Microsquirt/MS2 based transmission controller

[oysteinbno]

Great,thanx for a quick answer.
I think I'd use the GPIO board to controll my 4L60 then.

[UnaClocker]

And I wouldn't recommend it. James' firmware, on the other hand, great stuff! GPIO hardware, not so much.

[roarin_mouse]

Does anyone have or know the curve for EPC vs. TPS for a 4L80E?

[roarin_mouse]

Is there any further development going on with this board variant? This thing looks pretty cool but there are a couple of things that I'd like to see. Unfortunately, I don't know C-language so I'm hoping that this is going to be developed further.

1). Separate up-shift and down-shift curves as opposed to the simple hysteresis with one programmable speed delta.

2) Same thing for TCC.

3) I think that it would only need one TPS based EPC curve (instead of one for each gear).

4) TCC apply firmness (based on TPS).

[jsmcortina]

I haven't made any changes (for 4L80E) recently as the two/three users reported that it was doing what they wanted. My car build is dead slow and stop, so it will be next year earliest before I can try the 80 on the road.

Perhaps send the other guys a PM and see if they'll re-join the topic here?

James

[roarin_mouse]

Thanks for the reply. Who are the "other guys"?

[jsmcortina]

Check out page 5 in the topic - atomic6 and Joe.

James

[atomic6]

got the pm,here is my 2 cents.

On the epc, I wouldn't be much help, because we installed a vac. modulator to control the line pressures

Because of the power turbos can make at even a 25% tps we control line pressure different than the factory, we use the vac modulator to control line pressure (map reference vs throttle angle reference)

We also lock up the convertor at WOT so no lockup delay at all, during normal driving our high stall convertor could mask the harsh shifts, and lockup. so no lockup delay is needed for us, ever.

Are you installing a shift kit in the 4l80e? which one? you should have one with an application that makes good power.

is the concern about drivablity or power handling, both of which we have had exceptional success with the code the way it is.

The other tester, ran the system without the modifications we did, but I really can't speak for him.

The NovaWagon it is installed in is 3850 lbs, and makes about 700 hp to the wheels, 4l80e is stock other than a vac. moduator,and HD2 Transgo shift kit.

we did have 2 tunes(three if you count the tune for the dyno pulls) and would switch by flashing the "track tune" in when we got there. the track tune changed the shift points alittle depending on the track prep,and the moved the convertor lockup to over 110 MPH at WOT.

I'll keep an eye on this thread, so post up responses. Hope to help.

[Joe]

I am at the other end of the spectrum from atomic6. I use basically a stock 4L80E (Has the 85 upgrade) in my tow vehicle. ~375hp SBC in a 5000+ pound 3/4 ton 4x4. It's no speed demon, drivability, simple install, works well with MS2 and MS3. I've run them both with this setup, no complaints. Very functional. It just works well. I use it with CAN fetch engine variables which is a big reason I went with this setup. My truck was already running MS2 so this was a no brainer for me. I have not used it as a stand alone.

Is it OE grade 4L80E control? No. The GM software for trans control is very complex. Actually kind of a pain to tune at times.

The seperate upshift/downshift curves (in my opinion also) would be a welcome addition. The simple hystersis is not ideal. I found a happy medium for my setup but there are times a little more tunability would be nice.
Thinking about it, it's mainly a full power accel to merge on the freeway when I lift or if for some reason I'm driving a little aggressive. Quickly on/off the throttle.

Tcc- No real gripes . I ramp on fairly quickly. I can feel it apply. I'm good with that.

I like the TPS/EPC setup it has now

I also run an off the shelf MicroSquirt. No internal mods at all. It's been reliable and trouble free.
For the Pull up resistors I run them in the harness. I used some marine grade shrink tube (Has glue inside), placed several pieces on the 5v line, soldered a pullup resistor to the 5v line, the other end to the circuit needing the pullup.
Covered both wires and resistor with shrink tube and moved on to the next pullup. I did it this way so that if I ever had a failure I could just use an off the rack MicroSquirt ,flash it and be on the road again.
I have yet to have any failures and I have a lot of miles on this so far.

Now I'm just rambling.

EPC- There are two GM EPC frequencies for the 4L80/85E I would like to see a user option to double the existing EPC frecuency. Mine needs double the available EPC cycles. As a result the EPC makes some racket on my setup. Nothing bad I just notice it. Nothing like the early days, James will remember.

I can dig up my EPC data if you are still interesed. I changed (Reduced) the stock settings for a softer feal. The stock settings are almost full line pressure most of the time if I remember correctly.

TCC Race mode. Cool option. Again works well. Being my application is a tow vehicle I fantasize about Tow/Haul mode.

Tow/Haul Mode
Would require full table upshift and downshift ( x2) Main table and tow/haul table
1 user input to trigger the second table.
TCC full Lock in second on up to control heat.

When fully loaded it would be nice to have delayed shifting and different upshift/downshift hysterises.

I'm happy with it. I'll post my EPC data when I dig it up. It will probaly need some retuning if EPC Hz is changed.

My $.02
I'd recommend it.

Joe

[quote="
1). Separate up-shift and down-shift curves as opposed to the simple hysteresis with one programmable speed delta.

2) Same thing for TCC.

3) I think that it would only need one TPS based EPC curve (instead of one for each gear).

4) TCC apply firmness (based on TPS).[/quote]

[roarin_mouse]

I like the TPS/EPC setup it has now

But does having separate pressure curves for each gear help? Can you try it with identical curves and see if there is any advantage either way?

I was looking at the Baumann Tuning System (as a reference). You can download their software but it's strictly for their hardware. In their system, there's only one EPC curve and it has separate upshift and downshift curves. Their TCC is nothing special though.

Tow/Haul Mode
Would require full table upshift and downshift ( x2) Main table and tow/haul table

I think that you would have the same effect if the curves were separable.

Frequency selection would be nice to select between the older and newer solenoid valve.
Let me know what you think.

[Joe]

I like the TPS/EPC setup it has now

But does having separate pressure curves for each gear help? Can you try it with identical curves and see if there is any advantage either way?

For me I don't think there is any real advantage, never really gave it much thought though. Just figured it was a step toward OE grade trans control. GM uses lot's of correction factors Per gear. Can't tell you why, some times the data is identical(Per gear) but this is also a universal type controller.
Not sure on other trans .

Haven't thought about trans tuning in a while. Now that I have some miles on the system another thing I think would be useful would be an EPC vs temp correction.

I'm happy with it. Does what I need to do very well. Oh, and the cost / available factor. Rates real good there also.

Joe

[roarin_mouse]

As far as the buzzing sound from the EPC solenoid, I was wondering if the circuit should allow the solenoid to flywheel during the pulse off-time. As it is now, the driver opens and closes the solenoid at the pulse rate but by letting it flywheel, the solenoid would see a relatively constant current that is a function of the duty-cycle. This could be easily accomplished by removing Q3 and R18 and connecting the emitter pad of the former Q3 to +12V. Please tell me what you (anyone) think.

[atomic6]

sorry I don't have any input for the buzzing EPC right now(because we are not controlling it that way), but I should have a stand alone type transmission contoller install of the Ms2/microsquirt coming up soon.

[roarin_mouse]

I've been doing a little number crunching regarding upshift vs. downshift. In my opinion, the hysteresis should be changed to a constant that is multiplied by the upshift trigger point. It seems that by multiplying the upshift point by a factor of 0.75 and using that result for the downshift trigger point, more realistic values are obtained. I did an excel spreadsheet and it looks pretty good. If anyone is still developing this, I recommend investigating this.

[UnaClocker]

Oh yeah, it's definitely still in development. I've been petitioning for seperate upshift and downshift tables. As well as the ability to choose whether I want one of the axis to be KPA/%load or TPS, for some, TPS might be best, and for others (definitely me) %Load would be better.

[roarin_mouse]

Thanks for the input 'clocker. I'm glad to hear that there's still interest in developing this. I'd also like to see TCC lockup/unlock tables as opposed to a single point. There's lots of code space available but I'm just learning C-language and hope that some of the software gurus re-engage.

[UnaClocker]

Thanks for the input 'clocker. I'm glad to hear that there's still interest in developing this. I'd also like to see TCC lockup/unlock tables as opposed to a single point. There's lots of code space available but I'm just learning C-language and hope that some of the software gurus re-engage.

Yeah, I proposed a change to the TCC as well. I noticed with the factory trans controller in my PT Cruiser, it doesn't seem to use the brake pedal for TCC control, it unlocks the TCC anytime I get off the gas pedal, and locks it back up a second or two after I get back on the gas. Seems like we could do the same if you didn't want to dedicate an input pin for the brake pedal. I haven't even wired in my brake pedal yet, so I've had no chance to try out TCC control at all. I know I want it to disengage when I go into more than a couple lbs of boost, but I haven't looked to see if I have that option yet. So far I've just been working on the timing of the solenoids to get from one gear to the next without flare.. These Dodge FWD automatics are a bad bad word. ;)

[roarin_mouse]

I think that you'll find that your PT unlocks for either the brake or 0% TPS. The release at 0% TPS would be nice to have as it keeps the car from bucking when you let off the gas. That would be a good addition as it save drivetrain wear and tear.

[jsmcortina]

That TCC unlock should be easy enough. Just been working on other things recently.

James

[roarin_mouse]

That TCC unlock should be easy enough. Just been working on other things recently.

James

If you would, also have a look at changing the downshift hysteresis to a percentage of the upshift point. I found that 75% looks good but could be a user selectable variable (60-80%).