Hello all.

I have an issue which I would like to ask about.

Piggy Back ECUs seem to all work by intercepting the PCM signal and adding or subtracting either fuel injection or ignition timing or both.

The RX8 has 3 injectors per rotor, The (smaller) Primary injector, the Secondary injector and the P2 injector.

Now seeing as the smaller Primary is solely responsible for adding fuel until around 3500 RPM, and both Greddy Turbos and most superchargers seem to spool up immediately from like 2000 RPM this seems to be a "conflict of interests"

How much power / fuel can the Primary injector deliver safely solo until the other 2 injectors join in the party?

Is there a way to use a piggy back to somehow trick the other injectors to join the party early?

I guess switching the Primary injectors for the bigger P2 injectors is a (risky?) option for intermediate power boosts? or just adding bigger Primarys so all injectors are the 380CC ones? But adding / fiddling with actual car parts is something I would like to avoid.

Any ideas? (again forgive my ignorance, I am slowly trying to grasp A: The vagaries of tuning and B: the mysteries of rotaries!)

 

At first I thought the search feature was broken, then I realized its just you.

https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/so-you-wanna-tuner-100333/
https://www.rx8club.com/showthread.php?t=53406
https://www.rx8club.com/series-i-major-horsepower-upgrades-93/definitive-greddy-turbo-fixes-here-they-81825/
https://www.rx8club.com/series-i-tech-garage-22/rotary-math-106294/
https://www.rx8club.com/series-i-major-horsepower-upgrades-93/e-manage-ultimate-success-93286/
https://www.rx8club.com/series-i-engine-tuning-forum-63/na-emu-tuning-108455/
https://www.rx8club.com/series-i-major-horsepower-upgrades-93/perfect-management-110004/

I threw that last one in for grins.

 

I read lots of threads about piggy back stuff, but it didnt seem to answer exactly what I wanted to know...

Thanks for links, will plough through them now....

Edit: Thread one: I already have that printed out as my beginner tuner bible..haha!
Thread 2, reading now. Its interesting that the E-manage allows direct control of 2 injectors which you can use to independently fire the P2 injectors. I wonder how many other Piggybacks allow this kind of "bonus control" rather than just intercepting PCM signals? Trying to track down actual specs of various systems online is hard because you usually just get stupid sales places...
Rotary Math thread: Already downloaded both spreadsheets. Very interesting stuff, especially seeing the injector breakdowns like that. The math stuff is a bit mind blowing for me, but I try and grapple with it sometime..(rarely)
Last thread : read already.

Still ploughing on, but hunger is now making it difficult!

 

Almost all of the "fuel computers" on the market (Haltech, Microtech, TEC3, MegaSquirt, etc.) can do independent control and can be wired for full or semi-autonomy.
"Interceptors" like the EMU can be wired for a bit of both.