Subject: [FlyRotary] One more = question=20 (Tracy, see comments inred)

Good explanation and I agree with everything except the part = about=20 RPM not being used by the EC2. Engine speed is a primary = input to=20 the system, hence the term "speed - density system".   =

Ok, if I understand you = correctly,=20 Tracy, then RPM IS a computational variable in=20 determining fuel injector pulse duration and not just the = "frequency of=20 injection" factor. Is RPM an adjustment for "Volumetric = Efficiency" at different rpms or used for a different=20 purpose??

Ed

Guess a little more detail is needed to explain this. = The EC2=20 re-computes the injection requirements in real = time.  Just=20 before the intake cycle starts, it computes the required fuel for=20 this individual intake cycle. You can't get any more = closely=20 tied to RPM than this.

The volumetric efficiency is very = much affected by the=20 design of the intake system. Since there are no two alike = out there=20 (at this time), it is not possible to take VE into = consideration as a=20 function of RPM. Detroit has it much easier in this respect = because=20 they can control every detail of the engine.

Tracy

Ok, one more time for us = slow=20 folks. I understand that the EC2 calculations some = "adjustment" to=20 the fuel requirement for each intake cycle. Since the intake cycle = is=20 certainly tied to rpm in so far that the rpm determines the number = of=20 intake events per unit time. I think I follow that = each intake=20 cycle can be different as far as fuel requirement.   I = had=20 assumed that the fuel injection adjusment is primarily based = on the=20 manifold pressure it senses. In otherwords, if the Ec2 = senses 17" Hg=20 manifold pressure at a specific intake manfiold air temp it=20 calculates X milleseconds of injection time. I had assumed = that this=20 amount of injection time would be the same whether 17" = at 3000=20 rpm or 17" at 5000 rpm but that since the injector fires more = times/sec at=20 5000 rpm than 3000 rpm there would be more fuel injected. = In=20 otherwords, I had assumed that since the EC2 does its calculation = for each=20 cycle, it didn't know(orcare) whether the cydle was happening at = 3000 rpm=20 or 5000 rpm only what the manifold pressure was at each = rpm.

Since my assumption is = apparently=20 incorrect, then over a beer, you need to explain it to me one more = time=20 how the RPM is a factor in the computation of fuel injection=20 time.

I strongly suspected that = Ve wasn't=20 really a factor for the reasons you stated, too bad = {:>)

Ed=20 = Anderson