Kangaroo Petrol?

J

James_G

Member
 Guildford, Surrey
With it being such a nice weekend I volunteered to pick up my GF from a night in London on Saturday night. I did this because I thought it would be fun to seek out some tunnels and cruise around the sights a bit. And it was, especially Blackfriars underpass and seeing a lovely new 911 GT3 RS in Parliament Square.

Anyway, at one point I needed to do a full bore start from the lights (as you do) as I was in the wrong lane. When I changed from from 1st to 2nd at circa 5-6krpm, the car juddered quite violently, kangaroo like as if the clutch was bouncing. To be fair, it probably wasn't my smoothest change, but is this the dreaded effect of the CDV raising its ugly head. This has happened just once before, but in both case it's been with a large amount of revs and a rushed change. Low revs it doesn't happen and a smooth change at high revs it doesn't happen either.

Anyone experienced something similar?
 
The only time ive ever experienced something like this on an 'emergency start' is on a FWD car when the wheels bounce under the wheelspin and shake the whole drivetrain. To fix this you needed to get or uprate the dog-bone mount for the engine.

Im pretty sure the M would have this however but may be worth checking. Do you think the clutch was fully engaged? Its very unlikely that clutch slippage would do this. If you were in sport mode with a sensetive throttle pedal, its quite likely that the jolt of the gear change moved your accellerator foot blipping the throttle (which then perpetually continues the jerking)?
 
Thanks for that. No wheelspin in this instance, as it was dry and it wasn't "that" aggresive a start. I see what you mean about my foot bouncing on the accelerator - that would explain the rare instances that it has happened.

However a friend has suggested engine and/or diff mounts. I recall some early Z4Ms suffered early failures on the engine mounts. Or was that a one off? I wouldn't have expected anything to be failing with just 23k on the clock, although I'm not the first owner, so its early life is unknown.
 
If it's the rear wheels spinning, the gripping, then spinning - I think it's called 'axle tramp', but the DSC shouldn't let that happen (unless you've switched it off of course).

I used to get it in the M5 a bit if I shot off with the revs between 3000 & 4000rpm - below 3000 it would bog down, above 4000 it would chirp a little and launch. Between those revs it would bounce from side to side until I lifted off (more powere didn't help once it started).

However, this was very noticably coming from the rear wheels.

The CDV kangarooing tends to happen when you try to do a medium throttle pull away, and don't quite time the throttle & clutch right, which then means you start putting more throttle in just as the clutch bites which causes it to jerk.
 
Perhaps difficult to isolate this to a single cause factor but a combination of all of the above... :thumbsup:
 
mmm-five said:
If it's the rear wheels spinning, the gripping, then spinning - I think it's called 'axle tramp', but the DSC shouldn't let that happen (unless you've switched it off of course).
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The DSC was on, and there was definitely no wheelspin as I was rolling when I gave it full throttle. But, the issue comes when I let up the clutch after the change to 2nd, so I'm increasingly pointing the finger at either a fluffed change on my part, or a bad change made worse by the CDV. Trouble is the 125i I also drive has a CDV too, and that's never done it. But maybe it is, as has been suggested, a combination of all these elements working against me.

About time I took it on the track anyway, it's been pent up in the gridlock that is the South East road network for too long.
 
That kangarooing is fairly common until you get to know the drivetrain's peculiarities. It's mostly a combination of the sensitive throttle, the CDV and unfamiliarity with the car. I wouldnt think it's a mechanical fault of any sort.

I used to get it somewhat frequently in the first few weeks. Since removing the CDV i've seen some difference but by then i was used to the car and didnt kangaroo it any more anyway. One thing is definite though, with or without the CDV the Z4M does not like brisk starts in city traffic. It's not like a hatch when you spot a gap in traffic and you just depress the clutch, mash the throttle and you're off, you have to take your time and plan your start in the M or else you kangaroo all over the place or take off like you're doing a 0-100 run or something. I do a lot of stop start, city driving and that's what i noticed.
 
YEAH , HAD EXACTLY THIS a few days ago,tried to get off the lights quickly and just got clutch slip , no not clutch slip so much as the clutch took a long time to engage ,i have been driving sporty cars for thirty five years when i had a 3litre capri which in 1977 was the dogs for an 18yr old petrolhead, consider myself pretty good driver with a fair bit of mechanical understanding , tho not trained engineer but can certainly handle a set of spanners , and in all the years and all the vehicles i have owned, nothing has been as rediculously awkward to live with and drive as this stupid cdv , mine is coming out very soon. we can all make do with it and adapt our driving accordingly if we have to , but we DONT have to so i feel get rid !!! as others have said its not on the m5 so it 's not essential to my mind :x
 
mad4slalom said:
as others have said its not on the m5 so it 's not essential to my mind :x
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Sorry but the MANUAL version of the latest (f10) and former (e60) M5s do have CDVs - it's just not mentioned much in the UK as we don't get offered the manual gearbox and the SMG/DCT gearboxes in the UK cars don't have a clutch pedal or CDV.
 
mad4slalom said:
as others have said its not on the m5 so it 's not essential to my mind :x
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Sorry but the MANUAL version of the latest (f10) and former (e60) M5s do have CDVs - it's just not mentioned much in the UK as we don't get offered the manual gearbox and the SMG/DCT gearboxes in the UK cars don't have a clutch pedal or CDV.

So if it's good enough for an M5, is it good enough for you :poke:

:P
 
i've not had the privelige of driving an m 5 , manual or otherwise, if as you say they do have a cdv fitted and they are as bad as the z4m then i would think they are detrimental to the enjoyment of an otherwise fantastic vehicle,which reinforces the question , why the hell do they fit them ??? :headbang:
 
mad4slalom said:
i've not had the privelige of driving an m 5 , manual or otherwise, if as you say they do have a cdv fitted and they are as bad as the z4m then i would think they are detrimental to the enjoyment of an otherwise fantastic vehicle,which reinforces the question , why the hell do they fit them ??? :headbang:
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It sacrifices the clutch to stop the drive-train being trashed when the driver is in 'bank robber' mode :cpilot: I don't think BMW are the only maker to fit them
 
I've had the 'M' off the lights sharply on many occasions over 5 years including scalping a Boxster S and a Subaru Imprezza quite recently ( need to grow up :P ) so it was red line changes all the way and never had any issues with the clutch which has the CDV.
 
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