S_AUJP Version 7 - Now Supports Turbo (August, 2021)

Revision 2 November 22, 2021
Provides:

C4 Corvette CCM Commands.ADX

For these cars, includes the CCM Commands that must be added to the S_AUJP ADX.

Updated ADX files to allow cars with 4L60 transmissions to report 2nd and 3rd gear status in addition to the currently available 4th gear status. Details here:

https://www.thirdgen.org/forums/diy-...ar-status.html

***** END REV 2 *****

Revision 1, October 15, 2021
Documentation was updated to reflect an omitted description of a correction to the Shift Light logic. No other files were changed. Below is a summary:

Beginning with the first version of S_AUJP (v4), the factory shift light provision applicable to manual transmission cars was removed because the fuel efficiency portions of that feature were deemed to not be applicable to a high performance application (1st to 4th shift, etc.). The removed factory provision was replaced with simpler logic providing shift indication at only a single calibration-specified RPM. This made the function available to both manual and automatic transmission cars. However, the logic was flawed because not all cars are factory-equipped with a shift light bulb in addition to the Check Engine Light (CEL) bulb. Under certain circumstances, a constant flickering of the CEL and possibly an installed Shift Light bulb was noticed.

This revision corrects that problem. The CEL now correctly indicates the Shift Point RPM in all cars. Cars with a factory shift light bulb (manual transmission cars), will find that the Shift Light bulb operates in concert with the CEL.

Also in this revision, the previous requirement to be in-gear for Shift Light operation was removed. Now the Shift Light operates in P/N to allow testing of the light-ON duration.

***** END REV 1 *****

In one BIN, S_AUJP Version 7 (v7) now provides 2 and 3 Bar Turbo support while continuing as before to support 1 Bar Normally Aspirated (NA) engines.

What v7 does

• Provides extensively-in-car-tested 1 Bar NA and 2/3 Bar Turbo support.
• Allows immediately running Boost by merely entering the MAP sensor Bar type (2 or 3), and updating or entering a few Turbo-related values.
• Automatically handles MAP conversion from 2/3 Bar to 1 bar equivalency for 1 Bar NA operation when not in Boost.

Details and files here to avoid duplicate posting and maintenance: https://www.thirdgen.org/forums/diy-...ml#post6437472

All feedback appreciated. Happy Boosting!

Neat.

Any plans for adding ECM controlled boost?

Unlikely to add anything. Looked at what GM did with the Buick GN turbo thinking using PWM for the solenoid would work by mirroring the CCP or EGR logic. But the GN is basically a somewhat dumb system. Boost is turned on if air flow exceeds 75 gm/sec, and there is progressively less boost applied in 3rd and 4th gears. That's it. Not worth it. And talking to GN racing guys, they seem to favor removing the actuator from ECM control while keeping it plugged in to avoid a code, and using one of the available mechanical pressure solutions, sometimes even over the electronic.

Turbo Sunbird/SYTY, Turbo Grand Prix, and Lotus Carlton all have boost control code in P4 ecm's. TGP and Sunbird code is known for overboost and spiking. I've played with some of the parameters and it's possible to adjust the code for better response. But I ended up setting desired boost tables to max and using throttle to modulate HP. However, it might be worthwhile to include safety functions if ECM is detecting knock that can't be resolved by retarding timing. Could save a piston or two if you could increase fueling and decrease boost.

1Proj --
Agreed. Thanks for your suggestions. They along with others were considered during development, much like what was done in $12P with a staged shutdown if issues. But had to end somewhere to get this beast released. Took the approach that anyone who installs a Turbo and immediately goes WOT at 2 or 3 Bar is not sane. Easy does it and always on the rich side with low SA is the proper approach. If that's done, many issues are solved as we noticed during our extensive testing and logging.

Programming is somehow a task that never ends.
Elky

I was thinking more along the lines of the Sy/Ty and Code59 type boost control, which has worked well for me. The tables are there and allow for lots of adjustment.

Quote:

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anyone who installs a Turbo and immediately goes WOT at 2 or 3 Bar is not sane

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And that is why youtube videos are so fun to watch. :laugh:

Started planning a NON gm i4 to run S_AUJP. Would run 4 saturated injectors NA and use electric fans, manual transmission. I have downloaded and the docs. Just to be clear before I throw money at a project, would a 7749 work with an i4 memcal?
Would it need to be pinned as a 7730? What pinout would I use?

I seen the recommended settings for i4 but it says untested on i4, am I really in uncharted territory?

Would i be able to make use of the two injector drivers in the 7749, and run bank fire, or is it batch fire only with this code?

Any info is appreciated ��
Thanks