061 | Optimising Injection Timing

Hey Team,

I am probably a couple of weeks off giving my car (Altezza M/T 3SGE in an MR2) a big tune up

I can see that there is probably not much to be gained however I was wondering if I should tune a couple of different portions of the map (idle, low and high load at 2500 and 5000 rpm) to maximize the tuning before I do a full fuel map or if I should just leave it at something like 400 deg EOI like Link has in the base maps.

I am planning on basically fully utilizing all tuning options to ensure the most optimized tune. My hope is that after tweaking all of the settings I can gain a small amount of power and efficiency throughout the engine rev range.

Another question (although theoretical) is what if I had rather oversized injectors (but high quality ones that can sustain low load fueling accuracy). Would this mean that injector timing has a larger effect at WOT?

Thanks heaps,

Reuben

In most cases you will only see a difference from injector timing if the inj DC is less than about 50%, so this will mean with typical road car sized injectors and injection strategy you will unlikely see any difference at high loads. For high-end NA engines we generally use staged injection and high fuel press so that DC at WOT is lower and we can get all fuel in the ideal window. A single large injector is not necessarily the best way to achieve the shorter injection window, as spray pattern/atomisation is generally poorer with larger injectors and has just as much influence as timing when you are looking for the last couple of %.

With most road engines where the injector is close to the intake valve and you have an injector with decent atomisation the ideal timing for idle and low loads will generally end up not far from the 360-450 range that you will find in our base maps.

Hi Adam,

Thanks for that.

I think I will stick with 400 degrees like in the basemap and call it good enough.

May revisit it after the rest of the full tune

Thanks, Reuben