Cat Overtemp Thresholds table
Thread Starter
Joined: Jan 2002
Posts: 4,069
Likes: 74
From: Casselberry FL
Cat Overtemp Thresholds table I downloaded a predator tune from a friends car last night. He doesn't have cat's, and the COT Enabled switch is set to True, but the Overtemp tables are all set to 1200.
I'm trying to determine why it was done this way and how the tuner arrived at the 1200 value. Any ideas?
I'm trying to determine why it was done this way and how the tuner arrived at the 1200 value. Any ideas?
The temperature is some kind of wild-eyed
calculation made by the PCM with very loose
connection to fact (especially once the
exhaust manifolds are replaced by headers).
Basically it's a hoax as far as I can see and
you pick something you think will save your
cats.
That said, my stock table in the COT temp
threshold vs altitude, shows all 1500-1600F
values. So -IF- these are being displayed on
the same basis (which is not necessarily a
good bed, HPTuners for me vs {whatever}
for you) then the tuner has made things
worse, made COT quicker to jump in and
wet-blanket your campfire.
calculation made by the PCM with very loose
connection to fact (especially once the
exhaust manifolds are replaced by headers).
Basically it's a hoax as far as I can see and
you pick something you think will save your
cats.
That said, my stock table in the COT temp
threshold vs altitude, shows all 1500-1600F
values. So -IF- these are being displayed on
the same basis (which is not necessarily a
good bed, HPTuners for me vs {whatever}
for you) then the tuner has made things
worse, made COT quicker to jump in and
wet-blanket your campfire.
OK, your tool must be displaying in degC
where mine's showing degF. So those
values are probably well up out of the
way and COT should never trigger. I have
a copy of an SAE paper on COT modeling
(2000-01-0651, I got it off the Internet)
that indicates sane EGT values are between
600C and 900C (though nothing on what
the temp a cat can safely stand, is).
I think 1200C is a "go away, far away" value.
where mine's showing degF. So those
values are probably well up out of the
way and COT should never trigger. I have
a copy of an SAE paper on COT modeling
(2000-01-0651, I got it off the Internet)
that indicates sane EGT values are between
600C and 900C (though nothing on what
the temp a cat can safely stand, is).
I think 1200C is a "go away, far away" value.
