SantaCruz163

I hear a lot of talk about timing but I never really understood the concept of it. What is might by 'retarding' or 'advancing' the timing by different degrees? How does 'knock' play a role in timing? I don't want to be an expert at this by any means but I would like to know the basics so when people are talking about it I can understand what they are talking about.

tom2

Some info here: http://www.2quicknovas.com/happytiming.html

Your car has no timing adjustment, all computer set. Sometimes using better gas or higher octane will allow the computer to advance the timing, or not retard it, to give better performance.

DonHood

Starting to realize that 87 ain't gonna cut it?

Basically, "timing" refers to ignition timing, or when the spark plug fires, and is expressed in degrees before TDC. TDC being top dead center, or when the piston reaches the top of it's compression stroke. "Knocking" occurs when the fuel ignites before the plug fires, and can cause damage to your engine. LT1's come from the factory with a 10.5:1 compression ratio, which is crazy by most car standards, and is the reason you have to run premium gas. 93 octane is more resistant to "knocking" in a high compression engine than 87 octane. When the knock sensor in your car detects a knock, it retards the timing, which means it tells the plug to fire closer to TDC. This causes a drop in performance, and a decrease in gas mileage.

I installed my Scanmaster last week, so I can see the computer playing with the timing in real time.