Quote:
Originally Posted by dznucks
I am no expert but I just finished teaching myself how to tune my demon with a A/F gage and a vacuum gage. I think you can squeeze out a few more mpg's by fine tuning that carb.
You say your primaries are 69 and the secondaries are stock. Did you raise or lower the primaries? what were they stock? What is your idle A/F?
When you say you give it gas on the highway and it goes lean to 16-18, is this when you just barely tip into the throttle or it goes that lean before the power vavle and/or secondaies open up?
Do you know your idle vacuum reading? might want to swap your power valve to a 8.5" or 10.5" if you have a high idle vacuum to cover that lean spike.
What happens at WOT? are you pig rich or is it perfect.
Here are some target numbers that Holley recommends when tuning with an A/F gage. I was getting numbers like you until I got my power valve, accel pump cam, and secondary spring right. now i get numbers like these.
Stock and Moderate Performance Engines
Idle and Cruise: 14:1 to 15.5:1
Moderate Load: 13:1 to 14:1
Wide-Open Throttle: 12.2:1 to13:1
Large Cams and Race Engines
Idle and Cruise: 13:1 to 14:1
Moderate Load: 12.5:1 to 13.5:1
Wide-Open Throttle: Typically 12.5:1 to 12.7:1 at peak torque and 13 to 13.2:1 at peak HP
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I went up from 65 to 69 on the mains. Think it idles at close to 16-18 in park. Not sure about in gear. My engine will not idle leaner the about 13.5 deff not 14 or 15. My cam wount alow that. WOT is 12-13 and cruise is like 9.9 to 15. It is all over depending on how fast i am going. If i am only steping on peadle lightly and going 5 mph it is 9 something. Same if i am going down hill and just ever so soft toutch the peadle to keep speed steady and not accel or decell it is 9 or so. But if i push it little more it goes to 13 or so. Idle and wot and most cruse air fuel is ok but it is that 9 to 1 that kills me. Also smell like fuel at idle i guess due to cam. But it is not even that big of a cam.