E36 M3 and KW V2 Discussion

[fiveightandten]

I've been putting together e36 track cars for a while. Explain what you are saying that lowering the car by x amount isn't a valid performance reason.
Lowering the center of gravity is no longer going to produce gains in handling?
I'm giving you the benefit of the doubt that you didn't word that correctly.

There are many people that buy coilovers simply because they want to spin the adjusters until the car looks cool. Buying coilovers only for the infinite ride height adjustability isn't a valid performance reason, it's an aesthetic one.

As an expert in building E36 race cars, i'm giving you the benefit of the doubt that you're also paying attention to the alignment settings, spring rates, dampening, sway bar adjustments, etc.

[Socali E36]

-With sways, you’ll need adjustable end links. This is to prevent preload on the bar, and make sure it’s at the right angle so it doesn’t bind up or stress the mounts, and so it works properly. Stay away from anything with a hiem joint on a street car, and use sealed ball joints only. There are a number of options for that, but the last time I looked the Turner motorsport ones were the best high quality end links with ball joints. Adjust so the bar is perpendicular to the front rails. Make sure you can slide the end links in and out of the holes while the car is on a level surface (get it on ramps to adjust them like this).


-Set the sways on full soft. The more suspension travel you have, the more sways work. They have a more profound affect on a stock car than they do on one with high spring rates and minimal bump travel.


-After you set your ride height, roll the rear end up on ramps and loosen (then re-tighten) the rear inner control arm bushings where they meet the subframe. This will keep them from twisting at the lower ride height. You’ve eliminated that issue with the poly RTAB’s and FCAB’s, but the inner rears are still rubber with rotational loading.


-Shock mounts are a balancing act. The harder a mount is, the longer it lasts. The softer it is, it’s less harsh on the rear shock towers. Stiffer dampers will wear stock mounts quicker. Whatever is “optimal” for your setup will depend on what your spring/shock rates are, and whether you want to worry about mounts wearing, or shock towers breaking. Whatever you run, definitely use reinforcement plates. The VAC ones are the beefiest i’ve seen. I hate VAC, but I do run their mounts. Even the OE Z3 plates are fine though. Personally, I run the Bimmerworld lifetime mounts. I’ve had them since roughly 2009, with my TC Kline SA coilovers (400/400), and they’re still going strong with no shock tower damage. But there are lots of decent RSM’s out there. Personally, i’d go soft, like OE, BW lifetime, or JTD.


-See Scott’s (joenationwide) great post on alignment. I’d run between -2.0º and -2.5º up front with zero toe, and max out the rear camber with a little bit of toe in. After they corner balance the car, keep an eye on the tires for any signs of rubbing. It’s hard to reproduce the clearances in play when the car is rolling into a corner. What doesn’t rub at rest, may rub under cornering load. Keep an eye on things for a little while.


-Now would be a good time to weld in RTAB pocket reinforcements. I’d consider those a very prudent thing to do on any E36, especially a track car.




To setup the coilovers, here’s a cut and paste from a previous thread I commented on link with more of my banter here: http://www.m3forum.net/m3forum/showp...0&postcount=26 ). I know you’re getting it corner balanced, but this might help to get it set up enough to drive it over there.:


You will need the following:
-A large ruler (24" or so) that measures at least down to 1/8" increments,
-A small ruler that measures down to 32nds, or at least 16ths
-A level
-Some painter's tape
-A sharpie.


1) Get the car on completely level ground. Ie. a poured garage floor.
2) Disconnect the sway bars. One side off will do.
3) Put some painters tape over the center area of each fender/quarter panel
4) Put the level up against your ruler, position the ruler with one end in the middle of the roundel on a wheel. Tilt it upright until the level indicates that it's perfectly straight. Mark that point on the fender with a sharpie. Repeat for the other 3 wheels/fenders. Any time you make a ride height measurement, make sure the ruler is on those points.
5) Measure each corner and write down the ride heights.
6) Spin the ride height adjusters in the front down the amount you want the front end to drop. I recommend using the small ruler and measuring the perch.
7) Spin the ride height adjusters in the rear down in a smaller increment. Remember that the motion ratio for the rear spring is not the same as the wheel because the spring is inboard.
8) Put the car back on the ground, drive it back about 25 feet, then forward again.
9) Measure your heights again.
10) Repeat this process until you have the heights you want. Re-check every wheel every time you change any wheel. Write down every change. If you don't, you'll wish you did.
11) Connect your sway bars. If the links don't line up with the holes, you need adjustable links.
12) Drive the car for a while, come back, see what has shifted (most likely just the rear) and readjust to compensate.


Keep the following things in mind:
1) Changing the height at any one corner will throw all the others off.
2) The goal is to get the weight distributed evenly at all 4 corners, though some forward or rearward bias may be desired. You will not really know how the weight balance is, but measure the rake between front and rear by measuring under the rocker panel so you have a rough idea (front and rear fenders are not comparable, so you can't go by those).
3) When you sit in the car, the driver's side will sag a little more than the passenger side. The stock car is staggered to compensate for this. You can predict how much your weight will make the car sag if you know your spring rates, and stagger the sides to compensate. On the E36 M3 (TCK coilovers), my driver's side is slightly less than 1/8" higher than the passanger side for this reason. The stock suspension is 1/4" higher. Lower spring rates mean more sag under the same weight.
4) Setting coilover ride height by eye with a ruler is a faulted process to begin with. The car really should be corner balanced to get it perfect. So make your measurements as accurate as you possibly can in order to minimize any measurement error/inaccuracy, paying particular attention to changes when you re-adjust, and attention to the rake.
5) This is not something you do in 5 minutes. Many people just spin the adjusters without really measuring things. To do this right will take a few hours, and numerous times of putting the car up and down, and backing it in and out to settle things.
6) Certain bushings on the car are designed to be at a position of rest when the car is at its normal ride height. When you lower the car, you twist them. This wears them prematurely and binds things up a bit. You can re-preload the RTAB's and some of the bushings in the rear subframe to compensate for this. You will need to get the car aligned again anyways, so i'd recommend pre-loading the RTAB's at your new ride height (as you can't take the carrier down without an alignment).
7) When you change the ride height (and especially the rake), your headlight aiming will be off, and you have even made your oil dipstick a bit inaccurate.

That's great info, thank you.

[malter]

Bringing this from dead as I was researching some stuff and got annoyed in process. So with all these experts I'm surprised nobody talks about something as fundamental as roll center going ass backwards when lowering the car on MacPherson garbage. I seriously doubt anybody other that serious track budgets like Turner or Bimmerworld installs mods to adjust roll center changes, which exist for E36. i dont think I ever read anybody asking, what RC correction kit they should run? Maybe on track forum? You lower the car only to have less grip as you messed up roll center.

TCK custom valved koni ..bla bla extenstive testing in Holland bla bla. Are Dutch smarter than others?
Dinan specifically tuned for E36 bla bla bla. Congrats, you've eaten their marketing like a good buffet.
GC kit custom valved bla bla. 5 guys from Sacremento? Or is it 2?

Meanwhile BMW with their multi million $ budget, army of PhD engineers, millions in software, risk assessments, endless testing from Artcic circle to dry andhot Spain, snow, rain, city potholes, variety of terrain, conditions, testers etc know less about the product they designed? Really? Think about how many BMW testers ran the same developmental setup, then reported and compared notes. Then adjusted. Then rinse and repeat before settling on design. For years. You think these companies do that to this extent? Our suspsension recommendation questions on forums end up something along the lines how you heard it from a friend who ran Bilsteins in canyons and it was very compliant. Oh wow, ok. GC allows you to pick your spring rates as if it is was ordering McDonalds. Oh dude, get 300/400 TCK SA setup for street. It is the best. 525/550 for track is the best. Says who? You? Based on feel? Did you also feel it when spring was fully compressed at cork screw or when going 110mph into series of uphill esses? Bunch of damn nonsense.

But Funniest is when people who run HPDE 3x a year say their car is 50/50 track/street duty. Math fail. If you put 400miles on the track and drive 12k/year that's 3% track time. Think about that next time you pick $2k coilovers over stock sachs that are true lifetime on fcp. How many times have you adjusted your Vorschlag plates or corner balanced for specific track? Never? Once at install? Thrice? Surely not all tracks are the same. I prefer leaving my life to BMW engineers over Johnny at local indy to correctly corner balance my life as Im flying rear end first towards the track wall at 80mph. I start asking them if they are using NIST traceable calibration certificates for their scales. You think they do?

[jayjaya29]

lol someone has an axe to grind. Please be sure to give me a point by when I'm on your tail at the track in your stock suspension car. Do you only run the stock Michelins too?

[RBNetEngr]

Bringing this from dead as I was researching some stuff and got annoyed in process. So with all these experts I'm surprised nobody talks about something as fundamental as roll center going ass backwards when lowering the car on MacPherson garbage. I seriously doubt anybody other that serious track budgets like Turner or Bimmerworld installs mods to adjust roll center changes, which exist for E36. i dont think I ever read anybody asking, what RC correction kit they should run? Maybe on track forum? You lower the car only to have less grip as you messed up roll center.

TCK custom valved koni ..bla bla extenstive testing in Holland bla bla. Are Dutch smarter than others?
Dinan specifically tuned for E36 bla bla bla. Congrats, you've eaten their marketing like a good buffet.
GC kit custom valved bla bla. 5 guys from Sacremento? Or is it 2?

Meanwhile BMW with their multi million $ budget, army of PhD engineers, millions in software, risk assessments, endless testing from Artcic circle to dry andhot Spain, snow, rain, city potholes, variety of terrain, conditions, testers etc know less about the product they designed? Really? Think about how many BMW testers ran the same developmental setup, then reported and compared notes. Then adjusted. Then rinse and repeat before settling on design. For years. You think these companies do that to this extent? Our suspsension recommendation questions on forums end up something along the lines how you heard it from a friend who ran Bilsteins in canyons and it was very compliant. Oh wow, ok. GC allows you to pick your spring rates as if it is was ordering McDonalds. Oh dude, get 300/400 TCK SA setup for street. It is the best. 525/550 for track is the best. Says who? You? Based on feel? Did you also feel it when spring was fully compressed at cork screw or when going 110mph into series of uphill esses? Bunch of damn nonsense.

But Funniest is when people who run HPDE 3x a year say their car is 50/50 track/street duty. Math fail. If you put 400miles on the track and drive 12k/year that's 3% track time. Think about that next time you pick $2k coilovers over stock sachs that are true lifetime on fcp. How many times have you adjusted your Vorschlag plates or corner balanced for specific track? Never? Once at install? Thrice? Surely not all tracks are the same. I prefer leaving my life to BMW engineers over Johnny at local indy to correctly corner balance my life as Im flying rear end first towards the track wall at 80mph. I start asking them if they are using NIST traceable calibration certificates for their scales. You think they do?

Was there a point to summarize your rant? Like, most commenters on suspension setups are talking out of their ass?

Speaking for myself, I recently installed a set of ST Suspension XTA Plus 3 coilovers on my E36 M3. I’ll be posting a writeup soon. But when setting the ride height, I used the BMW ride height specifications listed in the Bentley E36 Service Manual (for the Sport suspension). So, I would trust that BMW would not publish ride height numbers that would screw up the roll center.

In the case of KW/ST, they also provide maximum and minimum ride height specifications for these coilovers, that are TÜV certified.

The ride height of the car looks and is perfect. No scraping, no weird handling. No ‘slammed’ look.

For those who buy the $300+ Maxpeedingrods coilovers and then set them for the lowest possible ride height, because “slammed is cool”, that’s another story. The coolness factor probably outweighs the drastically wrong suspension geometry for them. Maybe they’ll learn on a future car…

[pbonsalb]

To me, the most obvious fact missing from the rant is that BMW compromises towards the lowest common denominator of the intended market when producing cars. The buyers who are most interested in matching their driving slippers and watches don’t want the suspension that a performance driver wants.

I have read the “you are not smarter than a BMW engineer” thing many times. Those engineers are told what to do by the accountants. Lifetime transmission fluid…. More seriously, I agree the engineers are good at making cars that the average intended driver should like. If you have wants that differ from the average and can easily modify your car to meet that want, go for it. Yes, you know that the suspension will be rougher over a pothole filled street; the guy with the driving slippers and Rolex who wants an M badge for the golf club parking lot would get upset.

[E36 Em Tree]

What's the easiest way to adjust the rear spring perches on the V2s? I tried to adjust with the wrench and the trailing arm was super tight and wouldn't move.

I guess my only option is taking out the 18mm bolt?

Or ... has anyone tried doing this... https://www.youtube.com/watch?v=_8oPbxxOnGo

[jayjaya29]

Take out the lower shock bolt to release the tension on the spring.

[E36 Em Tree]

Take out the lower shock bolt to release the tension on the spring.

I thought so... didnt wanna do that again because torquing that bolt while the suspension is under load is a PITA haha