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The xpipe removes 2 of them without any consequence at all. So why are they there if there's no monitoring of them?
My wife asks me "how much was this pipe crap anyway" and I say, as a wise husband, "$250" She looks at me skeptical, which is a nuance to her normal frown-scowl.
I get it installed (couldn't wait 9balls! We'll have a supercharger install fest instead), and I return with the 300 pound stock xpipe with cats.
She says "throw that out." And I say, "it's worth a lot of money with the cats being full of precious metals."
A nuanced frown-scowl. "You're telling me that you installed a $250 part to replace a $500 part?" And I said, knowing how it sounds, "um, yeah."
Then I had to explain how the ECU doesn't care about the cats, the car runs nicer without them. But everything fell apart when I couldn't explain why GM spent the money on unmonitored secondary cats to start with.
Well, I'm no expert... but I did stay at a Holiday Inn Express last night. While there someone told me the idea of having 4 cats is so each cat has less mass. This makes the two cats closest to the engine heat up faster and thus begin being effective sooner than if you just had two fat cats.
Sounds good to me.
Last edited by Steve Garrett; 06-03-2016 at 11:18 PM.
Reason: No need to re-quote the OP, especially if you're the next person posting.
Hell, I have 5 cats, 2 sleep under the car, 2 on top of the car and the 5th one sleeps on the front porch. The 2 under the car do get hot faster...don't know if that helps them work better or not.
The EPA is super **** over startup emissions, so they jam these cats way up by the exhaust manifold for quick light off. Honda takes it to an extreme on a lot of their cars, the cat is literally incorporated into the manifold itself. Look at the BMW 4.0 v8 M3, it has 4 cats and gains about 10-12hp from eliminating the first two, again jammed up into the headers. AFAIK they still pass smog tests with only the rear two cats.
The xpipe removes 2 of them without any consequence at all. So why are they there if there's no monitoring of them?
My wife asks me "how much was this pipe crap anyway" and I say, as a wise husband, "$250" She looks at me skeptical, which is a nuance to her normal frown-scowl.
I get it installed (couldn't wait 9balls! We'll have a supercharger install fest instead), and I return with the 300 pound stock xpipe with cats.
She says "throw that out." And I say, "it's worth a lot of money with the cats being full of precious metals."
A nuanced frown-scowl. "You're telling me that you installed a $250 part to replace a $500 part?" And I said, knowing how it sounds, "um, yeah."
Then I had to explain how the ECU doesn't care about the cats, the car runs nicer without them. But everything fell apart when I couldn't explain why GM spent the money on unmonitored secondary cats to start with.
So what's up with that?
Why do you have to explain car purchases to your wife? If you just did and kept quiet you would have less grief.
Are we sure the post O2 sensor units are catalytic converters and not mid-pipe mufflers? A lot of cars have mid-pipe mufflers to control noise and exhaust flow.
Emissions is all done by the ECM/PCM, so anything post the O2 sensor can't be a part of the emissions control system, unless it's a "passive" component, and I'm not aware of passive emission components on the exhaust system.
Where the US has an additional catalytic converter is on turbo cars, pre-turbo. Europe doesn't require those, it's why European tuned cars have more turbo pep and less lag.
06-03-2016, 10:54 PM
Well, why do we have 4 cats anyway?
