Wideband O2 Sensor

[Audacity Racing]

Originally Posted by Fulofstl

I between 15 to 16, sometimes a lil more. I always thought our cars ran rich, and these readings confirm it. What do you usually get, it shouldn't be too much different, even though your car is boosted.

Uh... that's pretty good but running lean, not rich

[Audacity Racing]

Originally Posted by e12345b

This discussion always confuses me. Other than know exactly how your carbon emmissions are doing, what is the purpose of this?

AFR stands for Air/Fuel Ratio. When you burn gasoline, the best mixture is about 14.7 parts of air (by volume) to 1 part of gasoline (by volume). If there is too little air, the engine will run cool and waste gas. If there is too much air, the engine will run hot and run the risk of premature explosions in the cylinder (called knock, detonation, pinging, etc)

Wideband oxygen sensors are able to read the amount of chemicals in your exhaust. It can tell you if the engine is using too much, too little, or the perfect amount of fuel. When you do mods to the car, this is a way to ensure everything operates safely. If the AFR rises above 17-18 it's a good idea to check into the issue. On the flip side, if the ratio drops below 10-12 it should be looked at. This is also how custom tunes are created. Base maps are made by hand and then modified based on what the engine actually outputs as its burn characteristics.

Most also data log... so you can see across the entire RPM band and TPS band where the ratio lies.

[tallkid]

heres my question...if i were to get a piggy back, how hard is it to tune? is it more of a trial and error thing? can i do it myself, or do i need to do it on a dyno or something?

[exist3nce]

Originally Posted by Fulofstl

I between 15 to 16, sometimes a lil more. I always thought our cars ran rich, and these readings confirm it. What do you usually get, it shouldn't be too much different, even though your car is boosted.

15 to 16 isn't rich at all, especially for full throttle, I would consider it on the lean side. I'm pretty sure these cars were designed to run slightly on the lean side to save fuel. At my shop they tune NA cars for 13.5 - 13.9 under full throttle for max power. Mine runs about 14.2 - 15.5 at all times before boost hits.