burst knock enable, for pinging?
burst knock enable, for pinging? In the table for burst knock enable load delta, what do the numbers mean exactly? Rate of change in MAP? I'm wondering why the numbers are bigger at lower rpm - wouldn't you want the burst knock prevention to kick in easier at lower rpm than at higher rpm?
I'm asking since just moved to AZ, where the gas is crappy (91 octane) and the temps are still in the upper 90s or more. Now getting definite tip-in pinging, trying to figure the best way to deal with it.
I'm asking since just moved to AZ, where the gas is crappy (91 octane) and the temps are still in the upper 90s or more. Now getting definite tip-in pinging, trying to figure the best way to deal with it.
Delta Dynamic Cylinder Air. Grams/cyl, per 12.5mS
time-tick. If you are logging at 10/sec, divide the
frame-frame difference in CylAir by 8 to get it to
the same basis the PCM uses.
Drive around, make it ping and find the delta value
in this way that precedes ping bursts, and what is
sub-critical. Do it at varying RPM points with varying
throttle position and rate of roll-on until you have a
solid map of where you need to put the dividing line.
time-tick. If you are logging at 10/sec, divide the
frame-frame difference in CylAir by 8 to get it to
the same basis the PCM uses.
Drive around, make it ping and find the delta value
in this way that precedes ping bursts, and what is
sub-critical. Do it at varying RPM points with varying
throttle position and rate of roll-on until you have a
solid map of where you need to put the dividing line.
Originally Posted by jimmyblue
Delta Dynamic Cylinder Air. Grams/cyl, per 12.5mS
time-tick. If you are logging at 10/sec, divide the
frame-frame difference in CylAir by 8 to get it to
the same basis the PCM uses.
Drive around, make it ping and find the delta value
in this way that precedes ping bursts, and what is
sub-critical. Do it at varying RPM points with varying
throttle position and rate of roll-on until you have a
solid map of where you need to put the dividing line.
time-tick. If you are logging at 10/sec, divide the
frame-frame difference in CylAir by 8 to get it to
the same basis the PCM uses.
Drive around, make it ping and find the delta value
in this way that precedes ping bursts, and what is
sub-critical. Do it at varying RPM points with varying
throttle position and rate of roll-on until you have a
solid map of where you need to put the dividing line.
Also, should I be messing with this, or maybe with transient fueling instead?
Delta value is only the trigger threshold. You lower it to
bring in burst knock retard at less of an air-step.
You also want to figure out how much retard you need
to suppress ping reliably. This is in the retard vs RPM table.
The delta threshold in my stock tune is less than is normally
seen. So effectively it's not in play. Trucks however seem
to come with a much lower threshold (probably coupled to
the holding off of PE mode) and burst knock can really dog
them out.
bring in burst knock retard at less of an air-step.
You also want to figure out how much retard you need
to suppress ping reliably. This is in the retard vs RPM table.
The delta threshold in my stock tune is less than is normally
seen. So effectively it's not in play. Trucks however seem
to come with a much lower threshold (probably coupled to
the holding off of PE mode) and burst knock can really dog
them out.
