Quote:
Originally Posted by Yoshi
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Thank you for posting that helpful table. I should have known better than to doubt you (when I suggested that no correction factor is needed). The table you posted has convinced me that there is indeed a need for a correction factor. However, I am going to risk repeating my mistake, by doubting you again, but this time in the other direction.
Quote:
DYNAMIC = STATIC * ( 2.5mS - X ) / 10mS
0.487 = 2.44 * ( 2.5 - X ) / 10
X = 0.5mS
This injector has 0.5mS mechanical delay.
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Your equation is correct. And when you apply it to the first injector on the list, it does show that the proper correction factor is 0.504mS. Trouble is, the other injectors on that table seem to behave differently. When you apply your equation to the other injectors, they all have correction factors higher than that. The other correction factors range from 0.550mS to as high as 0.805mS. That latter number applies to the last injector at the bottom of the second table.
(I guess I was doing this at the same time dcb's wife was. And it's nice to see that we found the same maximum!)
And it turns out that using 0.500mS instead of 0.805mS (for that particular injector) will lead to an overall error of almost 18%. The error is large because the absolute difference between those two numbers represents a large portion of the pulse width (2.500mS).
I also looked at other injector specs (like here:
http://www.racetronix.com/), and they support my finding, that the discrepancy between static and dynamic flow cannot be handled by a single, universal correction factor.
I think this is ultimately a very manageable problem, because there are various ways an end-user could determine the proper correction factor to apply for his vehicle. But I think it's probably a good idea to make this a parameter that can somehow be altered by the user.