Craigorypeck
Craigorypeck Reader
8/3/18 3:30 p.m.

Playing around with injection timing on my ms3. 

It's set at 360 from factory.

What gains can be had? 

I can see change at idle as that's easy to monitor but should I be aiming for more rpm.. More vacuum or leaner/richer afr? 

 

Matthew Kennedy
Matthew Kennedy Reader
8/3/18 3:38 p.m.

On a port injected engine there isn't much improvement to be had outside of improving efficiency, emissions and idle quality.  As a rule of thumb, finishing the injection somewhere near the time that the intake valve starts to open is reasonable.

jimbbski
jimbbski Dork
8/3/18 6:06 p.m.

What he said.  As engine load goes up and fuel needs increase the injector duty cycle increases. On some engines at full throttle that may mean near 100%!

Craigorypeck
Craigorypeck Reader
8/4/18 11:56 p.m.

I wacked 400 in across the entire injector timing table and it pulled fuel pretty much everywhere.

 

 

Red areas are where it pulled fuel. 

GameboyRMH
GameboyRMH MegaDork
8/5/18 1:37 p.m.

I use an injector timing table based on this one with 4 squirts per cycle:

It works OK. No major difference in AFRs from the stock setting of 360deg everywhere.

Matthew Kennedy
Matthew Kennedy Reader
8/5/18 8:39 p.m.

In reply to GameboyRMH :

With 4 squirts per cycle, the injection timing is doing almost nothing anyway.

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