THE LARGEST BMW 2-SERIES FORUM ON THE PLANET
2Addicts
2Addicts
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read
2Addicts | BMW 2-Series forum Technical Topics N55 (M235i) Engine, Transmission, Exhaust, Tuning Transmissions and performance limits

Post Reply
 
Thread Tools Search this Thread
      05-09-2018, 03:51 PM   #1
TwistedX
Really Twisted
United_States
28
Rep
265
Posts

Drives: 2015 M235i F23 8AT
Join Date: Jan 2015
Location: Irvine, CA

iTrader: (1)

Transmissions and performance limits

So I've been read and searching to see what the limitations are for the 8A transmission, seems to be worrisome after 350lbs.
So I thought, the m2 and the m235 have similar engines I think (n55/s55), so are the bolt patterns for the M2's DCT and the M235 8A the same? Could this be a swap possibility?
__________________
2021 Jeep Gladiator Rubicon
2015 BMW M235i F23 - Sold
Appreciate 0
      05-09-2018, 09:05 PM   #2
Joe240
Major
Joe240's Avatar
United_States
2924
Rep
1,303
Posts

Drives: 2021 C8 Corvette 1LT
Join Date: Jul 2016
Location: Pensacola

iTrader: (0)

Garage List
Quote:
Originally Posted by TwistedX View Post
So I've been read and searching to see what the limitations are for the 8A transmission, seems to be worrisome after 350lbs.
So I thought, the m2 and the m235 have similar engines I think (n55/s55), so are the bolt patterns for the M2's DCT and the M235 8A the same? Could this be a swap possibility?
You’d have to move the TCU as well and getting it to integrate would probably be a pain. Honestly I don’t know where this 350lbs comes from. The b58 puts 369lbs stock (actually is more) and also plenty have tuned and modded their m2xx (including myself) that easily adds 100lbs over that factory number. No issues on my end so far and I’ve put almost 20k modded, and I drive like a race car every time.
Appreciate 0
      05-09-2018, 09:56 PM   #3
Tcmcec
Private First Class
43
Rep
103
Posts

Drives: '16 Mineral Gray M235i
Join Date: Aug 2017
Location: BC, Canada

iTrader: (0)

Quote:
Originally Posted by Joe240 View Post
Quote:
Originally Posted by TwistedX View Post
So I've been read and searching to see what the limitations are for the 8A transmission, seems to be worrisome after 350lbs.
So I thought, the m2 and the m235 have similar engines I think (n55/s55), so are the bolt patterns for the M2's DCT and the M235 8A the same? Could this be a swap possibility?
YouÂ’d have to move the TCU as well and getting it to integrate would probably be a pain. Honestly I donÂ’t know where this 350lbs comes from. The b58 puts 369lbs stock (actually is more) and also plenty have tuned and modded their m2xx (including myself) that easily adds 100lbs over that factory number. No issues on my end so far and IÂ’ve put almost 20k modded, and I drive like a race car every time.
What mods are you running?
Appreciate 0
      05-10-2018, 06:05 AM   #4
Joe240
Major
Joe240's Avatar
United_States
2924
Rep
1,303
Posts

Drives: 2021 C8 Corvette 1LT
Join Date: Jul 2016
Location: Pensacola

iTrader: (0)

Garage List
CAI, sport-cat downpipe, Remus catback, jb4 map3, and heavier 19s. Haven’t dyno’d yet but stock numbers had it at 308 awhp, forget the torque number off hand. Point is, it’s still above that 350 number people keep throwing around.
Appreciate 0
      05-10-2018, 09:47 AM   #5
Dambro61
Enlisted Member
9
Rep
38
Posts

Drives: '15 M235xi (Sold); '07 s2k
Join Date: Mar 2018
Location: Swedesboro, NJ

iTrader: (0)

Quote:
Originally Posted by TwistedX View Post
So I've been read and searching to see what the limitations are for the 8A transmission, seems to be worrisome after 350lbs.
So I thought, the m2 and the m235 have similar engines I think (n55/s55), so are the bolt patterns for the M2's DCT and the M235 8A the same? Could this be a swap possibility?
I think the better option, if strictly speaking about higher power output applications, would be to modify / upgrade the ZF 8HP to handle a higher torque output. ZF has 8HP variants capable of holding up to 900N-m (664ft-lb) and many in between.

Per wikipedia:

8HP30 300N-m (221ft-lb)
8HP45 450N-m (332ft-lb)
8HP50 500N-m (369ft-lb)
8HP55 550N-m (406ft-lb)
8HP70 700N-m (516ft-lb)
8HP75 750N-m (553ft-lb)
8HP90 900N-m (664ft-lb)

ZF does advertise that their 8HP transmission is modular, however I would imagine the higher torque variants are dimensionally different.
Appreciate 0
      05-10-2018, 10:21 AM   #6
XutvJet
Major General
5491
Rep
5,339
Posts

Drives: 2011 Cayman Base, 2016 M235
Join Date: Mar 2016
Location: Kansas City

iTrader: (-1)

A bonestock 8AT RWD M235 makes around 320 torque to the wheels on a Dynojet. That equates to 380 ft/tq at the flywheel.

To swap in a different 8AT or DCT would require a monumental amount of reverse engineering to get all the various computers to talk to one another. You'd be FAR better off just getting a 6MT M235/M240/M2 (the 6MT can handle a ton of power), or new/used M2, or used M3/M4 for the amount of money we're talking about here. BMW electronics are crazy complicated. It's not like a Subaru or Honda where many things swap over and are plug and play. BMWs are much much much more advanced, for better or worse.

I seriously wouldn't worry about the 8AT if you're running a tune and downpipe only and don't race/track the car all the time. If you plan on running a ton of power and/or race/track often, then you should consider a 6MT M235/M240 or DCT/6MT M2. Simple as that.
__________________
The forest was shrinking, but the Trees kept voting for the Axe, for the Axe was clever and convinced the Trees that because his handle was made of wood, he was one of them.
Appreciate 0
      05-10-2018, 04:55 PM   #7
TwistedX
Really Twisted
United_States
28
Rep
265
Posts

Drives: 2015 M235i F23 8AT
Join Date: Jan 2015
Location: Irvine, CA

iTrader: (1)

Personally I dont plan on going 400hp crank. I have the convertible so I know it's not #racecar. It was an idea that I thought of, didn't know if it was possible with swap and some coding/tuning since the m235 and m2 are similar.

I wonder what vehicles have the 8HP90 in them... would that be an internals swap or could the whole transmission be a direct swap?
__________________
2021 Jeep Gladiator Rubicon
2015 BMW M235i F23 - Sold
Appreciate 0
      05-10-2018, 06:45 PM   #8
Joe240
Major
Joe240's Avatar
United_States
2924
Rep
1,303
Posts

Drives: 2021 C8 Corvette 1LT
Join Date: Jul 2016
Location: Pensacola

iTrader: (0)

Garage List
Quote:
Originally Posted by TwistedX View Post
Personally I dont plan on going 400hp crank. I have the convertible so I know it's not #racecar. It was an idea that I thought of, didn't know if it was possible with swap and some coding/tuning since the m235 and m2 are similar.

I wonder what vehicles have the 8HP90 in them... would that be an internals swap or could the whole transmission be a direct swap?
I’m sure dimension wise it is different, possibly bolt pattern as well since it’s designed for higher hp, it will probably be a larger bell housing for a larger motor such as a v8 or something. I’m just speculating though. There might be some internals that are swappable, but I wouldn’t count on it for beefing the tranny in the m2xx
Appreciate 0
      05-10-2018, 09:15 PM   #9
Dambro61
Enlisted Member
9
Rep
38
Posts

Drives: '15 M235xi (Sold); '07 s2k
Join Date: Mar 2018
Location: Swedesboro, NJ

iTrader: (0)

Quote:
Originally Posted by Joe240 View Post
I’m sure dimension wise it is different, possibly bolt pattern as well since it’s designed for higher hp, it will probably be a larger bell housing for a larger motor such as a v8 or something. I’m just speculating though. There might be some internals that are swappable, but I wouldn’t count on it for beefing the tranny in the m2xx
It says the HP90 is used in the hellcat / trackhawk
Appreciate 0
      05-11-2018, 12:02 AM   #10
TwistedX
Really Twisted
United_States
28
Rep
265
Posts

Drives: 2015 M235i F23 8AT
Join Date: Jan 2015
Location: Irvine, CA

iTrader: (1)

According to Wiki(questionable resource) the 8HP50 and 8hp70 are both used in the f10, while the 8HP50 is used in the M240 also. I'm thinking that if the 8HP50 can be used in both the F2x and F10, while the 8hp70 is also used in the f10, maybe there isn't a huge size difference in the 8HP45 and the 8HP70. Maybe it's a bolt pattern adapter/difference and sensor swap, could be interesting to research for those who want high hp/torque without worrying. Considering that the 70s is rated for over 500 torque
__________________
2021 Jeep Gladiator Rubicon
2015 BMW M235i F23 - Sold
Appreciate 0
      05-11-2018, 12:18 AM   #11
TwistedX
Really Twisted
United_States
28
Rep
265
Posts

Drives: 2015 M235i F23 8AT
Join Date: Jan 2015
Location: Irvine, CA

iTrader: (1)

Just reached out to ZF to see if they can help answer any questions, waiting for response so let me know if you can think of anything to ask them
__________________
2021 Jeep Gladiator Rubicon
2015 BMW M235i F23 - Sold
Appreciate 0
      05-11-2018, 11:59 PM   #12
Dambro61
Enlisted Member
9
Rep
38
Posts

Drives: '15 M235xi (Sold); '07 s2k
Join Date: Mar 2018
Location: Swedesboro, NJ

iTrader: (0)

Quote:
Originally Posted by TwistedX View Post
Just reached out to ZF to see if they can help answer any questions, waiting for response so let me know if you can think of anything to ask them
Awesome, interested to see if you get a response. If it's a dead end, I might be able to get in touch with someone from engineering. My company supplies parts to ZF. I work as a manufacturing engineer so I have little to no contact with our customers, but one of our applications engineers is a car guy, he might be willing to help get me a contact...
Appreciate 0
      05-12-2018, 12:45 AM   #13
TwistedX
Really Twisted
United_States
28
Rep
265
Posts

Drives: 2015 M235i F23 8AT
Join Date: Jan 2015
Location: Irvine, CA

iTrader: (1)

Quote:
Originally Posted by Dambro61 View Post
Awesome, interested to see if you get a response. If it's a dead end, I might be able to get in touch with someone from engineering. My company supplies parts to ZF. I work as a manufacturing engineer so I have little to no contact with our customers, but one of our applications engineers is a car guy, he might be willing to help get me a contact...
I flat out asked them about the bolt patterns, sensors and locations and size. If all those are similar or feasible with an adapter then it's a matter of TCU coding I would think.
__________________
2021 Jeep Gladiator Rubicon
2015 BMW M235i F23 - Sold
Appreciate 0
      05-12-2018, 08:25 AM   #14
frenchfry675
Private First Class
United_States
44
Rep
151
Posts

Drives: M235i xdrive
Join Date: Feb 2012
Location: reading pa

iTrader: (0)

Quote:
Originally Posted by TwistedX View Post
Personally I dont plan on going 400hp crank. I have the convertible so I know it's not #racecar. It was an idea that I thought of, didn't know if it was possible with swap and some coding/tuning since the m235 and m2 are similar.

I wonder what vehicles have the 8HP90 in them... would that be an internals swap or could the whole transmission be a direct swap?
The m2 dct is $17,000 new not sure what you could get a used one for but I'm sure it's not worth the swap. You'd be better off just trading in your car on an m2 imo.
Appreciate 0
      05-12-2018, 11:30 AM   #15
TwistedX
Really Twisted
United_States
28
Rep
265
Posts

Drives: 2015 M235i F23 8AT
Join Date: Jan 2015
Location: Irvine, CA

iTrader: (1)

Quote:
Originally Posted by frenchfry675 View Post
The m2 dct is $17,000 new not sure what you could get a used one for but I'm sure it's not worth the swap. You'd be better off just trading in your car on an m2 imo.
We've established that the DCT isn't feasible, now were trying to see if the higher performing 8HP transmissions will work
__________________
2021 Jeep Gladiator Rubicon
2015 BMW M235i F23 - Sold
Appreciate 0
      05-12-2018, 11:43 AM   #16
frenchfry675
Private First Class
United_States
44
Rep
151
Posts

Drives: M235i xdrive
Join Date: Feb 2012
Location: reading pa

iTrader: (0)

Quote:
Originally Posted by TwistedX View Post
We've established that the DCT isn't feasible, now were trying to see if the higher performing 8HP transmissions will work
Sorry I have a habitat of not reading all the posts haha. I’m seeking help for it.
Appreciate 0
      08-25-2020, 12:44 PM   #17
2Slow2Win
New Member
0
Rep
26
Posts

Drives: 14 m235i
Join Date: May 2020
Location: florida

iTrader: (0)

Any updates on this?!
Appreciate 0
      08-25-2020, 05:22 PM   #18
XutvJet
Major General
5491
Rep
5,339
Posts

Drives: 2011 Cayman Base, 2016 M235
Join Date: Mar 2016
Location: Kansas City

iTrader: (-1)

Quote:
Originally Posted by 2Slow2Win View Post
Any updates on this?!
The 8AT in the RWD is fine up to Stage 2 power/torque and likely a bit more, assuming you're not beating on it every moment.

The AWD cars can suffer from transfer case issues, but that's not really an issue with the 8AT.

You're not going to be able to swap in a DCT unless you've got a huge amount of cash to burn. You'd be far better off getting a used M2 if you want a DCT. I'd also argue that the DCT likely can't hold as much torque as the ZF 8AT used in the M235.
__________________
The forest was shrinking, but the Trees kept voting for the Axe, for the Axe was clever and convinced the Trees that because his handle was made of wood, he was one of them.
Appreciate 0
      09-07-2020, 09:56 PM   #19
2Slow2Win
New Member
0
Rep
26
Posts

Drives: 14 m235i
Join Date: May 2020
Location: florida

iTrader: (0)

So... no updates.

No clutch packs etc?
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 03:36 AM.




2addicts
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST