stratified lean burn tuning aem

[koji_kabuto]

vtec-e uses stratified charge mixture at the spark plug. valve #1 opens directing air and part mixture to the cylinder wall creating a vortex while valve #2 slightly opens(fraction of a mm) to siphon the fuel that puddled around the valve seat into the cylinder. this creates a rich mixture at the center and lean around the cyl walls.

i noticed a couple of people are running aem ems. if i go to aem forum, i think nobody will care about economy since everyone in there wants to go fast.

stratification is also influenced by injector phasing. if we inject fuel earlier relative to valve opening. fuel is more atomized. if we inject late, fuel is concentrated though this may be beneficial in a stratified condition since only part of the cylinder has rich mixture and everything else is lean.

i just got the car running with aem ems and havent thought about economy. anybody played with injector phasing yet?

[GasSavers_RoadWarrior]

I thought about it on another car... but it seemed like you'd just gain in one place and lose somewhere else. Was thinking of phasing Marvin 60* early by swapping all the injector plugs round, allow more time for the fuel to cook off in the intake I thought, but it appeared that it wouldn't work like that because the ECU doesn't always do just one pulse per injector, even on SEFI systems, it will swap between paired and batch mode and single.

So, simple methods of doing it, look more likely to mess things, up, especially during cold starting, warmup and wide throttle openings.

If however, one took over injector timing totally, then experimentation with earlier/later injection could get you somewhere.

However, I've been thinking about it from a more "homogenized, fully vaporized lean mixture" approach rather than a locally rich stratified approach.

[koji_kabuto]

aem allows its user to take total control of injector phasing.
i havent set a baseline on mpg so i cant play with this yet.

man thats a lot of work that fuel vaporization, why not propane injection?

[dkjones96]

On an SFI vehicle adjustment of the cam position sensor will change when in the cycle the injectors fire.

However, on MOST vehicles this will be impossible because of the simple fact that an SFI vehicle also has advanced ignition control and advancing one also does the other and a vehicle old enough to have mechanical advance won't be SFI.

[GasSavers_RoadWarrior]

On the Escort and other Fords, the EDIS electronic ignition runs only off the crank timing signal from a PIP (Profile ignition pickup?) on a tone wheel under the pulley. The cam sensor is in the head... drilled right through the side of it, no hope of making that adjustable.

If you have injection run off crank timing rather than cam timing, it's probably a good idea to index the cam before playing with phasing in the cal. With a cam pickup it doesn't matter it' will be locked to the cam.