3rd & 6th gear torque limits on the 8HP45 - Elephant in the room?

zinner · 09-05-2018, 08:15 AM

sounds like you guys need to get a tune from a custom tuner. If it's really safety limits to prevent hard failure, maybe the off the self tuners want to stay away from harming the drive train. Reminds me of my CTS-V days, the auto guys would be like X transmission tune is great and a few weeks/months later would be getting their transmissions rebuilt with stronger parts. Maybe it's a matter of determining an upgrade path for the ZF8 speed that allows the tq limits to be raised.

valve float · 09-28-2018, 09:07 AM

mHD tq limit fix is out of beta...!

EstorilMSport · 09-28-2018, 09:11 AM

It looks like MHD just released a fix for the tq limiter today per their facebook. Any word from bootmod3?

MHD F-Series 1.01:
- New N55 flash option: "8AT: fix for reduced power in 3rd / 6th gear"

https://www.facebook.com/MHDtuning/p...74086306186688

badbread · 09-28-2018, 11:05 AM

For anyone wondering like I was:

My question in Whatsapp:
"... so there is no concern about "tricking" the transmission into seeing lower torque figures? The transmission can mechanically handle it ok?"

MHD's reply:
"The trans is fine till around 700. But it must "see" less than 550. Just like the 6AT we've work with for years on e-series"

afranke · 09-28-2018, 12:13 PM

Quote:

Originally Posted by valve float

mHD tq limit fix is out of beta...!

Quote:

Originally Posted by EstorilMSport

It looks like MHD just released a fix for the tq limiter today per their facebook. Any word from bootmod3?

MHD F-Series 1.01:
- New N55 flash option: "8AT: fix for reduced power in 3rd / 6th gear"

https://www.facebook.com/MHDtuning/p...74086306186688

proTUNING Freaks

XxThe_RemedyXx · 09-28-2018, 07:11 PM

Quote:

Originally Posted by afranke

Quote:

Originally Posted by valve float

mHD tq limit fix is out of beta...!

Quote:

Originally Posted by EstorilMSport

It looks like MHD just released a fix for the tq limiter today per their facebook. Any word from bootmod3?

MHD F-Series 1.01:
- New N55 flash option: "8AT: fix for reduced power in 3rd / 6th gear"

https://www.facebook.com/MHDtuning/posts/2174086306186688

proTUNING Freaks

Bueller?

harkes · 09-30-2018, 10:12 PM

FYI

Dzenan is looking for cars to test out the torque limiter fix...

EstorilMSport · 10-01-2018, 09:25 AM

Quote:

Originally Posted by harkes

FYI

Dzenan is looking for cars to test out the torque limiter fix...

I’m working with PTF on test tunes for a fix. I’m sure they’d welcome more testers, submit a ticket if you want to join.

Bimmertodd88 · 10-01-2018, 12:58 PM

Quote:

Originally Posted by EstorilMSport

Quote:

Originally Posted by harkes

FYI

Dzenan is looking for cars to test out the torque limiter fix...

I’m working with PTF on test tunes for a fix. I’m sure they’d welcome more testers, submit a ticket if you want to join.

I'm also doing it. Join and help the cause!

XxThe_RemedyXx · 10-01-2018, 01:42 PM

Quote:

Originally Posted by Bimmertodd88

Quote:

Originally Posted by EstorilMSport

Quote:

Originally Posted by harkes

FYI

Dzenan is looking for cars to test out the torque limiter fix...

I'm working with PTF on test tunes for a fix. I'm sure they'd welcome more testers, submit a ticket if you want to join.

I'm also doing it. Join and help the cause!

Dzenan asked me for some logs in different gears. I will do some pulls today and get them over to him. How are you guys submitting data? Starting 2K RPM to redline pulls are OK? Which gears?

harkes · 10-02-2018, 03:30 AM

Quote:

Originally Posted by EstorilMSport

I’m working with PTF on test tunes for a fix. I’m sure they’d welcome more testers, submit a ticket if you want to join.

Luckily I never experienced any limiters in 3rd and only in 6th at above 20psi so not really an issue for me. My car is a 2012 M135i - strange how some cars have very low limiters and others dont. Does anyone with MPPK have these limiter issues?

bradsm87 · 10-02-2018, 03:38 AM

Quote:

Originally Posted by harkes

Luckily I never experienced any limiters in 3rd and only in 6th at above 20psi so not really an issue for me. My car is a 2012 M135i - strange how some cars have very low limiters and others dont. Does anyone with MPPK have these limiter issues?

M135i and all other N55B30O0 (235kw and 240kw) variants don't have the limits. From what I could see, all N55B30M0 (225kw variants) do have the limits. Apparently there are some exceptions but I haven't seen any factory files for such exceptions.

I suspect MPPK has the limit in 6th but probably not 4th as MPPK does have slightly under-reported torque (to get under 3rd gear limit).

harkes · 10-02-2018, 10:36 AM

Quote:

Originally Posted by bradsm87

M135i and all other N55B30O0 (235kw and 240kw) variants don't have the limits. From what I could see, all N55B30M0 (225kw variants) do have the limits. Apparently there are some exceptions but I haven't seen any factory files for such exceptions.

I suspect MPPK has the limit in 6th but probably not 4th as MPPK does have slightly under-reported torque (to get under 3rd gear limit).

Interesting info. I would expect the hardware to be the same so how does that make sense?

bqik · 10-02-2018, 10:53 AM

Quote:

Originally Posted by harkes

Luckily I never experienced any limiters in 3rd and only in 6th at above 20psi so not really an issue for me. My car is a 2012 M135i - strange how some cars have very low limiters and others dont. Does anyone with MPPK have these limiter issues?

I have a 435i Xdrive with MPPK and the limiter in 3rd and 6th gear is just there.

Entering the sport display menu in the idrive makes obvious the limiters are there doing their work.

all gears show max torque 450Nm.

3rd shows less, like 420-430Nm.
6th gear shows 400Nm.

the MPPK has done a very bad effect in 6th gear.

it seems the 7th gear pulls more than 6th...

I know that all gearboxes have some torque margins but I don't understand why ZF puts these limiters and then people say it can handle 700Nm.

Just FYI I have a W211 OM648 tuned with 700Nm knowing that the transmission is officially limited to 580Nm...

regards

harkes · 10-02-2018, 11:16 AM

Quote:

Originally Posted by bqik

I have a 435i Xdrive with MPPK and the limiter in 3rd and 6th gear is just there.

Entering the sport display menu in the idrive makes obvious the limiters are there doing their work.

all gears show max torque 450Nm.

3rd shows less, like 420-430Nm.
6th gear shows 400Nm.

the MPPK has done a very bad effect in 6th gear.

it seems the 7th gear pulls more than 6th...

I know that all gearboxes have some torque margins but I don't understand why ZF puts these limiters and then people say it can handle 700Nm.

Just FYI I have a W211 OM648 tuned with 700Nm knowing that the transmission is officially limited to 580Nm...

regards

I have yet to hear about a failing ZF8HP due to excessive torque so indeed it is strange why BMW see the need for these limiters.

enemigo13 · 10-02-2018, 01:02 PM

torque converters are different for the N55B30M0 and N55B30O0 models. Transmission doesn't know and doesn't care if you have 20 or 30psi. It cares about torque numbers only and it gets them from engine ecu. Your transmission is limited to 550Nm in all gears while N55B30M0 transmissions are limited to same 550Nm in all gears except 440Nm in 3rd and 400Nm in 6th. If you're getting more than 550nm it's JB4 or whatever flash tune you use lying actual Nm to the gearbox. Problem is that with 440/400Nm limiters in these 2 gears engine ECU should lie more, which affects ride smoothness. I've tested N55B30O0 gearbox software on a few cars (e.g. from M135i) and they are running fine for ~2 years. But this will be not needed anymore as xHP will set Nm limits whatever you like, no more 550Nm limitations for N55B30O0 owners also.

Quote:

Originally Posted by harkes

Luckily I never experienced any limiters in 3rd and only in 6th at above 20psi so not really an issue for me. My car is a 2012 M135i - strange how some cars have very low limiters and others dont. Does anyone with MPPK have these limiter issues?

afranke · 10-02-2018, 01:41 PM

Got two test maps today (for the AH3), provided PTF with five logs on each map. I noticed a new graph value "stage2 agg Limiter test2" (and test1 on the other map) that seems to be a 1/0 true/false value, and it seems to have stayed at 0, meaning it didn't hit the limiter (though boost looks a bit low here): http://www.bootmod3.net/log?id=5bb3b663d10b4353a30a065c

harkes · 10-02-2018, 07:00 PM

Limiter in 6th on my M135i (N55B30O0)

http://www.bootmod3.net/log?id=5a559202d10b431206902bef

MTWO · 10-02-2018, 07:09 PM

Sounds like BM3 guys fixed the limiter issue that some N55s had.

bradsm87 · 10-02-2018, 07:26 PM

Quote:

Originally Posted by harkes

Limiter in 6th on my M135i (N55B30O0)

http://www.bootmod3.net/log?id=5a559202d10b431206902bef

M135i doesn't have the 6th gear limiter in the transmission so I'd be asking PTF about that one.

MTWO · 10-03-2018, 06:14 AM

Quote:

Originally Posted by harkes

Limiter in 6th on my M135i (N55B30O0)

http://www.bootmod3.net/log?id=5a559202d10b431206902bef

You have 17psi target in there and that’s not the limiter people were talking about

harkes · 10-03-2018, 08:54 AM

Quote:

Originally Posted by MTWO

You have 17psi target in there and that’s not the limiter people were talking about

Nope, that is the boost target... At some point the TCU is telling the DME that "hey buddy - fun is over" and then the TCU is dropping load target.

We VERY MUCH look forward to xHP to solve this for us

09-05-2018, 08:15 AM	#67
zinner Major 559 Rep 1,127 Posts Drives: `17 X5 35d/`15 335i/`18 M550IX Join Date: Oct 2014 Location: Raleigh, NC iTrader: (0)	sounds like you guys need to get a tune from a custom tuner. If it's really safety limits to prevent hard failure, maybe the off the self tuners want to stay away from harming the drive train. Reminds me of my CTS-V days, the auto guys would be like X transmission tune is great and a few weeks/months later would be getting their transmissions rebuilt with stronger parts. Maybe it's a matter of determining an upgrade path for the ZF8 speed that allows the tq limits to be raised.
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09-28-2018, 09:07 AM	#68
valve float Private First Class 163 Rep 136 Posts Drives: b6 a4 avant 6sp, e90 M3 6sp Join Date: Sep 2017 Location: BC - Canada iTrader: (0)	mHD tq limit fix is out of beta...!
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09-28-2018, 09:11 AM	#69
EstorilMSport Second Lieutenant 84 Rep 210 Posts Drives: 2014 335i M Sport Join Date: Apr 2010 Location: Tampa, FL iTrader: (0)	It looks like MHD just released a fix for the tq limiter today per their facebook. Any word from bootmod3? MHD F-Series 1.01: - New N55 flash option: "8AT: fix for reduced power in 3rd / 6th gear" https://www.facebook.com/MHDtuning/p...74086306186688 __________________ 2014 335i M Sport: bootmod3 Stg 2 E30 Custom, AA CP, CSF FMIC, GFB DV , VRSF catless DP, aFe stage 2 intake, KW Clubsport coilovers, MP LSD, aFe sway bars, F80 LCAs, monoball thrust arms, Delrin rear subframe bushings, xHP Stage 3. IG: German_car_connection Last edited by EstorilMSport; 09-28-2018 at 09:17 AM.. Reason: Broken Link
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09-28-2018, 11:05 AM	#70
badbread not good, but bad 333 Rep 361 Posts Drives: 2013 335i Join Date: Jun 2016 Location: Bay Area, CA iTrader: (3)	For anyone wondering like I was: My question in Whatsapp: "... so there is no concern about "tricking" the transmission into seeing lower torque figures? The transmission can mechanically handle it ok?" MHD's reply: "The trans is fine till around 700. But it must "see" less than 550. Just like the 6AT we've work with for years on e-series" __________________ They are spelled BRAKES not breaks!!!! Oh FFS, not another spark plug thread! BreadsBMW on Youtube
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09-30-2018, 10:12 PM	#73
harkes Colonel 1077 Rep 2,357 Posts Drives: M135i, E39 M5, NSX and AE86 Join Date: Apr 2014 Location: Xiamen, China iTrader: (0)	FYI Dzenan is looking for cars to test out the torque limiter fix... __________________ M135i 8AT PWG, MHD, Pure Stage2, WMI via Torqbyte CM5-LT, Custom tuned by PureBoost (A Dane in China)
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10-02-2018, 01:41 PM	#83
afranke Lieutenant 207 Rep 488 Posts Drives: 2013 ActiveHybrid 3 Join Date: Jan 2016 Location: Raleigh, NC iTrader: (0)	Got two test maps today (for the AH3), provided PTF with five logs on each map. I noticed a new graph value "stage2 agg Limiter test2" (and test1 on the other map) that seems to be a 1/0 true/false value, and it seems to have stayed at 0, meaning it didn't hit the limiter (though boost looks a bit low here): http://www.bootmod3.net/log?id=5bb3b663d10b4353a30a065c __________________ 2013 ActiveHybrid 3 (335ih) • N55 PWG • Meisterschaft GT catback • Wagner tuning catless DP and Stage 2 Evo Comp Intercooler • ER chargepipes • CTS intake • io2V3 O2 simulator • Pure Stage 2 turbo with high-flow inlet and DV upgrade • Fuel-It Stage 2 LPFP • JB4 ISO firmware • Fuel-It DIY PI Kit • bootmod3 •
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10-02-2018, 07:00 PM	#84
harkes Colonel 1077 Rep 2,357 Posts Drives: M135i, E39 M5, NSX and AE86 Join Date: Apr 2014 Location: Xiamen, China iTrader: (0)	Limiter in 6th on my M135i (N55B30O0) http://www.bootmod3.net/log?id=5a559202d10b431206902bef Attached Images __________________ M135i 8AT PWG, MHD, Pure Stage2, WMI via Torqbyte CM5-LT, Custom tuned by PureBoost (A Dane in China)
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10-02-2018, 07:09 PM	#85
MTWO Captain 473 Rep 931 Posts Drives: M2 Join Date: Dec 2016 Location: Innisfil iTrader: (0)	Sounds like BM3 guys fixed the limiter issue that some N55s had.
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