Injector timing
Discussion
Gelf VXR said:
Batch fire? isn't GM small block a sequential multi port fuel injection fuel system?
Yes, but I'm saying thousands....millions of cars around the world use batch fire too with no issue.Sequential in the case of modern stuff is as always largely aimed at emissions and efficiency where they do enormous amounts of testing to optimise..
Something you or I cannot easily do.
You'd probably spend more money on fuel trying to achieve something....than it would ever save lol
KMud said:
right now I'm running a cam with IVO ~16 degrees earlier, but stock injector timing (so at least partially spraying onto an open valve)...I am just looking to align the events again really.
This to me seems like something sensible to aim for. GM spent plenty of time setting the timing of EOI compared to IVO, it was presumably set where it was for a reason. So if you've changed IVO because of a different cam, it'd make sense that you need to shift EOI too.However, we are assuming that EOI is timed where it is based exclusively on IVO, whereas perhaps there are other factors that influence its timing as well?
Interesting thread anyway, any posts I have to read a couple of times to make sure I understood are a good thing as far as I'm concerned
SturdyHSV said:
This to me seems like something sensible to aim for. GM spent plenty of time setting the timing of EOI compared to IVO, it was presumably set where it was for a reason. So if you've changed IVO because of a different cam, it'd make sense that you need to shift EOI too.
However, we are assuming that EOI is timed where it is based exclusively on IVO, whereas perhaps there are other factors that influence its timing as well?
Interesting thread anyway, any posts I have to read a couple of times to make sure I understood are a good thing as far as I'm concerned
There are more tables on the later OSs, but I think just timing offset with respect to ECT on LS1B. HP tuners have another value for the boundary between cycles (basically IVC I think) which EFI live lacks.However, we are assuming that EOI is timed where it is based exclusively on IVO, whereas perhaps there are other factors that influence its timing as well?
Interesting thread anyway, any posts I have to read a couple of times to make sure I understood are a good thing as far as I'm concerned
SturdyHSV said:
However, we are assuming that EOI is timed where it is based exclusively on IVO, whereas perhaps there are other factors that influence its timing as well?
From my observations, I think the boundary and IVO are the two main reference points in the cycle. The cycle is 720°, EOI is 220° before the end of boundary of the current cycle, that leaves 500° for the injector off time and injection duration with the inlet valve closed.As rpm increases, the boundary advances up to a further 180°, like wise when cold it advances up to 490°.
SOI and EOI duration normally happens on a closed valve, but when injector off time and IPW are greater than 576° (IVO 16°ATDC at 0.050) which is around 80% duty cycle, EOI has no place to go other than to retard towards the end of boundary when the inlet valve is open and during the induction stroke.
When IDC is maxxed out, installing larger injectors allows for SOI to EOI injection on a closed valve, for improved efficiency and emissions.
Its logical to maintain GM's duration between EOI and IVO.
By the way, I work away, I travel a lot and stay in hotels with plenty of time to think about these things, to relive the boredom
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