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downstream second cat removal
Posted: Fri Jul 11, 2014 8:35 pm
by JohnP
I have read the upstream 2-into-1 catalytic converters should be kept what about the second downstream catalytic converter any better benefits from removing it?
Re: downstream second cat removal
Posted: Sun Jul 13, 2014 4:52 am
by wtdash
Hi,
Depends on your mods. I recently removed mine as part of a 3" exhaust upgrade and my dyno #'s definitely went up. But I'm also running a bigger turbo/injectors/more boost.
TD
Re: downstream second cat removal
Posted: Sun Jul 13, 2014 7:00 am
by rallyak
I removed mine also when installed stainless headers.
Re: downstream second cat removal
Posted: Mon Jul 14, 2014 1:20 pm
by cj91legss
haven't had a cat since 2006
Re: downstream second cat removal
Posted: Wed Jul 16, 2014 2:29 am
by mike-tracy
I don't think removing the second cat on a stock engine setup will make a huge difference in the scheme of things, but if you have more upgrades planned for later I don't think it could hurt.
Re: downstream second cat removal
Posted: Sat Sep 13, 2014 1:46 pm
by czei
When the 2nd cat is removed, what happens to the oxygen sensor? Just take it off?
Re: downstream second cat removal
Posted: Sat Sep 13, 2014 1:59 pm
by wtdash
There is no O2 sensor in the second cat on the first GEN legacies just up by the turbo.
Td
Re: downstream second cat removal
Posted: Fri Jan 16, 2015 11:02 pm
by GTEASER
Does anyone know what the size and thread pitch is for the factory o2 sensor? I need to add a bung at the stock location on my newly purchased Invidia Bellmouth Catless DP.
Re: downstream second cat removal
Posted: Sat Jan 17, 2015 4:46 pm
by cj91legss
They're mostly the same. Any exhaust shop will have them for around 10 bucks.
Re: downstream second cat removal
Posted: Sat Jan 17, 2015 6:34 pm
by GTEASER
Got it thanks. It appears that the standard size is M18x1.5.