[baldeagleman]

Have you guys heard of any issues with transmission strength? The ZF8HP50 is only rated for 500NM of torque, but pretty much everyone with tunes is running quite a bit more than that. Is that just a conservative estimate or is there a risk of longevity? I obviously know running more power hurts longevity, but I am wondering to what degree.

[Solid67]

Originally Posted by baldeagleman

Have you guys heard of any issues with transmission strength? The ZF8HP50 is only rated for 500NM of torque, but pretty much everyone with tunes is running quite a bit more than that. Is that just a conservative estimate or is there a risk of longevity? I obviously know running more power hurts longevity, but I am wondering to what degree.

I believe those are conservative estimates, but its honestly hard to tell what the longevity will be considering the 8HP50 has only been out for a few years and only a small percentage of them are in cars with high hp/tq. Time will tell, but I have faith it will hold up.

[JD11937]

I agree, seems like manual guys are having more transmission trouble than auto right now. Obviously a manual is easier to upgrade but if you aren't turbo swapping you should be fine.

[seansurfn2]

Originally Posted by baldeagleman

Have you guys heard of any issues with transmission strength? The ZF8HP50 is only rated for 500NM of torque, but pretty much everyone with tunes is running quite a bit more than that. Is that just a conservative estimate or is there a risk of longevity? I obviously know running more power hurts longevity, but I am wondering to what degree.

i thought theres like a zf8hp70 or 90 in these cars? thats like 700 to 900.. maybe the article i read was wrong?

edit yup your right 8hp50

https://www.bimmerforums.com/forum/s...ted-with-a-m70

[Peakrunner]

Here's a good article to read: https://www.xhpflashtool.com/blog/li...engine_torque/

[baldeagleman]

Originally Posted by Peakrunner

Here's a good article to read: https://www.xhpflashtool.com/blog/li...engine_torque/

Very interesting. Would the MHD backend flash with JB4 also basically be a transmission flash? It says it removes torque limiters. Or would I also need a transmission flash in addition to an MHD backend flash?

[Peakrunner]

Originally Posted by baldeagleman

Very interesting. Would the MHD backend flash with JB4 also basically be a transmission flash? It says it removes torque limiters. Or would I also need a transmission flash in addition to an MHD backend flash?

No, I don't believe so but that's a question for your tuner. While I do think the MHD can make adjustments to the torque limit table in the ECU it does nothing to program the TCU or adjust the line pressure and shift timing etc.

[baldeagleman]

So then what is the best transmission flash?

[Solid67]

Originally Posted by baldeagleman

So then what is the best transmission flash?

Lol the link that you posted- xHP. Its the only legitimate TCU flash on the market. Even Bootmod3 came out with a transmission flash but all it does is remove the torque limiters in 3rd and 6th gear. It doesn't give you any of the other improvements or benefits that xHP will.

[greg21040]

I have the Mission Performance.

https://missiontuning.com/bmw-transm...lash-tune.html

[USA-RET]

Originally Posted by baldeagleman

Have you guys heard of any issues with transmission strength? The ZF8HP50 is only rated for 500NM of torque, but pretty much everyone with tunes is running quite a bit more than that. Is that just a conservative estimate or is there a risk of longevity? I obviously know running more power hurts longevity, but I am wondering to what degree.

Dunno, but 500 NM translates to just under 369 Lb. ft. which is the max shown for the M240i by the maker. Dynos of the stock car show numbers in excess of 400 Lbs. Ft. which would be exceeding the transmission's limit by quite a bit w/o any tunes).

I'm guessing as long as you don't constantly "flog" the car and use launch control as a normal, the transmission should be beefy enough to hold up with most of the tunes being sold. I would certainly be concerned if I was spending weekends at the local drag strip and pushing the car to its limits as my entertainment outlet.

[MassNerd]

Originally Posted by Peakrunner

Here's a good article to read: https://www.xhpflashtool.com/blog/li...engine_torque/

That article has some gaps which I'm curious to know.
#1: Why would middle of the range (4th for the 6 speed, 3rd and 6th for the 8 speed) have lower torque limits and lower line pressure? That doesn't seem to make sense? Maybe a gradual decrease in limits as you go up the gears would make more sense? I would be surprised if BMW and ZF just randomly tuned the transmission that way.

#2: What are the effects of messing with line pressure? If 1st gear has the highest line pressure when stock and the tune just brings other gears up to that level, then that's probably not a big deal reliability wise. But even for that case there must be a reasons for wanting to run lower line pressure. Is it for comfort of shifts? Is it for longevity of the transmission in some way? And does the xHP trans tune push the line pressure limits to higher than stock (1st gear)? That would be a reliability red flag if that were the case...

[Hekler]

Interesting topic. Anyone use this and have any feedback on this? Thank you

[MAILIYAT]

Originally Posted by Hekler

Interesting topic. Anyone use this and have any feedback on this? Thank you

Is that just a conservative estimate or Sarkari Result Pnr Status 192.168.1.1 is there a risk of longevity? I obviously know running more power hurts longevity, but I am wondering to what degree.

[Dreculah]

I'm sticking with a Stage 1 91 octane Bootmod tune (even though I live in the land of 93 octane). Why? Because I don't trust the 8AT to be able to handle much over stock torque. It would be awesome to make more power and get a transmission tune so the shifts are crisper, but it's just asking for trouble.

Maybe in a couple of years if ppl with Stage 2+ tunes are not grenading their 8ATs, then I'll jump in.

[YamaLink]

Originally Posted by Dreculah

I'm sticking with a Stage 1 91 octane Bootmod tune (even though I live in the land of 93 octane). Why? Because I don't trust the 8AT to be able to handle much over stock torque. It would be awesome to make more power and get a transmission tune so the shifts are crisper, but it's just asking for trouble.

Maybe in a couple of years if ppl with Stage 2+ tunes are not grenading their 8ATs, then I'll jump in.

For your driving style, would you say shifts are still crisp with the S1 91octane and stock 8AT tune?

[Solid67]

Originally Posted by Dreculah

I'm sticking with a Stage 1 91 octane Bootmod tune (even though I live in the land of 93 octane). Why? Because I don't trust the 8AT to be able to handle much over stock torque. It would be awesome to make more power and get a transmission tune so the shifts are crisper, but it's just asking for trouble.

Maybe in a couple of years if ppl with Stage 2+ tunes are not grenading their 8ATs, then I'll jump in.

Dude there are plenty of people making big hp on stock ZF8 and not grenading their transmissions. How many stories have you seen on the forums of people claiming or complaining that their ZF8 grenaded? Hell, how many transmission upgrades have you seen offered or are available for the ZF8?

The ZF8 is absolutely underrated from the factory and thats for liability purposes. Better to say your transmission can handle only a certain amount and let the aftermarket find out that it can handle more rather than claiming your transmission can handle a lot and then when it doesn't, you have a class-action lawsuit.

[Dreculah]

Originally Posted by Solid67

Dude there are plenty of people making big hp on stock ZF8 and not grenading their transmissions. How many stories have you seen on the forums of people claiming or complaining that their ZF8 grenaded? Hell, how many transmission upgrades have you seen offered or are available for the ZF8?

The ZF8 is absolutely underrated from the factory and thats for liability purposes. Better to say your transmission can handle only a certain amount and let the aftermarket find out that it can handle more rather than claiming your transmission can handle a lot and then when it doesn't, you have a class-action lawsuit.

How many of those ppl making big HP have put 50-75-100k miles on their cars yet? Just 'cause there's not many problems now, doesn't mean they won't crop up en masse over time when possible lack of durability is evidenced.

[Dreculah]

Originally Posted by YamaLink

For your driving style, would you say shifts are still crisp with the S1 91octane and stock 8AT tune?

This is the first car I've owned in 20 years with an AT, so I am a poor judge of shift crispness. They feel mushy to me, and WOT on the freeway is a crap shoot...the transmission makes worse choices than a teenager on crack, like upshifting to near the redline, where it's all noise and no power.

[Solid67]

Originally Posted by Dreculah

How many of those ppl making big HP have put 50-75-100k miles on their cars yet? Just 'cause there's not many problems now, doesn't mean they won't crop up en masse over time when possible lack of durability is evidenced.

The ZF8 has been in production since 2008. There are plenty of high power N55 cars out there that have been using this transmission with hardly if any transmission upgrades besides a tcu flash.

Also, car owners who are putting down big power aren't worried about their transmission going to 75-100k. What made me laugh about your initial comment was the fact that you think stg 2 93 is big power (it's not). Unless you are planning on running "high power", you should not be worrying about stg 2 93 grenanding your transmission or significantly reducing the life of the transmission.

[MassNerd]

Originally Posted by Dreculah

This is the first car I've owned in 20 years with an AT, so I am a poor judge of shift crispness. They feel mushy to me, and WOT on the freeway is a crap shoot...

Are you in Sport mode? That changes the shift aggressiveness. I think the shifts are very fast (and I think most people are impressed if you read/watch reviews on the ZF8). If you want even more aggressive shifts, you can get a TCU flash.

Originally Posted by Dreculah

the transmission makes worse choices than a teenager on crack, like upshifting to near the redline, where it's all noise and no power.

That's why I've never even driven the car in auto mode once its warmed up. I drive manual 99% of the time because I know what gear I want to be in. I will agree that its very annoying that when you mash the throttle and hit downshift (not upshift like you said) that is selects a gear that puts you so close to redline. It's cool that is skip shifts, but what is the point of being so close to redline? You have to almost immediately upshift.

[marcthedark]

Originally Posted by Dreculah

How many of those ppl making big HP have put 50-75-100k miles on their cars yet? Just 'cause there's not many problems now, doesn't mean they won't crop up en masse over time when possible lack of durability is evidenced.

The ZF is used worldwide and I'm sure some people running big TORQUE (aka diesel owners) in Europe did a lot of miles.