what's your catalytic converter's operating temperature?
Just wondering what observations have been made. If someone with an OBDII reader and a new car could read the operating temperature that'd be awesome. Looking specifically for new cat temps if possible.
My cat has 60k miles, looked clear visually, from the front anyway (nothing obvious st least), and runs around 800 C. That seems in love with others.. I know people say a sign of a clogged cat is that it glows red, but would like to know what a fresh one runs at, specifically on a rotary motor. |
IIRC during my last spirited drive, my Torque BT OBD-2 registered a range from 750C to low 900C. At idle, it usually hovers low 800C.
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This is a chart of my cat temp at the track in June in Texas.
https://cimg2.ibsrv.net/gimg/www.rx8...a2b2c06eb1.png |
Ah, very cool. Thanks. Steve, was this with the cat in your sig? Is that a high flow deal or what?
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Mine is around 1050F when idling, and 1600F when flooring it. I have a gutted cat though.
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Originally Posted by ZiG
(Post 4759165)
Ah, very cool. Thanks. Steve, was this with the cat in your sig? Is that a high flow deal or what?
Here is a chart showing temps with my BHR midpipe before I had the HJS welded in. https://cimg9.ibsrv.net/gimg/www.rx8...0f2c4c657d.png |
Huh, very interesting. Thanks! Can't believe how hot these get, no wonder they say not to park on grass!
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Originally Posted by Steve Dallas
(Post 4759117)
This is a chart of my cat temp at the track in June in Texas.
https://cimg2.ibsrv.net/gimg/www.rx8...a2b2c06eb1.png You might be interested to know they are almost exactly mine which is a 07 6speed auto GT with only 34k miles and BHR coils. I had scanguage II in before coils and I think temps were about the same. It reads 604 C mostly at idle anytime after warmed up which is 1119 Fahrenheit. Highest temps I see driving hard up to 7k rpm is about yours of 1746 f or 952 C. If we see a change we might conclude the CAT is dieing. |
Originally Posted by 40w8
This is the first time I've found the real temps for our cats.
You might be interested to know they are almost exactly mine which is a 07 6speed auto GT. My scangauge II reads 604 C mostly at idle anytime after warmed up which is 1119 Fahrenheit. Highest temps I see driving hard up to 7k rpm is about yours of 1746 f or 952 C. If we see a change we might conclude the CAT to dieing. |
Originally Posted by Nisaja
(Post 4823060)
Seeing the same temps over here, except my CAT is gutted and I live in 95F weather.
So both panes of CAT are gutted? Now what we need is for some RX8 owner with CAT going bad to give us his OBDII CAT temp to see if it's higher, and can be caught before overheating engine, too. |
Originally Posted by 40w8
Maybe this temp isn't exactly CAT temp, but I'm surprised you don't have CAT, and exhaust is still same temps.
So both panes of CAT are gutted? Now what we need is for some RX8 owner with CAT going bad to give us his OBDII CAT temp to see if it's higher, and can be caught before overheating engine, too. I hear it's around 2000F with a clogged CAT. |
Careful how you're reading these, too. Since posting the OP I have realized that Torque or the car or the ODBII reader or some combination of the three, like to infer information and don't always get it right. There is no cat temp sensor in these cars and I am unsure if the O2 sensor is somehow reading the temp (internal sensor?).
What clued me in to this is when I was looking at available data channels and found 'intake manifold boost/vac'. It would read a slight vac at idle/cruise but as soon as I got on it, it was reading like 7psi of boost on a stock engine. Now I know the rotors have a slight supercharing effect etc but it's nowhere near 7 psi. Then I realized the engine has no MAP sensor and it was just guessing at these values, probably based on MAF reading and average VE for a piston engine or something like that. Anyway, my point is I wouldn't trust the OBDII cat temp data. Measure it some other way IMO. |
In case it isn't clear, one of the charts I posted above is with a factory cat, and one is with a catless BHR midipe. There is really no significant difference.
The EGT is measured by the O2 sensor. That is the major secondary function of an O2 sensor. |
Thanks for info.
That's a serious EGT. |
I gutted my cat last night and expected to see a drop in temps. But this morning on the highway, I was still at almost 1700F.
If this is an "inferred" thing (i.e. calculated from rear O2), it could be that my rear O2 isn't working properly since I'm getting P0037 and P0138. Is that possible? 1700 degrees just seems hot, even though I was (admittedly) accelerating pretty hard. |
1600-1700 is roughly normal for EGT around 14.7 AFR?
It is inferred from the O2, yes. |
Originally Posted by Loki
(Post 4851072)
1600-1700 is roughly normal for EGT around 14.7 AFR?
It is inferred from the O2, yes. It looks like I'm going to end up going with a VersaTuner in the next few days. I can lean out a bit, right? What AFR will I be shooting for (in equivalent conditions) and how much will that raise my EGT? Thanks! |
I don't recommend tuning it just like that unless you're OK with shopping for a new engine :/
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Originally Posted by Loki
(Post 4851093)
I don't recommend tuning it just like that unless you're OK with shopping for a new engine :/
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One more quick question. With no cat, the rear O2 sensor serves no useful purpose, correct?
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Originally Posted by E.Murray
(Post 4851161)
One more quick question. With no cat, the rear O2 sensor serves no useful purpose, correct?
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