Brainstorming 8HP70 transmission swap to M50: What is required smart people?

[wgknestrick]

I know the expertise exist here (cough volloso, someguy, 22RPD) on the forum to figure most of this swap out. High HP transmissions are a bit of a problem for E36s and I was wondering if the 8HP70 isn't the best all around transmission for this car for ultimate acceleration. They can be had for about $1000 used, but have many, many different variants/bellhousings and have run 8s quarter miles in gen 5 Supras. Custom standalone TCU tuning is opening the door to this transmission for all kinds of swaps for the hemi/jeep platforms. I know my 5sp is living on borrowed time.

This swap has been done before (so don't say it's impossible):

8HP into E46
https://www.youtube.com/watch?v=qLOiyzvkxco
https://www.youtube.com/watch?v=Ar4htpJYzyQ

8HP into Miata
https://www.youtube.com/watch?v=F59fuspn-Eg


Potential BOM for swap:
M50 Bellhousing adaptor plate:https://pmcmotorsport-shop.com/produ...-E60-530D.html
(this is the only available plate that I can find and unfortunately limits you to a pretty rare in the US variant of the 8HP70...ones made for the N57 diesel). It's a start
HTG GCU : https://htg-tuning.com/shop/htg-gcu-...-control-unit/
8HP TCU wiring harness https://htg-tuning.com/shop/dct-gs7d...al-wiring-kit/
F30 Gear selector: 61319296896 (maybe need a different PN, but these are only about $40 on Ebay)
M54 DBW Throttle Body 13547502445
M54 Throttle pedal assembly
M54 DBW TB to M50 Manifold Adaptor Plate: https://www.seemslegitgarage.com/pro...ld-adapter-kit


Custom/Fabrication BOM
Custom transmission mounts
Custom Driveshaft
?M50 crank to 8hp70 spline adaptor? PMC may already have something

Optional
Universal Paddle Shifter assembly

[vollosso]

Yeah shouldn’t be a problem off the top of my head. Just hard to control, the trans tuning from scratch (htg) isn’t a walk in the park.

That’s an impressively big trans too.. might have some fun fitting it.


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[wgknestrick]

HTG supposedly have a "base map" for the 8HP70, but I would love to get some native english speaker's perspective on how close they are on "first try". The thing that worries me is the E36 cable throttle, and what needs to be done canbus / I-bus wise on E36. Converting to DBW would not be fun, but I'm sure some BMW DBW pedal and TBs can be adapted. I never thought I'd ever be envious of canbus on my "fun" car.

[someguy2800]

Need to talk with K64 performance in Poland. They have done this and they are coming out with an aftermarket controller for swapping into older BMW’s. The 8 speed is a clutch to clutch shifting transmission so it requires a sophisticated controller to time the shifting.

On a side note I am going to be starting to work on an adapter to run the ford 6r80 and 10r80 transmissions. These are the transmissions that they use in the newer mustangs and f150’s. There is already a controller for the 6r80 and one in the works for the 10 speed. These are cheap and plentiful and they already have proven parts for these transmissions to handle 1400 whp.

- - - Updated - - -

They also have good torque converters for the domestic transmissions also. I don’t know what exists for the bmw zf’s. As someone that already runs an auto I can tell you the torque converter is the most important piece of the puzzle.

[wgknestrick]

I have a 10r80 transmission in my Expedition and it is not a transmission that I think would pair well in an E36. I'm sure they can be tuned better than what I have, but just put me down as skeptical for now. They shift so slow in manual mode.

[m3boost]

https://vadersolutions.com/collectio...assis-dct-swap

[vollosso]

@m3boost

What’s that for? Definitely not related to this platform or topic at all.


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[someguy2800]

I have a 10r80 transmission in my Expedition and it is not a transmission that I think would pair well in an E36. I'm sure they can be tuned better than what I have, but just put me down as skeptical for now. They shift so slow in manual mode.

I’d have to chock that up to whoever programmed the TCU in the trucks because the 10 speed in the mustang and camaro’s shift very fast.

[wgknestrick]

I’d have to chock that up to whoever programmed the TCU in the trucks because the 10 speed in the mustang and camaro’s shift very fast.

I'd also rather keep it "BMW" as I think there are less overall compromises. Transmissions designed for a slant I6 should have more features near or in the proper locations. There is still an unwarranted stigma about swapping brands on major components (warranted or not) in a car. I'll be getting a lift installed this year and will finally have the capability to try to tackle something like this. The tuning of the TCU is complex, but doesn't seem to overwhelm me at this point since I'm fairly familiar with standalones. The tech "generation" mismatch integration between the E36 and the 8HP70 bothers me more. The E36 doesn't seem to be capable of all the TCU safety protections since it's a much more mechanical car and I'd really like to keep my NickG tuned DME. My E36 just runs so well, ALL of the time, on E70. I'm not going to step backwards on that for a transmission.

This place "seems" to be the lone US distributor of the HTG and have done some DCT swaps (which has a lot of carry over) with the HTG. The DCT swap vids are IMO fairly "rough" once running from what I've seen, and not something I'm looking for in a street car. You still have use the clutch pedal when taking off and it looks sketchy AF for a street car, plus the danger of having an alternator go out while moving and having the DCT auto revert back into park while moving. I'll reach out to Seemslegitgarage and hopefully they are responsive. I'm going to need some place with first hand experience with the HTG to lean on if I go forward with this. Their BMW background is even better.
https://www.seemslegitgarage.com/pro...CuhQHTHeKxNraY

[NOTORIOUS VR]

This has been a consideration for me as well as a next step for my E36...

How much power do you make/plan on making? The HP50/51 is proven to very high power levels (see new Supra, etc).

DCT doesn't require a clutch pedal to take off.

[wgknestrick]

This has been a consideration for me as well as a next step for my E36...

How much power do you make/plan on making? The HP50/51 is proven to very high power levels (see new Supra, etc).

DCT doesn't require a clutch pedal to take off.

Car currently makes 643whp@22psi on E70, but I have the turbo and engine to make more (probably around 800whp capable on E70). My 5sp is already slow to shift and doesn't like to be slammed under stress.

A couple of the DCT swap videos showed some DD issues with take offs (forward/reverse) on the DCT, and DCTs have the reputation of this issue in stock form. Both (8HP and 7DCT) swaps will probably involve the same BOM though as you need to reduce torque somehow to shift ie DBW. I'm just trying to compile and brainstorm everything that needs to be resolved here as a "group thought" project. If there is anything I'm missing or to be corrected in the list, please bring it up. I am still concerned about the DBW because I think the DME needs involvement between the DBW throttle and DBW pedal to run. The HTG just sends trigger signals to whatever ECU you are running for the ignition cut and throttle blips. If I have to drop the custom tuned DME for this, it will be a showstopper from my POV. I have a street car that needs to be seamless on OBD2 inspections, and I'm not going back to a standalone again. Not going to take 2 steps forward, 2 steps back.

Also note that the transmission here is most likely going to be the 8HP70 out of a N57 diesel. Others may fit, but this looks to be the best candidate at the moment, and I highly recommend any pioneer of this to start with the least amount of problems to solve.

Bill

[wgknestrick]

https://www.youtube.com/watch?v=2lsIC8HkMcI

Working on the Romanian translation. Thankfully I have a Romanian friend.

[someguy2800]

Car currently makes 643whp@22psi on E70, but I have the turbo and engine to make more (probably around 800whp capable on E70). My 5sp is already slow to shift and doesn't like to be slammed under stress.

A couple of the DCT swap videos showed some DD issues with take offs (forward/reverse) on the DCT, and DCTs have the reputation of this issue in stock form. Both (8HP and 7DCT) swaps will probably involve the same BOM though as you need to reduce torque somehow to shift ie DBW. I'm just trying to compile and brainstorm everything that needs to be resolved here as a "group thought" project. If there is anything I'm missing or to be corrected in the list, please bring it up. I am still concerned about the DBW because I think the DME needs involvement between the DBW throttle and DBW pedal to run. The HTG just sends trigger signals to whatever ECU you are running for the ignition cut and throttle blips. If I have to drop the custom tuned DME for this, it will be a showstopper from my POV. I have a street car that needs to be seamless on OBD2 inspections, and I'm not going back to a standalone again. Not going to take 2 steps forward, 2 steps back.

Also note that the transmission here is most likely going to be the 8HP70 out of a N57 diesel. Others may fit, but this looks to be the best candidate at the moment, and I highly recommend any pioneer of this to start with the least amount of problems to solve.

Bill

The 8HP is not a DCT trans. It is a conventional 8 speed automatic trans with a torque converter. These new 6+ speed automatics do shift clutch to clutch though unlike the older auto transmissions that had sprags. Because they are clutch to clutch they require shift timing similar to a DCT because for each shift it has to release one clutch while it engages another. For takeoff there is no clutches engaging because they have a torque converter and it should not require an ignition cut to shift because its never actually in neutral during the shift unlike a DCT.

[NOTORIOUS VR]

Even for DCT it is not absolutely necessary to have DBW integration, and with an auto box like the ZF8 probably even less so? However you will obviously NOT get the best end result without it on downshifts as rev's cannot be matched/blipped by the ECU. BUT for upshifting under load/power you WILL need some form of ignition cut. to quickly and temp. reduce load/engine power to perform the shift. This is a MUST. How you will handle this on the stock ECU I do not know however.

This exercise will be much easier with a standalone for sure. If you go with a PnP solution you can keep the stock ECU for emissions and go back to the standalone for the other functions.

[vollosso]

The 8HP is not a DCT trans. It is a conventional 8 speed automatic trans with a torque converter. These new 6+ speed automatics do shift clutch to clutch though unlike the older auto transmissions with sprags. So they require shift timing similar to a DCT because each for each shift it has to release one clutch while it engages another. For takeoff there is no clutches engaging because they have a torque converter and it should not require an ignition cut to shift because its never actually in neutral during the shift unlike a DCT.

If you don’t have power cut the shift tuning has to be perfect at every power level, every throttle Position.. etc.. I think I’d work out a coil based cut which would allow some shift error and therefore driveability.


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[someguy2800]

I don't know about the 8hp, but the ford 6r80 (which is a licensed copy of the 6hp ZF) does not need to use torque management to shift. Even on 1400 whp mustangs they are shifting them under full power.

On an unrelated note, the old ford C4 and C6 transmissions were actually a clutch to clutch shifting trans. Unlike a Th400 or TH350 they did not have an intermediate sprag so they had to shift clutch to clutch and they accomplished that completely mechanically which is pretty neat.

[wgknestrick]

So I talked to Mike from Seemslegitgarage today about the details of the 8HP -> E36 swap. He doesn't think we need to do anything with the throttle body or ECU in the E36s. I may need to temper my expectations on the polish of the final product though compared to a factory 8HP. E36 has some Canbus features according to him (I'm a little skeptical of this statement), but they've done one already. They can source the HTG and provide support but haven't done any 8HP swaps first hand, but have done several DCTs with it. The 8HP is by far the easier swap for E36s compared to the DCT according to him due to lack of throttle control. They can also source all engine to transmission adaptors once we identify the transmission variant. We would still need mounts and driveshaft fabricated, but nothing overly difficult. DCTs fit into the E36 tunel without modification, so he seems to think the 8HP shouldn't be an issue.

He estimated that it would be about $1000 for the adaptor and flex plates for M50 to 8HP70.
Does anyone have an estimate on how much a custom driveshaft would run? Assuming around $1000.
HTG is $1500 or so
8HPs are around $1000 used
Probably another $500 in random parts/wiring/shifter, etc.
$5K for this isn't too bad at all to drop about 1s off your 1/4m time.

[mutty]

Perry got something up his sleeve. 6r80 with two overdrive gears and launch control , Motec controller. For under a grand you have a 800hp stock transmission right there.

[PEI330Ci]

I think I'm the only person here that has taken a stand alone controller for an automatic transmission, and programmed it from scratch to run with BMW turbo engine.

It was obscenely frustrating.

If I was to do it again, I would want to start with a fully operational controller, with the ability to tune those maps. One of the key things I learned was that the transmission controller needs "LOAD" data to make good shifting decisions. This is not to be confused with throttle position, or manifold pressure. (Both of which can vary load with cam timing, ignition timing, and fuel delivery)

If anyone does want to take a stab at this with a GM or Ford trans, I have a TCM-2000 with brand new connector and pins to make a harness from scratch that I can sell you.

https://www.powertraincontrolsolutio...on_Controller/

[budgetbmw3]

The guy from Sound German auto said his kits need limited inputs to run the dodge parts(i think it was rpm, tps, brake). I looked into this a little bit before because I was seeing ram and Maserati ones with low miles under 500 bucks. I ultimately ended up going with a 420g, but hopefully someone comes up with something as I would like to do one of these newer auto transmissions that can shift quickly.

[someguy2800]

The guy from Sound German auto said his kits need limited inputs to run the dodge parts(i think it was rpm, tps, brake). I looked into this a little bit before because I was seeing ram and Maserati ones with low miles under 500 bucks. I ultimately ended up going with a 420g, but hopefully someone comes up with something as I would like to do one of these newer auto transmissions that can shift quickly.

Are you talking about the controller for the 5 speed mercedes/chrysler trans?

[budgetbmw3]

Are you talking about the controller for the 5 speed mercedes/chrysler trans?

He said it was for the ram 8hp70 models and I believe the hellcat 8hp90 or 95 also (can’t remember which model they have). They have done the swap into lots of older dodge based cars already. I am not sure how smooth/operational it is as I didn’t look into it further when I couldn’t find readily available adapters. But HTG and Sound German were the two controller options I saw.

[wgknestrick]

Per the HTG tuning wiki
Required inputs from ECU:
"RPM, TPS or PPS sensors, or if your engine is boosted also MAP sensor"
https://update.htg-tuning.com/wiki/H...uirements.html

This page goes over setting up the inputs:
https://update.htg-tuning.com/wiki/?...ts_Config.html

I've found that the OBD2 E36 does indeed have Can L and Can H wires (in the main harness plug), but I'm still trying to figure out what all devices are on the E36 canbus. I do believe the AT, cluster, and some other devices outside the scope of this are on it. I am relatively new to E36 platform "tribal knowledge" at this point, but learning quick. The big question I still have is...are there any differences in the DMEs between AT and MT or if there are any flags that need to be set in the DME to switch between? Tons of info about going AT to MT, but nothing going the inverse. I don't think there is anything different in DMEs, but would like some verification. I'm guessing if the DME sees an AT on the canbus, it starts communicating with it?

The good thing is that I have some time to allow all the tuning options to mature and maybe some other brave and capable pioneers to tackle this before me. My 5MT is still alive (knocks woods). There is a stupid cheap 8hp75 on ebay tempting me to pony up now though. It would also be nice to know how long these transmission last with a non OEM tune. I'm sure we are sacrificing some life with hacked tunes on these as people learn the 8HP platform.

[jrode34m5]

bump

This coul be a very interesting swap as well for the s85!!!!

[ba114]

FYI the stock DME can use the ASC inputs on gearshift to reduce timing and/or close the asc-t.
Sending 5v to pin 80 (from memory) will retard the timing sufficiently to reduce torque for shifts.