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Old 08-24-2013, 10:25 AM   #20
mad_sb
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Quote:
Originally Posted by xjohnx View Post
I'm assuming those are the port injectors that are at 100% and that you plan on upgrading, as there are no aftermarket DI injectors available yet. What's your DI injector utilization look like? i can't imagine you're maxing out both port and DI on 93 octane.
It's more complicated to determine the DI duty cycle since you have a smaller window for injection time on the DI side.. Standard duty cycle calculations do not work. And, start of injection point is variable to make it a little more complicated. I have been trying to figure it out myself even though i am still NA but on E85.... with plans to do an innovate next year.

For the most part, at say 7,000 rpm, the SOI for the DI's is 10 degrees inside the exhaust stroke. So, you have at most 1 revolution or 1/2 cycle for the injection window. That gives you at most 8.5ms for injection on the DI side, again assuming you can spray all the way up to 10 degrees btdc on the compression stroke (in most cases the plug would already be firing at this point).
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Last edited by mad_sb; 08-24-2013 at 10:39 AM.
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