HPTuner methods
Thread Starter
Joined: Jan 2002
Posts: 4,069
Likes: 74
From: Casselberry FL
HPTuner methods What are the general steps for getting your tune right with HPT? I'm waiting for 1.5, but my only experience is LS1-Edit. I've read about smoothing the VE table, smoothing the timing tables, etc. Which sequence does one follow?
For power, get the fuel about right, then push as much
spark as doesn't ping (steady state load).
For drivability, probably a fair bit of VE table, idle air
fiddling to get it smooth and knock down any transient
ping /KR. Forcing open loop hot operation will show you
which way to go at any load point (MAP, RPM) if you
exercise and log it; lather, rinse, repeat.
A wideband O2 meter is nice but not strictly necessary;
a good item to borrow rather than buy. If you can trust
your MAF and injector tables then you can just command
the right AFR in the PE and open loop fuel tables. Trick
is, knowing whether. But some open-loop, non-enrichment-
mode testing should readily indicate the degree of fidelity
there.
Think experimentally and there's almost always a way, to
find out what you need to know using the logger and maybe
a custom, diagnostic-oriented tune to expose some of the
underlying tune (normally covered up by closed loop, PE or
what-have-you.
Smoothing is good because the engine is really a pretty
orderly machine, and in general has a pretty continuous
response surface vs speed and pressure. So if you see a
table that looks like two porcupines practicing unsafe sex,
it's probably not entirely realistic. But the smoothing
algorithm is fairly dumb, it only tries to tamp down spikes
and fill in holes but in a lot of cases you're really trying
to tilt or bend the thing, not just make it smooth. That's
where you want to apply your understanding of how, say,
the cam might affect the low and high end VE of a motor,
take what quantitative info you can get from diagnostic
logging and hand-beat the table until it fits reality, then
use the auto-smoothing as your "finish coat".
It's not necessarily a linear sequence. You start with the
obvious and the most annoying, then you chase the
weasel around the mulberry bush as long as you think
there's "drivability" or an iota of power left to gain, and
by then you're having so much fun with the tuning that
you start looking for stuff to mess with even when it's
relatively pointless, just because.
spark as doesn't ping (steady state load).
For drivability, probably a fair bit of VE table, idle air
fiddling to get it smooth and knock down any transient
ping /KR. Forcing open loop hot operation will show you
which way to go at any load point (MAP, RPM) if you
exercise and log it; lather, rinse, repeat.
A wideband O2 meter is nice but not strictly necessary;
a good item to borrow rather than buy. If you can trust
your MAF and injector tables then you can just command
the right AFR in the PE and open loop fuel tables. Trick
is, knowing whether. But some open-loop, non-enrichment-
mode testing should readily indicate the degree of fidelity
there.
Think experimentally and there's almost always a way, to
find out what you need to know using the logger and maybe
a custom, diagnostic-oriented tune to expose some of the
underlying tune (normally covered up by closed loop, PE or
what-have-you.
Smoothing is good because the engine is really a pretty
orderly machine, and in general has a pretty continuous
response surface vs speed and pressure. So if you see a
table that looks like two porcupines practicing unsafe sex,
it's probably not entirely realistic. But the smoothing
algorithm is fairly dumb, it only tries to tamp down spikes
and fill in holes but in a lot of cases you're really trying
to tilt or bend the thing, not just make it smooth. That's
where you want to apply your understanding of how, say,
the cam might affect the low and high end VE of a motor,
take what quantitative info you can get from diagnostic
logging and hand-beat the table until it fits reality, then
use the auto-smoothing as your "finish coat".
It's not necessarily a linear sequence. You start with the
obvious and the most annoying, then you chase the
weasel around the mulberry bush as long as you think
there's "drivability" or an iota of power left to gain, and
by then you're having so much fun with the tuning that
you start looking for stuff to mess with even when it's
relatively pointless, just because.
