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As i understand it you can alter the duration of injector events but i have been looking at tunerpro and can't see anything to work with the timing of injector firing in relation to crankshaft position which could be usefull with big cams or radically altered duration and especially phasing of the inlet lobes. Am i merely overlooking something obvious?

Injector timing only applies to Sequential ECU's ie. VSV6 onwards.
All of the earlier stuff fires the injectors either simultaneously, or in 2 groups (VrV6).

UCMatt wrote:Injector timing only applies to Sequential ECU's ie. VSV6 onwards.
All of the earlier stuff fires the injectors either simultaneously, or in 2 groups (VrV6).

I realise the old VN's fire all six injectors simultaneously but when? Theres a heap of fuel hanging around in the plenum but i believe there could be an advantage from firing the injectors when the piston on the intake stroke is at 70-75 degrees past TDC which is maximum piston velocity - thats the best place for phasing the intake flow for cylinder filling to make power so it makes sense to time the injector to get a homogenous intake charge. Might work even better with a bigger injector and reduced duty cycle.

Your thoughts guys???

VNracer34G wrote:I realise the old VN's fire all six injectors simultaneously but when? Theres a heap of fuel hanging around in the plenum but i believe there could be an advantage from firing the injectors when the piston on the intake stroke is at 70-75 degrees past TDC which is maximum piston velocity - thats the best place for phasing the intake flow for cylinder filling to make power so it makes sense to time the injector to get a homogenous intake charge. Might work even better with a bigger injector and reduced duty cycle.

Your thoughts guys???

but as you only have one injection event it will give no advantage as there are six points that are potentially optimum for injection

i think the long and the short of it is, without have sequential injection your always going to have fuel hanging around in the inlet tract at some point in the combustion cycle.

Doctor Bob wrote:
but as you only have one injection event it will give no advantage as there are six points that are potentially optimum for injection

agreed, but how many injector events are there for 720degrees crank rotation and when do they occur? i spose i'm missing the boat somewhere hear buy if i give someone a laugh at my own expense all good

my guess here is there would be an injection event evert time a cylinder get to firing

One injector event per rev is the standard config, so two events for every engine cycle (720deg)

The early ECUs did not know what cyl number is what so they just get fired once per rev after whatever cyl was lucky enough to be first when the engine was started. There is a table called "Injector delay Table (% of Ref period vs RPM & TPS)" to adjust how far after the reference pulse the injection event happens.

VL400 wrote:One injector event per rev is the standard config, so two events for every engine cycle (720deg)

The early ECUs did not know what cyl number is what so they just get fired once per rev after whatever cyl was lucky enough to be first when the engine was started. There is a table called "Injector delay Table (% of Ref period vs RPM & TPS)" to adjust how far after the reference pulse the injection event happens.

VL400 you da man, thats the answer i wanted thank you