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      10-08-2012, 10:28 AM   #243
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Nearing 60k on mine (a 2006 car) and i get frequent 1st to second gear grinds (if trying to shift really quick).
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      10-08-2012, 10:47 AM   #244
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I wonder if a survey is needed...
I have observed more coupe owners with this issue than roadsters.
One could surmise the coupe's extra chassis rigidity may be less forgiving in the total package when you factor all things.... tranny mounts, engine mounts, bushings, not to mention the actual MT fluid used, age/wear, and mileage.
whadyathink?


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      10-11-2012, 06:12 PM   #245
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I have found with my Roadster that I get the 1 -> 2 grind more often when the DSC is flashing.
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      10-12-2012, 10:05 AM   #246
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Quote:
Originally Posted by 330indy View Post
I wonder if a survey is needed...
I have observed more coupe owners with this issue than roadsters.
One could surmise the coupe's extra chassis rigidity may be less forgiving in the total package when you factor all things.... tranny mounts, engine mounts, bushings, not to mention the actual MT fluid used, age/wear, and mileage.
whadyathink?


anyone?

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I don't think there's a whole lot of flex causing the issue, the motor mounts and tranny mounts are both softer to begin with. I really think it's just not a good tranny designed for this motor. Do we see a lot of 3.0si folks with this issue or just S54 equipped E85/6?
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      10-12-2012, 10:39 AM   #247
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I have to say I've tried a few different things to get the perfect shifting, from small mods to forcing myself to let the clutch out slower. End of day, the one mod that I was most skeptical of (based on its price) turned out to the be the best in terms of effectiveness - the Mason Engineering clutch pedal. I bought it after reading Bill's review but its really amazing, the engagement point is so precise. Between that, ssk, Jaffster, cdv delete and RE trans mounts I have *smooth*, precise, short shifts. I actually reverted to the stock clutch stop too.

http://www.billswebspace.com/BMWZ4MM...stallation.htm
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      10-12-2012, 11:22 AM   #248
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Quote:
Originally Posted by DSC_OFF View Post
I have to say I've tried a few different things to get the perfect shifting, from small mods to forcing myself to let the clutch out slower. End of day, the one mod that I was most skeptical of (based on its price) turned out to the be the best in terms of effectiveness - the Mason Engineering clutch pedal. I bought it after reading Bill's review but its really amazing, the engagement point is so precise. Between that, ssk, Jaffster, cdv delete and RE trans mounts I have *smooth*, precise, short shifts. I actually reverted to the stock clutch stop too.

http://www.billswebspace.com/BMWZ4MM...stallation.htm
I think you are onto something here. I noticed the shift is really smooth when I make an effort to get the clutch pedal all the way down. The clutch was pressed really hard where you can hear it hit the floor.
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      10-12-2012, 12:09 PM   #249
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Quote:
Originally Posted by RobMCoupe View Post
I think you are onto something here. I noticed the shift is really smooth when I make an effort to get the clutch pedal all the way down. The clutch was pressed really hard where you can hear it hit the floor.
You should always go all the way to the stop. You should hear it thump every time you shift.

If you look at the pedal linkage and then the hydraulic advantage you will find that the throw out bearing is actually moving only a small amount when you push the pedal all the way to the floor - probably 1/4" or less.

It is possible that not going all the way to the floor could almost simulate shifting without the clutch - that process will definitely crunch, particularly so if you are shifting fast. I suspect that the high speed crunch problem is related to this as well - you may be trying to get it to the floor but everything is happening so fast that you may not be.
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      10-12-2012, 12:37 PM   #250
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Quote:
Originally Posted by DSC_OFF View Post
I have to say I've tried a few different things to get the perfect shifting, from small mods to forcing myself to let the clutch out slower. End of day, the one mod that I was most skeptical of (based on its price) turned out to the be the best in terms of effectiveness - the Mason Engineering clutch pedal. I bought it after reading Bill's review but its really amazing, the engagement point is so precise. Between that, ssk, Jaffster, cdv delete and RE trans mounts I have *smooth*, precise, short shifts. I actually reverted to the stock clutch stop too.

http://www.billswebspace.com/BMWZ4MM...stallation.htm

+1 on the Mason Engineering Clutch. Much more solid feelling arm & engagement. He can adjust the angle of the arm too, to lower the default resting point of the clutch, if you ask. Great for those of us with artifical knees.

Also, Royal Purple Synchromax Manual Trans fluid is HUGELY bettter than OEM fluid for smoothing out notchy shifter. Dealership recently replaced my MTF at Inspection II. Difference was noticibly harder & notchier. Replaced it myself with RP two days later; night and day improvement.

Last edited by blender; 10-12-2012 at 08:31 PM.
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      11-21-2012, 03:34 AM   #251
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From my experience, the 1st to 2nd gear grind in the Z4M is coming from the huge difference between the 1st gear ratio and 2nd gear ratio and the fact that there's play between both engine and transmission.

In order to shift correctly, some say that pushing pressure to the left on the shift knob all the way in the 1-2 shift.

I would say that is not enough, what's "key" here is to start applying pressure on the shift knob before touching the clutch pedal because i think that the synchros stop to be driven by engine power the moment you touch the clutch pedal and this will be inadequate for the 2nd gear due to the huge ratio difference, so to summarize the shift will feel like you stole away 1st gear.

The second aspect is to wait for your transmission is at full temp. The gearbox has a tendency to grind much more when cold (especially if after a session of stop and start traffic where you're fed up and just want to get on it on the open road)

I still grind it to this day because I don't pay attention to this and my engine mounts may have probably gone too soft, so I bought some replacement polys AKG just to help me do the trick for the 1-2 shift.
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      11-21-2012, 09:50 AM   #252
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Originally Posted by tikamak View Post
From my experience, the 1st to 2nd gear grind in the Z4M is coming from the huge difference between the 1st gear ratio and 2nd gear ratio and the fact that there's play between both engine and transmission.

In order to shift correctly, some say that pushing pressure to the left on the shift knob all the way in the 1-2 shift.

I would say that is not enough, what's "key" here is to start applying pressure on the shift knob before touching the clutch pedal because i think that the synchros stop to be driven by engine power the moment you touch the clutch pedal and this will be inadequate for the 2nd gear due to the huge ratio difference, so to summarize the shift will feel like you stole away 1st gear.

The second aspect is to wait for your transmission is at full temp. The gearbox has a tendency to grind much more when cold (especially if after a session of stop and start traffic where you're fed up and just want to get on it on the open road)

I still grind it to this day because I don't pay attention to this and my engine mounts may have probably gone too soft, so I bought some replacement polys AKG just to help me do the trick for the 1-2 shift.
These will more than likely drive you nuts if you drive it for any length of time and actually want to enjoy the cabin. The transmission is just poorly matched to the E85/86 chassis and was an obvious last choice when BMW decided to actually make an M version of the car.
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      11-21-2012, 03:22 PM   #253
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Actually the Z4M transmission is more advanced than the e46 M3 unit and it's just that new transmissions with high 1st gear ratio do not focus on 2nd gear synchro as much as they focus on synchros everywhere else.

Shifting in any other gear in the Z4M is as smooth as butter. Am i correct?

Look at e92 M3 transmission and porsche transmissions, same 1st to 2nd grind issues.
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      11-21-2012, 03:48 PM   #254
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^ I agree.
I also use the method of moving out of 1st gate while on the way down with clutch.
....right at the point when clutch is filly disengaged ....shift to 2nd.
Also keep revs up past 3k for that 1st shift.

If really cold then double clutch. (true dbl clutch blipping throttle in between)

This is now second nature for me & I never grind going into 2nd gear,
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      11-21-2012, 04:57 PM   #255
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At the risk of repeating several comments...
  1. I did the CDV replacement with a dummy valve (funny, my indy mechanic was fooled and said 'you should take that out'.)
  2. I put in some really high-end trans fluid during my total fluid replacement upon purchase (not going to get into a brand debate, do your research and choose the best you can, i.e. Royal Purple or the like)
  3. I replaced the bushings with Rogue products
  4. I installed the longer clutch stop (I recently posted my experiences)

All are common mods/swaps and each improved the shifting. Frankly, the clutch stop had the most dramatic effect - look at the order I did things in and draw your own conclusions.

Now, as far as technique goes, until the car warms up a bit, I short shift into second at around 3000 rpm. No shudder, no grind, smooth as goose poop.

After I see some heat on the temp gauge, I shift above 5000 and often above 6000. Again, all smooth as goose poop.

I have found that adding a little gas as I re-engage the clutch makes the sport mode (especially) a real joy. So does shifting over 6000 generally.

Yes, it sounds like the Batmobile turbine at that speed but if I wanted a quiet car I would have bought a Prius.

If I had to choose one thing it would be the clutch stop. The thing I'd drop from the list first is the bushings - but even though the improvement was subtle for street performance there was an improvement. But my list is pretty inexpensive so I did it all.

inTgr8r - After a brief but enjoyable early career driving big rigs and dump trucks (15 speed in one and 5 & 4 in the other) I nearly always double clutch... especially downshifting.

Nothing new here, I suppose. But perhaps this provides some confirmation of some really good ideas posted above.

Carry on.
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      11-21-2012, 05:55 PM   #256
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Quote:
Originally Posted by inTgr8r View Post
^ I agree.
I also use the method of moving out of 1st gate while on the way down with clutch.
....right at the point when clutch is filly disengaged ....shift to 2nd.
Also keep revs up past 3k for that 1st shift.

If really cold then double clutch. (true dbl clutch blipping throttle in between)

This is now second nature for me & I never grind going into 2nd gear,
Would you wear out the synchro prematurely using this method? I would assume moving out of 1st gate while the clutch hasn't completely disengaged would add stress to the synchro At times, I can still feel some resistance pulling out of 1st gate even when my clutch is fully at the floor.
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      11-21-2012, 09:53 PM   #257
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You develop a feel for it.
It almost pops out of first on its own.
AFAIK, Synchro wear is more related to going into gear, not coming out.
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      12-04-2012, 04:59 AM   #258
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I agree with inTgr8r about the 1st gear poping out when you start moving it before having the clutch pedal all the way down.

I even start applying pressure with my hand on the gear knob in first gear before touching the clutch pedal while shift 1st-2nd, this seems to shift like butter.

Regarding the OEM transmission fluid, what i have noticed is that you need a lot of time to have it heat up, but once heated up, it will shift like butter.

This transmission really likes to be shifted lightning fast and brutally if and only if there was very precise hand-feet coordination, everything should happen at the same time with a heated up transmission oil and you will feel like shifting in a DTM sequential dogbox.
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      12-04-2012, 05:09 AM   #259
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I was thinking about talking with ZF to provide a polished helical and straight gear sets for our transmission that would make:
1st gear more usable
6th gear 1.0 drive ratio instead of overdrive
making the gears close ratio more than it is now

I am doing the calculation to make each gear shift on redline 8K, drop RPMs to 5500 RPM in a sense that everytime you shift the car is climbing the revs similarly to a ferrari 458 and you are never away from the 6-8K RPM range where the S54 (boosted) is in its most brutal power delivery zone.

Is what i said interesting to anyone over here?

Please note that making 1st gear with a lower drive ratio and 2nd gear with a slightly higher drive ratio will bring those 2 gears closer and synchro effort drastically down which means that you might be able to shift 1st-2nd drastically faster
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      12-04-2012, 02:41 PM   #260
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Quote:
Originally Posted by tikamak View Post
Is what i said interesting to anyone over here?
I've been interested in doing that too, but from the little research I did it seemed prohibitively expensive.

The only difference is... I'd like a longer 6th. 5th gear at redline is 150+ mph with 3.91 gears. There's no need to make 6th shorter, so instead I'd like it to be longer to gain back some of the mpg from going to 3.91 or 4.10. For cruising it would be really nice to stay at low rpm at 80mph.
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      12-04-2012, 02:44 PM   #261
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I've been talking about changing the transmission gears, not the diff gears.
You will not need a diff gear change, the stock would do just fine.
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      12-04-2012, 02:49 PM   #262
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Quote:
Originally Posted by tikamak View Post
I was thinking about talking with ZF to provide a polished helical and straight gear sets for our transmission that would make:
1st gear more usable
6th gear 1.0 drive ratio instead of overdrive
making the gears close ratio more than it is now

I am doing the calculation to make each gear shift on redline 8K, drop RPMs to 5500 RPM in a sense that everytime you shift the car is climbing the revs similarly to a ferrari 458 and you are never away from the 6-8K RPM range where the S54 (boosted) is in its most brutal power delivery zone.

Is what i said interesting to anyone over here?

Please note that making 1st gear with a lower drive ratio and 2nd gear with a slightly higher drive ratio will bring those 2 gears closer and synchro effort drastically down which means that you might be able to shift 1st-2nd drastically faster
I guess, as a non drag racing-designed car, I don't really see the point of the fast 1->2 shift. Others may drive it differently though.
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      12-04-2012, 03:13 PM   #263
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I guess, as a non drag racing-designed car, I don't really see the point of the fast 1->2 shift. Others may drive it differently though.
Just need to point out that the purpose is not a fast 1st-2nd shift and the ratios will probably give you a slower 0-60 time since the ratio of 1st gear will be closer to 3.6 instead of 4.35 as well as 2nd gear not hitting the 65 mph but rather 55 mph. and 3rd gear will be closer to 2nd gear than it is now (you know how 3rd gear feels like the car gained a few pounds)

The car's purpose will not be a drag car but rather a time attack car using all 6 gears (instead of 2-3-4-5 gears) which are laid out in a way to keep your RPMs above 5500 RPM similar to this car over here:



check the gear ratios for a Lambo Murciellago for example. note that while driving one of these on the track, downshifting into 1st gear is a pretty common
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      12-04-2012, 03:25 PM   #264
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Originally Posted by tikamak View Post
Just need to point out that the purpose is not a fast 1st-2nd shift and the ratios will probably give you a slower 0-60 time since the ratio of 1st gear will be closer to 3.6 instead of 4.35 as well as 2nd gear not hitting the 65 mph but rather 55 mph. and 3rd gear will be closer to 2nd gear than it is now (you know how 3rd gear feels like the car gained a few pounds)

The car's purpose will not be a drag car but rather a time attack car using all 6 gears (instead of 2-3-4-5 gears) which are laid out in a way to keep your RPMs above 5500 RPM similar to this car over here:



check the gear ratios for a Lambo Murciellago for example. note that while driving one of these on the track, downshifting into 1st gear is a pretty common
I thought these two vehicles were using auto-manual gearboxes though. I do see what you're saying though, just seems not enough ROI for the mod.
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