Air/Fuel gauges, and EGT temps

Dave B. · 02-10-2005, 11:21 PM

I got one of those Autometer air/fuel ratio gauges, and yes I know its only readable at wide open throttle, but does anyone know if its just supposed to peg all the way rich at WOT?

Its not good for anything if thats the case, does anyone know how to read one of these? and or know what exhaust gas temp an EGT should read for correct air/fuel mix?

smashedheadcat · 02-11-2005, 07:09 PM

What you need to do is go to a dyno, and read the EGT at the leanest point on the chart. Or just get take the highest EGT recorded throughout the whole graph. Not everyone mounts their thermocouple in the same place so there's really no way to tell you what your car should run at blindly. After reading the peak temp on the dyno, expect it to increase a touch when on the street due to increased load (spining rollers vs moving the car).

A typical production vehicle uses oxygen sensors that have a very narrow resolution. When you are cruising / idling (closed loop), the vehicle is concerned with maintaining an A/F ratio of 14.7 (stoich). When you put your foot on the floor and go into power enrichment (open loop), the factory sensors do not have enough resolution to tell you an exact A/F ratio. Any system that ties in to the factory oxygen sensors can only tell you if you are richer or leaner than 14.7.

This is what you'll need for your a/f guage. Click

02-10-2005, 11:21 PM	#1
Dave B. Registered User Join Date: Dec 2003 Location: Florida Posts: 479	Air/Fuel gauges, and EGT temps I got one of those Autometer air/fuel ratio gauges, and yes I know its only readable at wide open throttle, but does anyone know if its just supposed to peg all the way rich at WOT? Its not good for anything if thats the case, does anyone know how to read one of these? and or know what exhaust gas temp an EGT should read for correct air/fuel mix? __________________ 03 Cobra 10th Anniversary Red Stiegermeier Stage 4 ported Eaton 511.9 RWHP 467.7 RWTQ 2,76 Billetflow SC pulley Billetflow Aux-idler all billetflow idler pulleys Accufab single blade MAC cold air BBK Ceramic LT headers X-pipe Magnaflow exhaust Gordsford heat exchanger PST Carbon fiber drive shaft lowered 1.5 inches 18 X 9's AFS running Toyos 275/35/18's front 18 X 10.5's AFS running Toyos 295/35/18's rear Cobra "R" rear wing Cobra "R" hood 4:10 gears Pedator tuned Pro short shifter Hurst "T" handle Promotion Clutch Quad AEM widband gauge Boost & fuel Press gauges drilled & slotted rotors

02-11-2005, 07:09 PM	#2
smashedheadcat Registered User Join Date: Oct 2001 Location: Geneva, Switzerland Posts: 1,727	What you need to do is go to a dyno, and read the EGT at the leanest point on the chart. Or just get take the highest EGT recorded throughout the whole graph. Not everyone mounts their thermocouple in the same place so there's really no way to tell you what your car should run at blindly. After reading the peak temp on the dyno, expect it to increase a touch when on the street due to increased load (spining rollers vs moving the car). A typical production vehicle uses oxygen sensors that have a very narrow resolution. When you are cruising / idling (closed loop), the vehicle is concerned with maintaining an A/F ratio of 14.7 (stoich). When you put your foot on the floor and go into power enrichment (open loop), the factory sensors do not have enough resolution to tell you an exact A/F ratio. Any system that ties in to the factory oxygen sensors can only tell you if you are richer or leaner than 14.7. This is what you'll need for your a/f guage. Click __________________ Josh 2003 Oxford White Cobra Coupe Twin Turbo Solid Axle Automatic Return Fuel System 1997 Triple Black Cobra Convertible Forged and Blown. 511rwhp 398 rwtq Sold

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