Octane

[jrinjax]

Detonation is more likely under high loads and temps and is happening close to bottom of the stroke. The high temperature gasses reignite causing an almost immediate thermal/shock piston failure.

Pinging [preignition] is a condition that most newer "Green" engines operate close to/or with a small amount of, across all loads and most normal temps. The new loop tuning systems are constantly adjusting the "tune" of each cylinder until the "Ping" becomes unacceptable.

Small amounts of "Ping" do not damage the engine, if kept within the design limits of the FI system.

The sharper the loop can tune [octane wise] and the more room on the "Map" to sharpen tuning [leaning the a/f, advancing timing] the more HP/MPG.

JR

[N_Jay]

Originally posted by jrinjax
Detonation is more likely under high loads and temps and is happening close to bottom of the stroke. The high temperature gasses reignite causing an almost immediate thermal/shock piston failure.

Pinging [preignition] is a condition that most newer "Green" engines operate close to/or with a small amount of, across all loads and most normal temps. The new loop tuning systems are constantly adjusting the "tune" of each cylinder until the "Ping" becomes unacceptable.

Small amounts of "Ping" do not damage the engine, if kept within the design limits of the FI system.

The sharper the loop can tune [octane wise] and the more room on the "Map" to sharpen tuning [leaning the a/f, advancing timing] the more HP/MPG.

JR

http://en.wikipedia.org/wiki/Engine_knocking

Close but no cigar.

[jrinjax]

The 1985 article was accurate, for the time, but dated. The more modern engineering of the present FI systems use "ping" as the tune setpoint on a per-cylinder basis, using microprocessor speed that had not been dreamed of in 1985. Ping, back then was almost always fatal, now it is the [inaudiable] endpoint of the loop and the best a/f-timing setting.

Detonation is always fatal.

I have ascociates that work with the Honda Engineers on their sponsored "projects" and Mercury Marine Engineers who help on mine.

Enjoy your opinions.

JR

[N_Jay]

Originally posted by jrinjax
The 1985 article was accurate, for the time, but dated. The more modern engineering of the present FI systems use "ping" as the tune setpoint on a per-cylinder basis, using microprocessor speed that had not been dreamed of in 1985. Ping, back then was almost always fatal, now it is the [inaudiable] endpoint of the loop and the best a/f-timing setting.

Detonation is always fatal.

I have ascociates that work with the Honda Engineers on their sponsored "projects" and Mercury Marine Engineers who help on mine.

Enjoy your opinions.

JR

If "Detonation is always fatal", and running on is detonation, then how have I had cars that have run on all the time (old carburetor days), and not died?