This is a question I should have asked years ago... never really occured to me...
Is it possible to have engine-damaging detonation at light or part throttle?
I have my S-AFC tuned for mileage... and I've increased by a good 5 MPG easily.
I have it leaned on my LO map by as much as it will go without the car hesiating or stuttering at any point, leaned around 15-20% and the LO throttle point is 50%.
My o2 sensor voltage sometimes won't even read, and can hover around .6 or so at very light throttle.
Of course my HI map isn't leaned out that much, so whenever I hit the gas over 50% it and gives me around a 13.5:1 ratio.
I have never heard any detonation at light throttle, but I do have a pretty loud exhaust (leaks!) Can you only hear it at the engine or can you hear it in the exhaust as well (as a misfire or something)?
I just want to know if I can keep running it nice and lean like this. The car doesn't stink, runs well, and my plugs are finally tan instead of black.
Can you feel the engine stuttering when it detonates?

Thanks

 

bumpity

 

Tan plugs? No smell? Man, I am getting a S-AFC today!! Well, mabye this weekend after I get paid!!

 

Yep, the S-AFC I would almost list as a requirement once you have an intake and exhaust. Fantastic piece of electronics! It's paid for itself in 2 months with my mileage savings- not to mention the fact that I am getting an astounding amount of midrange (and peak too) HP increase. You would never know the VDI is locked in the hi position.

Anyways, since no one has really answered, I am going to voice my theory- I don't think it's really possible to get bad detonation at 25% throttle because the combustion chamber isn't hot enough, like it would be at full throttle.
At full throttle for a few seconds there is suffecient heat built up in the chambers to pre-ignite the fuel when it compresses, but maybe not at light throttle.
Someone correct me if I'm wrong please.