N54 w/ZF8 transmission...potential new option for auto guys

dyezak

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So I had a nice conversation with the owner of Brintech Customs https://www.brintechcustoms.com.au/ this weekend. He has successfully done the N54/M3/DCT conversion that I have been trying to figure out. He also managed to get it fully operational with alternate final drive ratios (he's using a 3.85 instead of the stock 2.56/N54 or 3.15/M3).

He pointed out what he did differently and I'll be applying his lessons learned to my build. But afterwords he said that he was ready to tackle the next big thing.

ZF 8HP behind an N54. He has a method that sounds crazy, but seems to work allowing him to tackle these retrofits. The ZF 8HP is widely used and besides being an ultra fast shifting 8sp auto, it also is generally accepted that it will hold 1000tq. https://en.wikipedia.org/wiki/ZF_8HP_transmission

He said he has 3 transmissions with all associated control modules and he's just looking for that first customer. Someone who can be without their car for a month while he does the conversion and works out the bugs.

It is an interesting idea if anyone in Australia is interested.
 

fmorelli

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I have the ZF 8HP in the F10 N57 535d ... I was super hesitant to buy a car with the automatic. Every car I've owned, except a Suburban for towing, has been manual. The ZF 8HP is absolutely fantastic. Shifts are blindingly fast, and in Sport mode very aggressive.

Filippo
 
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island road

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This would be awesome to see done. Does the bell housing match up with the bolt holes though or will an adapter plate be needed?
 
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dyezak

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This would be awesome to see done. Does the bell housing match up with the bolt holes though or will an adapter plate be needed?

I didn't ask that q as my interest lies in the DCT.

But the ZF 8HP has an N55 bellhousing....so wouldn't that bolt up to the N54? I do believe it will ;)
 
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doublespaces

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Oh WOW... The 8HP is a beast. The question I have, is how much and which modules exactly and how factory will it seem? Not really excited to have a bunch of modules dangling around and what other conflicts would this have on some of the custom retrofits I've done? Gotta get that guy in here :)
 
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doublespaces

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Also, you said alternate final drives...Meaning, the GTS flash with the 2.56 rear end will be doable? Or an M3 rear end with some custom 2.56 gears(hypothetical)?
 

doublespaces

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According to him yes...no sweat on either of those.

Interesting. So long as the flash understands the ratio change then I'm all ears. This makes the M3 rear end an option for me again, damn.

But if the 8HP swap is legit and feasible, then none of this really even matters.
 

doublespaces

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It looks like the F15 X5 came with the 8HP75 and used an N55 engine but it probably doesn't have the trans case we need.
There may be 8HP70's that come in the N55 with a non-xdrive case like the F10 535i, but I have a feeling the 70 only appears in diesel, V8 or xDrive vehicles where the trans case wouldn't fit.

Did he say which 8HP he was swapping exactly? The one that is most common in BMWs appears to be the 8HP45 and 8HP50(Second gen 45). For the 8HP50, at first glance that looks to be only for the B engines but perhaps an N55 powered M135i comes with an 8HP50(45Z or 45TU). One of these two transmission is the most likely to be swapped, but if we can get the second gen 8HP into the car, that might be pretty cool since a lot of refinements usually come with those updates.
https://www.zf.com/corporate/en_de/magazine/magazin_artikel_viewpage_22067944.html

EDIT: After reading that, it seems the second gen updates were primarily efficiency related, did not read anything about shift speeds or any monumental power handling increases.
 

Christian87n

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So after talking to him, does this mean we’re soon going to have the DCT thread up and running again with the solutions to the issues y’all had? I’d love to tackle that project and while I personally don’t have a need for the launch control or a different ratio, it’d be nice to have the issues ironed out.
 

dyezak

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So after talking to him, does this mean we’re soon going to have the DCT thread up and running again with the solutions to the issues y’all had? I’d love to tackle that project and while I personally don’t have a need for the launch control or a different ratio, it’d be nice to have the issues ironed out.

That’s the desire. I have all the suggested parts inbound.
 
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veer90

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ZF 8HP is awesome. Stupid fast shifts and none of the mushy torque converter feel.

The 340xi I drove felt really weird in a good way, slams through gears like a manual but I wasn't shifting it lol
 
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Waisteg8t

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I was thinking DCT swap when I eventually blow up my AT, but this has me very curious. I’ve heard nothing but great things about this trans.