- Wed May 31, 2023 4:51 am
The STM32 and Teensy variants can do full sequential injection and ignition (8X8). The the mega256 based "standard" speeduino lacks the the number of timers (Or at least thats my understanding).
In My case the desire for for sequential injection on a V8 is mostly for individual cylinder fuel trim capability. Not a big deal on stock type engines which is probably something like 95%+ of the speeduino instalations, but for something thats a lot higher output with the VERY real potential of self harm due to just having one hole a little lean, its worth it. Of course you need to tune with multiple widebands to get all eight dialed in evenly.
A little side benefit may possibly be a tiny bit better idle control, but thats not the real main benefit. horsepower wise you'll make the same peak power with full sequential as you would batch fire.
Even with a Tunnel-Ram, on a V8 you will have uneven airflow from one cylinder to the next. Part of the problem is adjacent ports in the manifold disrupting airflow depending on the firing order and runner enterance placement. A wideband in a header collector is just an average of the cylinders feeding it. Once again, on stockish mild cam engines this isnt a big deal and they dont vary that much. But with more cam, displacement and compression, you start to see the effects of runner length and port design become more and more significant. Add on high boost and heat running right at the detonation limit of whatever the fuel is being used, and it becomes worthwile. At least, thats what I think.