Z4M gearbox

[exdos]

John

What are your thoughts about fitting on a normal road car ?

Is engine feel and noise transmitted through the chassis ?

My thoughts on mods are that, if you don't think you've got a problem, then you've got nothing to fix. I would say that there is virtually no increase in NVH when idling when parked and none when driving.

I think that the stiffness to the front suspension that the V-T engine mounts adds, will help to redress the gross imbalance that I see F <-> R with the OEM suspension, so I would expect that this would be a good and relatively cheap upgrade to an otherwise OEM suspension set-up. As soon as I drove my car up the road today for the first time with the engine mounts, it had a similar feel like the first time that I drove my Z3MC with H&R ARBs. The H&R ARB upgrade is now acknowledged as THE most cost-effective upgrade for the Z3MC and I would wager that the V-T engine mount upgrade will, in time, be considered THE most cost-effective upgrade for the Z4MC. Controlling lateral bodyroll really does make handling so much better.

However, the reason that I did this mod was to attempt to improve the gearshift problem I've had, and I think it will be only after another trip to The Ring that I'll know if this mod is the answer to gear-shift denial I experienced, but I am optimistic on this front. The benefit to the handling isn't altogether a surprise to me, but it has been much more pronounced than I expected and is warmly welcomed by me. Had I known the improvement to handling this mod has, then I would've done this before now.

I think Beedub is right to rave about this mod and I have to thank him for bringing this mod to my attention!

 

[Beedub]

john.... certain this will stop your shift issue.... certain.

 

[ChawenHalo]

I fitted the Vibra-Technics "road" Engine Mounts yesterday. It took me 2 hours in all to do the job and it was easier than I anticipated. Whilst I was at it, I also removed the clutch delay valve completely.

I went for a test drive earlier and I have to give this mod a big I did this mod as an attempt to improve the gear shifting but what I noticed most was the general effect that the engine mounts have had on the car's suspension and handling. I've already got the ACS Racing suspension and H&R ARBs but with the Vibra-Technics mounts, the suspension feels as though it's just been upgraded some more! The feel now is that the whole mass of the car is "as one" which makes the front suspension now feel like it has coilovers with linear springs. Because the engine doesn't move in the horizontal plane with the V-T mounts, when you turn, the engine stays put, so the car turns sharper than it does when centrifugal force pushes the engine mass to the outside, as it does with OEM engine mounts.


Interesting that we are all experiencing the same problems. Whilst most can be remedied with driver input, such as taking a bit more time with the shift (one does get stressed on a trackday), clearly repeated track use puts the mounts and bushes under added pressure causing premature wear and deteriorated performance.

2 of of you have made a point about the "togetherness" feeling of the car. True, its better at speed and it makes sense that if things are moving around more than they should it inside the wheelbase, added to the disjointed feeling when shifting by the driver, it harder to reach that lovely flowing sense.

Sounds like a decent mod to do. My car is pilling on the km so I get those checked and changed if needed. Great result guys, you may well have solved the infamous gearbox problems.

Question: gearbox oil is lifelong and there is a magnet to catch the metal particles in the gearbox which is sealed. Does that give a problem trying to change it?

 

[XMetal]

Gearbox oil on the ///M is definitely NOT lifelong. I recalled the maintenance manual called out for changing it every inspection II. I've changed it on my inspection I (at about 23k miles) and the fluid still appeared to be fairly clean (to the naked eyes)...so every inspection II would be about perfect. I only wanted to change it out early to see if it can smooth out the shift, but it didn't.

In regards to the VT road mounts, depending on how sensitive you are, there is definitely a slight increase in vibration (ever-so-slightly) at idle when compared to the OE mounts. Not sure if this minor vibration is completely being contributed by the VT mounts alone since I also have the RE transmission mounts (no added vibration when I had OE engine mounts paired with RE transmission mounts). I do agree with everyone's assessment on these engine mounts. Should be on everyone's mod/upgrade list

 

[Woots]

hmmm everyone seems very certain these are a must have mod

 

[ChawenHalo]

Gearbox oil on the ///M is definitely NOT lifelong. I recalled the maintenance manual called out for changing it every inspection II. I've changed it on my inspection I (at about 23k miles) and the fluid still appeared to be fairly clean (to the naked eyes)...so every inspection II would be about perfect. I only wanted to change it out early to see if it can smooth out the shift, but it didn't.

In regards to the VT road mounts, depending on how sensitive you are, there is definitely a slight increase in vibration (ever-so-slightly) at idle when compared to the OE mounts. Not sure if this minor vibration is completely being contributed by the VT mounts alone since I also have the RE transmission mounts (no added vibration when I had OE engine mounts paired with RE transmission mounts). I do agree with everyone's assessment on these engine mounts. Should be on everyone's mod/upgrade list

Well its what it says in the manual and on the gearbox over here. it does not say "longlife" but "lifelong" indicating that its good for the intire life of the gearbox! That's odd...

 

[DONDP]

Funny enough, these were on my list to get done as my next mod. Glad to hear all the great feedback.

 

[BMWZ4MC]

sounds like a must, where did you buy the mounts and how much, is the fit a fairly easy diy ? thanks

See: http://www.vibra-technics.co.uk/bmw/z4/528/BMW360M/front_engine_mount_

This isn't the easiest of DIY jobs and you've got to be confident with your lifting method and working underneath the car, so it all depends on what jobs you've done before and the equipment you have as to how hard/easy you'd find it. Also you have to lift the engine off its engine mounts to do the job so you've got to be happy about that too. If you do your research before you start and plan the job, it's definitely DIY but not for a novice.

On this job, rather than lift the car onto axle stands, I ran the car on to two 16' long 10" x4" planks which are supported at various points along their lengths to form a ramp, so that when I lifted the engine, there was no possibility of lifting the car off axle stands.

So, presumably we need four of the same part... Added to the list of bits to order this year :roll:

 

[Beedub]

sounds like a must, where did you buy the mounts and how much, is the fit a fairly easy diy ? thanks

See: http://www.vibra-technics.co.uk/bmw/z4/528/BMW360M/front_engine_mount_

This isn't the easiest of DIY jobs and you've got to be confident with your lifting method and working underneath the car, so it all depends on what jobs you've done before and the equipment you have as to how hard/easy you'd find it. Also you have to lift the engine off its engine mounts to do the job so you've got to be happy about that too. If you do your research before you start and plan the job, it's definitely DIY but not for a novice.

On this job, rather than lift the car onto axle stands, I ran the car on to two 16' long 10" x4" planks which are supported at various points along their lengths to form a ramp, so that when I lifted the engine, there was no possibility of lifting the car off axle stands.

So, presumably we need four of the same part... Added to the list of bits to order this year :roll:

we need 2....

tranny has two different bobbin style mounts that are imo and VTs very nicely designed pieces....

 

[Beedub]

john.... wondering if us guys using the car alittle harder are overheating the GB oil..... maybe we should consider GB and diff oil coolers...
completed agree with you john on the stock ///M diff, they are incredible.... handles every drop of power i throw at it and really puts the power down nicely...

 

[BMWZ4MC]

we need 2....

tranny has two different bobbin style mounts that are imo and VTs very nicely designed pieces....

Ah, okay cheers

 

[DONDP]

john.... wondering if us guys using the car alittle harder are overheating the GB oil..... maybe we should consider GB and diff oil coolers...
completed agree with you john on the stock ///M diff, they are incredible.... handles every drop of power i throw at it and really puts the power down nicely...

Overheating was my first thought too. I considered it might be clutch fluid and/or GB oil overheating that might be causing this issue. It always seemed to occur with me be towards the end of my sessions. I would then slow it all down, cool the car down, I was then unable to repeat the issue on the same corner when the car was cooler.

 

[Beedub]

john.... wondering if us guys using the car alittle harder are overheating the GB oil..... maybe we should consider GB and diff oil coolers...
completed agree with you john on the stock ///M diff, they are incredible.... handles every drop of power i throw at it and really puts the power down nicely...

Overheating was my first thought too. I considered it might be clutch fluid and/or GB oil overheating that might be causing this issue. It always seemed to occur with me be towards the end of my sessions. I would then slow it all down, cool the car down, I was then unable to repeat the issue on the same corner when the car was cooler.

hmmmm to be fair it always seems to happen so way into a session..... overheating is something none of us have explored really.... theirs plenty of space to mount GB/diff- oil coolers... i may look into this....

 

[Beedub]

john, did you bleed the clutch line after you swapped out the CDV?? what process did you use...

 

[exdos]

john.... wondering if us guys using the car alittle harder are overheating the GB oil..... maybe we should consider GB and diff oil coolers...
completed agree with you john on the stock ///M diff, they are incredible.... handles every drop of power i throw at it and really puts the power down nicely...

Byron,

It could be the case, but the few occasions when I had the gearshift denials at The Ring it was always under heavy braking with a turn. Now that I've fitted the VT engine mounts and felt the difference they make, it seems clear to me that it's the engine and connected transmission weight that is moving the gear selector out of line under centrifugal and braking force, that's making shifting difficult when the loading is at the limits. My OEM mounts look perfect and are undamaged, so I think that they are just a bad design and not up to the job of restraining a heavy cast iron block. A bit like driving a van with a fridge in the back which isn't tied down!

Funny you should mention gearbox and diff oil cooling because when I was refitting the metal strengthening plate I noticed the NACA duct in the metal plate as in my photo below, and this is almost directly in line with the gearbox, so it already gets air cooling. Likewise, the rear OEM bumper is designed to take some air above the black plastic diffuser section, where the air passing underneath acts as a venturi to draw the air over the differential. BMW engineers have got most of it right but not everything! :wink:

 

[exdos]

john, did you bleed the clutch line after you swapped out the CDV?? what process did you use...

Yes. I clamped the clutch hose just in front of the CDV with a G-clamp before I removed it, then I reconnected the hose to the metal clutch line that goes upwards (to the rear of the car). When I removed the CDV, virtually no fluid came out.

To bleed; at the top of that metal clutch line, there's a horizontal section at the top of the tunnel with a black plastic dust cap on the end which covers the bleed nipple. I removed the dust cap and placed a 7mm (?) ring spanner over the nipple onto the hex section which is immediately behind the nipple and opened it and waited a second or so before some brake/clutch fluid came out. I let it flow for a few seconds before I retightened the bleed nipple. I guess about 10cc of fluid came through. I'd done a brake fluid change only a few months ago, so the fluid was very clean and the brake fluid cylinder was very full to start. I think gravity has done the job for me, but if it hasn't I'll simply put my Gunson bleeder on and do the same thing again, but with some pressure behind it.

 

[Beedub]

john, did you bleed the clutch line after you swapped out the CDV?? what process did you use...

Yes. I clamped the clutch hose just in front of the CDV with a G-clamp before I removed it, then I reconnected the hose to the metal clutch line that goes upwards (to the rear of the car). When I removed the CDV, virtually no fluid came out.

To bleed; at the top of that metal clutch line, there's a horizontal section at the top of the tunnel with a black plastic dust cap on the end which covers the bleed nipple. I removed the dust cap and placed a 7mm (?) ring spanner over the nipple onto the hex section which is immediately behind the nipple and opened it and waited a second or so before some brake/clutch fluid came out. I let it flow for a few seconds before I retightened the bleed nipple. I guess about 10cc of fluid came through. I'd done a brake fluid change only a few months ago, so the fluid was very clean and the brake fluid cylinder was very full to start. I think gravity has done the job for me, but if it hasn't I'll simply put my Gunson bleeder on and do the same thing again, but with some pressure behind it.

whe i did this i was wondering if i should have pumped the clutch.... i also used gravity.....

 

[exdos]

whe i did this i was wondering if i should have pumped the clutch.... i also used gravity.....

I think you're more likely to suck air into the clutch line when you lift off the clutch pedal if you did that. The fact that you've not had trouble since you did the job shows that the way we've done this job, it must work.

 

[XMetal]

hmmm everyone seems very certain these are a must have mod

I was skeptical as well, but it certainly lives up to all the hypes

Gearbox oil on the ///M is definitely NOT lifelong. I recalled the maintenance manual called out for changing it every inspection II. I've changed it on my inspection I (at about 23k miles) and the fluid still appeared to be fairly clean (to the naked eyes)...so every inspection II would be about perfect. I only wanted to change it out early to see if it can smooth out the shift, but it didn't.

In regards to the VT road mounts, depending on how sensitive you are, there is definitely a slight increase in vibration (ever-so-slightly) at idle when compared to the OE mounts. Not sure if this minor vibration is completely being contributed by the VT mounts alone since I also have the RE transmission mounts (no added vibration when I had OE engine mounts paired with RE transmission mounts). I do agree with everyone's assessment on these engine mounts. Should be on everyone's mod/upgrade list

Well its what it says in the manual and on the gearbox over here. it does not say "longlife" but "lifelong" indicating that its good for the intire life of the gearbox! That's odd...

This is what we North Americans get for Service Maintenance Checklist => http://www.bimmerfest.com/forums/showpost.php?p=2760482&postcount=21

 

[tertius]

sounds like a must, where did you buy the mounts and how much, is the fit a fairly easy diy ? thanks

See: http://www.vibra-technics.co.uk/bmw/z4/528/BMW360M/front_engine_mount_

I'm very tempted to fit these. Just to confirm the Vibra Tech mounts are actually engine mounts, not gearbox mounts?

And are there one or two of them?