Custom 4T40E Trans Controller - Page 2 - Tuning Forum

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Re: Custom 4T40E Trans Controller
Monday, October 04, 2010 4:57 PM
I have listed the connector and pins the PDFs are listed on here.




Re: Custom 4T40E Trans Controller
Saturday, October 09, 2010 3:14 PM
Update...

The entire code is functioning properly. All range switch operations work as expected. Manual and Auto trans control under Drive work correctly. The table interpolation transitions the duty cycle seamlessly between table bins. The original VR calculator has been rewritten (admittedly, the original method sucked pretty hard ) and separated into two different routines for the CPS and VSS. The result is a much faster and more accurate RPM and Vehicle Speed calculator.

However, there is one unexpected hangup. I was foolishly expecting the PC and TCC solenoids to operate at the same PWM frequency, as well as hoping that I could just scale the PWM down to the appropriate frequency. Neither of these is the case. So, I'm going to have to instead use the microchip timer and isr interrupt to generate the two PWM frequencies (PC = 614 Hz, TCC = 42 Hz). I also found out some other critical information that would have likely been burning up PC solenoids left and right. Apparently 40% Duty Cycle corresponds to 1.1A (i.e. max safe current and 50psi line pressure).

When I get this sorted out, I'll try to upload a video showing the outputs for different load conditions and explaining the circuit as best I can.




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Re: Custom 4T40E Trans Controller
Monday, October 11, 2010 3:28 AM
So can you adjust the Duty cycle for more line pressure?





Re: Custom 4T40E Trans Controller
Monday, October 11, 2010 7:48 AM
-MD- Enforcer wrote:

So can you adjust the Duty cycle for more line pressure?

I explained it before in another thread. The pressure control solenoid is a bleed valve. That means max line pressure is achieved when the solenoid is deenergized (duty cycle 0, which corresponds to 160 psi. There's no way to achieve higher line pressure without changing out the transmission internals.




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Re: Custom 4T40E Trans Controller
Monday, October 11, 2010 7:52 AM
Whalesac wrote:

-MD- Enforcer wrote:

So can you adjust the Duty cycle for more line pressure?

I explained it before in another thread. The pressure control solenoid is a bleed valve. That means max line pressure is achieved when the solenoid is deenergized (duty cycle 0% ), which corresponds to 160 psi. There's no way to achieve higher line pressure without changing out the transmission internals.

Fixed




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Re: Custom 4T40E Trans Controller
Monday, October 11, 2010 8:13 AM
How is the B&M shiftplus and auto-interceptor increasing the line pressure then?

Also, I'll have to look inside HPTuners to see what variables can be changed.





Edited 1 time(s). Last edited Monday, October 11, 2010 8:20 AM


Re: Custom 4T40E Trans Controller
Monday, October 11, 2010 10:22 AM
The factory pressures are nowhere near 160 so those do up the pressure but probably still not near 160psi



Re: Custom 4T40E Trans Controller
Monday, October 11, 2010 4:56 PM
-MD- Enforcer wrote:

How is the B&M shiftplus and auto-interceptor increasing the line pressure then?
Also, I'll have to look inside HPTuners to see what variables can be changed.

Because these devices are ran in parallel with the PCS, there's only 2 ways to achieve this.
1) linearly reduce the voltage output
2) alter the duty cycle by grounding (actually just very low resistance relative to the solenoid's resistance) for a given period relative to that duty cycle

Both methods will reduce current through the solenoid, reducing how far the valve opens, causing higher line pressure. However, #2 would require far more circuitry, so I highly doubt that's the case. I'll take some measurements and do some tests on my shiftplus sometime and let you guys know for sure what it does.




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Re: Custom 4T40E Trans Controller
Monday, October 11, 2010 5:03 PM
Oh, and everything you could possibly want to know about the 4t40e can be found here...GM 4T40E POWERTRAIN MANUAL

...the page is slow, so you'll have to be patient.




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Re: Custom 4T40E Trans Controller
Monday, October 11, 2010 7:52 PM
Well, I think I have the pwm frequency problem resolved



If you can't read it,
Freq(1) = 43.10 Hz
Freq(2) = 625.0 Hz






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Re: Custom 4T40E Trans Controller
Tuesday, October 12, 2010 3:42 AM
lots of good info here.....Subscribed






RIP JESSE GERARD.....Youll always be in my thoughts and prayers...




Re: Custom 4T40E Trans Controller
Sunday, October 17, 2010 10:00 AM
As promised

http://s141.photobucket.com/albums/r44/whalesac/?action=viewĄt=VIDEO0019.mp4

I didn't know photobucket cuts off after 10min. All that was shown was that the Line pressure signal goes to 0% duty cycle when the pot reached some value.




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Re: Custom 4T40E Trans Controller
Sunday, October 17, 2010 10:18 PM
^^^^^^^^^^ Sorry guys. I'm not sure what the deal is with photobucket and sharing video. I can watch the video just fine from my album. Anyways, I uploaded it to youtube as well, so here you go...







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Re: Custom 4T40E Trans Controller
Monday, October 18, 2010 6:13 PM
thats awesome man! so, when you making me one?????lol
Re: Custom 4T40E Trans Controller
Tuesday, October 19, 2010 5:51 PM
I have considered making multiples for whoever wants. I would like to make a GUI first, though, so you can have easy access to all the parameters. This might require external ROM or even another PIC. We'll see.

BTW, the 8MHz clock came in and I have a nice 42.02 Hz and 615.8 Hz signal with roughly 200-bit resolution on both PWM's. I'm starting work on the amplifier circuitry right now.





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Re: Custom 4T40E Trans Controller
Tuesday, October 19, 2010 8:41 PM
how much might one be?

its a piece of artwork you have created sir.
Re: Custom 4T40E Trans Controller
Tuesday, October 19, 2010 9:30 PM
Whalesac wrote:

I have considered making multiples for whoever wants. I would like to make a GUI first, though, so you can have easy access to all the parameters. This might require external ROM or even another PIC. We'll see.

BTW, the 8MHz clock came in and I have a nice 42.02 Hz and 615.8 Hz signal with roughly 200-bit resolution on both PWM's. I'm starting work on the amplifier circuitry right now.

Wow, that was stupid. I meant a resolution of 200 (i.e. 200 steps between 0-100% duty cycle), which is slightly less than 8-bit. Sorry about that.
Dave De Stefano wrote:

how much might one be?
its a piece of artwork you have created sir.

It's still much too early to tell, but it should be considerably less than the Megasquirt GPIO board...probably less than half, even.




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Re: Custom 4T40E Trans Controller
Thursday, October 21, 2010 5:17 PM
Another little update...

Used another PIC today to provide two seperate pulsewidths, simulating the CPS and VSS signals. I've tested all conditions, and everything works perfectly.
A testable prototype shouldn't be too far off




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Re: Custom 4T40E Trans Controller
Sunday, January 02, 2011 6:57 PM
I received an email from a concerned individual about the current status of the project. I figured I might as well just let everyone know what the deal is...

The project had to be put on hold. The company I was having do the boards forgot to put my order in (over a month after ordering back on Nov. 3). The boards should be here within the next few weeks. So, if everything is alright with them, then I can do some testing. After I can verify it works properly, I'll begin working on writing a GUI so someone like yourselves will have access to altering the tables. I would like to make it programmable through USB, but there are some astronomical fees associated with that, so it will almost definitely be through RS-232.

I also just invested in a new programmer, so I might migrate the code over to a more versatile PIC (likely a 44-pin QFP PIC24 or possibly a PIC32) which has an assortment of nice features (greater memory depth, CAN communication for Megasquirt users, among others) which will allow for a far more feature rich device.

That's about it for now. I'll update again when the boards get here.




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Re: Custom 4T40E Trans Controller
Monday, January 03, 2011 6:09 AM
I see no reason why RS-232 will not work just fine. Ideally USB would be the best choice, but RS-232 will be just fine.





Re: Custom 4T40E Trans Controller
Friday, January 07, 2011 4:49 PM
WOOOHOOO




I WAS going to start cutting pipe for my Turbo Header tomorrow...but now I just don' know




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Re: Custom 4T40E Trans Controller
Friday, January 07, 2011 6:38 PM
This seems like a heck of a lot of work to just get control of a slush box. I bet I could have had shifting control with a weekend and trip to the junkyard, manual swaps aren't that hard.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Re: Custom 4T40E Trans Controller
Friday, January 07, 2011 11:13 PM
Leafy wrote:

This seems like a heck of a lot of work to just get control of a slush box. I bet I could have had shifting control with a weekend and trip to the junkyard, manual swaps aren't that hard.

I have had manual control over my shifts for some time via manual switches, which took me but minutes to install. What's your point?

If you didn't read the thread, this is basically just something I wanted to try...mainly to test my abilities as an Electrical Engineer and learn from the experience. This is merely a starting point. Joshua has given me a good idea for another project (albeit not really profitable, considering how few of us use Megasquirt...but I'll try it anyways), and I have some ideas of my own for other future products. My original intent was just to design, test and showcase the controller, but it seems there is now some interest for it. So, I'll entertain those requests and push myself to develop my embedded programming knowledge/techniques further. Make sense?




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Re: Custom 4T40E Trans Controller
Saturday, January 08, 2011 6:31 AM
My sarcasm skills were weak last night.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Re: Custom 4T40E Trans Controller
Monday, January 10, 2011 4:17 AM
Finished yet. lol




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