Switched over to two squirts per cycle from??..
The way I see this is, the required fuel value calculated is the fuel required by one cylinder for the given size of injector and does not take into consideration the type of injector sequence being used except for sequential injection.
Leaving the size of injector alone for now and using a calculated required fuel value, if you run batch fire on a four cylinder engine with a divider of 1, the required fuel value as calculated is 4 times as big as it should be, or, your injectors are 4 times as big as they need to be, or, the VE values are 4 times less than they need to be. You are only using a quarter of the injectors capebility and idle could suffer. You could possibly sumise that if the injector was already big for the engines requirements, the error has now multiplied by 4?
With the same required fuel value, setting the divider to 2, the calculated required fuel value is twice as big as it needs to be, or, your injectors are twice as big as they need to be, or, the VE values are twice as less than they need to be. You are now using half of the injectors capebility and idle will have improved over the above.
Same Required fuel value and sequential ,divider set to 1, the calculated required fuel value is the required fuel, the injector size is as originaly sized and the VE values are representative of the injector. you are now using the full capability of the injector.
Going back to the injector size. It is important to select the correct size injector for the expected full load demand of the engine, while taking into consideration which 'type' of injection you wish to use, sequential, semi sequential, or batch. Most 'calculators' I have come across will give you the size of the injectors to use on your engine, its basicaly telling you the required fuel in cc per cylinder. If running batch with a divider of 1, the injector size could be divided by 4. If the divider is set to 2 on batch, the injector size could be divided by 2, and if running sequential, with the divider set to 1 and simply use the calculated injector size. In doing this, the injectors are matched to the engines expected full load demand.
One other thing on injector sizing, most people say to use a max injector duty cycle of 80%. Fair enough, but does this leave enough room for EGO correction or Warm Up and Acceleraion enrichments for it to be safe? I know that Rover rated their injectors at roughly 60% duty. It may be possible to have a 10% EGOc with 5% warm up enrichment and 5% acceleration enrichment at the same time?? theres the 80%. If the original max duty was 80%, you can see that you might already have maxed out the injector.
Its all retrospective, as you can usualy tune the system by changing many settings, the problems arise when you use injectors sized way too big for the engine in the first place. Really big injectors dont like really small pulse widths.
I read that the idle PW needs to be in the region of 2ms for a decent idle quality, fair enough, and probibly a good rule of thumb. I know you can get the engine to idle reasonably well with PW of 1.2ms, but there must come a point where the injector just doesnt like anything less (ramp up time?), resulting in poor idle and 1.2ms must be getting close.
LOL, waffled on for too long and probibly got it all wrong, bit of a brain dump im afraid
Please discuss, and sorry to have hijacked your topic