Originally posted by nmyeti
Just wondering did the tuner check the detonation level with a microphone on the block and a head set? I'd be surprised if you were not getting detonation at that level that was too slight to hear over the engine noise in the dyno room.
The advance helps keep the EGTs cool, so you can advance and lean the car out if you have enough octane to support it in your fuel, but frankly pump fuel in most of the US does not have enough to keep the small detonation away from your motor at the A/F level you're quoting. It's even worse when you also know that the car is going to lean out a bit on the road because of additional air flow over the intercooler.
Actually we were out driving. He'd already set the timing before taking me for a spin. I believe he uses a setup with 2 knock sensors, each going to 1 channel in a set of stereo headphones.
If I'm hearing detonation with my bare ears then it's very severe! As in blow your engine severe forged pistons or not. Personally I just have a small audio preamp on the factory knock sensor. That goes into a set of headphones. Used that with good success with the tec-II.