Catalytic Converter
#1
93.5 octane
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Catalytic Converter
What is the best high-flow cat and where can i get one? I'd love to eliminate the cat but won't b/c of warranty issues. Thanks guys.
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Both are warranty voidable items. But the straight pipe will probably check the CEL light. The best hi-flow cats out there right now are the SR Motorsports & RP Motorsports units.
#5
Why would a high flow cat void warranty? More precisely, on which part? Only the catback is after it.... so logically it could somehow void the warranty on the muffler.
Just curious...
Just curious...
#6
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Originally Posted by bxb40
Why would a high flow cat void warranty? More precisely, on which part? Only the catback is after it.... so logically it could somehow void the warranty on the muffler.
Just curious...
Just curious...
Two - it is monitored by the PCM via an O2 sensor, so its presence or lack thereof will affect fuel delivery.
That said, I took mine out and replaced it with a test pipe when I only had 4k miles or so. No CEL or any other problems for that matter, but my exhaust sure is stinky!
#7
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Has anyone ever looked into trying expanding the exhaust diameter to fit a larger diameter high flow cat? It seems to me that a larger diameter would not only flow better, but be more efficient, and most importantly also lower catalytic temps allowing for better tuning and the car to not go into granny mode so easily.
... seems to simple though to actually work
... seems to simple though to actually work
#8
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Originally Posted by MazdaManiac
One - it is an emissions item and any alteration to an emissions item violates the entire powertrain warranty and is a Federal felony.
Also, a street legal cat can be used by a car owner as a replacement part. Car companies have different requirements or laws than individuals. That is to Mazda has to make the meet the new draconian Tier II requirements, but that doesn't mean a replacement part has to.
Now there is some speculation as to whether the part has to be damaged before the owner can replace it. Some say you can't touch the part unless you think/know it broken. Regardless, the law at that point is unenforcable. If you have to, damage your factory cat and put on an aftermarket street-legal version. For the RX-8 this is a very valid story since it is by far the lowest point on the underside of the vehicle.
The government (not necessarilly the EPA) is very leary of making a car manufacturer a sole source for a particular replacement part. (albeit, the factory cat is supposed to last the "life" of the car.)
Two - it is monitored by the PCM via an O2 sensor, so its presence or lack thereof will affect fuel delivery.
That said, I took mine out and replaced it with a test pipe when I only had 4k miles or so. No CEL or any other problems for that matter, but my exhaust sure is stinky!
Last edited by MrWigggles; 06-27-2005 at 06:54 PM.
#9
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Originally Posted by r0tor
Has anyone ever looked into trying expanding the exhaust diameter to fit a larger diameter high flow cat? It seems to me that a larger diameter would not only flow better, but be more efficient, and most importantly also lower catalytic temps allowing for better tuning and the car to not go into granny mode so easily.
... seems to simple though to actually work
... seems to simple though to actually work
-Mr. Wigggles
#10
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Ah, true. It is a civil penalty to remove a CAT as the end user with a $25,000 fine.
As a professional, it is a felony.
Clean Air Act section 203(a)(3)
As far as violating the MM act, what is law and what is probable are two different things.
It is cheaper in the long run for Mazda to say your warranty is void and then wait for the law suit than it would be to do otherwise.
The reality is that removing the CAT does little if anything adverse to the drivetrain.
As a professional, it is a felony.
Clean Air Act section 203(a)(3)
As far as violating the MM act, what is law and what is probable are two different things.
It is cheaper in the long run for Mazda to say your warranty is void and then wait for the law suit than it would be to do otherwise.
The reality is that removing the CAT does little if anything adverse to the drivetrain.
#11
I would see why is unlawfull to remove it - but to change it to a high flow one should not be punishable. Plus, the RP one should be CARB certified soon... and as it retains the O2 sensor, unless you get a CEL, how can it damage the engine? But true, MNAO can claim whatever they want - they even told me that is normal for the car to shoot 200mL of engine oil in the air intake, causing the car to almost stall driving in traffic on the highway... How is that any safer than a high flow cat - beats me...
#12
For a replacement cat to be legal, it would just have to pass the same emission test as the original one, that's all. It probbaly includes an ageing test. So it is quite costly.
A replacemnt cat (or no cat at all) will not damage the engine in any way. No cat might trigger a CEL if you fit the cat monitor HEGO back in place.
mazdaManiac, did you re-connect your cat monitor HEGO?
A replacemnt cat (or no cat at all) will not damage the engine in any way. No cat might trigger a CEL if you fit the cat monitor HEGO back in place.
mazdaManiac, did you re-connect your cat monitor HEGO?
#13
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Originally Posted by MrWigggles
...your factory cat and put on an aftermarket street-legal version. For the RX-8 this is a very valid story since it is by far the lowest point on the underside of the vehicle.
And if it is "ok" could there be internal damage? Any thoughts on this is appreciated.
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Originally Posted by MrWigggles
To meet Tier II the RX-8 cat HAS to be very thermally reactive. It has to heat up quickly. It is the cold start emissions that are the EPA's concern since this is about the only time the car ever actually pollutes any measureable way.
-Mr. Wigggles
-Mr. Wigggles
#15
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Dinged cat....
The dimpled cat you see underneath is actually the heatshield, offset from the cats' body by about 3/8". So a sizeable ding on the outside could mean no cat damage, the cat body itself is fairly robust, solid steel, not thin like a muffler. The catalyst itself even has a ceramic 'wool' between the steel and the honeycomb.
That said, a really good bash will crack and powder the ceramic, no doubt. The first sign would be a CEL or chunks of cat rattling around in the muffler body.
S
That said, a really good bash will crack and powder the ceramic, no doubt. The first sign would be a CEL or chunks of cat rattling around in the muffler body.
S
#18
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Originally Posted by MazdaManiac
That said, I took mine out and replaced it with a test pipe when I only had 4k miles or so. No CEL or any other problems for that matter, but my exhaust sure is stinky!
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