Critique my A/F Numbers

[threewood]

Cross post from my resto build thread but decided to get more looks here.

440, auto, Edelbrock Thunder 800cfm, Holley SD Intake, Aluminum heads, 1 7/8" headers, Pertronix 3 ignition, 24 initial / 36 total

Idle - During warm up it was lean which with my cam and single plane air gap I kind of expected. But after warm up it settled to 13.4 to 13.8.

Mid Throttle / cruise - part throttle and cruise seemed lean, from 15.5 to 16.0

3/4 hard throttle - 13.4 to 13.7

WOT - seemed pretty consistent at 12.2 to 12.3. Should I lean out the secondaries a touch?

What do you think and what adjustments should I make?

Video

 

[oldbee]

Not nearly an expert,especially w/O2 sensors; but I’m thinking richer up primaries a tad with narrower rods on your eddy? Interested to see responses.

 

[JimKueneman]

Cross post from my resto build thread but decided to get more looks here.

440, auto, Edelbrock Thunder 800cfm, Holley SD Intake, Aluminum heads, 1 7/8" headers, Pertronix 3 ignition, 24 initial / 36 total

Idle - During warm up it was lean which with my cam and single plane air gap I kind of expected. But after warm up it settled to 13.4 to 13.8.

Mid Throttle / cruise - part throttle and cruise seemed lean, from 15.5 to 16.0

3/4 hard throttle - 13.4 to 13.7

WOT - seemed pretty consistent at 12.2 to 12.3. Should I lean out the secondaries a touch?

What do you think and what adjustments should I make?

Video

Idle is good a little rich make it smoother

Mid is too lean. Is that jets in a carb?

3/4 is just right if this was under load (MAP in the 60-80kPa range)

WOT is perfect. Lamda of 0.85 which is the peak power point.

Just your cruise needs to be richened up

 

[threewood]

Idle is good a little rich make it smoother

Mid is too lean. Is that jets in a carb?

3/4 is just right if this was under load (MAP in the 60-80kPa range)

WOT is perfect. Lamda of 0.85 which is the peak power point.

Just your cruise needs to be richened up

Thanks. Mid was under light load like normal street driving. On and off the gas pedal.

The cruise / mid is adjusted with either rod or rod / jet combo. I looked through my tune kit and didn't see a combo to raise cruise without changing the others so I need to order the correct rods.

 

[hunt2elk]

How do you like that AEM meter? Would you buy it again?

 

[62 Dart Convertible]

How do you like that AEM meter? Would you buy it again?

Keen to know too... I'm about to install one myself.

 

[Kern Dog]

I have one in my 70 Charger. I aimed for mid 14s at idle and at cruise but it actually runs better a little richer than that. Winter in CA isn't like the NorthEast but I still have to fatten it up a little to keep it smooth. It runs strong at mid 13s at cruise and 12.0-12.8 at WOT in my case. I have a 440/493 with a MP 528 solid, Demon 850 VS and 2 inch TTI headers. When I reduced primary jets to lean it out, I had to go 4 jet sizes and it lost power. Some guys say to "Check the plugs" but screw that! Pulling spark plugs on a hot engine with headers and limited clearance...?

 

[threewood]

How do you like that AEM meter? Would you buy it again?

Keen to know too... I'm about to install one myself.

I would buy it again in a heartbeat. It seems instantaneous and accurate, easy to read and they ship out both a black and white gauge face along with a silver and black bezel. The mount option for the gauge is face mount but column mount was easy with a zip tie. The kit has plenty of wire, the extra is coiled up under the dash. Instructions are very good and you can hook up a data logger.

 

[threewood]

I have one in my 70 Charger. I aimed for mid 14s at idle and at cruise but it actually runs better a little richer than that. Winter in CA isn't like the NorthEast but I still have to fatten it up a little to keep it smooth. It runs strong at mid 13s at cruise and 12.0-12.8 at WOT in my case. I have a 440/493 with a MP 528 solid, Demon 850 VS and 2 inch TTI headers. When I reduced primary jets to lean it out, I had to go 4 jet sizes and it lost power. Some guys say to "Check the plugs" but screw that! Pulling spark plugs on a hot engine with headers and limited clearance...?

I actually tweaked the idle up to around 14.0 to 14.4 and it still idles fine. It goes lean 15 to 15.8 right off idle at about 1/4 throttle if I feather it. When I put my foot into it a bit more it richens out. I am going to swap in a size smaller rod and see what that does but it is running great as is.

 

[1969CoronetR/T]

There is a good article in the current April 2018 Mopar Muscle magazine about obtaining the correct A/F mixture on a Hemi. May not apply directly to your case, but it is very informative.

 

[JimKueneman]

Lambda = AFR/14.7
so Lambda of 0.8 is simply 14.7*0.8=11.75.

WOT is different as you want it richer to help cool the valves and such 12.4 or so as KernDog says

 

[WileE]

Although the mid range is on the fringe of too lean, I like your numbers. During the conditions where it counts, your A/F ratio is rich enough. Under light/cruise conditions, you don't need a ratio above (numerically lower)14.7, slight lean compensates for other throttle conditions that require enrichment.