Tuning process/advice
05-18-2010, 09:04 PM
#1
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Tuning process/advice Guys,
Looking for info on a few things here. I just got some tuning software and was wondering what order should I tune in?
A/F then timing then etc?
Also, let's say I mill my heads and dial in my cam timing after reducing squish...WHAT effect will this have on my ignition timing??? Will it advance it or retard it?
Looking for info on a few things here. I just got some tuning software and was wondering what order should I tune in?
A/F then timing then etc?
Also, let's say I mill my heads and dial in my cam timing after reducing squish...WHAT effect will this have on my ignition timing??? Will it advance it or retard it?
05-19-2010, 09:25 AM
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First, go for "fidelity". That is, commanded AFR ought
to equal delivered AFR across the driving envelope
(especially at the big end where it's most likely to
hurt itself, but generally). This is the airflow model
stuff primarily, compensating for post-factory mods.
Hopefully no fuel delivery mods are in play (yet). Be
sure the fuel system is factory-like, clean filter, check
rail pressure for normalcy.
Then with stock timing, get the fueling where it should
be, going by conventional wisdom.
Next, tweak timing up until more quits helping and/or
you run into ping; then back off a few for safety and
weather.
You can repeat the last two iteratively until you run
out of ambition, or call it good.
There will probably be more detail work to do, like
when you run into your first patch of real hot summer
you may find ping you didn't have, and chase that
through the IAT / ECT spark tables (if AFR is holding
tight) or, where available, temperature modifiers for
fueling if the delivered AFR wanders with ambient
temp or coolant temp.
More compression means hotter charge and faster
burn (other things being roughly equal) so less
advance needed for the same power-pulse position.
Knowing where you want that position, wants some
real-time measure of delivered power or acceleration.
A rollup like quarter mile time / MPH, lacks the detail
to fit any particular table cell. You can rough it in but
have to do it "by eye", best guess.
to equal delivered AFR across the driving envelope
(especially at the big end where it's most likely to
hurt itself, but generally). This is the airflow model
stuff primarily, compensating for post-factory mods.
Hopefully no fuel delivery mods are in play (yet). Be
sure the fuel system is factory-like, clean filter, check
rail pressure for normalcy.
Then with stock timing, get the fueling where it should
be, going by conventional wisdom.
Next, tweak timing up until more quits helping and/or
you run into ping; then back off a few for safety and
weather.
You can repeat the last two iteratively until you run
out of ambition, or call it good.
There will probably be more detail work to do, like
when you run into your first patch of real hot summer
you may find ping you didn't have, and chase that
through the IAT / ECT spark tables (if AFR is holding
tight) or, where available, temperature modifiers for
fueling if the delivered AFR wanders with ambient
temp or coolant temp.
More compression means hotter charge and faster
burn (other things being roughly equal) so less
advance needed for the same power-pulse position.
Knowing where you want that position, wants some
real-time measure of delivered power or acceleration.
A rollup like quarter mile time / MPH, lacks the detail
to fit any particular table cell. You can rough it in but
have to do it "by eye", best guess.
05-22-2010, 09:01 AM
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First, go for "fidelity". That is, commanded AFR ought
to equal delivered AFR across the driving envelope
(especially at the big end where it's most likely to
hurt itself, but generally). This is the airflow model
stuff primarily, compensating for post-factory mods.
Hopefully no fuel delivery mods are in play (yet). Be
sure the fuel system is factory-like, clean filter, check
rail pressure for normalcy.
Then with stock timing, get the fueling where it should
be, going by conventional wisdom.
Next, tweak timing up until more quits helping and/or
you run into ping; then back off a few for safety and
weather.
You can repeat the last two iteratively until you run
out of ambition, or call it good.
There will probably be more detail work to do, like
when you run into your first patch of real hot summer
you may find ping you didn't have, and chase that
through the IAT / ECT spark tables (if AFR is holding
tight) or, where available, temperature modifiers for
fueling if the delivered AFR wanders with ambient
temp or coolant temp.
More compression means hotter charge and faster
burn (other things being roughly equal) so less
advance needed for the same power-pulse position.
Knowing where you want that position, wants some
real-time measure of delivered power or acceleration.
A rollup like quarter mile time / MPH, lacks the detail
to fit any particular table cell. You can rough it in but
have to do it "by eye", best guess.
to equal delivered AFR across the driving envelope
(especially at the big end where it's most likely to
hurt itself, but generally). This is the airflow model
stuff primarily, compensating for post-factory mods.
Hopefully no fuel delivery mods are in play (yet). Be
sure the fuel system is factory-like, clean filter, check
rail pressure for normalcy.
Then with stock timing, get the fueling where it should
be, going by conventional wisdom.
Next, tweak timing up until more quits helping and/or
you run into ping; then back off a few for safety and
weather.
You can repeat the last two iteratively until you run
out of ambition, or call it good.
There will probably be more detail work to do, like
when you run into your first patch of real hot summer
you may find ping you didn't have, and chase that
through the IAT / ECT spark tables (if AFR is holding
tight) or, where available, temperature modifiers for
fueling if the delivered AFR wanders with ambient
temp or coolant temp.
More compression means hotter charge and faster
burn (other things being roughly equal) so less
advance needed for the same power-pulse position.
Knowing where you want that position, wants some
real-time measure of delivered power or acceleration.
A rollup like quarter mile time / MPH, lacks the detail
to fit any particular table cell. You can rough it in but
have to do it "by eye", best guess.
Thanks!