Whats That Noise? Options

[ne14914]

Hey Guys,

I was driving home today and started hearing this ping noise - like when you put bad gas in your car. When I started going up a hill and needed to accelerate I noticed more. The car runs fine - but did seem to lose power going up the hill.

[airsix]

What does advancing the timing do? Does it give you more power at the bottom end, middle or top end? I've heard what it was but (with the onset of grey-ness... I forget (IMG:style_emoticons/default/huh.gif)
bruce

Let me put it this way "Lower-than-optimal timing advance will result in less power". More is only better if you are using less than what is optimal. The question is what is optimal timing advance? For a D-jet type-IV that lives in a warm climate I'm going to have to say 27 degrees BTDC. I've tried to get more max advance but can't without richening the mixture beyond the point of max power (to prevent pinging). I know some carb guys are running more advance, but I suspect they are also running pretty rich. (somebody jump in if you've had different experience)

On my PEFI/ignition engine I am running more low-rpm advance than stock, but it still maxes out at 27 BTDC at ~3,000rpm. This gives more torque off-idle, but probably raises emissions as well.
-Ben M.