'd like to get everything dialed in after finishing up some other work on the car.

[bigjae46]

I don't understand this statement. What about them makes their service life shorter?

Typical rebuild interval that I've seen is 10k-20k miles or 4-6 years. I'm not a damper expert to tell you why that is. I'm assuming higher pressures = higher wear? MCS and Moton aren't that different from JRZ for service intervals.

[cobra]

The JRZs are a high performance damper with a relatively short service life.

...

I don't understand this statement. What about them makes their service life shorter?

[bigjae46]

The JRZs are a high performance damper with a relatively short service life.

I have TC Kline doubles. I think these are the best balance between performance and daily drivability. TC Kline does extensive testing so it makes setup relatively easy. On track I'm pretty damned close to MCS equipped cars on Hoosiers and slicks - maybe 1-2 seconds off. My limitation is spring rates, I need more spring rate to run tires stickier than an NT01 or RR. I am at the limit on the rear shocks.

The TCKs even with 600 fr/700rr springs are surprisingly comfortable on the street.

TCKs get my votes unless you are running a racing slick or Hoosier.

[Nate047]

^V3 and Clubsports are the same dampers, differences are different springs, and Clubsports have top mounts. V1 and V2 dampers are definitely not as good, they're cheaper, shouldn't be a surprise.

[cornerbalanced]

My understanding is the V3 and Clubsport kits are on their own tier of quality from the V1/V2 which are "entry-level."

Either way, I was thinking about posting the details behind my flatride MCS 1WNR setup at some point. A few things were trial and error, but the setup is dialed now and they are fantastic. I figured someone might make use of the info, but just have to find the time to write it all out...

Following for this!!

[zaharias]

Bought it used with oem 19s & B6s with stock springs but i wanted to lower the car a bit and also didn't like the way they absorb in our awful Greek roads.
So i went with Koni yellows, Eibach springs (rear bottom pads removed), Ground Control street camber plates and CSL sway bars.
Apex 8.5/10.5x18 235/40/18 - 265/35/18
No track use.
I want to check alignment and i think i will go back to stock sways..
Can't corner balance here that i live, iam trying to find where to go.
Wanted to weight the car out of curiosity since it does not have many extras and i also added SS LTW muffler/Recaro sportsers/Apex 18...

[MPowerZ32]

Any opinions on the Bilstein Clubsport kit? I'm considering the kit for a dedicated track car build. So far I've found very little info. The only discussion I found was for E9X M3 where the OP had a very positive experience with the kit.

https://www.m3post.com/forums/showthread.php?t=1354492

https://www.youtube.com/watch?v=07fTsF5BiSM

[oceansize]

Just an idea but it would be cool to have a repository similar to the wheel setup thread for suspensions – setup, application, alignment settings, etc. Given lots of members have progressed through multiple setups I think those points of comparison in particular would be valuable.

I once started a thread for this type of information but most didn't seem to want post their setup. Not sure if it was all super secret info lol. I was hoping people would go into great detail to help others.

https://nam3forum.com/forums/forum/m...n-great-detail

[dukeofchen]

🤣

Kdubski, completely reasonable question but much deeper and more complicated than it seems. Too many variables involved to just rank brands.

If you want over-generalized guidelines, here's a list in no particular order:

- Bilstein
- Öhlins
- Koni
- KW
- Dinan
- Swift
- H&R
- Eibach

Not everything from those brands is good value / worth buying. But pretty much everything ELSE is either super niche (i.e., if you're asking about value, probably useless for you) or cheap to the point of being a clear downgrade from stock. There are exceptions, but that's probably a good starting point.

Also, BC Racing is not one of the exceptions. They're firmly in the downgrade category, as is everything cheaper than them.

If you want more, post a thread, tell us about your goals and preferences, and we'll help you. Sound good?

Just an idea but it would be cool to have a repository similar to the wheel setup thread for suspensions – setup, application, alignment settings, etc. Given lots of members have progressed through multiple setups I think those points of comparison in particular would be valuable.