Need help with MCS setup

[fbirch]

Don't let my clumsy trial-and-error experience dissuade you. These look like really well made shocks. So far I've only driven the car with MCS on the rear and I love it - a vast improvement over the old Bilsteins I had before. I'll let you know how I like the fronts after next weekend, but I'm expecting them to be a big improvement.

Just follow a few guidelines:

1. Go with 6 inch springs, unless you can get a clever extendo-perch such as Jake did above. Even in that case, don't go less than 5.5 inch springs, unless you are running massively high rates. A 5 inch spring with modest rate (i'm running 700 lb) won't have enough travel in mishap scenarios - e.g., hopping over a curb
2. Skip the helper spring idea. I wasted a lot of time trying to make it work. A helper spring adds too much length to a 6 inch or 5.5 inch main spring, pushing the perch too low
3. Get the seat near very near the top of the threads
4. Avoid excessive thickness in the camber plate area - get some that have removable bushings (like Ground Control) or buy some that are thin to begin with. I think Vorshlag camber plates are known to work with this setup.

If you just follow these simple guidelines you can dial it right into position on round 1. And you are correct - no matter what brand you buy, things will get tight on the front end of an E36 when you

A. Put in a spring with decent travel (e.g., 6 inches)
B. Stuff in a tire with a wide tread patch and/or a wide section width
C. Lower the nose to race car ride height

There just isn't an abundance of space to do the above without paying attention to clearances. If you're willing to slap in some big/wide wheel spacers and pull fenders you can make anything work without giving it as much thought, but where's the challenge in that, right?!

[aeronaut]

Good guidance. I'm just surprised no one else has shared similar struggles with the MCS. They have become a very popular brand over the past few years.

[fbirch]

Good guidance. I'm just surprised no one else has shared similar struggles with the MCS. They have become a very popular brand over the past few years.

After screwing up round 1, I found some old threads that provide decent guidance. Terry Fair has posted some good info in some old threads here and elsewhere. I think the reason you don't read about more people struggling is because so many racers have either pulled or cut/flared their fenders a long time ago. So these struts (or any other brand) are very easy to make work with big spacers in that case. My stubbornness in not wanting to go the pulled fender/big spacer route made things tougher than they probably needed to be. But I have an engineering background so I sometimes lead myself down rabbit holes like this!

[aeronaut]

So can you post exactly what you ended up with? I know you've given bits and pieces, but I'd be interested in your final setup.

TIre
Rim (width and ET)
Spacer
Springs (rate, diam, height)
Camber plates, and mods to plates
Anything else needed for someone to replicate your results.

I'm thinking BW or someone else really should consider selling an adjustment collar like posted by jakermac in post #10.

[aeronaut]

Also, if you could measure the diameter of the threaded portion, and the thread pitch? I know that's asking a lot, but I'd really like to investigate a raised spring seat.

[fbirch]

So can you post exactly what you ended up with? I know you've given bits and pieces, but I'd be interested in your final setup.

TIre
Rim (width and ET)
Spacer
Springs (rate, diam, height)
Camber plates, and mods to plates
Anything else needed for someone to replicate your results.

I'm thinking BW or someone else really should consider selling an adjustment collar like posted by jakermac in post #10.

Final setup:
1. Tire - BFG R1 245/40/17. These 245's have very wide tread patch for a 245, almost as wide as the section width
2. Wheel - DFORCE LTW5, 17X9, ET 41
3. Spacer - 12.5 mm Turner spacers. Bought some BimmerWorld 15 mm spacers but I ended up not needing them
4. Springs - Front: 6 inch tall Hyperco's, 2.25 inch diameter, 700 lb. Rears: Unchanged from prior setup - 800 lb H&R, 5.5 inch height, 60 mm diam on H&R adjustable perches. I like the thinner coil cross section and steeper pitch of the Hyperco springs (more travel!), and would change the rears to Hyperco if they made 5.5 inch, 60 mm springs
5. Camber plates - Ground Control. They come with two lower spacer bushings that push the plate up closer to the shock adjuster tip. I currently have one bushing removed and will likely remove the 2nd one if I need to drop the nose. Current front ride height is 12 +7/8 inches, but things may settle when I bounce the car around a bit on track.
6. Front spring seat & lock ring - Currently stock MCS hardware that comes with shocks. These are both relatively big. Top edge of spring centering cone about even with top of shock body, full thread engagement, so actual spring seat surface is below the top of shock body. I could probably drop these down 3-5 mm with the MSC seat & lock ring, and even more with a thinner lock ring like the one on my Bilsteins. I'll change to smaller lock rings when I have a reason to pull it apart again.
7. Shock body threads - I haven't confirmed, but I THINK they are M52 X 1.5 mm. Will measure them tomorrow when I'm at the garage
8. Camber - Neg 3.5 front, which tucks the tire in nicely inside the unpulled/uncut fender

That collar Jake posted is nice, and you'd need something like that if you wanted to run 5.5 inch front springs. If you run 6 in springs you don't need it. You'll get the right ride height with a 6 inch spring by threading the stock spring seat very near the top of the shock body. The seat and lock ring are just slightly bigger in OD and thickness than ideal, but there is enough clearance with a 12.5 mm wheel spacer. As stated above, just replacing the lower lock ring with a slightly smaller one would let me thread everything down lower than needed with a 6 inch spring.

[fbirch]

BTW, I haven't even tried the 15 mm wheel spacer, but I feel pretty confident that would give me all the flexibility I need on moving the spring seat down with good clearance and PROBABLY allow the tires to just clear the unpulled/uncut fenders or just very slightly rub under extreme compression. But at this point my setup is pretty darn close to where I think it'll need to be with the smallest wheel spacers I can get away with.

I have a test and tune day at the track tomorrow. I may stick the 15 mm spacers in there for one session and chalk the tires just to see if they rub. If they clear it will be very tempting to just stick with those as a way to lower the nose without pulling everything apart again. I've read various feedback that big spacers should be avoided if possible (bad for motion ratio, scrub radius, etc), but a 15 mm spacer would only be 2.5 mm more than I have now, so maybe not too bad.

[aeronaut]

Excellent fbirch, great info! Thank you very much.

[fbirch]

Measured the shock body yesterday and it looks like M52 x 1.5 mm.

So during a test and tune yesterday I played around with the setup. I was able to run 15 mm spacers with just a tiny kiss of rubbing on the fender liner. The nose of the car measured a little higher and I was able to lower it back down to 12 + 7/8 inch (wheel center to fender lip) no problem with those 15 mm spacers. I could have gone at least another 1/8 inch and maybe 1/4 inch lower if needed, but the car felt pretty good at that ride height up front.

Best of all, the MCS shocks are a big improvement over my old Bilsteins, which always felt harsh and "crashy" over sharp bumps or big discontinuities, such as tall-ish curbs. Where the Bilsteins sent a sharp shock through the steering wheel and seat of the pants, these MCS shocks just give a muted thump, almost plush in comparison. I really think my old setup was coil binding. For the first few laps on MCS the car almost felt too soft and comfortable, like you are running on springs with soft rates, but then you realize body roll is no more than before. You are just feeling less harshness and more composed suspension movement. On my home track I could easily increase the rate of my springs - probably by a lot - and still have a composed ride. I think I can feel more compression travel on the front end, even though I'm running 700 lb springs vs 685 lb before. I just think the old springs were bottoming out.

The other nice thing is elimination of all the crazy power-on oversteer I was struggling with before. This is a combination of improving the rake and replacing some worn bushings in the rear suspension. I had to keep reminding myself to feed in more throttle earlier in several key corners. I have to trail brake deeper into a couple fast turns to tame some mid corner push I didn't have before, but overall the car feels much better and I think will ultimately be faster on some fresh rubber.

[aeronaut]

Excellent!!

[olemiss540]

My experience with the higher end shocks have been that you can actually run much stiffer rates with similar compliance. We were running 1000 lb springs on an e46 with JRZs and I swear it felt smoother than the OE setup.

[fbirch]

Another update: Did my first race weekend since upgrading to the MCS shocks. Car felt great, and was 3.5 sec faster than before. Some of that is attributable to other maintenance items and improvements I did at the same time. There is definitely more speed to be found through seat time and further tweaks. I'm hoping for another 1.5 sec. Biggest change in feel was much less harshness over bumps and curbs. I can now widen the track surface in several places by using curbs that would have upset the car before. Overall, I’m very pleased.

One sobering reality is that I now have five “knobs” to turn on each end: Ride height, camber, shock stiffness, adjustable aero and sway bar stiffness. Lots of combinations to play with to improve the overall balance, but lots of wrong ones too. I did notice in the last session that my rear tread temps were hotter on the outside and that was after a cool down lap and slow roll back to the garage. So I’ve already added another half degree of rear camber. I have the nose down to 12.75 inches now and still have 5 mm of tire-to-spring seat clearance on the inside (using 15 mm wheel spacers). I haven’t yet tested the car with these last two changes.

I recently found some M52 X 1.5 mm locking rings made from steel. They are a bit less thick than the aluminum MCS rings and have significantly smaller OD (64 mm vs 74 for MCS). I also ordered some aluminum spring perches from Bilstein that are substantially less thick than the MCS perches. Taken together, these two items should allow me much more freedom to move the nose down farther, lower than I’d want to go anyway, and perhaps even revert back to 12.5 mm spacers.

[ScotcH]

Good stuff. A few things to consider:

- Your camber is too low ... with R1, or any decent slick and good suspension, you should be at -4.5 front, and ~-3-3.5 rear (depends on diff too). A bit of toe-out or 0 front, toe-in rear. We used to run -4.7-4.8 on the e46, -4.5 on the e36 on slicks. Ignore what manufacturers tell you ... it's not the fast setup (especially Pirelli ... -3 max, lol). You won't get this without slotting the upper mount holes and some cutting, but it SO worth it.
- While running a space does change the geometry during suspension movement, this is insignificant in the world or these cars .... sure if it was the last thing to do, it might make a difference. The 3mm of spacer is NOT going to be noticeable. Run the 15mm if it works, and don't sweat it.
- More camber will allow you to lower a bit. But don't be too tempted by that until you get roll/bump correction. The front control arms MUST be parallel to the ground, or outside lower a bit. Do not go below that line. e36 is worse for this, front end grip really suffers
- make sure you have 1/2-3/4" rake (front lower) at the jack points.
- don't underestimate a good front splitter ... a 3" splitter will make a huge difference in high speed stability, and a rear wing will make the car way more comfortable to drive, leading to faster laps.

Have fun and good luck! A good set of shocks on a car is so much fun ... especially paired with good rubber

Good luck and have fun!

[aeronaut]

Awesome feedback fbirch, and thanks for the insight Schotch!!

[fbirch]

Thanks for the excellent info. An e36 in the garage next to mine holds all the track records for GTS3 and he runs big camber as you suggested.

In tweaking my setup prior to the race weekend and then measuring things on level ground afterward, it appears I ended up with about -3.9 deg front camber and -1.9 deg rear. As part of the shock upgrade, I replaced my old Turner camber plates with new Ground Control plates. It seems I can get a ton of camber on the front with those new plates. When I realized how big the camber split was front-to-rear, I measured the rear tread temps and saw I needed way more rear camber. The extra half deg I added might still be insufficient. I can go bigger if needed.

I’ll have to check those front control arms for horizontal positioning. The front isn’t super low, 12.75 inches wheel center to fender lip.

I can’t use my rocker panels to get accurate rake info because they appear to have been bent a bit from years of use. It would be a big help if someone could measure wheel center to fender lip front and rear and then do the same at the jacking points. I only need one baseline measurement (and simple geometry) to infer rake at the jacking points from any future fender measurements. Based on some old threads, I think it’ll work out that 0.75 inches positive rake measured at the fender lips will correspond to somewhere around 0.5 to 0.75 inches of negative rake at the jacking points.

[aeronaut]

fbirch, I measured my heights. Note, it's difficult to get accurate wheel-center to bottom of arch numbers. Ruler must be nearly perfectly verticle. And I don't have hub covers, so eyeballing where the center is. Jack points were measured from ground to the chassis immediately next to the hole that a t-hook would go into. All that said, here you go:

Left Front,
wheelcenter-to-arch=13-7/8
ground-to-jackpoint=5-11/16

Left Rear,
wheelcenter-to-arch=12-1/2
ground-to-jackpoint=7

Right Front,
wheelcenter-to-arch=13-7/8
ground-to-jackpoint=5-11/16

Right Rear,
wheelcenter-to-arch=12-7/8
ground-to-jackpoint=6-3/4

[fbirch]

Thanks, aeronaut! That's much appreciated. I'll plug that info into a little calculator I set up on my work PC to see where my car stands on rake at lift points.

Rationale for my setup:

Bimmerworld's setup guide for the MCS recommends setting front ride height such that there is 0.5 to 1.0 inches of clearance between top of front tire and fender lip. I run 245/40/17 tires, so the diameter should be around 24.72 inches, radius = 12.36 inches. 0.5 inch gap would imply 12.86 in. I ran 12.88 (12+7/8) inches last race and feel like it could stand to be a touch lower. Of course I'm sure those guidelines are pretty rough and highly dependent on all the rest of the setup.

Given your relatively tall ride height, I'm a bit surprised you needed a roll center correction kit on your car. I haven't measured my LCA's yet, but will let you know what I find.

Looks as if you're running a full 1+ inch of rake. BW recommended 0.5 - 1.0 inches, pretty much in line with most threads here.

[aeronaut]

I don't need roll center correction, and would prefer not to have it. But, I *LOVE* the quicker steering. It completely changes the car, in a very very good way. Sounds trivial, but it makes the car so much more enjoyable to push.

Or, I can (should) lower the car at least a bit. Probably 1/2" in front and a trivial more in rear for slightly less rake. If I lower more than about 1/2", I'm pretty sure I'd need stiffer springs to stay off the bump stops.

And there we have it, so rather than drop the car an inch, buy new springs, which then would require me to rebuild my dampers, or of course, MCS, I just do nothing. lol.

[fbirch]

When you're ready for new dampers MCS is a great option, even the least-expensive version that I bought.

Based on the measurements from the right side of your car and taking into account the geometry of wheelbase vs jacking points, I figured my rake at the rocker panel should be close to 0.75 inches. Recall that my current hub-center-to-fender-lip measurements are 12.75 in front and 12 in rear. Well, I was at the garage today and measured rake at the lift points again, and this time I got 5.5 in front and 6.25 in rear, exactly 0.75 in! Not sure what I was doing wrong before leading me to conclude I had bent lift points. The initial rake was probably so far out of whack that I concluded my measurements must be wrong. Nice to know that's not the case.

Based on a quick and rough measurement, my LCA outer ends are around 0.5 inches higher than the inner end. This is just measuring the arm itself, not ball joint height. Not sure if that's a big enough delta to warrant roll center correction.

I have a test and tune day next Sat and will try to recruit someone to help me get pyrometer readings while the tires are fully hot. If I'm able to find a static camber setting that gives me uniform temps across the front tires, does that mean I don't need roll center correction?

[ScotcH]

When you're ready for new dampers MCS is a great option, even the least-expensive version that I bought.

Based on the measurements from the right side of your car and taking into account the geometry of wheelbase vs jacking points, I figured my rake at the rocker panel should be close to 0.75 inches. Recall that my current hub-center-to-fender-lip measurements are 12.75 in front and 12 in rear. Well, I was at the garage today and measured rake at the lift points again, and this time I got 5.5 in front and 6.25 in rear, exactly 0.75 in! Not sure what I was doing wrong before leading me to conclude I had bent lift points. The initial rake was probably so far out of whack that I concluded my measurements must be wrong. Nice to know that's not the case.

Based on a quick and rough measurement, my LCA outer ends are around 0.5 inches higher than the inner end. This is just measuring the arm itself, not ball joint height. Not sure if that's a big enough delta to warrant roll center correction.

I have a test and tune day next Sat and will try to recruit someone to help me get pyrometer readings while the tires are fully hot. If I'm able to find a static camber setting that gives me uniform temps across the front tires, does that mean I don't need roll center correction?

Tire temps won't really give you that info .. certainly it will add a data point, but really it's the geometry. Basically, the car will just turn in better with roll correction when lowered. Just look at the LCAs in these images (our cars ages ago!) ... do not go lower than that, and you'll be fine.

As far as tire temps, you also don't want them even across the tire. Depends on tire of course, but typically, optimum grip shows hotter inside, with even spread of about ~10C. So a good tire reading might look like 65, 60, 55 (with 55 being the outside).

LCA.jpg

bumpsteer_car.jpg

[aeronaut]

Yea, that's what the Hoosier reps say too, 20F inside hotter.

[fbirch]

Scott and aeronaut, thanks for the info. Scott: Would you happen to know how low the car is at the point of horizontal LCAs, such as wheel to fender gap or lift point height?

[aeronaut]

Scotch KNOWS it, I was just repeating what a Hoosier rep said.

[ScotcH]

Scott and aeronaut, thanks for the info. Scott: Would you happen to know how low the car is at the point of horizontal LCAs, such as wheel to fender gap or lift point height?

Sorry no ... we haven't ran stock ball joints in years (we have GC and custom roll center and bump correction now). 5.5 and 6" at jack points rings a bell though. Also, name is Arek (ScotcH is just a dump handle )

[fbirch]

Thanks, Arek. Felix here.