Air Fuel Ratio

darkstar_one

Registered User
ok somebody please tell me what these 3 terms mean

lean -
stoich.-
rich-

if i install a AIR FUEL RATIO gauge which one is normal???



also what other gauges do u think i will need... just out of curiousity... and ideas people?
 
Lean=Too much air not enough fuel.
Stoich= Ideal mixture.
Rich= Too much fuel not enough air.

Your looking at a mixture gauge arent you?
Stoich(short name) or Stoichametric(proper name) ia an air fuel mixture ratio of 14.7 to 1. Stoich is considered the ideal ratio of fuel and air to produce good combustion, thats 14.7 parts air to 1 part fuel.
Any reading above 14.7 is leaner meaning more air in proportion to the same amount of fuel.
Any reading below 14.7 is richer meaning more fuel in proportion to the same amount of air.

Did I make any sense?
You dont really want to know what all gauges I have, Its kinda gonna resemble a fighter jet cockpit.:eek: I'm monitering everything!
 
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hmmm kool... ima install one on my SC then... but i want to know what other gauges should i install? OIL PRESSURE??
 
Well for me the basics would be:
1. Engine oil pressure.
2. Engine coolant temp.
3. Engine oil temp.
4. Tranny fluid temp.
With good qaulity gauges it will help you to keep from doing something stupid to your engine and tranny if you pay attention to them.
The stock gauges are not real gauges, there just idiot light with needles. You really dont have much of an idea whats going on relying on the stock gauges.
 
i say u send me a pic of ur gauges if u can... cuz im really thinking about putting gauges while i replace sensors and stuff...
 
Well I dont have a camera any longer and I havent installed them yet so it wouldnt matter anyway. My gauge clusters will be one of the last things I make and install. Gotta get out the carbon cloth and resin for that.
 
i see... well yeah me too about the gauges... they are gonna be probably the last things... but for now ima just stick with th ones i have... later
 
Not that it really matters, but.....

14.7:1 is called Stoich. It is based on "ideal" from an emmissions standpoint only. All emmissions controlled cars are tuned to run at or near that ratio so that the converters function properly and emissions are lowest.

15.5:1 is actually the best for fuel economy, but NOx emmissions will be higher and the converters will not work properly.

Your computer does not ever run at 14.7:1. What it does instead is switch back and forth between about 16:1 and 12:1 continually as you drive. The blinky lights as the EEC switches back and forth will either drive you nuts or you will learn to like it. :D

Under WOT conditions a naturally aspirated motor likes to see about 13.5:1 (richer than stoich), and a boosted motor like ours likes to see about 12:1. Our motors are typically tuned from the factory to run at about 9.5-11:1 under WOT, which is beyond the ability of the gauge you are looking at buying to read (too rich). So the gauge is neat, but kind of worthless.

A WB02 gauge is useful because it reads from 17:1 - 10:1, but are expensive ($350) and don't come with that neat round gauge face. They are typically a hand-held digital device.
 
Dave is correct as I was just speaking in general terms.
Ideal mixtures are not really etched in stone, there are alot of variables involved in acheiving that ideal mixture.
 
HMMM.... i see.... so that really doesnt matter right? well kool... i guess ill put gauges for other things... cuz im pretty sure it would drive me nuts and i would just end up busting a cap in the engines ***... thanx anyways
 
darkstar_one said:
HMMM.... i see.... so that really doesnt matter right? well kool... i guess ill put gauges for other things... cuz im pretty sure it would drive me nuts and i would just end up busting a cap in the engines ***... thanx anyways
Good move! You will get far more benifit by monitering more critical engine opporations than watching the O2 sensors work.
 
yeah man... well tommorow is saturday and ima wake up early and put my car back together cuz its in pieces right now.... as for the gauges... ima wait like a month cuz i need to buy the belts and sensors cuz mines are dead... thanx brotherens
 
I had the A/F ratio gauge (light show) in my car for a couple months, and like Dave said it didn't provide any usefull info and the constant flashing of lights was driving me crazy.

I now have two gauges in the pillar pod that I think are the most important for my car. Fuel Pressure and Transmission Temp.

David
 
A wideband Air/Fuel is useful when tuning. Tells approximate air/fuel ratio better than those other A/F gauges.

Oh, and it's stoichiometric. Good ol' college chemistry
 
well i think ima go with the FUEL PRESSURE and OIL TEMP and maybe i will add more... as for the FUEL/AIR thingy i ma just not get that gauge... yeah well any other things...???
 
I highly recomend an engine coolant temp gauge as well. The stock cooling system is puny on this car so you need a good gauge that actually tells you the temp so you can keep from accidentaly overheating the engine. The stock gauges are CRAP and tell you absolutely nothing.
 
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