Can someone help me understand what's the difference between running too rich and running too lean, especially in terms of air fuel ratio. Trying to figure it out with modding the intake coupled with a bypass valve.

 

running rich is running too much fuel and not enough air. running lean is the opposite ( and running lean is a much hotter burn in the combustion chamber)

 

A perfect Stoichiometric mix is 14.7 parts air to 1 part fuel. Leaner is more air, richer is less air per given amount of fuel.

Leaner burning tends to run hotter/more prone to detonation while richer is often a bit safer since it burns cooler.

Most turbo cars run rich under boost (often to a fault) since more fuel helps the mix burn cooler and reduce the likelyhood of detonation.

I had my Subaru on the wideband and at steady state, it was 14.7:1, under full boost we tuned it to run about 11:1 (stock was in the 10-10.5:1 range). I had some issues where it would run below 9:1 and the engine would sputter.

 

Okay thanks guys.
I'm just trying to figure out how an aftermarket bypass valve would affect this.
So far I can't really get a good fix on how to prevent backfiring.

 

I'm guessing I'm running lean since I'm getting a detonation in the intake. Would I be correct? So in order to alter this, I'll need less volume of air intake?

 

You can't get detonation in the intake. Detonation occurs in the combustion chamber.

I doubt you are running lean by definition, though you could be leaner than ideal. From what I remember, the Hondata/CP-E tests were still running in the low 12's for AFR. That might be leaner than ideal, but it's still considered rich. Hondata said they thought it was safe - though close to the limit.

I had some intake popping when I was stock, so I'm not convinced it has anything to do with mods.

 

Okay, so just a lil mixed up on words.

But on the popping, I get it every single time i push hard with the mods. And stock I never had that problem, that's why I rule on the mods.