Air flow gauge?

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Aug 4, 2021 | 06:16 AM

ronaldfilion

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Air flow gauge?

Hi yall, a couple of old timers told me that in order to get the best mileage out of my '89 460 was to get a air flow gauge and "keep it in the green". I haven't found one anywhere. Does anyone know what these guys are talking about and what it's called so I can order from amazon?
I've ordered a shorter belt because after gutting the cat I'm going to bypass the air pump. I'm hoping the end of the gauge fits in one of the holes left by the intake tubes for my smog pump, if that makes a lick of sense.

Aug 4, 2021 | 07:16 AM

Conanski

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From: Ottawa, Ontario

They are talking about an air-fuel ratio gauge which displays the actual A/F ratio in the exhaust when connected to a wideband O2 sensor. These aren't exactly cheap, if you're not paying around $300 for the parts or a complete kit you're not going to get the functionality you are expecting. The key part is the wideband sensor, that is what produces graduated readings, there are cheaper kits that use the factory narrowband sensor but they will only display rich or lean with nothing in the middle.
You could also use a simple vacuum gauge, that is what was used as an economy gauge in some older vehicles. The general idea is that keeping the engine in the high vacuum range equates to low engine load which is where it gets it's best fuel milage.

Aug 4, 2021 | 07:54 PM

maples01

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From: Maryville

You can use a vacuum gauge too, that indicates no vacuum with your foot in it, more vacuum, less pedal, better mileage.

Aug 5, 2021 | 08:44 PM

ronaldfilion

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Thanks for the help. It was easy to find this one on amazon. The A/F ones were about 220$ but I think I'll just start with this. Apparently the gauge is descent but the hose collapses too easily. I would have ordered some vacuum hose from amazon as well but wasn't sure of the diameter required. If it saves me a tank of gas it'll be worth it.

Aug 5, 2021 | 11:26 PM

maples01

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From: Maryville

I had one in my 73, tho I enjoyed hearing the exhaust so that meant it read zero a lot, never had the hose collapse with it, but old rubber lines will, had one on a Chevy do that.