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- Engine/Transmission/Performance Adders (https://montecarloforum.com/forum/engine-transmission-performance-adders-12/)

- - ZZP Powerlog (https://montecarloforum.com/forum/engine-transmission-performance-adders-12/zzp-powerlog-52821/)

turbo monte, I will be taking out the U-bend myself without replacing the downpipe.

Quote:

Originally Posted by schroederchevelle (Post 657247)

Alright, thanks guys. I'm not too worried about the finish of it. So I don't think ceramic coating it will be necessary. I've considered getting the high flow cat with the downpipe too but I don't want it to throw the O2 code. I don't know of anywhere around here that can delete it from the pcm for me. If I decide to get it I'll let you guys know how it turns out.

If you want the P0420 code deleted, I can help with that. I offer a small PCM service. Read the link below, I believe I cover everything in it. Feel free to PM or email me with questions:
https://montecarloforum.com/forum/pr...-3100-a-42773/

Quote:

Originally Posted by schroederchevelle (Post 657325)

turbo monte, I will be taking out the U-bend myself without replacing the downpipe.

There really is more to the ZZP downpipe then just the High Flow CAT and u-bend delete. Below is a link about my downpipe swap.
'04 Monte Carlo SS - ZZP Downpipe

I actually cut open my old down pipe before sending it back. As far as the construction of the stock down pipe, I found everything ZZP said to be true (a little tighter on the inside because of being double lined steel and such). If you are not doing headers, I would not hesitate to doing a down pipe with all of this.
I actually did the downpipe before the PLOG and I noticed a little change for the better and it became another supporting mod to a bigger picture.

Alright, when do you think it's a good time to change the cat? My car has 163k but the engine only has 14k on it. To my knowledge the cat has never been changed. Would a new car be a good idea?

Quote:

Originally Posted by schroederchevelle (Post 657424)

Alright, when do you think it's a good time to change the cat?

When it is bad. There's no real set time, all depends on how the car is running.

Yeah that's what I've always thought. But it couldn't hurt to replace it anyway. Or should I just wait til it plugs up?

Unless you are upgrading to a performance cat or the cat fails, leave it alone. I know factory cars that are still running with over 200k on them.
To my knowledge there is no maintenance or recommended cat replacement interval.

i also agree there is more to a downpipe then just getting a highflow cat and u bend delete. the factory downpipe is the worse part of the exhaust, if your not changing the downpipe dont bother with the plog. and if you decide to get a downpipe as well then at that point just buy headers.

I installed a ZZP powerlog on my Monte Carlo SS Supercharged,
& I installed a ceramic coated cross over exhaust pipe & a down pipe with a high flow cat with a u bend delete..

https://scontent-iad.xx.fbcdn.net/hp...16&oe=55D5DA17