This is a 2 part question
1) How do you know if you have a top rear adjustable shock, or if i have to remove the shock. The bottom of the shock has an arrow pointing up near the word adjust???
2) I hear some posted a thread on where to drill a hole for rear top adjustmenbt shocks. I did a search but could not find..any body recall this link?
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This is what I did with the help of a couple of board members:
http://www.bimmerfest.com/forums/showthread.php?t=85889
Florian
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| Reply » Adjusting rear Koni - yellow |
Quote: This is a 2 part question
1) How do you know if you have a top rear adjustable shock, or if i have to remove the shock. The bottom of the shock has an arrow pointing up near the word adjust???
2) I hear some posted a thread on where to drill a hole for rear top adjustmenbt shocks. I did a search but could not find..any body recall this link? | I have the single adjustment Koni's. The rears are adjustable from the bottom. The fronts from the top.
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the standard Koni rear shocks for most BMW's are internally adjustable; they have to be compressed with the bumpstop removed to engage the internal adjuster.
You can get them converted to be externally adjustable (or buy them already custom converted); the tab at the top of the shock that adjusts with a knob, but this costs quite a bit more and you have to either drill out the factory rear shock mount bushing or run an aftermarket RSB with a larger shaft hole because the shock shaft diameter has to be increased from the factory 10mm to 12mm for the adjuster to run up the middle. That and the access issue is the reason Koni doesn't offer the rear shocks as externally adjustable as standard.
If you have this conversion in a Coupe you then need to cut an access hole in the top of the rear side panels in the hatch area to be able to make the adjustment. In Roadsters I think you can just pull the carpet back to access the top of the shocks. Some of the people here have made some rather elaborate access ports, my personal choice is to cut a hole and use a round snap-in plug because it's clean and simple. The easiest way to locate the access port is to use a long drill bit the same diameter as the RSB sleeve ID, run it up from the bottom through the RSB sleeve until it hits the top of the cargo panel, drill through the panel, and then use that as the centering hole to make the larger access port. Essentially you're using the RSB sleeve centerline to center the access port perfectly in the interior coupe trim panel.
FWIW, I was the first person to ever get the BMW rear Koni shock external adjustment conversion done back in 1996 for a '95 M3, which I did in conjunction with Truechoice. I also had one of the first Z coupes and was most likely the first person to make the mod, same for the Z4. I don't say this to be a braggart, but rather to point out my experience with it. Feel free to PM if you have additional questions or need further explanation.
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I have to assume then that I have the externally adjustable rears. I installed the
Rogue Engineering RSM so that I do not have to take the carpet liners out to remove the shocks- as I understand.
I have them set on medium at the moment- seems easier to leave them as they are. I have no bounce related or squatting issues. Car seems to stay neutral under braking and as I roll on throttle car does not seem to squat. ( thats the real killer in the Z cars- going from brakes to throttle as you initiaite turn in- if your suspension bounces so does your aligment  )
Between Alignement settings, adjustable sway bars, shocks, spring height adjusters, air pressure and tire choices, wheel spacers- etc...there are so many variables you could spin your self just thinking about them all.
My thoughts and they are my opinion since I am not a chassis engineer-
Have a set up for dry that is middle of the road settings- this way the chassis is complient on any imperfect road conditions- yet firm enought to give the rsponse we want. Set the car for slight push ( understeer) and enjoy it.
For the rain- soften the set ups to allow the car to absorb some energy to allow the tires to hold onto what traction they can find. ( thats what we do with karts- I figure the principals are the same- the way we do is is different since karts have no suspension)
All the information and set up variables that many of you have are great..but for guys like me who are not doing testing or racing, it may be too much 
Some of the set ups with 3 degrees or more of negative camber seem extreme- but again- personally don't now and no one has put any test data up to the contrary.
I can see if you ar doing one lap and need the car to to come in quickly and stay optimum for a few laps ONLY- extreme set ups like those might be needed. But for a driver day at the track- ( again racers have different needs) a nice balanced set up that lets lets the car last the day, is easy on the tires and lets you drive your heart out is whats needed.
( IMO- brake heat has plays a bigger role in determining the course of the day then anything else- get proper cooling and you can drive harder longer. Its the Viagra of driving !!)
Does anyone have ideas to add? I think a suspension project could include:
1) get some good tires for what ever is your intended purpose
2) for the Z cars- I think the IE bushings ( sub chassis and trailing arm)would be next in prioroty having done them
3) get a good alignment
4) invest in shocks, then springs if you cant do both
5) get sway bars- but be sure to re-enforce your rear trailing arm tabs
6) Do front strut tie bar
7) do camber plates- front and A arm bushings
8) do rear camber / toe plates ala IE
9) Full cage
10) metal bushings- and a dental plan 
I am at 8.5 at the moment- 1/4 cage with the HMS bar.
Sway bar- front Neutral, rear soft
Konis- Med front and rear- at the track I go to fulll stiff front only
Tires- Mich Pilot Cup Sport - cold air pressure usually 28 to 30... to 36 hot. ( try to keep under 40 hot)
alignement- ran stock set up - this year will be trying ( stock caster) Front Camber -2 with 1/16 toe in and rear -2.25 and 1/8 toe in.
Please share thougth and feedback
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| Reply » Adjusting rear Koni - yellow |
Only thing is, I would put the strut bar further up th elist. I noticed a big difference installing one. Smae on the M3.
On the M Roadster, I have Bilsteins (no adjustment), and H&Rs and swapped front hats (gives about 1.5 degrees negative). I set the sways mid range front and rear. ANd I like the basic setup.
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Adjusting rear Koni - yellow