[bimmer456]

According to their website, the maximum torque for the 8 speed ZF transmission is 730 lbs ft. What's the most torque that the F30 non M3 can be modified to? Since the B58 is closed deck and can handle more boost. Is there anyone with a B58 that produces this power level or maybe even 1000 HP like the Toyota Supra 2JZ is known to produce in the wild? I was surprised to learn the ZF tranny could handle this power level, most likely you'd have to replace the rear diff as well.

[bri1042]

The B58-equipped F30's have the second generation ZF 8HP50. Max torque is 500 nm of torque...or about 368 ft-lbs. The 8HP90 can take 737 ft lbs of torque from a diesel application.

[bimmer456]

Originally Posted by bri1042

The B58-equipped F30's have the second generation ZF 8HP50. Max torque is 500 nm of torque...or about 368 ft-lbs. The 8HP90 can take 737 ft lbs of torque from a diesel application.

That's close to the figure with MPPSK. It probably could take a bit more as they factor in some margin for safety reasons. I think with the Dinan tune it is producing over 400 lb ft. Does the 335d have the same transmission or the diesel version? Perhaps a tranny swap for the diesel version could be done if you're going to tune the car to beyond 400 lb ft.

[CirrusSR22]

The Dodge Demon has the ZF auto and that might have somewhere around 800 ft-lbs. Also a trans brake... I'm sure they've done plenty of work to modify and strengthen it.

[bri1042]

The Chrysler variant isn't the stock ZF. They may have altered it significantly...or, knowing Chrysler, they haven't altered it enough and all those goofy Demons will have trouble down the line.

[CruzM3]

Originally Posted by bri1042

The B58-equipped F30's have the second generation ZF 8HP50. Max torque is 500 nm of torque...or about 368 ft-lbs. The 8HP90 can take 737 ft lbs of torque from a diesel application.

Yep this is the max of the trans. I wouldn't try to push it too much more than that as then your eating into longevity and realiability. I doubt anyone is making more than 420hp/390tq even if they are using meth as no one has been able to get past the fuel limit set in the DME by BMW.

[bimmer456]

Originally Posted by Cruz28/40

Yep this is the max of the trans. I wouldn't try to push it too much more than that as then your eating into longevity and realiability. I doubt anyone is making more than 420hp/390tq even if they are using meth as no one has been able to get past the fuel limit set in the DME by BMW.

You would have to upgrade the fuel injectors and ECU like what's commonly done with the 2jz

[teaston]

Originally Posted by bri1042

The B58-equipped F30's have the second generation ZF 8HP50. Max torque is 500 nm of torque...or about 368 ft-lbs. The 8HP90 can take 737 ft lbs of torque from a diesel application.

I have the 8HP90 and probably running close to 700nm (not ft lbs as you've written).

[STR8-6IX]

Originally Posted by bimmer456

According to their website, the maximum torque for the 8 speed ZF transmission is 730 lbs ft. What's the most torque that the F30 non M3 can be modified to? Since the B58 is closed deck and can handle more boost. Is there anyone with a B58 that produces this power level or maybe even 1000 HP like the Toyota Supra 2JZ is known to produce in the wild? I was surprised to learn the ZF tranny could handle this power level, most likely you'd have to replace the rear diff as well.

yea the gasoline versions cant handle more then 400 ft/lb and it would also be a good idea to remap your transmission.

a new driveshaft and diff (LSD) would be a good idea.

all in all, it would be a nice build but just get a manual if you want a build with real power and less issues

[BMWILUVU]

Originally Posted by teaston

I have the 8HP90 and probably running close to 700nm (not ft lbs as you've written).

An alpina has an 8HP70 a 7 has 8HP75 and so how do you have an 8HP90?

[teaston]

Originally Posted by BMWILUVU

An alpina has an 8HP70 a 7 has 8HP75 and so how do you have an 8HP90?

Oh yea HP70, don't know why he put HP90!?

[bimmer456]

Originally Posted by STR8-6IX

yea the gasoline versions cant handle more then 400 ft/lb and it would also be a good idea to remap your transmission.

a new driveshaft and diff (LSD) would be a good idea.

all in all, it would be a nice build but just get a manual if you want a build with real power and less issues

Maybe a manual Getrag tanny? Does ZF make the manual also? I think someone should build a modified F30 with over 1000 horsepower that can take on a Lamborghini Aventador like the late 90s and early 2000's Lexus SC and IS or Honda Civic of same vintage were able to back in the day.

[harkes]

No tranny swaps needed. The ZF8HP45 is proven reliable at 700nm. The torque converter will allegedly fail before the transmission.

[BMWILUVU]

Originally Posted by harkes

No tranny swaps needed. The ZF8HP45 is proven reliable at 700nm. The torque converter will allegedly fail before the transmission.

I doubt this very much

[harkes]

Originally Posted by BMWILUVU

I doubt this very much

Suit yourself. We are several people running right around 700nm through that box. The highest I have heard about is 775nm (for a limited time though) - no issues.

This is my daily map

[Polo08816]

Originally Posted by harkes

No tranny swaps needed. The ZF8HP45 is proven reliable at 700nm. The torque converter will allegedly fail before the transmission.

Originally Posted by BMWILUVU

I doubt this very much

Originally Posted by harkes

Suit yourself. We are several people running right around 700nm through that box. The highest I have heard about is 775nm (for a limited time though) - no issues.

This is my daily map

harkes , that's a flawed understanding of how automatic transmissions work and how exactly they are rated.

Just because a transmission hasn't suffered a catastrophic failure at a measure of torque doesn't mean it's "proven reliable".

There's another major factor that most people are overlooking: heat capacity of the automatic transmission.

Heat capacity is the ability of the transmission to tolerate heat and exchange heat over a period of time. This is the reason it would appear as if the manufacturer and OEM torque rating for the ZF 8HP45/50 series is very conservative. The heat properties for every transmission are different. This is part of the reason why the the ZF 8HP45 and the 8HP50, while very similar, won't use the same heat exchanger.

Now if you have significant powertrain modifications and only go WOT for 10-20 seconds, chance are you won't exceed the heat capacity of the transmission. However, I can almost guarantee you that if your use case is bringing the car out to HPDE events and driving it at 8/10ths or greater for extended periods of time 20+ min at modified torque levels, your transmission will be proven to be unreliable relatively quickly.

[lens]

Originally Posted by Polo08816

harkes , that's a flawed understanding of how automatic transmissions work and how exactly they are rated.

Just because a transmission hasn't suffered a catastrophic failure at a measure of torque doesn't mean it's "proven reliable".

There's another major factor that most people are overlooking: heat capacity of the automatic transmission.

Heat capacity is the ability of the transmission to tolerate heat and exchange heat over a period of time. This is the reason it would appear as if the manufacturer and OEM torque rating for the ZF 8HP45/50 series is very conservative. The heat properties for every transmission are different. This is part of the reason why the the ZF 8HP45 and the 8HP50, while very similar, won't use the same heat exchanger.

Now if you have significant powertrain modifications and only go WOT for 10-20 seconds, chance are you won't exceed the heat capacity of the transmission. However, I can almost guarantee you that if your use case is bringing the car out to HPDE events and driving it at 8/10ths or greater for extended periods of time 20+ min at modified torque levels, your transmission will be proven to be unreliable relatively quickly.

I would guess with PS2 wouldn't go circuit racing, but rather stick to straight line racing.

IMO I wouldn't trust the ZF8 to handle PS2 power at extended periods of time at the track. You can probably get away with PS1 at the most.

[Daftasabrush]

Originally Posted by teaston

Oh yea HP70, don't know why he put HP90!?

Because he's right

Although not fitted to F30s, the 8HP90 does have a diesel torque limit of 1000NM (which is 737 lb ft).

According to wikipedia, it's fitted to Rolls-Royce Ghost, Rolls-Royce Wraith (2013), Bentley Mulsanne, Dodge Challenger SRT Hellcat, Dodge Charger SRT Hellcat, Bentley Bentayga, Audi RS 6, Audi SQ7

[Polo08816]

Originally Posted by chaungo

I would guess with PS2 wouldn't go circuit racing, but rather stick to straight line racing.

IMO I wouldn't trust the ZF8 to handle PS2 power at extended periods of time at the track. You can probably get away with PS1 at the most.

Anything more than the MPPK for a lot of track exposure is asking to be a guinea pig. Price of entry (or...errr, replacement) is about ~ $6800 for the transmission not including labor.

https://getbmwparts.com/parts/index....&siteid=214672

You blow up one of these, and you should have just bought an M3 from the get go.

[insanecoder]

Our 8HP50 I believe has a clutchpad upgrade to make the 500Nm.. the 8HP45 is 450Nm.
Yea hes riding a timebomb.. to overstress a tranny that much (691 vs 450) will definitely cause tranny oil temps to go thru the roof when over.. which means sludge & clutchpad wear if not now then over time.. tick tock sure its ok now.. what about tomorrow.. next week when you are driving in the Gobi desert?
Slippage and seizure are coming to a theatre near you..

[harkes]

Originally Posted by Polo08816

harkes , that's a flawed understanding of how automatic transmissions work and how exactly they are rated.

Just because a transmission hasn't suffered a catastrophic failure at a measure of torque doesn't mean it's "proven reliable".

There's another major factor that most people are overlooking: heat capacity of the automatic transmission.

Heat capacity is the ability of the transmission to tolerate heat and exchange heat over a period of time. This is the reason it would appear as if the manufacturer and OEM torque rating for the ZF 8HP45/50 series is very conservative. The heat properties for every transmission are different. This is part of the reason why the the ZF 8HP45 and the 8HP50, while very similar, won't use the same heat exchanger.

Now if you have significant powertrain modifications and only go WOT for 10-20 seconds, chance are you won't exceed the heat capacity of the transmission. However, I can almost guarantee you that if your use case is bringing the car out to HPDE events and driving it at 8/10ths or greater for extended periods of time 20+ min at modified torque levels, your transmission will be proven to be unreliable relatively quickly.

We fully agree on what you wrote.

So let me rephrase: The ZF8HP45 has YET to fail in street driven cars with up to 775nm - good enough?

[harkes]

Originally Posted by insanecoder

Our 8HP50 I believe has a clutchpad upgrade to make the 500Nm.. the 8HP45 is 450Nm.
Yea hes riding a timebomb.. to overstress a tranny that much (691 vs 450) will definitely cause tranny oil temps to go thru the roof when over.. which means sludge & clutchpad wear if not now then over time.. tick tock sure its ok now.. what about tomorrow.. next week when you are driving in the Gobi desert?
Slippage and seizure are coming to a theatre near you..

If you dont want to take any risks - then dont tune your car As Polo is writing, the only application that has been throughly tested (by BMW) is the MPPK. I promise to let you know when my gearbox goes KABOOOM so you have a chance to give the "I told you so" speach