I have 2 banks of 2 injectors on my 4 cyl. I switched to running alternating/4 squirts as it seemed to give a smother feel, possibly due to the fact that now all cyls get a squirt when intake is open and one when its closed, whereas before some cyls were only getting squirts when closed?
Anyway, in terms of DC on my injectors, is the alt/4 config worse (max 7500rpm) for injector lifespan and should i return to alt/2? OR should i switch to one bank of 4 and do multiple squirts?
IE whats the best setup for a 4cyl, 4 injector engine at the limits of the injector sizing. I only ask as im about to re-wire my harness and thought i might as well get it right.
Ta
J
Alternating/4 instead of alt/2
Moderators: jsmcortina, muythaibxr
If I'm running single bank firing of all 4, only one intake valve will be open at any one time. If im 2 banks of 2 running alt/2 two will be open and two will be shut (the same two every time). alt 4 should give *each* cyl one squirt on a closed and one squirt open? (each injector squirts twice in an engine cycle of two revs?).
I see your point about opening time being increased - makes sense. The thing i want to avoid is uneven mixing across cyls. If I squirt all 4 injectors at once I'll always be squirting each cyl at the same point in its cycle. Which means only one (cyl 2 for example) will get squirted when intake valve is open, in any condition. Ideally you'd go with sequential obviously but as thats not possible i want to get to the closest alternative. alt/8 would give one squirt on each stroke which would be ultimate but the injector would spend its entire life opening lol.
So you're telling me that 1 bank of 4 would work just as well as two firing two alternating? I just dont want to stress the engine oddly, especially as its putting out out ~150bhp/litre.
Also, with multiple squirts per injector, does the fuelling get re-calculated more often? Hence the better responsivness?
J
I see your point about opening time being increased - makes sense. The thing i want to avoid is uneven mixing across cyls. If I squirt all 4 injectors at once I'll always be squirting each cyl at the same point in its cycle. Which means only one (cyl 2 for example) will get squirted when intake valve is open, in any condition. Ideally you'd go with sequential obviously but as thats not possible i want to get to the closest alternative. alt/8 would give one squirt on each stroke which would be ultimate but the injector would spend its entire life opening lol.
So you're telling me that 1 bank of 4 would work just as well as two firing two alternating? I just dont want to stress the engine oddly, especially as its putting out out ~150bhp/litre.
Also, with multiple squirts per injector, does the fuelling get re-calculated more often? Hence the better responsivness?
J
OK well thats fairly comprehensive - makes sense. In that case I'll stick with alt/2 as my fueling system is known to be OK to around my current power but not much more - no point stressing it.
Clears up all my thoughts, except why i feel more responsivity when running alt/4s. Maybe thats an AFR thing, interesting. I need all the DC i can get so 2 x alt/2 it is.
Cheers.
Clears up all my thoughts, except why i feel more responsivity when running alt/4s. Maybe thats an AFR thing, interesting. I need all the DC i can get so 2 x alt/2 it is.
Cheers.
If your entered injector opening time is off a bit, then you would be running a slightly different mixture with more squirts as well. That might change the 'feel' of the setup. There was a good thread about determining the correct injector opening time settings, but I can't seem to locate it now.coyoteboy wrote:...Clears up all my thoughts, except why i feel more responsivity when running alt/4s.
David