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I am getting an edelbrock AF monitor and I want to know what a safe reading is. I know that 14.7 is right on or something like that but what is the lowest lean ratio to worry about. The monitor goes from 12 to 15. Which one is rich and which one is lean? thanks for the help
__________________ Mods-----350 bored .040 over, 10.3:1 compression,Hedman LT headers with 2" true duals and Dynomax super turbo mufflers,Edelbrock RPm aluminum heads, Edelbrock Rpm intake, Comp cam 274* extreme energy flat tappet cam, Comp cams 1.6r Magnum roller tip rockers, holley 700cfm double pumper carb, Accel Distributor, MSD blaster 2 coil and NGK v power plugs, Msd 6 ignition box, 2800 rpm stall convertor, stage 3 turbo 350 tranny with 3.42 gear...Soon to come a NX express Hitman nitrous system!!
14.7 is stoich for maximum efficiency (air temps optimized and fuel efficiency is at its best). Peak power has its potential around 12.5, but is harder on parts. 13 sounds good.
As for what is what, think about it. It's the air to fuel ratio. Take 14.7:1 for example. 14.7:1 being air, 1 being fuel. Increase or decrease the first (larger) number. larger the number, more air, same amoung of fuel = lean. smaller first number, less air per fuel = richer.
AF ratio gages for our cars are eye candy only. The stock 02's are horribly inaccurate when stochiometric condictions stray beyond +/- 1 or 2%. A wide band 02 is the only tool you should really use to correctly base your AF ratio. Running slightly rich and lean can have performance, wear and tear as well as emissions effects. Most eninges out there are desinged either slightly rich or slightly lean. There are benifits and hinderances of both.
Well, you know we always wondered about them A/F Monitors. I had a K&N A/F M in my car for years and used it to dial in my jetting (Q-Jet). A friend of mine has built engines for years and finnished second in the first PHR Engine Masters contest. I swore by them so he bought two and took them to the dyno where he was going to run in a customers engine. They installed the O2 senors ( stock chevy) in the headers collectors and taped the monitor to the glass. Man they were dead nuts with the air/fuel ratios printed out on the dyno sheets.
Sinlge wire 02's are no where near as accurate as 3 and 4 wire heated ones. So I geuss it depends on what ones you use. You may be able to play around with them ar part throttle, but the ECM does not use 02 output when at WOT. That is where the wide band comes into.
Well, all the sinlge wire O2 sensors that I have installed for A/F Monitors are not using the ECM O2 sensor. I weld a bung (as in my case 84 Z28) just behind the "Y" pipe so it sees all eight cyls.
Doesn't make much difference, the single wire sensors for the aftermarket gauges with the pretty lights are the same type of cheap narrowband sensor as the ECM uses.
Well, all I can tell you is that those little red lites react instantly to the touch of the pedel. I can understand that if you have never used one that you might feel that way but the dyno testing that we did confirmed the accuracy of them there A/F Monitors. In fact the eng. builder that said he would never have one in his car ( Corvette) has two of them now. One for each bank. He had a power valve (Holly) failure and man all the lights lit up like a X-mas tree.
Of course they react instantly. Look at the graph that nsimmons posted, and mentally divide the vertical scale into 8 bars, each representing an LED on a gauge. Now look at what happens if the mixture changes from say 14.8 to 14.6. Not much of a change in mixture, but you've probably moved 3 or 4 LEDs. Now imagine going from 15:1 to a dangerously lean 18:1. Big change in mixture, but I doubt if you'd even change 1 bulb. The same goes for a change from 14:1 to a piggishly rich 12:1 or 11:1.
its wrong wrong wrong..ive done enough ecm tweaking to know they are useless for power tuning. get a wide band. disagree with me? hit the prom forum and state your claim.
Chevyboy07 91, I bought my first A/F Monitor from K&N in 1988 and the A/F ratio numbers came with the instruction sheet. I also have a Cyberdyne ( #7009) Vertical Bar Graph A/F Moitor on my 1999 Dodge Durango and here are the numbers that came with that instruction sheet.
well I got it installed and working. Heres what it has shown me. When at a steady speed I am running around the 12-12.5 lights but when I get on it heavily it pretty much goes to the red light which is 15 or so. Even if I am at a very heavy accel it still will flatten back out to 12.5 range. So would the lean condition be caused my the accel pumps?
__________________ Mods-----350 bored .040 over, 10.3:1 compression,Hedman LT headers with 2" true duals and Dynomax super turbo mufflers,Edelbrock RPm aluminum heads, Edelbrock Rpm intake, Comp cam 274* extreme energy flat tappet cam, Comp cams 1.6r Magnum roller tip rockers, holley 700cfm double pumper carb, Accel Distributor, MSD blaster 2 coil and NGK v power plugs, Msd 6 ignition box, 2800 rpm stall convertor, stage 3 turbo 350 tranny with 3.42 gear...Soon to come a NX express Hitman nitrous system!!
Well, on my horizontal gauge left is lean and right is rich. I guess you will just have to give them a call and see what they say. Let us know what they say.
