COT Enabled or Disabled
04-20-2009, 11:16 AM
#1
COT Enabled or Disabled I just got the car tuned last week and it is running great! I download the tune to my PC for backup and safe keeping (HP Tuners) and I compared it to the previous tune.
I noticed this time around he tunred off the Cat Over Temp, and I do have cats. Kooks headers with thier 3" cats/y-pipe.
Is this something I really want kept off all the time?
I noticed this time around he tunred off the Cat Over Temp, and I do have cats. Kooks headers with thier 3" cats/y-pipe.
Is this something I really want kept off all the time?
04-20-2009, 02:14 PM
#6
Moderator
iTrader: (11)
Join Date: Mar 2002
Location: East Central Florida
Posts: 12,605
Likes: 0
Received 6 Likes
on
6 Posts
You could play with the settings to reduce the
impact of it. 10.25:1 is probably stupid fat. With the
cats further back in the pipe you aren't going to
heat them as badly either. But GM had the research
to back their setup (probably bent by liability to
an absurdly conservative point) and we don't know
nuthin' from nuthin' about your max sustained EGT.
A metallic substrate cat is going to be more fragile
than a ceramic.
People burn out the Jet-Hot "Chore-Boy" cats
pretty easily. Which is why mine sit safely in a
box. Somewhere.
Now, unless your state mandates ***-to-mouth
or you loves da baby sealses, maybe you just
do not care a whole lot about the actual cat
performance and appearances are good enough.
Dunno about upstate New York, what you've got
to deal with.
impact of it. 10.25:1 is probably stupid fat. With the
cats further back in the pipe you aren't going to
heat them as badly either. But GM had the research
to back their setup (probably bent by liability to
an absurdly conservative point) and we don't know
nuthin' from nuthin' about your max sustained EGT.
A metallic substrate cat is going to be more fragile
than a ceramic.
People burn out the Jet-Hot "Chore-Boy" cats
pretty easily. Which is why mine sit safely in a
box. Somewhere.
Now, unless your state mandates ***-to-mouth
or you loves da baby sealses, maybe you just
do not care a whole lot about the actual cat
performance and appearances are good enough.
Dunno about upstate New York, what you've got
to deal with.
04-20-2009, 02:52 PM
#7
It's mostly a daily drive. I rarely go WOT.
I didnt follow all of that, but I do care about my cats and want to keep things running as well as can be expected.
You could play with the settings to reduce the
impact of it. 10.25:1 is probably stupid fat. With the cats further back in the pipe you aren't going to heat them as badly either. But GM had the research
to back their setup (probably bent by liability to an absurdly conservative point) and we don't know nuthin' from nuthin' about your max sustained EGT.
A metallic substrate cat is going to be more fragile than a ceramic.
People burn out the Jet-Hot "Chore-Boy" cats pretty easily. Which is why mine sit safely in a box. Somewhere.
Now, unless your state mandates ***-to-mouth or you loves da baby sealses, maybe you just do not care a whole lot about the actual cat performance and appearances are good enough. Dunno about upstate New York, what you've got to deal with.
impact of it. 10.25:1 is probably stupid fat. With the cats further back in the pipe you aren't going to heat them as badly either. But GM had the research
to back their setup (probably bent by liability to an absurdly conservative point) and we don't know nuthin' from nuthin' about your max sustained EGT.
A metallic substrate cat is going to be more fragile than a ceramic.
People burn out the Jet-Hot "Chore-Boy" cats pretty easily. Which is why mine sit safely in a box. Somewhere.
Now, unless your state mandates ***-to-mouth or you loves da baby sealses, maybe you just do not care a whole lot about the actual cat performance and appearances are good enough. Dunno about upstate New York, what you've got to deal with.
Trending Topics
04-21-2009, 11:25 AM
#9
TECH Enthusiast
Join Date: Nov 2006
Location: Katherine N.T Australia
Posts: 620
Likes: 0
Received 0 Likes
on
0 Posts
I disable COT on every car I've ever tuned. I haven't had a blown cat yet.
While we're on this subject. How does the PCM know to envoke COT? Do the o2 sensors provide an EGT feedback of sorts to the PCM off the heater circuit to estimate EGT perhaps? Thats really the only feesable way I could see it knowing.
While we're on this subject. How does the PCM know to envoke COT? Do the o2 sensors provide an EGT feedback of sorts to the PCM off the heater circuit to estimate EGT perhaps? Thats really the only feesable way I could see it knowing.
04-21-2009, 12:09 PM
#10
I disable COT on every car I've ever tuned. I haven't had a blown cat yet.
While we're on this subject. How does the PCM know to envoke COT? Do the o2 sensors provide an EGT feedback of sorts to the PCM off the heater circuit to estimate EGT perhaps? Thats really the only feesable way I could see it knowing.
While we're on this subject. How does the PCM know to envoke COT? Do the o2 sensors provide an EGT feedback of sorts to the PCM off the heater circuit to estimate EGT perhaps? Thats really the only feesable way I could see it knowing.
04-21-2009, 03:59 PM
#11
On some of the newer E38 processors (like in the trucks and SUVs), if you disable COT, the AFM will stop working and the converter will not lock up. Just adjust the fuel settings or raise the temp thresholds if it's a concern.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
04-22-2009, 10:26 AM
#16
Moderator
iTrader: (11)
Join Date: Mar 2002
Location: East Central Florida
Posts: 12,605
Likes: 0
Received 6 Likes
on
6 Posts
I've seen scholarly SAE papers that go into fitting
the CAT temp prediction from RPM, (believed) AFR
and load and time. Of course AFR and load are two
things that are easily hoaxed when you start
modding, and upping performance means upping
RPM and load while leaning out AFR, so you push
yourself further into COT territory.
As to whether a 4th gen F-body's implementation
is so scholarly, or just a hack-job lookup, I couldn't
do more than guess.
One half-measure is to set your COT enrichment
table so simply equal your PE value; then even if
it kicks on, it will have no ill effect except MPG
while the cats are "cooling" (in its tiny little mind).
the CAT temp prediction from RPM, (believed) AFR
and load and time. Of course AFR and load are two
things that are easily hoaxed when you start
modding, and upping performance means upping
RPM and load while leaning out AFR, so you push
yourself further into COT territory.
As to whether a 4th gen F-body's implementation
is so scholarly, or just a hack-job lookup, I couldn't
do more than guess.
One half-measure is to set your COT enrichment
table so simply equal your PE value; then even if
it kicks on, it will have no ill effect except MPG
while the cats are "cooling" (in its tiny little mind).
