15.0 mpg to 21.6 mpg!
mattax,
The below table comes right out of the Edelbrock carb manual. I look at that manual daily. I'm an engineer and have had to write some similar manual type info. And it's not easy to write that kind of stuff and be clear. The Edelbrock manual is very well written. I've gone further and created my own Microsoft excel carburetion tables. Which made it clear to me that I was stuck too lean on POWER, and too rich on CRUISE. Actually, I could stay where I am on cruise. But to be safe, I want to richen up the POWER. Based on my tables, and understanding how the metering rods work with the jets, I have designed my own metering rods. I'm working that out as I type.
And yes, my 1.5 second lean spike has a dead spot feel to it. It feels EXACTLY like it's running out of gas. And ... it is. I've adjusted the pump. Doesn't matter the setting, it's still there. Because when a driver lightly pushes the pedal, and holds it there, to gently accelerate, the engine consumes the limited amount of the shot. Unless your foot keeps pushing down, and manually activating the pump, the pump shot stops. It needs that pump shot spread out more, under light acceleration. When I slam the throttle down, it responds very nice, no hesitation, no dead spot, just spinning tire(s). Based on that, I'm not going to try to mess with the pump shot. My goal is 13.99, not to turn my Scamp into a Camry! :D
But what I'm doing to address the 1.5 second lean spot is, my metering rod blends the POWER portion up into the CRUISE section. And I'm running the biggest springs. My hope is that the biggest springs push the rods up enough when vacuum is first reduced (pushing the throttle from a dead stop) enough to get into the my more aggressive blend. I'd run a bigger spring if I had it, because while cruising, my engine seems to make enough vacuum to hold that rod down in the jet. A bigger spring may be the next thing I experiment with.
The below WOT numbers, I can't remember where that came from. But as my engine was approaching 12.2, I could feel it pulling harder. Could be that the rpms were coming up and just generating more power, but I don't think so. I had not felt that increase feel of power except when it was moving from 12.7 or so to right at 12.2. It did feel strong. And that AFR is safe, so I'll tune for that again.
7milesout
I don't think my engine would idle AT ALL at 14.7 AFR. And when I ignore that AFR gauge and set idle based on the Edelbrock manual, I wind up in the 13.0 range anyway.
WOT
12.8:1 - Lean best torque
12.2:1 - Mean best torque
11.76:1 - Rich best torque
11.01:1 - Fastest flame speed in cylinder
Right out of the Edelbrock carb manual below. The table below compared with the numbers above is what I'm shooting for.
View attachment 1715094711
