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? |
Mark Henry |
Feb 6 2017, 12:40 AM
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#2
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
I don't like to see much higher than 13:1 in an iron cylinder engine, my nickies engine I can easily run 14:1 no problem.
I can really see the performance degrade as the temps go up in a iron cylinder engine if you run much over 13:1, the nickies equipped engines doesn't suffer from this issue. Deceleration it doesn't matter...no load. I have a fuel cut below a certain TPS setting so on decel my meter goes off the scale. Fuel cut stops popping and/or backfiring on decel on wild cam engines. plays with cars I'll have to say you are wrong, those number might be fine on a watercooled car, but aircooled always needs to be a bit on the rich side. Trying for those numbers on an aircooled and you will hole a piston. Big issue on a performance, wild cam, ITB Type 4 is your vacuum signal will be total shit. This gives the MAP sensor a horrid signal that peeps chase forever, often blaming the FI system. I run TPS/O2 only program on my T4 2600cc engine, zero issues, runs on par with a modern FI car. |
Mueller |
Feb 10 2017, 03:52 PM
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#3
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914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None |
I don't like to see much higher than 13:1 in an iron cylinder engine, my nickies engine I can easily run 14:1 no problem. I can really see the performance degrade as the temps go up in a iron cylinder engine if you run much over 13:1, the nickies equipped engines doesn't suffer from this issue. Deceleration it doesn't matter...no load. I have a fuel cut below a certain TPS setting so on decel my meter goes off the scale. Fuel cut stops popping and/or backfiring on decel on wild cam engines. plays with cars I'll have to say you are wrong, those number might be fine on a watercooled car, but aircooled always needs to be a bit on the rich side. Trying for those numbers on an aircooled and you will hole a piston. Big issue on a performance, wild cam, ITB Type 4 is your vacuum signal will be total shit. This gives the MAP sensor a horrid signal that peeps chase forever, often blaming the FI system. I run TPS/O2 only program on my T4 2600cc engine, zero issues, runs on par with a modern FI car. Is there some sort of limp home mode if something with the O2 circuit craps out? Can you run 2 O2's for redundancy? |
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