Exhaust issues
 

Hello,
I have a 2012 Toyota 86 with an Invidia N1 and Tomei uel headers. Recently I blew the cat and took it to an exhaust repair shop that fitted a universal high-flow cat to replace it. The exhaust note has dramatically changed and become much quieter, as well as driving a bit sluggish. Anyone have similar experience or know of any potential solutions? Cheers.

Not sure about the drivability (likely due to the change of exhaust gas flow, just a guess), but I've heard the size of a cat (or a different cat) can change how the exhaust sounds. Hope you won't have an issue.

Hey mate. Do you mean 'blew' your cat as in the actual guts blew out? If so then your exhaust became more free flowing and would have been a free performance upgrade.

Your new cat is restricting flow compared to the old one that was probably disintegrated.

Get the exhaust shop to delete it (replace it with a straight through pipe) to get your sound and performance back.

I run UELs and a Q300 and no cats.


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How do you blow a cat? (srs)

Knew this was coming...meow

Usually from heat. Kinda weird he blew a front pipe cat. Usually FI guys have to worry about it or people running pop tunes.

Okay, thank you. This is my 10th post, maybe I can "thanks" now

A bad tune can burn one out in short order. Used to be a fairly common issue back in the early 90s when people were still learning how to tune ECUs. Too rich will flow more fuel into the cat than it can handle and POOF there it goes.

So would runing rich actualy physically disintegrate the substrate, or just stop it catalysing?

Im guessing one of those stupid pop tunes would physically damage it.



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Right, at the basis I understood it as misfires or running rich creates more heat and damages them. Or does the fuel itself cause issues with something like combustion in the cat since it holds so much heat itself

Both. I the case of the "pops" they of course are putting rapid pressure on the cats which are just simply not designed for such abuse.