Auto Manual idea - Can MaxxEcu do this?

[kinger]

I ran across this clutch actuator and it got me thinking about creating a semi automatic t56 magnum. Using a strain gauge on shifter, the MME actuator, and gear position. Then some maths and a table to command a certain RPM with a DBW throttle body. 

https://www.mme-motorsport.com/en/products/clutch-actuator

Floor the car, and never lift. Grab the shifter and pull through gear, never clutch with your foot.  Each shift it commands a rpm to rev match based on speed.  The actuator is faster than my foot.  And ECU is rev matching precisely easier on synchros.

Goal - I get 8hp shift times in a 50 lb lighter, and smaller magnum trans that has better ratios and  more fun? 

Here is my rudimentary logic can any maxx guys confirm if this is possible:

Strain gauge no pressure 2.5v pushing is 0-2.5 and pulling is 2.5-5v

MME clutch actuator - ON OFF


MaxxEcu :
Wiring-
Switch to enable auto man mode
GPO 1 to MME
GPO 2 Strain gauge
DIG 1 Digital input speed
DIG 2 gear position
DBW APP1 (accel pedal)

Maths:
Gear 1 - rpm = DIG1 x 2.66 x 3.55 x 26
Gear 2 - rpm = DIG1 x 1.78 x 3.55 x 26
Gear 3 - rpm = DIG1 x 1.3 x 3.55 x 26
Gear 4 - rpm = DIG1 x 1 x 3.55 x 26
Gear 5 - rpm = DIG1 x 0.80 x 3.55 x 26
Gear 6 - rpm = DIG1 x 0.63 x 3.55 x 26

Logic:
Idling - GPO2 = 2.3-2.6 V GPO1 OFF, engine rpm as is

1–> 2 shift and command rpm based on speed and gear  - GPO2 2.6-5v = GPO1 ON, gear position = 1, engine rpm = math 2, GPO2 = 2.5, GPO1 = OFF

2–> 3 shift - GPO2 0-2.4 V = GPO1 ON, gear position = 2, engine rpm = math 3, GPO2 = 2.5, GPO1 = OFF

Etc. for rest of the gears.

Likely want a CAN button to enable this,  maybe selectable for different maps based on TPS, WOT vs cruising around and being lazy not wanting to clutch.


Thanks for the input! 

[Exidous]

Short answer No, Maxx cannot do that. Maxx controls the DCTs via canbus essentially faking the factory systems. Using the OEM mechatronics with a custom firmware.

It would require custom firmware on hardware like the HTG GCU.

More importantly, why? I ask because SMGs are on of the most hated transmissions for the BMWs. It's the one thing wrong with the Lexus LFA. The Ferrari F1 trans gets swapped out for a manual all the time. Single disc automated manuals are just poo. The shifts are marginally faster than what you can do yourself.
Of course there is the just because factor and no one else has done it. If that's for you, by all means.

[MPbdy]

I'm not sure the mechanical action of the clutch actuator can keep up with yanking a shifter in anger.  Using the strain gauge for ignition cut is more understandable as that has an instantaneous response when paired with dog cut gears.

[digitalsolo]

I'd think for this to be viable you'd need to have their box control the clutch and shifts, with you requesting the shift via button, and the computer doing the rest.   It won't be fast enough otherwise.    That's just remaking a first gen SMG design though.

[kinger]

I never understood what the SMG was back in the day, just heard it wasn't good lol

I guess I was hoping a complete fuel and ign cut combined with a alum flywheel would help the Maxx rev match BUT if Benz couldn't get it I certainly am not going to. 

I basically want a 8HP sooo should probably just do a 8HP, just hate adding weight and making the exhaust all over again. 

When I added up all the cost of this I guess that is a detractor too!  $1400 for clutch solenoid, $1400 for the strain gauge, geez just buy an auto..

Or I could do that clutch solenoid and just push to clutch with a paddle and see if that makes the car more fun.  I'm old and tired of rowing gears 100% of the time, it would be nice to have both and row when I wanted to.   

[MPbdy]

I think the problem really comes down to a syncro trans.  Your shift times are still going to be 250-300 mS at the fastest, and if you try and go too fast or if your timing isn't quite right it'll balk and you'll be left trying to yank the lever into gear while the solenoid already let the clutch out.

[kinger]

I think the problem really comes down to a syncro trans.  Your shift times are still going to be 250-300 mS at the fastest, and if you try and go too fast or if your timing isn't quite right it'll balk and you'll be left trying to yank the lever into gear while the solenoid already let the clutch out.

For sure I could see that happening, I was thinking of a safety that if it doesn’t see the gear from a gear position sensor it wouldn’t release the clutch.  Then I looked for t56 gear position sensors and I only see them for sequential shifters not H pattern.  I was hoping I could set up the solenoid to only open once it was in gear so I could shift as slow or fast as I wanted.   

If I have to go sequential that’s another $1500 lol. 

I guess my foot works fine lol

[Exidous]

My engine with the DCT revs fast AF. I even have the 20+ lb flywheel. Most just run a 5-7lb flex plate. My tach is slower than the engine. The rpms will be back down to 3500 rpm after revving to 7k while the tach is just now reading 6k. Lol
The long ratio DCT isn't the best 1-2 shift but 2-7 are essentially the t-56 short ratio trans. Maxx can control the gen 1 DCT(short ratio 1:1 7th), gen 2 dct(long ratio .68 7th) or gen 1 8hp all via canbus. 8hp adds transbrake.

You can probably install an 8hp or DCT for less than what you can sell your manual setup for. Assuming you do it yourself.

Trans $1500(can be found under 1k)
DCT harness from Maxx $600
Best adapter and flywheel(clutch master) $2000
Driveshaft $700-1200
Rear adapter $250
1" square box tube $10
Misc $3-400

[kinger]

Yeah that makes sense.  I just worry about the exhaust, I don't have any skills with SS nor is that available in the area, so that is my only hold up.  Seems trivial in the grand scheme of things I understand but it's a PITA for me lol 

[Exidous]

It is a pain. If your running sikky headers, fitment isn't bad. If you're running long tubes it's a pain.

[kinger]

It is a pain. If your running sikky headers, fitment isn't bad. If you're running long tubes it's a pain.

Running JTR 1-7/8" I would love some 2" on the LS7 but holy heck that would be tight.  I haven't seen Sikky but it looks much shorter and get that collector our of the way of the trans oil pan and then maybe go oval or something around the trans.  Sounds easy but its not for me and my location. 

[Exidous]

No chance jtr will work without totally disassembling and rewelding and bashing the floor board.

I promise the shorter header won't matter with the LS7. So much torque. Haha. I'm using modded Ronin and had to do the same stuff you would to the jtr. Only reason I don't like the sikky is the 18ga stainless. So easy to dent.

[Cobranut]

I never understood what the SMG was back in the day, just heard it wasn't good lol

I guess I was hoping a complete fuel and ign cut combined with a alum flywheel would help the Maxx rev match BUT if Benz couldn't get it I certainly am not going to. 

I basically want a 8HP sooo should probably just do a 8HP, just hate adding weight and making the exhaust all over again. 

When I added up all the cost of this I guess that is a detractor too!  $1400 for clutch solenoid, $1400 for the strain gauge, geez just buy an auto..

Or I could do that clutch solenoid and just push to clutch with a paddle and see if that makes the car more fun.  I'm old and tired of rowing gears 100% of the time, it would be nice to have both and row when I wanted to.   

I looked at the available strain gauge shift knobs for my Elite sequential tranny.  The prices seemed ridiculous, so I built my own.
I found some strain gauges in various ranges, machined my knob to fit one inside, and built an amplifier modult to process the signal.
I also adapted a readily available hall effect rotary sensor to the trans, instead pf paying 3x the price for the specific one.
(I'm retired, and my time is free. LOL) 

[kinger]

Awesome info as always. 

cobra nut impressive DIY strain gauge! 

Thanks all!

[cholmes]

Cobranut, I agree with Kinger, that's impressive work on the strain gauge fab.
Any chance you can supply links to the strain gauge and rotary sensor you used? Maybe a schematic for the amplifier module? That would be awesome info for the rest of us DIY geeks!