 A/F Meter readings, what's the proper ratio ? |
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| DRPHIL914 |
 Apr 4 2014, 09:21 PM
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#1
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Dr. Phil  Group: Members Posts: 5,768 Joined: 9-December 09 From: Bluffton, SC Member No.: 11,106 Region Association: South East States 
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Just had my first good drive since putting the A/F meter in the car.
Once warm , idle is about 11.5 . And when running g out about 45-60 average is 13 and w.o.t. closer to 14. So for a.d-jet 75 2.0, running premium lead free gas(91 octane) what is correct ? |
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| Black22 |
Apr 4 2014, 10:11 PM
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#2
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Senior Member Group: Members Posts: 886 Joined: 1-November 07 From: Creswell, OR Member No.: 8,290 Region Association: Pacific Northwest |
I can't tell you how to adjust Djet (I run Ljet), but 11.5 @ idle is pretty rich.
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| dlee6204 |
Apr 5 2014, 01:37 AM
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#3
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Howdy Group: Members Posts: 2,162 Joined: 30-April 06 From: Burnsville, NC Member No.: 5,956 |
And 14 @ wot is a bit lean
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| ConeDodger |
Apr 5 2014, 04:51 PM
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#4
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Apex killer! Group: Members Posts: 23,613 Joined: 31-December 04 From: Tahoe Area Member No.: 3,380 Region Association: Northern California
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QUOTE(Black22 @ Apr 4 2014, 08:11 PM)  I can't tell you how to adjust Djet (I run Ljet), but 11.5 @ idle is pretty rich. I dis (IMG:style_emoticons/default/agree.gif) Idle is rich for a reason. There is no cooling air to cool the heads. These engines are Air and oil cooled. Those numbers are pretty much spot on, with WOT maybe just a little lean. But, that said, I wouldn't mess with it if it runs well. You spend very little time at WOT... The theoretical number you seek is 14.7:1. lower is richer, higher is leaner. I hear, you want to move richer with the lead free alcohol blended fuels but not much. |
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| brant |
Apr 5 2014, 04:58 PM
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#5
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914 Wizard Group: Members Posts: 11,640 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains 
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You need more fuel at wot.
14.7 is not right for an air cooled motor at Wot. And 14 is lean. 12.5 to 13 is correct at wot. |
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| ConeDodger |
Apr 5 2014, 05:07 PM
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#6
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Apex killer! Group: Members Posts: 23,613 Joined: 31-December 04 From: Tahoe Area Member No.: 3,380 Region Association: Northern California
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QUOTE(brant @ Apr 5 2014, 02:58 PM) You need more fuel at wot. 14.7 is not right for an air cooled motor at Wot. And 14 is lean. 12.5 to 13 is correct at wot. (IMG:style_emoticons/default/agree.gif) but, it's probably a street car. His only adjustment is for idle. He can always make it worse. (IMG:style_emoticons/default/sad.gif) |
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| ConeDodger |
Apr 5 2014, 05:07 PM
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#7
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Apex killer! Group: Members Posts: 23,613 Joined: 31-December 04 From: Tahoe Area Member No.: 3,380 Region Association: Northern California
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Wait, check your fuel pressure...
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| malcolm2 |
Apr 5 2014, 06:58 PM
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#8
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Advanced Member Group: Members Posts: 2,747 Joined: 31-May 11 From: Nashville Member No.: 13,139 Region Association: South East States
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QUOTE(Philip W. @ Apr 4 2014, 10:21 PM) Just had my first good drive since putting the A/F meter in the car. Once warm , idle is about 11.5 . And when running g out about 45-60 average is 13 and w.o.t. closer to 14. So for a.d-jet 75 2.0, running premium lead free gas(91 octane) what is correct ? I checked mine a couple weekends back. IIRC I got 17-18 at idle. 13 - 14 a 3000 rpm. And 13.5 - 12.5 under load (hills and accelerating) at about 4500 rpm. Mine is a 1911 L-Jet ( AFM gog adjusted) fuel was 93 oct pure gas, no ethanol. |
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| ConeDodger |
Apr 5 2014, 07:01 PM
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#9
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Apex killer! Group: Members Posts: 23,613 Joined: 31-December 04 From: Tahoe Area Member No.: 3,380 Region Association: Northern California
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QUOTE(malcolm2 @ Apr 5 2014, 04:58 PM) QUOTE(Philip W. @ Apr 4 2014, 10:21 PM) Just had my first good drive since putting the A/F meter in the car. Once warm , idle is about 11.5 . And when running g out about 45-60 average is 13 and w.o.t. closer to 14. So for a.d-jet 75 2.0, running premium lead free gas(91 octane) what is correct ? I checked mine a couple weekends back. IIRC I got 17-18 at idle. 13 - 14 a 3000 rpm. And 13.5 - 12.5 under load (hills and accelerating) at about 4500 rpm. Mine is a 1911 L-Jet ( AFM gog adjusted) fuel was 93 oct pure gas, no ethanol. Don't drive it till you dial up the idle... Or, don't idle! |
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| DRPHIL914 |
Apr 5 2014, 10:34 PM
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#10
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Dr. Phil Group: Members Posts: 5,768 Joined: 9-December 09 From: Bluffton, SC Member No.: 11,106 Region Association: South East States
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Guys, thanks for the input. I've had a busy day painting house! I do have the ability to adjust my mps and have a good understanding of how to adjust it. Right now when cruising at about 3000 rpm its around 13 - 13.5 which is what I seem to remember is pretty good. I had read that 14.7 was the theoretical neutral. But I think that's too lean for air cooled motors. My timing was a bit off and so idle was a bit rich at about 10.8, once adjusted that came up to about 12-. So I think I'm o.k.. if I get the mix down under 14 at wot. I plan on driving it a few weeks and then che king the plugs also .Oil temp yesterday after a 30 minute driive at 82 degrees out was about 185-190. Will see how that goes when its 95 out!
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| Black22 |
Apr 5 2014, 10:53 PM
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#11
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Senior Member Group: Members Posts: 886 Joined: 1-November 07 From: Creswell, OR Member No.: 8,290 Region Association: Pacific Northwest |
QUOTE(ConeDodger @ Apr 5 2014, 03:51 PM) QUOTE(Black22 @ Apr 4 2014, 08:11 PM) I can't tell you how to adjust Djet (I run Ljet), but 11.5 @ idle is pretty rich. I dis (IMG:style_emoticons/default/agree.gif) Idle is rich for a reason. There is no cooling air to cool the heads. These engines are Air and oil cooled. Those numbers are pretty much spot on, with WOT maybe just a little lean. But, that said, I wouldn't mess with it if it runs well. You spend very little time at WOT... The theoretical number you seek is 14.7:1. lower is richer, higher is leaner. I hear, you want to move richer with the lead free alcohol blended fuels but not much. I dis dis (IMG:style_emoticons/default/agree.gif) 11.5 at idle is washing down cylinders. I agree the fuel helps cool the motor, but that cooling can be done at 13 -13.5. 11.5 is not only rich for idle but WAAAAY rich. My car doesn't even hit 11.5 at any point in the curve! My set up is 13.9 at idle, 12.5 at WOT and 15.5 max lean during a freeway cruise (basically just enough throttle to maintain speed. My temps max out at 360F during 85mph freeway speeds and as soon as I come to a complete stop at the end of the off ramp I'm at 300F. All that and 25-28mpg. I have run it leaner but then head temps creep to 380F. I also got 31mpg! No way 11.5 is good at idle IMHO. Just a waste of precious fuel. (IMG:style_emoticons/default/agree.gif) with your comments on the new fuel, but we have real gas up here. "Clear fuel", so I don't need to compensate for that. |
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| Trekkor |
Apr 5 2014, 11:03 PM
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#12
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I do things... Group: Members Posts: 7,809 Joined: 2-December 03 From: Napa, Ca Member No.: 1,413 Region Association: Northern California |
13.1 here at WOT.
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| Trekkor |
Apr 5 2014, 11:03 PM
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#13
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I do things... Group: Members Posts: 7,809 Joined: 2-December 03 From: Napa, Ca Member No.: 1,413 Region Association: Northern California |
That is under load, BTW.
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