ZF 6HP26 to RB30 block

[ELVIS]

Hello all.  I am soon starting an RB conversion into my 280Z that is on its way from the USA.  Has anyone seen a ZF 6HP26 (auto trans that are installed in a FG FALCOON) installed behind an RB block?  I am planning on using an RB30 block with a RB26 head (I once saw some new RB26 heads in the USA - but not sure if they are still available).  Thanks.

[joshuaho96]

10 hours ago, ELVIS said:

Hello all.  I am soon starting an RB conversion into my 280Z that is on its way from the USA.  Has anyone seen a ZF 6HP26 (auto trans that are installed in a FG FALCOON) installed behind an RB block?  I am planning on using an RB30 block with a RB26 head (I once saw some new RB26 heads in the USA - but not sure if they are still available).  Thanks.

There are a bunch of ZF8HP swap kits out there for the RB26. A ZF6 is mostly the same thing mechanically as far as I can tell: https://www.e90post.com/forums/showthread.php?t=1569774

[ELVIS]

Hello joshuaho96, I did come across the GURU info, but I only found that they do kits for the ZF 8 to a BMW engine.  I prefer to stay with the ZF 6 rather than the 8 speed ZF - the 6 speed is plentiful here from behind a BARRA.  HA - if masking tape and rope was strong enough to hold the ZF to the RB - ALL my problems would be gone - HA.  Mechanically - possibly there are similarities between the ZF 6 and ZF 8 - but the bolt up bit is the crucial bit.  More research is required by me.  I did note that possibly I can start with a RB25 twin cam head and get it to work with the RB30 block - now I just need to find a suitable head to start with.  Thanks.

[LiamsSXYR34]

any further information on this? also interested in putting a zf6 in behind a rb30!

[GTSBoy]

5 minutes ago, LiamsSXYR34 said:

any further information on this? also interested in putting a zf6 in behind a rb30!

You'd be insane, when a brand new 8HP is ~$4k, and all the work to put a 6 in would cost the same as an 8 and the 8 is a completely established swap. If you think that getting a cheap Falcon box is going to make it a cost effective exercise, then you're not accounting for the extra $10-15k that the task will consume.

[joshuaho96]

Most people I know in the BMW world are swapping 6HPs for 8HPs. The 6HP has a big issue with one of the clutch drum bushings wearing out shockingly early which leads to them going into limp mode going into 5th/6th gear as the oil pressure loss from the worn bushing causes clutch slip. Even with the adaptations in shifting the TCU can't bump line pressure enough to keep the clutches from slipping and burning. I've personally looked at a 335d with 6HP28 with one owner and ~90k miles on it and the transmission adaptations were way out of spec and even though it nominally drove ok I'm confident it would have needed a full rebuild sooner than later.

Other than that they're fine, but the 8HP doesn't really have weird issues like this to my knowledge and they're in everything these days so pulling them out of crashed cars isn't too hard.

[ELVIS]

On 23/09/2025 at 9:54 AM, GTSBoy said:

You'd be insane, when a brand new 8HP is ~$4k, and all the work to put a 6 in would cost the same as an 8 and the 8 is a completely established swap. If you think that getting a cheap Falcon box is going to make it a cost effective exercise, then you're not accounting for the extra $10-15k that the task will consume.

Nobody said anything about getting a "...cheap Falcon box..."- it was JUST a question about a specific transmission.  And YOU may have a problem with not enough $ - HA - I do NOT - so please keep your comments like you are some financial guru to yourself.  BUT - much appreciated re the cost of a new 8HP and I twill probably be the way I go.  Thanks.  ELVIS.

[ELVIS]

18 minutes ago, joshuaho96 said:

Most people I know in the BMW world are swapping 6HPs for 8HPs. The 6HP has a big issue with one of the clutch drum bushings wearing out shockingly early which leads to them going into limp mode going into 5th/6th gear as the oil pressure loss from the worn bushing causes clutch slip. Even with the adaptations in shifting the TCU can't bump line pressure enough to keep the clutches from slipping and burning. I've personally looked at a 335d with 6HP28 with one owner and ~90k miles on it and the transmission adaptations were way out of spec and even though it nominally drove ok I'm confident it would have needed a full rebuild sooner than later.

Other than that they're fine, but the 8HP doesn't really have weird issues like this to my knowledge and they're in everything these days so pulling them out of crashed cars isn't too hard.

Thanks Joshuaho96, yes - as someone else also suggested, the 8HP seems the 'smart choice' - HA - and ZERO to do with cost, but I am sure 8 speeds will be better than 6 speeds - HA - maybe.  I will purchase a new 8HP,  Thanks.  ELVIS.

[ELVIS]

On 23/09/2025 at 9:47 AM, LiamsSXYR34 said:

any further information on this? also interested in putting a zf6 in behind a rb30!

Hello Liam - HA - somewhere in flies - possibly I have an update, but I have been so busy, projects have taken a back seat to getting business back on track.  I will let you know the outcome, but I think I am going to go for the 8HP,  CHEERS.  ELVIS

[GTSBoy]

Wow ELVIS. You have an....interesting approach to conversation. Did you not notice that I wasn't talking to you?

[MBS206]

1 hour ago, GTSBoy said:

Wow ELVIS. You have an....interesting approach to conversation. Did you not notice that I wasn't talking to you?

It appeared like someone was well triggered. Seems the way they mention finances, and business the way they do, that there's some major financial insecurities, or just insecurities in general and someone feels they need to try and put people down.