If you are considering upgrading the handling of your MC....

[exdos]

Sorry, but this posting is no longer available

[Broccers]

Fantastic post that John, and with my wallowy barge I may well follow some of your findings.

Simon.

[bigfish]

WOW what a great post - cheers for taking the time to put it together. I havent time to read it all tonight but will soon.
I agree - my MC is like a boat on the track and so i do want to change the set up. The only thing is, our roads here are awful country, lumpy roads and comfort must be maintained.
Have just got a StrongStrut front brace but wont get it fited til next week.
Fitted a GruppeM induction kit on Saturday - this is the business. There seems to be better power and response but maybe this is due to the powerful sound. It sounds so cool that it makes it great value :lol:

[c_w]

For me personally I would say the damping is the area most needing upgrading to get rid of the boaty feel and provide better body control on poorer roads.

I've got the Bilstein Sprintline kit on mine and I've come to the conclusion that the springs that come with this kit (VENTURA) are too soft which is what I initially thought when I inspected the springs; they are not shorter in height than the standard springs yet the car sits up to 30mm lower on them and the actual spring coil thickness (particularly at the rear) is much thinner too suggesting they are softer (I remember the standard spring being stiff off the car when pressing down on them, if that is anything to go by!!). I think Sprintline shocks on standard springs might work quite well, and that the VENTURA lowering springs rely more on lower CoG than a stiffer spring rate. This probably also why mine has bottomed out on undulating roads.

With regards the butt strut, I don't think this can be considered an alternative to uprated bushes since they are doing two different jobs; the butt strut is bracing the large stud bolts from the body where the subframe bolts too; the subframe still has the same amount of movement on the bushes (as the subframe "floats" on the bushes), just that the location of the studs is more "positive" (the studs are really flexible when the side brackets are removed). However I do find the butt strut a noticeable improvement and I've also "uprated" my rear bushes by pushing some DIY inserts in to the gaps of the bush which seems to have tightened up the handling and also made it feel more stable but at the expense of some harshness.

[steve1]

Very well written, I will be up to this standard in the next few weeks, I already have the strut-brace, KW3 suspension, 19" rims, and have just ordered H&R ARB's, will be swapping the front top mounts over at the same time as fitting the bars.
As Exdos says, it does take a bit of time to set the car up, I am still tinkering, but once done you will not believe it is the same car.
A lot of people talk about BHP and how to get more, and that is fine, but, if you can't carry what speed you already have into corners because your car isn't sorted, then all the BHP in the world isn't going to help.
And if you want proof, then come along to one of our meets, ( couldn't resist a plug ).

Steve.

[chippy]

Very good post with good information(without being too overly technical) and advice that should be of great benefit to a lot of owners in the future 8)

Its posts like these that really make this forum such a great resource for owners....Well done John and thanks for taking the time to share your findings :wink:

[maahny]

Good post John. Thanks for taking the time out to write out such a useful resource.

I've been intending to get some rear spacers for a while. I will probably do that, swap the front top mounts and ARB's before the Welsh Weekend so that I can try and keep up with Steve again :wink:

[Nessamot II]

Thanks Exdos,

Very much appreciated!

Regards

[exdos]

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[steve1]

You've got that bloody anorak out of the cupboard again haven't you. :wink: :lol:

Look forward to putting this to the test when the stuff arrives.

Steve.

[exdos]

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[steve1]

:lol: :lol: :lol: :lol: :lol: :lol:

[RogerE]

Exdos

Not been posting for a while for reasons explained in my PM to you. Needless to say work is still killing my life.

The other problem is that I still cannot access the Technical Forum on this site unless I go in through someones posting history!!

But, having been accused of putting work first and the car second and everything else a distant 3rd, I may as well indulge myself!!

I thought your article was superb. Hugely informative and written by soeone who has gone out and done it. Well done.

I now have a problem and am hoping for some advice.

I upgraded to ACS suspension about 18 months ago and have also fitted the Strong Strut front brace. The car runs on 18" BBS Le Mans alloys. I have ordered the ARBs but not yet collected or fitted them.

Problem. ACS suspension has now done about 80K miles. Is it worth fitting the ARBs?
Do I need new dampers? Should I stick with the ACS springs and try amd get hold of a new set of ACS dampers?

Any help gratefully received

Roger

[danp]

Wow, excellent post exdos, shame I haven't still got the MC to play with ! Will be in an S54 one day... ;-)

[exdos]

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[chippy]

Roger

I recentely fitted front and rear H&R ARBs to my car which has done 57K on standard suspension and was hugely impressed with the result (especially after chasing exdos's 'starship enterprise' :wink: across the Cotswolds)

So IMHO i'd say get the ARBs on with your current suspension and see how it feels before renewing the springs and dampers.

[MrMicko]

Guys, which ARB settings you decided to use?

[exdos]

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[exdos]

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[chippy]

:oops: Cheque in the post :lol:

Just in case anyone thinks maybe you don't need to go the whole nine yards as John has done, I have to admit that whilst on bumpy B roads my 'reletively' standard coupe held its own, but on the couple of accasions we were traveling through some quicker A road corners (ie smoother road surface) it was quite noticable that John's car had alot more to give than mine :shock:

So for me I think John has just about the perfect set up for fast UK road use.

I think some uprated springs and dampers will be purchased before another trip to the Ring :wink:

[chippy]

Guys, which ARB settings you decided to use?

I also went for softest (ie longest length) setting to start with.

[RogerE]

Thanks to all.

I will get the ARBs fitted and report back.

As I am paying to have them done, I will probably do the negative camber mod as well!!

Thanks again

Roger

[exdos]

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[p 5ary]

ive just ordered the kw variant 3 stuff thanks to this post exdos, 3 weeks before it arrives though, the misses is delighted :P :P ive just in her words "wasted over a grand" :lol: :lol: , i tried to explain its for safety but i dont think she is wearing it!!!!
have to order the rogue top mounts now

[Lee]

ive just ordered the kw variant 3 stuff thanks to this post exodus, 3 weeks before it arrives though, the misses is delighted :P :P ive just in her words "wasted over a grand" :lol: :lol: , i tried to explain its for safety but i dont think she is wearing it!!!!
have to order the rogue top mounts now

P 5ary

My misses allways rolls her eyes but has gotten better over time even encouraging me in certain parts that she likes(schnitzer flippers and hamman spoiler)

I will put it to a real test soon when I get on the supject of the new brakes I need(AP racing kit :D )

much safer!!

[p 5ary]

ive just ordered the kw variant 3 stuff thanks to this post exodus, 3 weeks before it arrives though, the misses is delighted :P :P ive just in her words "wasted over a grand" :lol: :lol: , i tried to explain its for safety but i dont think she is wearing it!!!!
have to order the rogue top mounts now

P 5ary

My misses allways rolls her eyes but has gotten better over time even encouraging me in certain parts that she likes(schnitzer flippers and hamman spoiler)

I will put it to a real test soon when I get on the supject of the new brakes I need(AP racing kit :D )

much safer!!

lol, it seems there are a few of us in this position then,

it may be a good time to strike for the brakes Lee with the distraction of the Lupo!! (looks very well)

[p 5ary]

7. Keep a proper written record of the full adjustment range of the dampers (i.e. number of turns from full soft to full hard) and then log all the settings that you use and any changes that you make thereafter, so you can think in terms of percentage and know exactly what settings you are using.


exdos would you be willing to share your records to date, to give a head start with my own when it eventually arrive, i realise with bushings and the nature of cars there will be slight variances but something to start on;
which brackets would you categorise in, im guessing something along the lines of;
track
fast road
comfort

[steve1]

P5ary,
I have the KW3 on my car, soon to fit the H&R ARB's and rogue top mounts,( fitting these will allow you to adj the rear dampers without removing the interior trim ) myself and exdos have discussed in some length the set-up of the suspension, and it was a drive in my car that convinced exdos to do the dead.
The set-up is very personal i think, depending on the way you drive the car, also on what other mods you have made, different wheels, ARB's etc. so you really need to set the suspension in mid range and go from there.
ideally, you want a particular section of road that tests all of the suspension requirements, you can then use this as your own personal test track and judge the difference that each adj. gives you, believe me you will feel the difference.

Steve.

[p 5ary]

P5ary,
I have the KW3 on my car, soon to fit the H&R ARB's and rogue top mounts,( fitting these will allow you to adj the rear dampers without removing the interior trim ) myself and exdos have discussed in some length the set-up of the suspension, and it was a drive in my car that convinced exdos to do the dead.
The set-up is very personal i think, depending on the way you drive the car, also on what other mods you have made, different wheels, ARB's etc. so you really need to set the suspension in mid range and go from there.
ideally, you want a particular section of road that tests all of the suspension requirements, you can then use this as your own personal test track and judge the difference that each adj. gives you, believe me you will feel the difference.

Steve.

cheers steve1

[c_w]

Where are people buying the roll bars from? How much are they delivered?

[p 5ary]

Where are people buying the roll bars from? How much are they delivered?


here ya go


http://www.z3mcoupe.com/forum2/viewtopic.php?t=3580

[exdos]

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[Jay]

Exdos has inspired me with his very informative post! Cleared a few doubts I had!

Was considering a change as ive had the MC nearly 2 years but there is nothing that i would change her for without loaning another 20K!!!
Just need to gain some confidence in the handling of the car, so have decided to start the ball rolling.
Ordered the H&R ARB kit from Maahny for £282 delivered which I thought was a good price. Next on the list is the KW3 but need a few more hours of overtime till I place the order :lol:

[p 5ary]

exdos,

thanks for the reply, point 3 is excellent regarding the differing stiffness to the front , that clears up a lot.

cheers

im probably going to fit this kit myself, with the help of my friend that has already fitted coilovers, ill try and create a "how to" document regarding installation of the kit for the m coupe incase anyone else fancies a go

[exdos]

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[c_w]

Exdos, you've mentioned that only the front is a coilover setup, the rear using the standard springs and seperate damper; how can you set the ride height 25mm lower than standard at the back, or is this just how it happened to be? or did you use different thickness spring pads?

I've managed to get mine to around 650mm rideheight at the back with some thicker spring pads, I'm happy with this but unsure if the Bilstein dampers at the rear offer enough bump resistance on some of the roads near me (ie horrible bumpy ones!). The front is noticeable more stiffer however, I think part of the reason the rear is softer is for traction and to make it less skittish.

[steve1]

I'll jump in here before exdos, the rear height is adj. by means of an adj. that sits between the spring and the chassis, as simple as that really.

[exdos]

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[p 5ary]

p 5ary,

if you need a "how to" change the suspension before you start, give me a shout, I can do one for you, it's simple enough.

that would be handy, thanks. i just found out the kit will not be here until the 17th of this month so plenty of time.


ps just fitted strong strutt yesterday, the difference is unbelieveable. for anyone that has not yet completed this upgrade .. do it! :lol:

[exdos]

I've now added a "How to fit KW suspension" to the original article at the beginning of this thread to make it an "all-in-one" resource.

[p 5ary]

I've now added a "How to fit KW suspension" to the original article at the beginning of this thread to make it an "all-in-one" resource.

excellent exdos, the kit arrived and im very dissapointed with kw's own instructions yours will be very helpful.
thanks

[exdos]

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[p 5ary]

p 5ary,

I think you'll find my level of service is infintely better than KW's efforts :wink:

lol :lol: :lol: ,

arrrgh, finished the front yesterday, very happy, no rounding of bolt or nut heads, lots of photos to show top mount fitting etc then......................... put the wheel on and crud, rubbing against the coilover, need 10 mm spacers! luckily had a set of 5 mm spacers on hand to prevent any damage but a sheet of paper between tyre and coilover just grazes the coilover/ tyre so new nuts all round now needed as im not happy with a thread length of 25mm being reduced to 15 when the new spacers are fitted, will order a set of 35mm thread long bolts all round (typical holidays when you need the shops open)

[exdos]

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[p 5ary]

exdos, couple of quick questions, the rear damper comes with a washer and 2 flat nuts for the top part, im putting the original top mounts in to get an idea of setting the car height then when the togue top mounts arrive ill put them in, what is the order of putting them in. ie does the large flat new waher go in first against kw damper then top mount then 2 flat nuts???

cheers

[exdos]

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[p 5ary]

p 5ary,

If I were you, I'd be patient and wait until you get your Rogue top mounts before you change the rear dampers, why do the work twice? Removing rear trim is such a pain.

There is one large washer (about 40mm diameter) which fits between the large bolt and the bottom end of the damper to prevent the bolt from working loose through the rubber bush. There was a case of someone on the zroadster.net forum who had the rear damper drop off because someone hadn't fitted a washer at the bottom of the damper with ACS suspension which had been fitted. :o :oops:

I haven't fitted the rear dampers with OEM top mounts so I can't tell you how you'd fit the washers with an OEM top mount set up. As for the height though, you'll get about 25mm lowering at the rear when you set the rear adjusters to lowest setting if you keep both rubber spring seats between the springs and their metal seats. Some people do remove one or both of these rubber spring seats to get further lowering. However, if I were you, for aerodynamic reasons, I would preserve the longitudinal level of the car where the finished height of the front is 5 mm lower than the rear and I doubt if you'll want to lower the front much lower than 640mm (25mm lowering).


i fitted the rear suspension with the oem top mounts, the rear suspension is so easy to do i thought id try and see what height changes would be involved and when the top mount arrives just throw them in ,car isnt moving until its done so the trim will not be going in twice as i would consider removing the rear trim being nearly the worst part of the entire suspension upgrade lol :lol: :lol: :lol: .
http://i31.photobucket.com/albums/c393/p5ary/GENERAL/DSCF0010.jpg

my ride height hardly changed with the rubber pads above and below the spring to the rear so removed the pad to the adjuster side of the spring, this has given approx 20 mm drop form standard for the rear. im very surprised at how much the coil compresses under the car weight , i would say nearly 3 coils are touching :? .
car has a much more agressive stance but sadly ill not be driving it until my spacers and longer bolts arrive, i realise you posted this in your initial post regarding wheel spacers however i thought this was for 18 inch diameter wider wheels , i cant believe kw can make something for a car that does not fit direct, if it didnt fit even a recommendation that they would be needed. The temp 5 mm spacers are too close for comfort between coilover and tyre and also a 25mm threaded bolt losing 5mm doesnt fill me with much confidence to try and find the "new " limits.

your post has been very usful and i fully appreciate and made use of the kw how to fit section, much appreciated Exdos :mrgreen: From what i saved by doing this upgrade myself i can now get the spacer and nuts for free lol, cheers!.

[steve1]

p 5ary,
What sort of ride height have you got at the rear of your car, mine is stting at 642mm from ground to top of wheel arch.
With 19" wheels this looks fine, ( I was running with 630mm, until I added the second rubber pad ).
The coils do seem to be more compressed than you would think, but according to KW, this is the way they are supposed to be, and that rear trim is a real pain, I've just put all mine back together.

Good luck, Steve.

[p 5ary]

p 5ary,
What sort of ride height have you got at the rear of your car, mine is stting at 642mm from ground to top of wheel arch.
With 19" wheels this looks fine, ( I was running with 630mm, until I added the second rubber pad ).
The coils do seem to be more compressed than you would think, but according to KW, this is the way they are supposed to be, and that rear trim is a real pain, I've just put all mine back together.

Good luck, Steve.

Hi steve,

My rear ride height has changed from 667 at the rear to 648 with 1 rubber pad (the finger like protrusion at the non adjuster side) at max lowness, to be honest this is just about right for an aesthetic view as the 17's wouldnt fill the arch the same way as 18's or 19's although i must say kw cut it a bit fine in that the front can lower it so much more than the rear! my front with a 40mm ( this is in the middle of kw's recommendation of 25 - 55) adjustment in the coil gives me a 627 ride height from 649, so the change is fairly even all round. i guess what im saying is the rear adjuster and front adjuster are definately not calibrated in the same way in that sitting between kw recommend fron height and rear height adjustment will not give an even drop front and rear.

ps your wheels look fantastic on your motor 8)

[exdos]

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[p 5ary]

A bunch of arrogant Krouts

Where did you buy the KW kit from?

lol :lol: :lol: ,

i got the kit from Demon tweeks, ive always been impressed with them although they are not always the cheapest.

[c_w]

P 5ary, you may find that the suspension settles a little on the first test drive so you may not have accurate ride heights by just dropping the car on the ground, at least that is what I found with mine; it would drop bt 10mm+ after it was driven and the springs settled in (this was regular lowering spring though).

[exdos]

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[c_w]

Perhaps not as much as that but I still think there would be a difference after a short test drive compared to dropping on the floor.

[p 5ary]

Perhaps not as much as that but I still think there would be a difference after a short test drive compared to dropping on the floor.

i must agree with you c_w, it is now a further 3mm lower than yesterday evening (645mm) which is great as this has made the rear drop the exact same as the front, this is exactly a 22mm drop front and rear.

[ZedVan]

There is only 10-12mm of free-play in the KW rear springs, so there is NO chance of any settlement of a further 10mm after a drive. The ride heights with KW appear to be repeatedly accurate at all 4 wheels whenever you measure them.

Actually there is more wheel travel available than spring travel, as the spring is located on the trailing arm closer to the pivot point than the wheel centre. From some calculations that were done for the E30 M3 trailing arms (which are geometrically pretty identical to the MC ones), the ratio of wheel travel to spring travel is about 1.5 times. i.e. the wheel will move ~ 1.5 mm for every 1 mm of spring travel. Therefore with your ~ 12 mm of free-play you will have ~ 18 mm of wheel travel.

However unless the KW springs are a completely different design than the "standard" ones, then because they are a barrel shape, there is actually more travel (i.e. compressibility) available. The smaller coils can can compress inside the larger ones so you can actual compress the spring to a shorter length than just removing the gaps beteen the coils.

I certainly hope this is the case, as otherwise only 18 mm of compression travel sounds way too little for the the typical British roads. If in fact the suspension became coil bound after only 18 mm of travel then the ride would be awful. When a coil spring becomes coil bound it is essentially a solid link and the spring rate becomes infinite, i.e. you would have no suspension.

[gsi]

certainly looks scarily close on Exdos' photos in the gallery :shock:

[exdos]

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[c_w]

I had a lowering kit on my 2.8 Z3 and now my M Coupe and the rears seem to spend most of their time with half the coils compressed together! But that KW springs looks like it could do with losing a coil and having a stronger winding or something, it may aswell be a block of wood with a 2" spring on the top. I suppose the only reaason for having the extra coils is for when the car lifts a bit.

[exdos]

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[c_w]

You'd have to have some coils bound when the car is standing as these will be softer wound than the others to allow enough length so that when the car is jacked up the spring doesn't become loose.

Do your front coil overs have very soft "helper" springs? these tend to just sit compressed all the time when the car is on the ground but make sure the spring doesn't come loose on the strut when jacked up or maybe going over a jump (although the stiff damper rebound would prevent this I'd imagine)

[exdos]

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[p 5ary]

there is something rattling or vibrating from my rear top mounts, i think its the bump stop vibrating against the lower washer of the top mount, has anyone any ideas. every bolt is tight

ps still waiting on front wheel spacers!!!! :roll:

[steve1]

p 5ary,
Could you explain a bit more about what you think is happening, after I fitted the top mounts found that i had developed a slight noise, like you i checked and double checked, but never really found anything.

Steve.

[p 5ary]

p 5ary,
Could you explain a bit more about what you think is happening, after I fitted the top mounts found that i had developed a slight noise, like you i checked and double checked, but never really found anything.

Steve.

hi steve, ill give it a go
photo showing parts talking about

http://i31.photobucket.com/albums/c393/p5ary/BMW/how%20to%20lower%20april%2006/DSC0023.jpg

the orage part is always agaist the top washer, (not in this photo :oops: as it was only fitted) but it is tight enough to hold itself against the topmount even when the suspension decompressess, i found the noise decreases it i pull it to the bottom position, or as near to as i can get.

i tried putting the rubber pad on the top of the adjuster for the spring and it made no difference as i thought it may have been metal against metal, although it is not a metallic sound.

i wonder if its just the coils on the spring vibrating??

or could it be the metal casing within the topmount that is surrounded by the rubber bushings??


got the phonecall, spacers have arrived so a good road testing session, at least i now know im not the only person with this problem so increases confidence, thanks steve1

[p 5ary]

regarding the rogue engineering top mounts, do you keep the metal hollow bar that slots inside the rubber bushings?

[steve1]

Yes.

Steve.

[fastdrive]

for yours
the double cost of kw variante 3 value compared to blisten sprint+eibach spring?

[RogerRally]

Ive got an old 4 door M reg pre evo E36 spec M3 coupe (Z3M gone now as kids demand more seats), and was thinking of tightening up rear lsd diff and improving springs and bushes, to get some z4m or E46 type tighter handling without spending 48k. for occasional track use
do you know if the mods mentioned here, would suit other bms too?
any one know about improving the LSD diff performance?

[Lee]

Ive got an old 4 door M reg pre evo E36 spec M3 coupe (Z3M gone now as kids demand more seats), and was thinking of tightening up rear lsd diff and improving springs and bushes, to get some z4m or E46 type tighter handling without spending 48k. for occasional track use
do you know if the mods mentioned here, would suit other bms too?
any one know about improving the LSD diff performance?


Roger you can change the diff on your car for shorter gearing no problem.

also the handling mods mentioned such as coilovers, arb's and bushes will improve your standard car immensely.

Lee

[manty]

Just a quick thanks to Exdos for his fitting instructions for the KW stuff. I think I would have struggled if I just used the KW instructions (they are crap) Put the Rear stuff on today after the Rugby, just had a test drive, all seems good, only concern is the rogue top mounts seem a little 'squeaky' sounds like the rubber bushes moving on the metal mount?, Haven't put all the rear trim back yet, would like to get rid of this noise first

Any ideas

[exdos]

You have PM

[manty]

Put the front KWs on today, swapped the front mounts over left to right, put on some subframe bush inserts, set it up as KW suggested to start with............... Truly awesome to drive :twisted: :-P 8-)

Rogue bushes are still squeaking even though i have sprayed them with silicon

Can anyone who has fitted the KW stuff, let me know the settings they have their car set up on, so I can try them out Please :-P

[manty]

Maybe a handy link to have for setting up adjustable suspension, and has a nice flow chart showing the fixes for understeer/ oversteer etc




http://www.thorneymotorsport.co.uk/content/site/images/suspension/suspensionsetup.pdf

[dabber]

Any chance that the first post by exdos could be put up again??

[David1975]

If you PM Exdos then he may email you the post.