The MegaSquirt Project has experienced explosive growth other the years, with hundreds of new MS installations occurring every week - a phenomenal success! MegaSquirt has been successfully used in all aspects of Internal Combustion engine applications including R&D, Industry, Race, and Research. The MS project has transformed itself from a simple R&D project into a full-featured mature engine control system. To reflect this the support structure has also changed to meet the needs of MegaSquirt Users.
Moving forward, the R&D forums for MegaSquirt project are in a read-only mode - no new forum posts are accepted.
However the forums will remain available for view, they still contain a wealth of information on how MegaSquirt works, how it is installed and used. Feel free to search the forums for information, facts, and overview.While the R&D forum traffic has slowed in recent years, this is not at all a reflection of Megasquirt users, which continue to grow year after year. What has changed is that the method of MegaSquirt support today has rapidly moved to Facebook, this is where the vast majority of interaction is happening now. For those not on Facebook the msextra forums is another place for product support. Finally, for product selection assistance, all of the MegaSquirt vendors are there to help you select a system, along with all of the required pieces to make it complete.
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.
I am interested in controlling an Allison 1000 with the MegaShift controller. I have done a little research into this transmission, and so far it seems that the current firmware might not support it. From what I have read so far, it looks like the newer Allison's have three solenoids to control line pressure, a main line pressure solenoid, an on coming shift pressure solenoid, and an off going shift pressure solenoid. They have 3 shift solenoids which seems pretty normal for a 5-8 speed auto, and finally a TCC solenoid. Thats a grand total of 7 solenoids on the '04 and newer Allison's. The '03 and older Allison's lack the main line pressure solenoid. '05 and earlier A1000's and 5 speeds, '06 and newer are 6 speeds. All versions have to be shifted sequentially. After looking breifly at the MegaShift application in TunerStudio, it doesn't appear that the Megashift is setup to control three line pressure solenoids. Can anyone confirm this, and if so is it something that could be easily added?
It depends on how the additional line pressure solenoids operate. Are they pulse-width-modulated? Do they run at a constant duty cycle when on? Or are they varied in response to some other parameter? If so, what is the logic used to control the solenoids (what gears, speeds, etc., and what PWM duty cycle under given conditions).
The GPIO board has 8 high current solenoid drivers (and 4 more low current drivers that could be connected to high current drivers), so that isn't a limiting factor. Sequential shift is already in the code, of course.
The three pressure solenoids are PWM at 1kHz. The TCC is PWM at 100Hz. The three shift solenoids are discrete on/off. I have yet to verify these myself. Most of the info I have found so far is from this site: http://www.4btswaps.com/forum/showthrea ... ide-thread They have done a very good job finding info about the Allison transmissions. From what I have seen so far, it looks like the on going/off going pressure solenoids could possibly be controlled together with the same output, and control the main line pressure solenoid seperately. My dad has an '08 Chevy truck with an A1000 trans in it, so I will try to borrow it sometime to verify its operation. I will try to get solenoid impedance, frequency, duty cycle, and see if I can figure out how the three pressure solenoids are operating.