4r70w setup

A forum for discussing applications and implementations of the MegaShift transmission controller code for the GPIO from B&G. This can control up to 8-speeds and 6 shift solenoids (plus a 16x9 table for controlling a PWM line pressure valve). It has manual and fully automatic modes (16x9 load x speed table), with under and over rev-limit protection, and full data logging of all inputs and outputs (among many other abilities). A TransStim to test your completed board is also available.
ashford
Posts: 89
Joined: Mon Oct 24, 2011 3:41 pm

Re: 4r70w setup

Post by ashford »

ill give it a try tomorrow. all testing has been done live on the car. the 150mph thing happened while i was slowing down :?: but one thing at a time i suppose.

i did do some driving on my factory equipped pickup to see how it reacts more closely, i will try my other car as well when the weather permits, i have a quarterhorse in it and have access ecu and how the factory controlls it so i will do some snooping around.
ashford
Posts: 89
Joined: Mon Oct 24, 2011 3:41 pm

Re: 4r70w setup

Post by ashford »

SUCCESS!!! mostly, now there is a bunch of tuning to do, vss likes to climb all by itself around 10mph, and the 2 point for the line pressure does not work. im gonna hafta do the ini change to get it to work if i can remember where i put my notes.
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: 4r70w setup

Post by Bernard Fife »

ashford,

Great, I'm glad it's working now. I will look into the 2-point pressure setup next. Thanks for testing this!

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
ashford
Posts: 89
Joined: Mon Oct 24, 2011 3:41 pm

Re: 4r70w setup

Post by ashford »

not to be a nag(trust me i appreciate the help) but could i get a few changes in the code

can i have shift tables based on tps and pressure tables based on map. this would be a huge help on a turbo car. a map based shift tabe is giving me no love.
another thing would be when the gear position is 2 it stays in 2 no downshifting to first.
pwm in neutral to be able to be set lower than 40

a few bugs?
tcc stays locked when decelerating shifting from 4th to 3rd
if i manuall shift(lever) it stays in 1st till mph goes to 0
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: 4r70w setup

Post by Bernard Fife »

ashford,

Different load measures for the tables ought to be an easy change, I will look into it. In dealing with these things, it helps if there is a separate thread for each topic, otherwise requests tend to get lost and eventually forgotten. So you might want to start another thread on this.

Having the gear stay in 2nd when the lever is set to 2nd isn't likely to happen. That code always assumes that the lever sets the highest gear, not the only gear. You can get the behavior you want with the current code, though. If you want the trans to stay in 2nd, you need to shift into 2nd using the shift buttons to enter manual mode and shift to 2nd, then the trans will stay in 2nd until you shift or go into auto mode (or exceed the upper or lower rpm limits, if you have enabled them). The general idea is that you should put the lever in P, and then shift with the buttons, that's the point of having an electronic controller with a manual mode and shift buttons.

The PWM minimum is set in the INI. So you can change it just by editing the INI in a text editor (such as notepad.exe). You can find it yourself, our you can wait for me to post the details when I am closer to my main computer.

If you find a bug, please report it by posting a datalog and MSQ that illustrates the problem. Be sure to describe exactly when the problem behaviour starts in the log, what it is actually doing, and what you think it should be doing (ideally based on what the manual says it should be doing). That way we are both looking at the same issue, and can define the problem properly.

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: 4r70w setup

Post by Bernard Fife »

The minimum line pressure is based on General Motors lower limit for the 4L60e/4L80e transmissions. This limit may not apply to other transmissions. No code changes are required to change the limit. You can lower it yourself simply by editing the INI with a text editor (like notepad.exe or notepad++.exe).

To change the PWM minimum, find a line in the INI like this:

Code: Select all

  pc_table         = array,   U08,   273,        [16x9],       "%",    -1.00000,    -100.00,     40,    100,        0    ; The PWM% for PC solenoid by load and mph 


the 40 value is the minimum. Suppose you wanted to change it to a lower number, say 20. Change the value of 40 to 20, like this:

Code: Select all

  pc_table         = array,   U08,   273,        [16x9],       "%",    -1.00000,    -100.00,     20,    100,        0    ; The PWM% for PC solenoid by load and mph


Then you would be able to set line pressure table values as low as 20. There are other places in the INI where similar limits apply to line pressure settings (minimum line pressure in neutral/reverse, shift pressures, etc.) and you change them in the same way.

However, use great caution doing this! It is possible to set the line pressure too low for the transmission to operate correctly, and you could quickly burn out internal friction elements and/or damage other transmission components.

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: 4r70w setup

Post by Bernard Fife »

ashford,

The latest 4.119 beta code ( viewtopic.php?f=4&t=240&p=3323#p3323 ) allows the user to set different options (either MAP or TPS or mixed MAP or TPS) for the pressure control and gear tables, as you requested. This more complicated to do than I originally thought, and you will need to change some settings in TS (see the link for details). I have tested this on the bench, but it is certainly not exhaustively proven, so use it with great caution.

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
ashford
Posts: 89
Joined: Mon Oct 24, 2011 3:41 pm

Re: 4r70w setup

Post by ashford »

MUCH better, with some off the top of my head table generation it almost shifts like a stock tranny.
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: 4r70w setup

Post by Bernard Fife »

Ashford, Great, that's good to know. Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
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