4 speed auto to 5 or 6 speed auto - any alternatives?

[lockeed]

Hey Guys, I recently bough a 91 850i auto, and I immediately started looking for manual options... like most of you I found out! But I decided the cost and effort needed wasn't worth it for me.

But is there a good 5 or 6 speed transmission alternative out there that could be done for much cheaper? The 5HP30 has been thrown out there as a possible candidate, but I found very little details on the actual upgrade and what's needed...

Thanks

[rjjablo]

Is your 4 Speed dead or dying?

If not it is a lot of time and effort to just swap the trans, I found a good used unit for mine and it is not a trivial task

Electronics are the hard part, Shogun might have some insight

[radlaw]

But is there a good 5 or 6 speed transmission alternative out there that could be done for much cheaper?

Why would one want to make this conversion???

[exalted]

I've seen kits for audi and bmw manual gearboxes being advertised no clue if they are any good.

Imagine any halfway competent motor shop could put pretty much any BMW gearbox by welding it and the current cover together. Diesel manual boxes are popular here in sweden.

Either way it will be a few thousand dollars unless you have the knowledge and tools to do it yourself.

[8eights]

Once you remove the exhaust and drive shaft it's not much. Getting the 5 or 6 speed auto mounted is easy, Getting it to work pass 4th gear, I've yet to see it done.

[JDP530]

PMC Motorsports in Poland makes all kinds of engine/ trans adapter kits. Here is one of several they have for the M70 V12: https://pmcmotorsport-shop.com/produ...ETRAG-420.html

I don't know anyone that has used the kit. They do have a distributor in Florida, Drift HQ, and they had the kit in stock. https://www.drifthq.com/

PMC just recently finished a kit for the M70 and the ZF 8 speed auto, 8hp70, that is used in several BMW models. But, I hAVE no idea if the TCM built into the ZF can be interfaced with the E31 chassis.

[rjbaren]

Why would one want to make this conversion???

Why wouldn't one? I thought my car was a total bore as an automatic. If I wasn't able to convert, I would have sold it.

[Hyper]

...Electronics are the hard part...

The OP's question got me doing some online investigating for my own situation as a V8 owner.

Long, short...
The 6HP26 onto my M62 w/5HP24 looks like a worthy project.
Re: Why? --> For hobby, fame, performance.

6HP26...
* Abundant, relatively cheap, easily rebuildable, parts available.
* Provides additional gearing both above and below the 5HP24 spread.
* Provides additional torque rating, valuable to say a 4.6L install.
* I'll guess it (and anything else) has a better shift character than the existing 5HP.

US$700 initial gamble, to check out N62 vs M62 mechanical compatibility and body compatibility.
Have on hand another $4K to clean it up, refresh the converter, build a drive shaft, fab mounts, fuss over the shifter.

The darkest cloud I see is systems integration, the messaging protocol whereby the transmission control module (TCM, aka the embedded EGS, aka mechatronic) needs info and commands from the engine control module (ECM, aka DME) and others.
Going the other direction the ECM et al might be looking for info or suggestions coming back from the EGS.
Ultimately this might require a translator to sit on the CAN bus to spoof in both directions so that both sides are satisfied that nothing is amiss.

This cloud could be made less dark by a someone bootlegging both the earlier and later protocols.
Absent such a lottery win, I might first drop a CAN scanner onto the existing E31 bus, to gain an education, see what direction things were heading, see whether spoofing is needed and possible.
If that cloud clears, only then proceed with the mechanicals and shop time mentioned.

The lessons learned might also carry over to 6HP onto a E31 V12.
There might be issues unique to V12 models or earlier E31's, like shifter compatibility (GM vs steptronic, mechanical parking vs e-park, etc).

That covers normal operations, but then additional nitpicks...
Scratching the surface, the problem of diagnostics when say the egs wants to report a 6spd problem that could not possibly exist in the earlier (4-5spd) vehicle.

[mandd]

Check out HTG Tuning for the controller.

Mark.

[Hyper]

Their 6HP/8HP support seems a bit sketchy, their pic running into a broken link.
***
For my plan, I don't think we are in need of a controller, rather we are in need of a CAN bus messaging adapter.
I'll assume the existing solenoid controller embedded into the 6HP is usable as-is.
***
Briefly reviewing my MID module knock-off, I see it has 2 CAN ports, perfect for snooping the existing system(s), looking at messaging between the DME and EGS.
The Hyperdrive-MID would then be swapped in as the supposed adapter solution.
Unfortunately my MID project got run over by other events and still needs development.
It's still sitting on my desk though, alive and running perfectly as far as it has been developed.



An even better candidate for mediating CAN messaging would be the Hyperdrive-ETV because it already resides in the E-box, controlling the vanos on the M62B46.



The most recent version has 1 CAN port, so it can snoop but it can't split the bus.
Don't know whether that is a deal breaker.
A next rev is coming, due to component footprint issues, so I'll proactively add in the 2nd CAN port.
Btw, the version shown has been updated with with VR sensing, to support a leap from M60 to M62 vanos.

***
Fyi, on other car channels I have had to supply the solenoid control function.
Bus protocols are a non-issue because I author the entire system.

Over in the Ford space, a 5R55E electronic 5-spd tranny gets swapped in in place of a 4-spd dumb hydraulic A4LD normally found on the back of a Aerostar's Vulcan engine.
Here shown with the bell-compatible SHO engine (minus the Medusa intake) from a Ford Taurus, a FWD app with a 4-spd transaxle.
Learned that, in general, even though bellhousings are compatible, it could be that the torque converter that goes with the tranny s might be compatible with the flex plate that mounts to the crank.
Had to fabricate a special flex plate that made the transition.



The early Aerostar EEC-4 (aka DME in Ford-speak) knows nothing about electronic transmissions.
Later Ford electronics know about the 5-spd, but are not plug compatible to the early Aerostar harness or its engine control methods.

Therefore we build an early EEC, plug compatible to the Aerostar harness, that adds solenoid control and extends the count out to 5-spds.
Since the solenoid drivers are peripherals of the CPU, there is no external bus with protocols.



Over in the MBZ space, an electronic 5-spd auto gets bolted up to a Mercedes M102 in place of the dumb 4-spd auto.
Note that the later, higher capacity tranny has a bigger girth, slightly different profile front to back.
This caused a collision with some features inside the tunnel, resulting in "adjustments".



The solenoid controller is a separate TCM box, one being available from the factory bin.
Communication is over CAN to the ECU.

To avoid having to learn the CAN messaging, and to gain control over shifting, I supply the TCM box in this one instance.
Since I am the author of both the TCM and the ECU, I get to use any messaging scheme I happen to dream up.

[JDP530]

Hello Hyper, glad to see you found some time to review auto projects. Are you finished with your most recent home improvement projects now? I bet there are plenty of people looking for door handle pieces again, lol!

[Hyper]

... home improvement projects...door handle pieces...

Shipped out 6 pivots in the past 2 weeks, then my Argon ran dry, waiting for lockdown to lift.
Am half way thru the kitchen remodel, then a bath from scratch, then a California roof-over to bump the master bedroom.
UPB46 now sits on fresh concrete but I still have another 65 cubic yards out of the initial 100 to pour, about 15 of it in the new shop building featuring a Bendpak.

[JDP530]

Shipped out 6 pivots in the past 2 weeks, then my Argon ran dry, waiting for lockdown to lift.
Am half way thru the kitchen remodel, then a bath from scratch, then a California roof-over to bump the master bedroom.
UPB46 now sits on fresh concrete but I still have another 65 cubic yards out of the initial 100 to pour, about 15 of it in the new shop building featuring a Bendpak.

Wow, very nice!

[Hyper]

A quick follow up, then I'll get off the OP's 850 thread, maybe start my own 840 someday.
****

...An even better candidate for mediating CAN messaging would be the Hyperdrive-ETV because it already resides in the E-box...

*** Good news ***
I've selected the ETV for the job, rather than the Hyperdrive-MID, and updated to include...
* More robust CAN hacking and commanding. Gets a 2nd CAN port so as to split the bus, creating a gateway to filter and modify messages as well as look at them.
* Real time clock. To timestamp CAN events, providing a better correlation between events and mystery messages.
* Shifter snoop. Normally these signals go directly to the E31 EGS, but the 6HP has no such input. We therefore assume that the ETV needs to package the shifter info and ship it via a CAN message.

Schematic updated, layout gets revised as time permits.
{update 04/13/2020: layout complete, CAD files out to PCB fabrication}





Then the long process of hacking both the CAN and the Datalink on the existing DME/EGS pair.
I might follow that up by bringing a 6HP EGS to the benchtop, along with (E65) modules that it communicates with.

*** Bad news ***
I had been alerted previously that, at first glance, the M62 and N62 bells were close but actually too far different to cross-swap.



After studying you'll find...
* Starter bolt locations differ
* The (N62) 6HP has a narrower upper segment, positioned higher up.
* The torque converters have a different dish profile. Not conclusive, but this could lead to incompatibility with the flex plate.

Knowing this, I won't be running out to buy one soon.
I'd first have to have time, space and a definite plan for how to proceed with mechanicals.

Modding the 6HP bell is possible, say by a cut and (aluminum) weld of a machined flange, but this puts a swap beyond the mass public.
A talented person or shop might do one or two, but would not want to make a biz out of buying, holding and shipping old transmissions, taking the risk that they need repair.

[whiteghost1]

Check out HTG Tuning for the controller.

Mark.

They definitely do some neat stuff at HTG! Has anyone reached out to them to see if they do a compatible controller to mate the V12 5HP30, to work synergistically with the M70 in the e31/e32 chassis?

[JDP530]

They definitely do some neat stuff at HTG! Has anyone reached out to them to see if they do a compatible controller to mate the V12 5HP30, to work synergistically with the M70 in the e31/e32 chassis?

I would rather see a compatible controller from HTG that will work for the ZF 8HP70 8-speed auto in the E31 with V12.

[TedBobo]

I would rather see a compatible controller from HTG that will work for the ZF 8HP70 8-speed auto in the E31 with V12.

Ditto!

[whiteghost1]

I would rather see a compatible controller from HTG that will work for the ZF 8HP70 8-speed auto in the E31 with V12.

Agreed. The reason I say 5HP30 is there are fewer variables regarding the physical fitment/compatibility point of view + significantly simpler controller tuning, which is our largest challenge.

[JDP530]

Agreed. The reason I say 5HP30 is there are fewer variables regarding the physical fitment/compatibility point of view + significantly simpler controller tuning, which is our largest challenge.

PMC does have the adapter kit to fit the ZF 8 speed to the V12 with original starter, but trying to adapt an aftermarket tunable controller will be a huge challenge.

[cartoonz]

PMC does have the adapter kit to fit the ZF 8 speed to the V12 with original starter, but trying to adapt an aftermarket tunable controller will be a huge challenge.

HTG controllers are used with 8HP transmissions all over the place. They are truly "Stand Alone" boxes that also have the flexibility to interface with the car, if need be. Compared with what Hyper is doing, interfacing one of those would be cake. (for him, anyway)
Seems to me that would be the way to go

[Hyper]

...what Hyper is doing...

Hyper is merely adding in a bus probe, to speak about the unspeakable trouble in the area called apps engineering.
He does not charge himself any NRE while doing so.

[lockeed]

Interesting read guys.... any simple options out there for the average Joe?

[Hyper]

Not simple but for me the only option would be to change GF's.
She's always reminding me that I am just average.

*** ed ***
Forgot to mention...update.
ETV rev G got an extremely fast turn around at the Printed Circuit Board fab house.
Probably I'm the only job in the shop right now.
I'll continue with the details as to firmware, desktop app and e-box hacking over on the Up Before Six thread.

[Hyper]

To summarize my findings on this end, with respect to the 6HP...
* ETV or TCM2650 is used to snoop DME signals and then broadcast state via CAN messaging to the embedded TCM which then does its tranny thing.
* The TCM character is programmable (by the dealer, reps) per the vehicle app.
* The GM cousin is the 6L80 which is available new, in bespoke form, ordered thru reps (see JEGS), list $4150. Same connector, different pinouts and signal definitions.
* {ed: In Ford land, its the 6R80, also on license from ZF who I'll now guess owns the essential gear and clutch technology. Ergo, there are "millions" of 6HP26 derivatives out there and the hack's are no secret.}
* The 6HP bell doesn't match our E31 engines. Unlike the 6HP, the GM 6L80 has a bolt-off bell.
* With all the electronics solved I'm now going to do a short run of cast aluminum bells, to adapt the 6L80 body to the M70 et al. However, there will be a slight delay in getting those out as I'm also teaching my pig to fly.

[TedBobo]

Fly pig, fly!