Z4mc bouncy suspension
Discussion
Hi all, new owner of a 2006 z4m coupe. After reading all the reviews about the handling at launch, I have been pleasantly surprised. The car drives turns in really sharply and feels very "special" unlike an m3 at anything less than 100%. It also felt pretty balanced and neutral the couple of times I've pushed it passed grip levels with the tcs off. What I haven't found to be exaggerated is the bounciness in the suspension. I haven't found it particularly harsh, no more so than my current m sport e90 daily driver or indeed past cars I've had like a 996 carrera and e46 m3. However the bounce and unsettled feeling particularly in the rear is really disconcerting, particularly when pushing on down back roads. From numerous searches I believe some of the issues come from the stiffness of the rear springs. Can anyone with more knowledge comment on whether eibach springs or the like would improve the bounciness, or whether it's a dampening issue? Would rather not spend a fortune going to coilovers, but may need to look into it if that is the best way to sort this out as I feel it's the main issue not making this the best drivers car I've owned!
Very topical given what I've just done...
But first a little background. I crashed my CLS last year on the M62 in torrential rain. I aquaplaned very suddenly, the ends swapped places and from what I recall, I hit the central reservation about 3 times. Luckily nobody else was involved and I escaped with only a few broken bones. First time in an ambulance!
I naturally, when out of hospital, bought a "safer" car in the Z4MC(!). However I too found the ride "bouncy" and, given my above experience, was a little nervous when it felt wayward. This was particularly the case given that the CLS had only done around 3k miles on the rubber it was on. I couldn't and still can't think of why it just went the the way it did and so any sense of vagueness in a car causes momentary panic.
Anyway, I just fitted some eibach springs today and at first didn't notice much of a difference. After a few hundred miles, I noticed that the feeling of disconnect caused by "bounce" has virtually gone... because the "bounce" has gone. I was actually quite surprised. It feels more taut, the ride is not noticeably firmer and the lowered stance suits better. Best of all, I live in speedhumpville and there are no issues whatsoever.
I'd recommend giving them a try.
But first a little background. I crashed my CLS last year on the M62 in torrential rain. I aquaplaned very suddenly, the ends swapped places and from what I recall, I hit the central reservation about 3 times. Luckily nobody else was involved and I escaped with only a few broken bones. First time in an ambulance!
I naturally, when out of hospital, bought a "safer" car in the Z4MC(!). However I too found the ride "bouncy" and, given my above experience, was a little nervous when it felt wayward. This was particularly the case given that the CLS had only done around 3k miles on the rubber it was on. I couldn't and still can't think of why it just went the the way it did and so any sense of vagueness in a car causes momentary panic.
Anyway, I just fitted some eibach springs today and at first didn't notice much of a difference. After a few hundred miles, I noticed that the feeling of disconnect caused by "bounce" has virtually gone... because the "bounce" has gone. I was actually quite surprised. It feels more taut, the ride is not noticeably firmer and the lowered stance suits better. Best of all, I live in speedhumpville and there are no issues whatsoever.
I'd recommend giving them a try.
Sorry to hear about the CLS and Thanks for the comments.I love your "safety car" being a 340hp rwd sports car!
The z4m engine is an absolute peach, I had it in an m3 for over two years and it performed without a hitch. It does need revved to get the best out of it, but it's relatively economical and bulletproof if properly looked after. Where the z4m scores is in the whole feel of the package. The M3 was epic at full attack, but driving at anything less it just felt like any other fast BM. The z4m looks and feels different and much more like driving a proper sports car all of the time.
I have had experience in the past with the eibach pro kit on the m3 and they were great. That said the car handled and rode really well from stock, the eibachs just lowered it slightly and tightened up some of the body roll. They will however have a much bigger job with the z4 as the bouncy ride is far from how I would like it. My concern was the spring rates on the eibach were still fairly soft front stiff rear as per the oe ones. Most coilover kits have significantly stiffer front springs with the back even being slightly softer on the rear with some kits. Based on your review as well a some other mixed ones, I think I'll order the springs to give them a go. For a couple of hundred pounds and a fairly easy DIY it's worth a try.
The z4m engine is an absolute peach, I had it in an m3 for over two years and it performed without a hitch. It does need revved to get the best out of it, but it's relatively economical and bulletproof if properly looked after. Where the z4m scores is in the whole feel of the package. The M3 was epic at full attack, but driving at anything less it just felt like any other fast BM. The z4m looks and feels different and much more like driving a proper sports car all of the time.
I have had experience in the past with the eibach pro kit on the m3 and they were great. That said the car handled and rode really well from stock, the eibachs just lowered it slightly and tightened up some of the body roll. They will however have a much bigger job with the z4 as the bouncy ride is far from how I would like it. My concern was the spring rates on the eibach were still fairly soft front stiff rear as per the oe ones. Most coilover kits have significantly stiffer front springs with the back even being slightly softer on the rear with some kits. Based on your review as well a some other mixed ones, I think I'll order the springs to give them a go. For a couple of hundred pounds and a fairly easy DIY it's worth a try.
Economical? Mine must be broken. 
It does feel very, very special both to look at and to drive. I think the feeling comes from sitting virtually over the rear axle and the very little bodywork/interior between driver and the exhaust. The engine is just legendary and the extra bits and bobs around the place from the CSL just add to the package, in my view. I don't think I'll ever get rid of mine... the only car that tempts me is a V8 F-type coupe but I doubt it is the £90k it would cost to change, better.
As for the springs, you're right. It isn't much money and if nothing else, you'll have a car that is just as useable but looks much better. Having said that, I think you'll be pleasantly surprised after a few hundred miles. I am quite sceptical about modifications in general (based on adding a throaty exhaust to a Type R when a laddie... only to see BHP drop when on a rolling road!) but this mod has been worth it.
It does feel very, very special both to look at and to drive. I think the feeling comes from sitting virtually over the rear axle and the very little bodywork/interior between driver and the exhaust. The engine is just legendary and the extra bits and bobs around the place from the CSL just add to the package, in my view. I don't think I'll ever get rid of mine... the only car that tempts me is a V8 F-type coupe but I doubt it is the £90k it would cost to change, better.
As for the springs, you're right. It isn't much money and if nothing else, you'll have a car that is just as useable but looks much better. Having said that, I think you'll be pleasantly surprised after a few hundred miles. I am quite sceptical about modifications in general (based on adding a throaty exhaust to a Type R when a laddie... only to see BHP drop when on a rolling road!) but this mod has been worth it.
Used to get 24-25 mpg out of my M3 on the daily commute. That said, mid teens weren't unexpected when driven properly.
I agree on there being not much out there as good or different in that price range, and I may also keep the z4m long term. That said, it would have been a 996 turbo had I had another £10k to spend.
The Mcoupe is special, but the 911 turbo is in a different league for around £25k once you get over the dated interior. Throw a couple of grand in tweeks at it and it'll genuinely hold on to most modern supercars on a b road. Has to be the performance bargain of the decade.
I agree on there being not much out there as good or different in that price range, and I may also keep the z4m long term. That said, it would have been a 996 turbo had I had another £10k to spend.
The Mcoupe is special, but the 911 turbo is in a different league for around £25k once you get over the dated interior. Throw a couple of grand in tweeks at it and it'll genuinely hold on to most modern supercars on a b road. Has to be the performance bargain of the decade.
Thanks Daz, havent really found the rear suspension that hard, just bouncy, although that may be down to the stiffness. Both rear springs were replaced 3000 miles ago, so should be ok.
Which coilovers did you go for? Obviously the more expensive the better, but don't want a sledgehammer to crack a nut. I wont be tracking the car as I have a supercharged Mx5 for that job as its cheap as chips to run or break. Ill take any on road handling improvements, but it really is the bounciness im looking to get rid of. Anyone tried BC or H&R coilovers as a budget option?
Which coilovers did you go for? Obviously the more expensive the better, but don't want a sledgehammer to crack a nut. I wont be tracking the car as I have a supercharged Mx5 for that job as its cheap as chips to run or break. Ill take any on road handling improvements, but it really is the bounciness im looking to get rid of. Anyone tried BC or H&R coilovers as a budget option?
Some reading for you Gav.....
http://www.z4-forum.com/forum/viewtopic.php?f=9&am...
http://www.z4-forum.com/forum/viewtopic.php?f=9&am...
Plenty more info that will answer your questions on that forum...
http://www.z4-forum.com/forum/viewtopic.php?f=9&am...
http://www.z4-forum.com/forum/viewtopic.php?f=9&am...
Plenty more info that will answer your questions on that forum...
Thanks for All the Info guys.
Plowy- some really interesting stuff and exactly what i was looking for
Checked all the tyre pressures were as per specs, but may run them a couple of pounds lighter to see if that makes any difference
I'm loathed to lay out the £1800 odd pounds for decent coilovers. I wont be tracking it and am effectively just looking for stiffer front and softer rear springs with dampers to match. I may give the Eibach's a go, but not 100% as they are progressive springs which are stiffer than OE and still matched to the standard shocks so soft front stiff rear. Shame no one seems to do a matched shock/ spring combo with spring rates similar to the coilover kits. Thats the downside to having a relatively rare car i suppose
Gavin
Plowy- some really interesting stuff and exactly what i was looking for
Checked all the tyre pressures were as per specs, but may run them a couple of pounds lighter to see if that makes any difference
I'm loathed to lay out the £1800 odd pounds for decent coilovers. I wont be tracking it and am effectively just looking for stiffer front and softer rear springs with dampers to match. I may give the Eibach's a go, but not 100% as they are progressive springs which are stiffer than OE and still matched to the standard shocks so soft front stiff rear. Shame no one seems to do a matched shock/ spring combo with spring rates similar to the coilover kits. Thats the downside to having a relatively rare car i suppose
Gavin
Front suspension is similar to e36 but with modified mounting points and the rear e46 although im not sure on the length of the springs etc
May be worth a try with some e46 springs on the rear as I believe the spring rates would be softer, although not sure on spring heights and how they would work with the OE damper.
More investigation required!
May be worth a try with some e46 springs on the rear as I believe the spring rates would be softer, although not sure on spring heights and how they would work with the OE damper.
More investigation required!
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