Quote Originally Posted by StraightSix
Uh, yeah. It is. Air-Fuel Ratio is defined as the mass of air to the mass of fuel in a combustion process. This is something that is immutable. It is fact; pick up an text on thermodynamics and look it up.




Now, let's actually think about this for a second. Knowing how an AFR is defined means that a 12:1 or 11:1 is really freaking rich. This is not good from the stand point of efficiency, or the chemical reaction of combustion. It's not good because not all of the fuel is being used.

It *is* good from the stand point of not blowing up a turbo charged engine. Too lean of a burn in that engine will cause combustion temperatures to rise; the excess fuel helps to keep combustion temps in the individual cylinders down. In a non-turbo charged application, combustion temps aren't as critical so the mixture can be leaned quite a bit.
I would ask you to stop trying to give advice about stuff you dont know about. but im sure you wont. but im going to try anyways. STOP TALKING!!! you have really no business talking about what A/F raitos should be.

Quote Originally Posted by green91
afr for optimal fuel usage and afr for optimal power are often different. most performance related vehicles will run slightly rich to ward off spark knock, and can allow a little more advanced timing. I would imagine 14.5:1 - 14.9:1 at idle, and approx 13.1:1 - 13.5:1 would be close for WOT, N/A. obviously the best bet would be to put it on a dyno and also have a detonation detection device of some sort.


how about you tune any turbo car @ 10+psi at 14.7:1 and lets see how long before it detonates itself to pieces. I generally tune my cars to 11.5-12.0:1 afr in boost and 14.5:1 part throttle driving.
+1

Quote Originally Posted by F8d2Blk
All this is great info. I really appreciate it.
Yes the Holley Carb is actually to big for the application. But the actual manifold that is made I think restricts it some more too.
I should be closer to a 300-350cfm but the one I have is 500cfm
I did the formula but don't remember exactly what it should be but I know there are a number of people running the same setup with better gas mileage and performance is still decent.
www. vg30.com

So I finally have it sitting at 14+ at idle
Wide open throttle is anywhere from 12.5-13.5
Partial throttle is the problem it is really rich ranges from 15+ to over 17+ or when I let off the gas.

" IS THIS BAD?"

so I am guessing this is going back to big of jets. Although my chevy guy also gave some advice about changing a cam on the carb to allow the gas to come in later on.
So all was this morning until my fuel pump quit. Can't go anywhere now. Doh!
dont do anything. what you just said sounds right on. part throttle could be leaner and the off throttle could be richer. but other than that. your good. to help the wanting to die when you let off try riching the idle up ever so slightly. this will help the dieing part.