SAFC and knock

[TobyCat]

Hello all,

Recently I've been playing around with my SAFC and came across the knock set function under settings. First off, does anybody know what these value's units are? I'm guessing knock/min as the motor is in rotations/min. But I'd just like to be sure.

Also, what is an acceptable # here? At idle when the car is cold I see about 15-20. As it warms up and idling at stop lights I hover anywhere near 50-75 depending greatly on the outside temperature. When it's cold at night, the knock value is lower, when it's warm afternoon i sit at about 75. Finally, after a hard drive and idling the car before shutting it off, the knock value is 100-120 range and will stay there for the full 3 minutes I idle.

It also makes sense that as temperature increases so does the knock value. It could very well be that my floating K&N intake is getting heat washed as the engine compartment temperatures increase.

Are these acceptable values for knock or is my timing off? I also use 94 octane fuel for reference.

Just looking for some insights into SAFC, knock, and their meanings!

-Chris

 

[Idealsupra]

the knock function on the afc2 is 100% utterly useless....i dont even set them up anymore for cars i install the unit on. apexi themselves dont know the scale of the readings.

i would just completely forget about it. its about as useful as a wet paper towel holding a bowling ball.

 

[TobyCat]

Hah, that's unfortunate. Well, it should just be tapped into the knock sensor line. What exactly does the sensor output? If it's a pulse train, then I could scope it (pain in the butt while in the car) or if it's analog I can always check it with a multimeter.

I can't seem to find in the TSRM how to check if a knock sensor is working correctly.

 

[Idealsupra]

Hah, that's unfortunate. Well, it should just be tapped into the knock sensor line. What exactly does the sensor output? If it's a pulse train, then I could scope it (pain in the butt while in the car) or if it's analog I can always check it with a multimeter.

I can't seem to find in the TSRM how to check if a knock sensor is working correctly.

what i do is put one multimeter lead on the sensor and the other to a ground and then tap the knock sensor on something metallic....if i get voltage on the MM then its good.

very rarely will a KS go BAD....not counting them breaking physically lol.