[M-terkait]

manual shifts are more aggressive & faster than DS shifts unless you haven't noticed that

[eyim1988]

Originally Posted by kyleb350

Went back and looked it up. The ZF 6 speed Steptronic (GA6HP19Z) transmission is rated at 400 nm. Very odd, since that is only 295 ft lbs. I think I'm noticing a pattern of these transmissions being underrated (for the most part). Either way, numbers aside, the F30 transmissions should be able to take a little more than the E90 ones.

the limits of the zf 6 speed is about 500 lb/ft. Thats the number people are experiencing slips and whatnot. I'm guessing the 8 speed will be similar.

[435iaffair]

Any updates from the Op?

[Eric SS]

Any update?
Also, these trannies are way underrated as ZF normally does. You think BMW would offer a factory tune that puts out more torque than the tranny is rated for if they were worried?

[Presario]

Originally Posted by Eric SS

Any update?
Also, these trannies are way underrated as ZF normally does. You think BMW would offer a factory tune that puts out more torque than the tranny is rated for if they were worried?

The PPK doesn't put out more torque than the tranny can handle. It's right underneath it.

[Eric SS]

Originally Posted by Presario

The PPK doesn't put out more torque than the tranny can handle. It's right underneath it.

F30 has the 8HP45 which is rated at 450nm which is 331.9 ft. lbs.

MPPK is (under)rated at 332 ft. lbs. Sorry I was off by .1 ft. Lbs.

I still stand by my statement that ZF has always under rated their trannies. We used to put a shit load of torque through the old ZF unit in the C4 Corvette

[2blu]

Originally Posted by Eric SS

F30 has the 8HP45 which is rated at 450nm which is 331.9 ft. lbs.

MPPK is (under)rated at 332 ft. lbs. Sorry I was off by .1 ft. Lbs.

I still stand by my statement that ZF has always under rated their trannies. We used to put a shit load of torque through the old ZF unit in the C4 Corvette

Do you have specific numbers of what it was rated at vs what you guys would put down ?

[Jay562F30]

Nothing yet guys terry has me running on Map 2 at the moment

[Eric SS]

Originally Posted by 2blu

Do you have specific numbers of what it was rated at vs what you guys would put down ?

It's been a while but I want to say the early ones were rated at 450 ft. Lbs. and the later ones with the different gears were rated around 525 ft. lbs.

These were manual trannies but we would regularly put 500-650 ft lbs through them. As long as you didn't power shift to often you would be fine.

Th point is, ZF (like another German company I can think of ) under rate their products

[Presario]

Originally Posted by Eric SS

F30 has the 8HP45 which is rated at 450nm which is 331.9 ft. lbs.

MPPK is (under)rated at 332 ft. lbs. Sorry I was off by .1 ft. Lbs.

I still stand by my statement that ZF has always under rated their trannies. We used to put a shit load of torque through the old ZF unit in the C4 Corvette

Why are you converting to ft lbs? No need. BMW claims 450nm for their PPK. Obviously the 8HP45 is underrated by a manufacture specified margin because they don't want their components running at it's absolute max capacity due to higher failure rate and they also need to factor in user error and safety precautions. Thus BMW takes it right up to the point where it is safe within 8HP45 operating guidelines to ensure consistent performance.

So when you say ZF underrated their trannies, you are citing an obvious fact. Now putting shit load of torque through a tranny without properly factoring in its limitation is just plain amateur.

You must upgrade your transmission along with your other engine mods so that you ensure proper, consistent, and safe operation for the new power output. So getting back on topic, if you are running more torque than what the ZF is rated at, you may very well be experiencing inconsistent performance. To what degree? That can never definitively be answered.

[M-terkait]

well look at this..

am sure thats beyond 450nm

it was a hot day tho, only thing was PPK nothing else.

[chetman7]

Originally Posted by M-terkait

well look at this..

am sure thats beyond 450nm

it was a hot day tho, only thing was PPK nothing else.

....it shows peak torque of 314....which is less than 450nm

Am I missing something?

[2blu]

Originally Posted by chetman7

....it shows peak torque of 314....which is less than 450nm

Am I missing something?

The 314 peak torque must be at the wheel. Add the 15% or so drivetrain loss and you're well over the safe "limit".

Stock N55s dyno at around 300 ft-lbs at the wheels, if you factor in the drivetrain loss once again you should be at or even above the factory tolerance of the transmission.

Also, the dinan tune that was is installed at BMW dealerships does not void your warranty and has over 400 ft-lbs of torque...

[chetman7]

Originally Posted by 2blu

The 314 peak torque must be at the wheel. Add the 15% or so drivetrain loss and you're well over the safe "limit".

Stock N55s dyno at around 300 ft-lbs at the wheels, if you factor in the drivetrain loss once again you should be at or even above the factory tolerance of the transmission.

Also, the dinan tune that was is installed at BMW dealerships does not void your warranty and has over 400 ft-lbs of torque...

Gotcha..duhhh. completely forgot to factor that in

[Presario]

I'm just citing what is stated by ZF and by BMW. If you're putting down more torque than what is quoted by ZF, you should probably change out your fluid more often and expect the transmission's life to possibly be shortened.

[btbossman]

Originally Posted by Presario

I'm just citing what is stated by ZF and by BMW. If you're putting down more torque than what is quoted by ZF, you should probably change out your fluid more often and expect the transmission's life to possibly be shortened.

And thats precisely why I lease cars.

[kaashia]

I just posted this in another thread...

Originally Posted by kaashia

While I agree with this, what I wonder is if some of the gasoline engines have the same tranny as the diesel.

http://www.zf.com/media/media/produc..._DataSheet.pdf

If you look at the torque converter for the diesel model
NW 240 DAT.

The gasoline model has the following torque converters -
NW 235 TTD/ZDW/DAT
NW240 DAT

So my guess would be that at least one of those '235 models is rated at 450 Nm.

The '240 model is 500 nM

According to the 8HP55A tranny, the ZDW and TTD models are rated at 650 Nm

http://www.zf.com/media/media/produc..._DataSheet.pdf

Having worked on production systems before, often times manufacturers will use common parts between products to reduce overall costs. Also, given lead times for various parts, manufacturers will have "back up parts" when the typical part is out of stock or back ordered.

In the case 8HP45 - since one of the parts listed can only handle 450 nM, ZF cannot rate the tranny for more than that, even if the other parts can handle much more torque.

Obviously I am making certain assumptions and the above is all theory, but it would explain why people are able to put down way more than 450 Nm without transmission problems. But unless someone can figure out which particular torque converter is installed in their tranny, you wouldn't know if you have the NW 235 DAT.

Just my two cents.

[Eric SS]

Originally Posted by kaashia

I just posted this in another thread...

The only problem with that is that the 8HP55 is a different size on the outside and is heavier than the 8HP45. I would think you would have to change other items such as the driveshaft (but I could be wrong)

EDIT: NM, I think I was thinking of the 8HP70

That begs another question on some data that I found on http://www.google.com/url?sa=t&rct=j...58187178,d.b2I

Hopefully that link works. It's a Chrysler bulletin. It says the 8HP45 has "Engine torque capacity" of 450nm but "Input torque capacity" of 550nm. Does that mean the torque converter is capable of 450nm but the tranny itself is capable of 550nm? At least at Chrysler anyway.

[kaashia]

Originally Posted by Eric SS

The only problem with that is that the 8HP55 is a different size on the outside and is heavier than the 8HP45. I would think you would have to change other items such as the driveshaft (but I could be wrong)

EDIT: NM, I think I was thinking of the 8HP70

That begs another question on some data that I found on http://www.google.com/url?sa=t&rct=j...58187178,d.b2I

Hopefully that link works. It's a Chrysler bulletin. It says the 8HP45 has "Engine torque capacity" of 450nm but "Input torque capacity" of 550nm. Does that mean the torque converter is capable of 450nm but the tranny itself is capable of 550nm? At least at Chrysler anyway.

Good find! I think that your interpretation would be true and would only corroborate my theory. By flipping out the torque converter with some of the models I've mentioned above, the tranny as a whole should handle much more than 450 Nm.

Also, from a logical perspective, it makes no sense for BMW to design the MPPK to output 450 Nm if that is the upper limit of the transmission. Doing so would risk transmission failures on a massive scale (i.e. BMW loses money).

I think its a combo of ZF underrating their transmissions and also I think BMW would like for us to believe that the transmission limit is 450 Nm in order to deter people from using 3rd party tunes (i.e. more money for BMW if MPPK is the only tune people think is safe).

Now that being said, I still plan on being conservative in my mods, but will have some confidence in knowing that the transmission isn't in jeopardy... The chargepipe is a different story...

[bosz]

cant wait for the snow to clear up, I miss my Jb stage 1 <3

[1azycat]

Hi all, my map 2 DP 335i has drivetrain errors and the transmission gets stuck at a single gear if I do full throttle from 2k rpm onwards. Its as if I am running with the torque converter only, without lock up. This happens about 5% of the time when I pull from low rpms at full load. I would then have to stop the car and restart for it to work normally. So now I will wait till im above 3.5k rpm before pushing full throttle. Sometimes I can feel the transmission slippage as well. I think we are at the limits for the 8sp auto...?

[M-terkait]

I don't think so, people are running map7 and daily driving it.
maybe an bad F30 produced for you