[allmotorh22]

All things being equal (hp/weight RWD Steptronic) which transmission would accelerate faster?

the ZF tranny? (found in 2006 325i/330i)

or

the GM tranny? (found in all 328i's)



I know you guys know the gear ratios, could be a good debate, so lets hear it

[guerilla twang]

I vote for ZF, with no info to back it up.

[mike-y]

I think they have the same gear ratios (last I checked), shouldn't be much of a difference, if any at all.

If anything, I think the programming on the shift patterns will make a more noticeable difference in casual driving. Has anyone tried to reprogram a steptronic yet?

[josephbet01]

I can't imagine my 6AT in the 07 328i being any better. I was surprised to learn it's GM. They got it right. The 6AT in my V8 LR3 was also silky smooth. Not sure where that was sourced though.

[allmotorh22]

looks like the 325 has a higher final drive than the 330, meaning it should shift faster (all things being equal):

http://webcache.googleusercontent.co...&ct=clnk&gl=us

[Express]

GM 100% shifts faster than my ZF, but the ZF is so smooth

[Marcumac]

So I have a ZF tranny? All this time I thought that I had the GM...

[e90pilot]

No you have a GM. The 2011 has a ZF.

[mike-y]

325 and 330 both have the ZF transmission. the 325 has a shorter differential gear though.

the 328 has the GM trans, but shares the same differential ratios as the 325i. When I drove a '08 328i I noticed that the programming in DS was different than the 325i. as soon as you put the 328i in DS, it downshifts to a lower gear, where the 325i does not. DS on the 328 seemed to be more sporting, in that it held the gears in a higher rpm than the 325i, which didn't downshift until you put your foot down.

[allmotorh22]

Originally Posted by mike-y

325 and 330 both have the ZF transmission. the 325 has a shorter differential gear though.

the 328 has the GM trans, but shares the same differential ratios as the 325i. When I drove a '08 328i I noticed that the programming in DS was different than the 325i. as soon as you put the 328i in DS, it downshifts to a lower gear, where the 325i does not. DS on the 328 seemed to be more sporting, in that it held the gears in a higher rpm than the 325i, which didn't downshift until you put your foot down.

right on, so apparently the 328 has more aggressive programming and their final drive is much higher (3.73) so there is alot of potential there.


*on a side note, do 325's typically hold their 4th gear pretty long before shifting to 5th (a second longer than 3rd->4th and higher rpm), or is my tranny going?

[mike-y]

both the 325 and 328 steptronic have the 3.73 rear end. it's only the M6 that has the 3.23 diff (on both cars).

not sure about the 4th gear being held longer though. the gear is taller, so it does make sense, but I'll try to pay more attention to it tomorrow.

[Raine]

Hm, hard to say...Despite the constant bitching about the 328i GM 6AT transmission, it's honestly not that bad in Manual Mode + modified stock airbox + BMS PBX. The shifts are a bit rough when the car is cold (expected?) but overall it's okay.

I still think the 325/330 ZF transmission shift faster and smoother.

[tony176000]

2007 328 with the GM.
I've been reading various posts with people ragging on the GM tranny (although not really on this thread) and I've got to say, its really ignorant! GM may get a lot of things wrong, REALLY wrong, but they make the BEST autromatic transmissions in the world hands down. Bullet proof, and essentially the benchmark. Think about it, from industrial applications, to the all-powerful BMW, these are selected for good reason. Problems arise from programming, not hardware.
BTW, I like the one I have. Love the DS mode, and if you just jab at the throttle once you start your drive, it will pick up on that and take a much more agressive approach.
ZF may be an innovator, but mile for mile and lb-ft for lb-ft, a GM will eat a ZF any day.

[Gavin@MMW]

Originally Posted by tony176000

2007 328 with the GM.
I've been reading various posts with people ragging on the GM tranny (although not really on this thread) and I've got to say, its really ignorant! GM may get a lot of things wrong, REALLY wrong, but they make the BEST autromatic transmissions in the world hands down. Bullet proof, and essentially the benchmark. Think about it, from industrial applications, to the all-powerful BMW, these are selected for good reason. Problems arise from programming, not hardware.
BTW, I like the one I have. Love the DS mode, and if you just jab at the throttle once you start your drive, it will pick up on that and take a much more agressive approach.
ZF may be an innovator, but mile for mile and lb-ft for lb-ft, a GM will eat a ZF any day.

Whats the ZF rated at?

The GM is rated at 332tq at the flywheel.

[Raine]

Originally Posted by tony176000

2007 328 with the GM.
I've been reading various posts with people ragging on the GM tranny (although not really on this thread) and I've got to say, its really ignorant! GM may get a lot of things wrong, REALLY wrong, but they make the BEST autromatic transmissions in the world hands down. Bullet proof, and essentially the benchmark. Think about it, from industrial applications, to the all-powerful BMW, these are selected for good reason. Problems arise from programming, not hardware.
BTW, I like the one I have. Love the DS mode, and if you just jab at the throttle once you start your drive, it will pick up on that and take a much more agressive approach.
ZF may be an innovator, but mile for mile and lb-ft for lb-ft, a GM will eat a ZF any day.

I think you are right. The transmission itself isn't bad, it's the software. A tune such as AA or OE may be the solution.

[rigdowntex]

GM tranny, all I can say is remember the ones they put in pickup trucks several years back, there were 2 types of owners, pre or post tranny failure......RDT

[tony176000]

Originally Posted by Craven 328

Whats the ZF rated at?

The GM is rated at 332tq at the flywheel.

I dunno man, I shoulda had these numbers ready to roll when I posted my big "GM trannies are God" post. I have also heard very similar figures for the GM (like 305 original then 325 tq) but I have no idea on the ZF right now, apologies.
However, my fam has owned many cars and from my own experience (which is a tricky source to rely on) Ford--got to be the worst autotrans out there, mazda (don't know source! but likely ford) was fair. Acura was solid, but not great. Audi (only one in the fam) has been golden SO FAR. But the GM, the body and engines rotted off and that thing would still tow monster loads and not even complain. Had a Suburban (again, my facts are weak right now) that we put a cooler on and basically abused the shit out of it and it outlasted the rest of the car. I mean BMW, BMW! buys and installs GM work...that's a credential right there. Also, got to throw a nod to the perennial small block, who else makes a pushrod engine of that caliber.
Off topic, but, it does make me sad that GM is SO DAMN good at the tough stuff, but can't pull off a single decent interior item to save its ass. WTH is going on there....

[guerilla twang]

Originally Posted by tony176000

2007 328 with the GM.
I've been reading various posts with people ragging on the GM tranny (although not really on this thread) and I've got to say, its really ignorant! GM may get a lot of things wrong, REALLY wrong, but they make the BEST autromatic transmissions in the world hands down. Bullet proof, and essentially the benchmark. Think about it, from industrial applications, to the all-powerful BMW, these are selected for good reason. Problems arise from programming, not hardware.
BTW, I like the one I have. Love the DS mode, and if you just jab at the throttle once you start your drive, it will pick up on that and take a much more agressive approach.
ZF may be an innovator, but mile for mile and lb-ft for lb-ft, a GM will eat a ZF any day.

Lol, then why is it not in the 335i, eh?

[tony176000]

Originally Posted by guerilla twang

Lol, then why is it not in the 335i, eh?

That's a silly question. BMW was obviously going for MAX FAIL on that model, injectors, HPFP, why would they want to put a good component in it and ruin their streak?

[tony176000]

Originally Posted by guerilla twang

Lol, then why is it not in the 335i, eh?

Seriously, though, I think the turbo motor makes significantly more power than BMW says, and that tranny is rated at something like 350 lb-ft. So with even a modest boost, it would shred the tranny. Now, GM has monsters available, with some older 4-speeds able to handle like 700+ lb-ft, and the 6-speed in the big SUVs rated at huge loads too. Again, I don't know the exact numbers right now.

[guerilla twang]

Originally Posted by tony176000

Seriously, though, I think the turbo motor makes significantly more power than BMW says, and that tranny is rated at something like 350 lb-ft. So with even a modest boost, it would shred the tranny. Now, GM has monsters available, with some older 4-speeds able to handle like 700+ lb-ft, and the 6-speed in the big SUVs rated at huge loads too. Again, I don't know the exact numbers right now.

This is false, there are guys running around KC with full bolt-ons at like 12psi with stock trannys. Word on the street is they can handle around 500/500 before giving out. I believe it.

[kjlonghill]

So, I've been wondering if my GM tranny was a lemon but now I'm reading it could be the software? 2007 E91, shipped from Virginia to my middle-of nowhere