How to read carb calibration chart?
Here's where I differ with most the others, and actually agree with J-Par here. Yea, nuts. eh. :realcrazy:
If you haven't already, go buy a note book or clipboard with a stack of paper.
Save your dough on the WBO2 and spend the time on systematicly tuning.
(I expect at least one big x at the bottom of my post now. Go ahead I can take it.
)
What I'm talking about is this. You glance down at the AFR gage on the dash and it shows 14.1 or 13.3 or 15. What does it tell you? Does it tell you the engine is making more power? No.
Its only useful if you can associate the reading with a specific condition, a change you made to the carburation, and a change in performance.
Systematicly trial and error for performance.
Do all the steady conditions first. Start at the idle and work up. If its crappy at idle then the engine is going to have to clear up before it can respond to additional throttle. So idle and off idle are your foundations.
Performance here is going to be demonstrated by running fairly clean exhaust output and how little throttle is needed to get into first gear without stalling. Work with initial timing, idle mixture and float settings. The step up springs should not be involved at idle.
Follow with confirmation of off-idle. performance is being able ot get into gear and very slowly accelerate with no hesitation. If that's good, then with more normal acceleration (for public streets) and make sure the pump shot is not too much or too little for this basic job.
Then you can test out steady driving at various speeds. The fuel ratio at steady highway speeds is determined by the rod and jet combination. A change of the rod or jet per the chart should let you test how lean it will run on the highway. When starts to rev and die - its too lean!
If you have access to the strip or dyno you can also test wide open throttle in 3 or 4th. AFR is controlled by the jets. Change jets for the best mph through the lights.
All the above is effected by timing. If you change timing at a given rpm and condition, then retest before change fuel mixture for that condition.
Once all that is tuned, then concentrate on transition conditions. That is part throttle (springs) and opening the throttle quickly from low rpm (pump shot). Reality is you may have to go out of sequence. You will almost certainly have to make repeats. How many depends on how much interest and persistance you have in tuning it in.
Good luck!
Here's where I differ with most the others, and actually agree with J-Par here. Yea, nuts. eh. :realcrazy:
If you haven't already, go buy a note book or clipboard with a stack of paper.
Save your dough on the WBO2 and spend the time on systematicly tuning.
(I expect at least one big x at the bottom of my post now. Go ahead I can take it.
What I'm talking about is this. You glance down at the AFR gage on the dash and it shows 14.1 or 13.3 or 15. What does it tell you? Does it tell you the engine is making more power? No.
Its only useful if you can associate the reading with a specific condition, a change you made to the carburation, and a change in performance.
Systematicly trial and error for performance.
Do all the steady conditions first. Start at the idle and work up. If its crappy at idle then the engine is going to have to clear up before it can respond to additional throttle. So idle and off idle are your foundations.
Performance here is going to be demonstrated by running fairly clean exhaust output and how little throttle is needed to get into first gear without stalling. Work with initial timing, idle mixture and float settings. The step up springs should not be involved at idle.
Follow with confirmation of off-idle. performance is being able ot get into gear and very slowly accelerate with no hesitation. If that's good, then with more normal acceleration (for public streets) and make sure the pump shot is not too much or too little for this basic job.
Then you can test out steady driving at various speeds. The fuel ratio at steady highway speeds is determined by the rod and jet combination. A change of the rod or jet per the chart should let you test how lean it will run on the highway. When starts to rev and die - its too lean!
If you have access to the strip or dyno you can also test wide open throttle in 3 or 4th. AFR is controlled by the jets. Change jets for the best mph through the lights.
All the above is effected by timing. If you change timing at a given rpm and condition, then retest before change fuel mixture for that condition.
Once all that is tuned, then concentrate on transition conditions. That is part throttle (springs) and opening the throttle quickly from low rpm (pump shot). Reality is you may have to go out of sequence. You will almost certainly have to make repeats. How many depends on how much interest and persistance you have in tuning it in.
Good luck!
