It was brought up in another thread, so apparantly, when going larger, you need to adjust it. I've read up on it but how do you know it needs to be adjusted as they say ALL injectors need it adjusting?
It was brought up in another thread, so apparantly, when going larger, you need to adjust it. I've read up on it but how do you know it needs to be adjusted as they say ALL injectors need it adjusting?
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It needs to be adjusted when the injector design or manufacturer changes. If you're running +20's or +40's, you're probably OK with the stock latency curve. But, if you switch to Accel 96lb injectors, for example, you need to get and input the latency table. Likewise for Mitsu injectors, or Ford injectors, etc.
There is not a direct relationship to the size of the injector. It's simply a measure of how long it takes to open the injector. IE, once you apply voltage, how long until it actually starts to flow fuel. It's not instantaneous, and when you consider the idle PW for a cal with big injectors is in the single digit milliseconds, the latency can be very significant - especially if it's wrong. It's much less of a concern at higher PW's (like in boost).
The latency is added to the pulsewidth. So, if it's too high, you end up with a PW bigger than you actually need and a rich idle.
EDIT: I added my excel file of injector latencies. I'm sure there are more than this out there...
Interesting... additionally, there is a correction for battery temp? I've always been a bit puzzled by that one, it seems to me that if the voltage is consistent, the actual temp of the battery shouldn't mean anything, as I assume the function of the injectors (reaction time/latency) would be the same for a given design and applied voltage... But I suppose if you had an alternator that was not keeping up or something, it might mess with the actual latency... Please set me straight if I'm off base here...
Mike
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The battery temp is only used to set the target battery volts. It has no effect on fuelling, directly...Originally Posted by zin
Last edited by ShelGame; 03-20-2012 at 02:53 AM.
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