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Thread: Need help with MCS setup

  1. #51
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    1999 e36 M3
    So I'm at -3.8 deg Front and -2.5 deg Rear now. Car feels pretty good, although I get understeer in a few medium speed turns, some of which I can drive around with trail braking, but others I can't. Haven't been able to get as much heat into the tires as I think they need. 160 F and it feels like I'm pushing pretty hard to get that. Will try some fresher tires for the next event.

    A couple events back, a guy in a Spec Racer Ford posted a rear-looking video that captured a couple minutes of decent video of my car. I started this race getting stuck behind a Spec Vette that was fast on the straights and very good at blocking me in the turns. So it took me the entire race to get past and catch up to the pack. This video shows the last couple laps. If you skip ahead to around 2:30 min you can see my car beginning to get close enough to the camera car to maybe make some rough judgement about my front suspension setup. It looks to me that the outside front wheel is fairly square to the ground under max loading. My tires are also showing good wear and the temp distributions are good - just not hot enough.

    My car is the yellow and black E36, aka Bumblebee. When the video opens, you may need to click the settings icon and bump the resolution up to maximum.

    https://www.youtube.com/watch?v=zBciHg-g4_g
    Last edited by fbirch; 09-12-2020 at 07:57 PM.

  2. #52
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    '95m3(Avus)/996tt/4.8is
    Understeer at turn in, mid corner, corner exit?

  3. #53
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    Quote Originally Posted by olemiss540 View Post
    Understeer at turn in, mid corner, corner exit?
    All the above in 3 of 16 turns on my home track. It seems to get a bit worse as the tires become heat cycled and less grippy overall. In two of the turns I can trail brake to at least tame the understeer at turn in, but not mid-corner and exit. It's weird because the car has good balance in most of the other turns on track.

    I tried softening the front shocks a couple clicks and stiffening the rear sway bar a bit. I can feel the impact of those changes elsewhere on track, but she still pushes in the three turns in question. I wonder if I need to lower the nose just a bit or go with a bigger front splitter. Right now I have the BMW adjustable splitter, which protrudes about 3.5 inches at full extension. With my big BimmerWorld V3 wing, I have terrific balance in the high speed esses (>90 MPH) on my home track.

  4. #54
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    I didn't see anywhere in here that you mentioned your sway bars. What are you running and (if adjustable) on what settings? I know I found out (the hard way) that I was running too little front sway bar.

  5. #55
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    Is there something about these 3 corners that share similarities? Decreasong/increasing radius, off camber, etc?

  6. #56
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    95 M3 GTS2/ST
    Quote Originally Posted by ScotcH View Post
    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!
    Arek - Would you run that much camber even with roll center correction on the cars? Also what spring rates were you running on the e36? For the OP, considering that you are getting understeer pretty much everywhere, the dampers are likely not going to be the major contributor. They will affect transitions, but sounds to me like you should probably add more front camber, add more rake or add more rear spring (rear wheel rate is about half of the spring rate) and experiment with a front sway bar to see if it will help to keep the front in check - as Jakermc is referring to. As for rake - by raising the rear, you are raising the rear roll center which will effectively raise the rear spring rate geometrically. Car is pushing, raise the rear. Car is loose, lower it. Also keep in mind that we are dealing with front engine sedans/pigs and they are always going to tend to push especially on entry and mid corner - when the front does finally hook up, it can then tend towards oversteer and the driver tends to say the car is loose. Fix the entry and mid corner and get the car to rotate and come off the corner getting to WOT earlier than the next guy.

  7. #57
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    Quote Originally Posted by jonb94118 View Post
    Arek - Would you run that much camber even with roll center correction on the cars? Also what spring rates were you running on the e36? For the OP, considering that you are getting understeer pretty much everywhere, the dampers are likely not going to be the major contributor. They will affect transitions, but sounds to me like you should probably add more front camber, add more rake or add more rear spring (rear wheel rate is about half of the spring rate) and experiment with a front sway bar to see if it will help to keep the front in check - as Jakermc is referring to. As for rake - by raising the rear, you are raising the rear roll center which will effectively raise the rear spring rate geometrically. Car is pushing, raise the rear. Car is loose, lower it. Also keep in mind that we are dealing with front engine sedans/pigs and they are always going to tend to push especially on entry and mid corner - when the front does finally hook up, it can then tend towards oversteer and the driver tends to say the car is loose. Fix the entry and mid corner and get the car to rotate and come off the corner getting to WOT earlier than the next guy.
    We do, yes, and a couple years age (when we thought we needed to win every race ) we did a lot of tire temps and testing. Pirelli and conti slicks both like camber apparently. Springs rates: On e46 varies for track ... Soft (ie, tight bumpy tracks), 700 front, 350 rear (full c/o), stiff 950 front, 500 rear. e36 ... going from memory, I think 800/900, or maybe 800/950 (not c/o). Our rake is around 1/2" ... not a lot. More rake will definitely help with turn in if you're pushing into entry.

    We also run a fairly big front bar (adjustable) and don't run a rear bar to help hook up (and have a super-duper diffs online diff), which really helps corner exit and mid turn (crazy, but the diff basically helps the car around a turn). Amazingly good setup.
    Last edited by ScotcH; 09-15-2020 at 02:12 PM.
    Check out the 8legs Racing page: https://www.facebook.com/8legsRacing/


  8. #58
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    Quote Originally Posted by ScotcH View Post
    We also run a fairly big front bar (adjustable).


    Details about the E36 front bar? And did you run the big front bar/no rear bar on the E36 at those spring rates? I'm at 800/900 with no rear bar, and I'm switching from the small (.120") GC front bar to a custom GC .187" E36 front bar. I am at 4 degrees front camber and hoping the new bigger (also adjustable) front bar will help with mid corner push.
    Last edited by jakermac; 09-15-2020 at 04:42 PM.

  9. #59
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    Quote Originally Posted by jakermac View Post
    I didn't see anywhere in here that you mentioned your sway bars. What are you running and (if adjustable) on what settings? I know I found out (the hard way) that I was running too little front sway bar.
    I have a Turner 27 mm front bar, set to the middle position and the small GC rear bar. also set to the middle position, which roughly corresponds to a 17 mm rear. Before switching to MCS shocks and fixing some worn rear bushings, I tried a 30 mm Turner front bar. WAY too much push with that setup.

    - - - Updated - - -

    Quote Originally Posted by olemiss540 View Post
    Is there something about these 3 corners that share similarities? Decreasong/increasing radius, off camber, etc?
    The first two are at the end of fairly fast straights (129 MPH on the first and maybe 112 on the second). The third is just a brief stab of the brakes to round a bend connecting a short straight to a long one. That one rewards getting on the throttle soon, to maximize speed on the long straight. If you look at the video linked above, it's the one that comes up around 3:18 in the video
    Last edited by fbirch; 09-15-2020 at 06:25 PM.

  10. #60
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    Quote Originally Posted by jonb94118 View Post
    ...... For the OP, considering that you are getting understeer pretty much everywhere, the dampers are likely not going to be the major contributor. They will affect transitions, but sounds to me like you should probably add more front camber, add more rake or add more rear spring (rear wheel rate is about half of the spring rate) and experiment with a front sway bar to see if it will help to keep the front in check - as Jakermc is referring to. As for rake - by raising the rear, you are raising the rear roll center which will effectively raise the rear spring rate geometrically. Car is pushing, raise the rear. Car is loose, lower it. Also keep in mind that we are dealing with front engine sedans/pigs and they are always going to tend to push especially on entry and mid corner - when the front does finally hook up, it can then tend towards oversteer and the driver tends to say the car is loose. Fix the entry and mid corner and get the car to rotate and come off the corner getting to WOT earlier than the next guy.
    Thanks for your feedback. I'd like to get the nose a little lower, but my front perch-to-tire clearance is a bit tight. I have new hardware on order to fix that issue. In the meantime, I can try boosting the rear instead.

  11. #61
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    You should be running at least 3/4” rake measure next to the jack pad rubbers. Go all the way to 1-1/4” in 1/8” increments. Set rear toe at low as 1/8” in. Reduce camber in rear to -2 in -.25 increments. Soften front bar. Soften front spring. Increase rear spring, increase rear compression.

  12. #62
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    Thanks for the feedback. I have about 3/4" rake now and I think it needs to increase a bit, given all the other particulars for my car. I've got some new hardware coming in on Mon that should allow me to drop the nose a bit more. That will be step one. I can work my way down the rest of that list if needed.

  13. #63
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    I’ve found that with my e36 runni 245 square, I never struggle with front grip. Lots of camber and a square tire setup the car has plenty of front grip with 400/500 springs. I find that I’m trying to tame the rear as it’s usually very anxious to step out.

  14. #64
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    The MCS lower seat and lock ring are really nice pieces, well made and strong. But the seat is a bit tall and the lock ring has fairly big OD. The net result is fairly tight tire-to-seat/ring clearance even with 15 mm wheel spacers. I found some really nice lower spring seats made by Euro Parts West that have M52 X 1.5 threads and a decent spring centering feature. The only advantage is that the OD element is a bit less tall than on the MCS seat. I also found some steel lock rings in M52 X 1.5 that have smaller OD than the MCS lock ring. Installed them today and I was able to lower the nose by 1/8 inch while also increasing tire clearance from 5 mm to 10+ mm. This will give me the freedom to drop the nose as low as I'd ever care to go.

    Strut and tire by F birch, on Flickr

    I also bumped the rear ride height up by a couple turns on the H&R adjustable perches. The rake now sits at 1 inch. Can't wait to try it at the next test day.
    Last edited by fbirch; 09-26-2020 at 08:14 PM.

  15. #65
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    GREAT info!!

  16. #66
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    Do you have part #s for the seat and lock ring you bought? Europarts West doesn't have much of a web page.

  17. #67
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    The spring seats are from the Euro Parts West kit for the Porsche 930 RSR. Here is the link to an ebay ad showing the entire kit.

    https://www.ebay.com/itm/PORSCHE-911...0AAOSwmAZe8a~1

    I emailed them and asked if I could just buy the seats from this kit. They had extra seats, so they agreed. The parts are beautifully made, extremely fine craftsmanship. As much as I hated to do it, I cut a small bevel into the lower corner of the OD using a fine wheeled bench grinder (you can see it in my post above). This changes the lower corner of the seat (as installed on the shock) from a 90 deg angle to a 45. Bilstein seats are made with the same bevel. These EPW seats are better than Bilsteins because they incorporate an adequately tall vertical feature to center the spring. BimmerWorld recommends a Delrin ring topped by an aluminum ring between the seat and spring to act as a bearing, and you need some height on the spring centering feature to accommodate this bearing and still provide enough centering for the spring. The MCS seats also have decent height on the spring centering feature.

    For the lock ring, I bought some steel rings on ebay. Because the material is steel instead of aluminum, the notches for the spanner wrench can be much shallower, which allows the OD to be much smaller (see picture below comparing to the MCS lock ring). The lower corners are also beveled, and all these little details add up for clearance. The size of the bearing surface for engaging the seat is the same as any standard aluminum lock ring. I couldn’t find any domestic sources for these small OD steel rings, only Chinese.

    https://www.ebay.com/itm/4-Pcs-M52-x...4e62ecab6662e2

    The rings themselves appear to be OK quality, but they came with some kind of anti-rust coating that fouled the threads. Three of the four wouldn’t thread on easily. Easy enough to clean up with any 1.5 pitch metric tap (run it over the threads by hand) and a wire brush to clean the grooves. Since this is a steel ring going onto an aluminum shock tube, be sure to use lots of anti-seize.

    Lock ring OD by F birch, on Flickr
    Last edited by fbirch; 09-28-2020 at 03:17 PM.

  18. #68
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    Nice job. And thanks for the info.

  19. #69
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    fbirch, re-reading your thread and experiences here.....

    What's the issue you had using helper springs?
    For my current setup, I'd like to lower both ends about 1/2", and I'm "out of room" to do that with 6" springs (650F/800R) and no helper springs.
    Moving to 5.5" springs (at least in rear, maybe stay with 6 in front), but with helpers on both ends, would fix THAT problem.

  20. #70
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    If I recall correctly, the fully compressed helper spring with the spring joiner adds about 0.5 inch of static stack height. I started with 6 inch main springs on my MCS setup, so the helpers basically turned them into 6.5 inch mains. With that much spring height, you have to lower the spring seats a LOT to get the nose low, which then pushes the seats down close to the fat part of the inner tire sidewalls. You'd likely need to run big wheel spacers (or skinny tires) with that arrangement. If you just have 6 inch springs and no helpers, you should be able to get the nose pretty low with modest wheel spacers (12 - 15 mm).

    If you want to lower nose while keeping the spring seats up high, you need to avoid excessively long springs. If you want to use helpers, you'll probably have to go to 5.5 inch mains. How low do you want the nose? At 650 pounds, you'd very likely have enough travel with a 5.5 inch main spring but I'd be very wary of any less. At static conditions, a 650 lb 5.5 inch spring will be compressed down to 4.5 inch or less, and the difference between that and the block height of a 5.5 inch spring only allows so much wheel travel when you are hopping gators or if you drive any really bumpy tracks.

    In the rear I had 5.5 inch springs (800 lb) to begin with and I just retained those. My car has H&R ride height adjusters, which add a few tenths of an inch to the rear ride height.

  21. #71
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    With my current 6" 650lb front spring, I have the lower adjuster adjusted to the point the spring is slightly loose at full extension. I can't go any lower without the spring coming completely off the perch at full extension. My current front ride height is 5-5/8" at the jack points.

    Yea, if the helper/joiner stack up is 1/2" thick, then I'd have to go to 5" front springs. Which, I don't see working that well at moderate spring rates (650-800)?

    Why go lower? Cause with the SLRspeed RC correction, I can.

  22. #72
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    I wouldn't worry about the spring coming off the top perch at full extension. Your sway bar will limit the amount of droop on the inside wheel. FULL extension only really happens when you lift both front wheels simultaneously, such as lifting the car on a 2 post lift or a bridge jack, and spring unseating isn't an issue there.

    5 5/8" is kinda tall for an e36 dedicated track car (mine is around 5 1/4" and I think it could afford to be lower), so I can see why you'd want to lower your nose. I bet you can do it with the 6 inch springs you have now and no helpers. I say give it a shot and see it if works for you. You can always drop down to 5.5 inch springs with helpers if spring unseating turns out to be a problem for you. I really wanted 2.25" diameter springs upfront, and I wasn't able to find any 5.5 inch tall, 2.25 inch diameter, 650 or 700 lb springs. In retrospect, I'm glad I stuck with 6 inch front springs. I have tons of wheel travel and the car has so much compliance and composure over bumps that it's a joy to drive.

    The GC camber plates are nice because they come with two 1/4" bushings that sit between the top of the shock piston and the underside of the camber plate. You can use those bushings to fine tune your front ride height. In my case, I only used one, dropping the nose by 1/4". GC told me they include two bushings because you may get more wheel droop by using one or both, helping the inside tire maintain contact a bit longer.

  23. #73
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    Great info on the GC plates. I'm running their hybrid plate right now, but will likely get their race plates, or Vorshlag, if/when I go to MCS.
    I'ma drop both ends 1/2" and see what happens.

  24. #74
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    Hey fbirch, I got my MCS dampers in! Waiting for my GC race camber plates (upgrading from sport plates).
    Question, in your final setup with 6" front springs, are your springs fully captured at full droop, or do they fall out of the top perch?

  25. #75
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    Quote Originally Posted by aeronaut View Post
    Hey fbirch, I got my MCS dampers in! Waiting for my GC race camber plates (upgrading from sport plates).
    Question, in your final setup with 6" front springs, are your springs fully captured at full droop, or do they fall out of the top perch?
    I realize this is a very late response. If you jack up the entire front end of the car - both front wheels off the ground - the top plate that sits atop the front springs unseats from the camber plate by maybe 1/2 inch to 3/4 inch. The spring itself stays seated in the top plate. When you lower the car, the top plate mates right back with the underside of the GC camber plate. On track, there is almost no scenario where both front wheels get airborne at the same time, so this is very unlikely to happen on track. Even if it did, I think it would be a non issue.

    BTW, what configuration did you end up with, and are you happy with it?

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