Air/Fuel ratio, is there a quick answer? |
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Air/Fuel ratio, is there a quick answer? |
malcolm2 |
Feb 5 2017, 05:50 PM
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#1
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Advanced Member Group: Members Posts: 2,745 Joined: 31-May 11 From: Nashville Member No.: 13,139 Region Association: South East States |
OK, I have been tinkering with the new-to-me AFM on my 1911cc engine all weekend. I have adjusted the spring about 20 teeth CCW to get to this point.
I have been using an A/F sensor and gauge. can someone tell me, or direct me to a chart/table of what A/F I should be shooting for on my daily driver. The last adjustment of the CO screw has left me here: I have always had a strange idle situation, so lets ignore that for now. any normal adjustments to reduce the idle at normal operating temp eventually stall the car. A problem for another post. (IMG:style_emoticons/default/blink.gif) the idle is high.... at 1200 the A/F is a smooth 12.2. I found a long hill and drove up it at about 3800 rpm and the A/F was 12.5. thoughts? |
veekry9 |
Feb 24 2017, 03:53 PM
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#2
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OldMember Group: Retired Members Posts: 3,068 Joined: 17-June 13 From: TO Member No.: 16,025 Region Association: Canada |
No quick answers,because it's complicated,many factors.
https://www.google.ca/search?q=fuel+mixture...WMeAvEQ_AUIBigB A lean cruise condition at low loads is at one end of the spectrum,highly loaded under acceleration is at the fat,rich end.(1910s) Change the fuel and the chemistry changes with it,as with methanol/water additives.(1930s) A turbo application at high boost pressure benefits greatly,stalling detonation and piston holing.(1930s) Those holes can be had by a lean loaded condition with air cooled engines,as some of you here know. All of this has been sussed out for 80 years,the military aircraft application the primary impetus.(1930s) A direct injection fitment to the Type 4 hasn't been done yet to date,and would yield great results with a fine 'smart' mapping.(2017) A constraint that aircooled engines have is the physical heat dissipation capacity,the mass and size of the fins and the amount of air that passes over them. Adiabatic cooling systems are a proven upgrade and an easy fit,tho only practical for above freezing climates.(1970s) Changing out the pistons and heads for a high quench design with piston squirters,a leaner mix can be had,and the application of ceramic coatings will shield them from the heat of combustion.(1970s) Carburetor jetting is best done on a dyno these days,less time consuming than road testing and plug reading,as was done in the past.(1920s) Double plugging your six or four has some advantage in flame-front size and expansion,so a leaner burn can be had. Ultimately,the engine's ability to dissipate conducted heat is the limiting factor,so,the simplest course is to cool the engine and intake charge. [url]https://www.google.ca/search?q=direct+injection+flame+front+simulation&espv=2&biw=1229&bih=598&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjPmJ7T2anSAhWG4IMKHW13AsEQ_AUIBigBue (IMG:style_emoticons/default/smile.gif) (IMG:style_emoticons/default/happy11.gif) Great advantage.Be the first. Be cool. / |
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