Injector Flow Variance
#1
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Injector Flow Variance
Just got my rx-7 550s back from DW and this time the spread has increased -- looking at 4% for low and 2.5% for high duty cycles. What's the rule of thumb here for what is considered acceptable?
By my math I'd be looking at .2 to .5 point difference AFR from the leanest to the richest cylinder at worst case under high load. Obviously under cruise conditions it isn't a big deal. It has been pointed out to me that the differences in air mass getting to each cylinder will likely exceed that of the injector flow rates. My gut feeling is that this spread isn't a big deal -- then again, running one cylinder at 12.0 AFR and the other three at 11.5 with a gauge readout of 11.6 seems like risky business.
What are your thoughts MT?
By my math I'd be looking at .2 to .5 point difference AFR from the leanest to the richest cylinder at worst case under high load. Obviously under cruise conditions it isn't a big deal. It has been pointed out to me that the differences in air mass getting to each cylinder will likely exceed that of the injector flow rates. My gut feeling is that this spread isn't a big deal -- then again, running one cylinder at 12.0 AFR and the other three at 11.5 with a gauge readout of 11.6 seems like risky business.
What are your thoughts MT?
#4
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I intend to get as close as my fuel system will take me to 300whp on a 2871R. The injectors will probably see a base rail pressure of 55-60psi, the effects of which I don't know for sure as far as the spread goes. To me it's looking like I will have to target a 11.2ish AFR in boost/under load to be safe across all cylinders, which means I will be giving up a bit of power even on a moderate tune.
+1 on aaronc7's question, could help with injector placement.
+1 on aaronc7's question, could help with injector placement.
#6
I assume it would make sense to put the "richest" one in #4 as it tends to run hotter unless you have a reroute?
Question for the masses: Is there any other rhyme or reason as to which cylinders typically run richer or leaner? I'd guess if you have a spread in the injectors you can at least use it to your advantage.
Question for the masses: Is there any other rhyme or reason as to which cylinders typically run richer or leaner? I'd guess if you have a spread in the injectors you can at least use it to your advantage.
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