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? |
Chi-town |
Oct 29 2018, 10:36 AM
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#2
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Senior Member Group: Members Posts: 850 Joined: 31-August 18 From: Disneyland Member No.: 22,446 Region Association: Southern California |
There is no "short answer" for this question.
There are some basic references for non forced induction though. WOT = 12.7-13.2 under heavy load Cruise = 13.7-14.7 under light load Idle = Hot-13.0-15.0 / Cold- 11.5-12.5 Now keep in mind all of these are dependent on timing. You need to know where your base timing is set, what your advance curve looks like and your peak advance. This is where those old SUN distributor machines come into play. You need to measure the weights and spring tensions, the diaphragm movement per inch of vacuum in the actuator. Even off the shelf reman distributors often have the wrong curve as they mix and match weights and springs. Now that you've got your distributor curved correctly, timing set, and your wideband O2 installed Now you can tune your carbs or check your F.I. to make sure it's operating correctly. Reading plugs is a good back up to the wideband and will tell you if you're too aggressive or not aggressive enough with timing. Here's some good reading on that: https://honda-tech.com/forums/forced-induct...%2A%2A-3063102/ Remeber always make minor adjustments and don't get crazy aggressive and your engine will last a long time. |
72hardtop |
Nov 1 2018, 12:04 AM
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#3
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Member Group: Members Posts: 120 Joined: 11-September 13 From: Seattle/HB Ca./Fujieda-Japan Member No.: 16,378 Region Association: Pacific Northwest |
There is no "short answer" for this question. There are some basic references for non forced induction though. WOT = 12.7-13.2 under heavy load Cruise = 13.7-14.7 under light load Idle = Hot-13.0-15.0 / Cold- 11.5-12.5 Now keep in mind all of these are dependent on timing. You need to know where your base timing is set, what your advance curve looks like and your peak advance. This is where those old SUN distributor machines come into play. You need to measure the weights and spring tensions, the diaphragm movement per inch of vacuum in the actuator. Even off the shelf reman distributors often have the wrong curve as they mix and match weights and springs. Now that you've got your distributor curved correctly, timing set, and your wideband O2 installed Now you can tune your carbs or check your F.I. to make sure it's operating correctly. Reading plugs is a good back up to the wideband and will tell you if you're too aggressive or not aggressive enough with timing. Here's some good reading on that: https://honda-tech.com/forums/forced-induct...%2A%2A-3063102/ Remeber always make minor adjustments and don't get crazy aggressive and your engine will last a long time. WOT = 12.7-13.2 under heavy load Cruise = 15.5-17:0 under light load (better MPG's) 14:0 - 15:0 is where the highest EGT's & CHT's will be. Get above that zone when on the progression circuit and below it when on the mains (WOT). Idle isn't where we/one drives so it's out of the pic. Reading plugs takes time. With new plugs you need a couple thousand miles for them to get seasoned. |
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