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Air/Fuel Ratio Gauge - Best/Affordable one to get?

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Looking into getting an AFR gauge set-up to help jet my Weber 32/36 and wondering which one to go with. I've heard AEM and Innovate are good, problem is there's so many to decide on. AEM has so many in their X-series, like 30-0300, 30-0310, 30-0334, 30-4110, and I don't know how many others. I understand some may use Lambda (no, not the newer Covid variant), and i don't quite understand Lambda and if i need it since all fuel in California contains 10% ethanol or if that matters. Any help would be great. It will be used on my 720 pickup.

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Both brands are good, I use an innovate in my 521, paid around 150 I believe,  it's an old model so part number wont help.....

Probably either brand product in that price range will do you good...

As you go up it just more features ... 

My guess is more data logging of more sensors for efi systems. All we have is a carburetor so we just need to know the air/fuel ratio... and even the 150 model will data long if you wanted... the only thing I wish mine did was need a tach signal so I could see air/fuel vs rpm.... right know if I used the data log it would only show me the air/fuel ratio ....

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If running gasoline and only gasoline an A/F gauge is fine as you know 14.7:1 is stoichiometric. If switching to E87 or straight alcohol or 'old gas that is alcohol free' or differing amounts of either in your tank you need to calculate a new stoichiometric for each fuel and this can be very uncertain. Lambda reads 1.0 for perfect mixture regardless the fuel.

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"For E10 gasoline (90 percent gasoline with 10 percent ethanol alcohol), the stoichiometric ratio is 14.08:1. "


I've been using 14.7 as an ideal a/f but I guess it should be 14 because I'm using 10% ethanol blend. It runs great and drops into the mid 12s under load. 


It's a bell curve with not much change or effect on either side of stoichiometric. There's the absolute perfect and then there's close enough on either side.

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