Maybe a crazy exhaust idea

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Mar 16, 2019 | 09:50 AM

Cronus1995

Thread Starter

Driver

Joined: Sep 2016

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From: Tustin, CA

Maybe a crazy exhaust idea

I have an idea that I'm not sure is legal or not.

I want to upgrade the factory exhaust to a 2.5 inch diameter true dual setup. However because I live in California I want to keep the secondary catalytic converters.

So the idea is yank the midpipe off, chop the secondary cats off, and modify the openings to accept 2.5 inch tubing.

I haven't been able to find anything that says it's smog legal or not. Can anyone advise me?

Mar 17, 2019 | 09:52 PM

whitebeast

Pole Position

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From: CA

according to state's smog law, any cat after the second o2 sensor will not affect the smog check condition. My cousin own a shop (including smog) had verified me about it already.

Mar 18, 2019 | 09:56 AM

bakalag

Intermediate

Joined: Feb 2013

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From: ca

Keep the secondary cats but chop off? Are you putting them back on?

I cut off from after the secondary cats and went x-pipe to true dual, passed smog with no issues.
whitebeast has heard my car =P

Mar 18, 2019 | 10:34 AM

Cronus1995

Thread Starter

Driver

Joined: Sep 2016

Posts: 108

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From: Tustin, CA

Sorry let me better explain.

I want to run 2.5 inch pipe from the primary cats to the secondary cats, modify the openings of the secondary cats to accept 2.5 inch, then continue running 2.5 inch all the way to the rear.

Mar 18, 2019 | 02:30 PM

2013FSport

Lexus Test Driver

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From: OR

This is a 350, yes? And what do you plan to do with the mid out to the tail? I'd suggest you include a crossover pipe positioned as far forward as possible to reduce the chances of droning.

This Borla product comes to mind...
this is 2.5" but they make the same in 2.25"
https://www.borla.com/products/proxs...t__400493.html

Mar 18, 2019 | 02:58 PM

Cronus1995

Thread Starter

Driver

Joined: Sep 2016

Posts: 108

Likes: 11

From: Tustin, CA

It's a 350. Basic break down will be exhaust manifolds, 2.5 inch tubing, secondary cats, borla xforce muffler with a built in crossover, more 2.5 inch tubing, magnaflow mufflers in the rear.

Should be a nice flowing quiet exhaust. As long as it will pass visual smog I'm happy.