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Discussion Starter · #6 ·
Anyone else? I'm still curious if anyone has ever done this and still passed smog. I thought that it was the Mustang guys that invented this trick. Maybe I should have posted this in the ppushrod forum...
 

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Discussion Starter · #10 ·
As in just increasing diameter inside with a tool or something ?
You take a piece of pipe and beat the guts out of the catalytic converter. Sounds brutal but they are pretty restrictive inside. I have 3.5 inch exhaust, but it looks like it gets choked down to about half that going into the cat. There's actually a screen at the inlet. Old school street ra er trick. Put the cat back on and visually looks like it did when it rolled off the assembly line. Heap horsepower.
 

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straybullitt said:
Anyone else? I'm still curious if anyone has ever done this and still passed smog. I thought that it was the Mustang guys that invented this trick. Maybe I should have posted this in the ppushrod forum...
We dont have smog in mississippi but both my stangs have gutted cats with x pipes and if you have to pass smog emission there then i can honestly say you would probably fail. Most ppl cant stand by my cars long because the smell is so rich. But man it makes the exhaust sound wonderful!
 

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This is a tricky question because it depends. Here in nj we don't have smog but we do have emissions testing and I use to work for the inspection station years back and I have seen cars with cats fail and cars that have straight pipes pass, it mostly depends how your car is running how clean it runs. Basically what I mean is the cats are only work when they have to if that makes me sense if your motor is running clean the cats are just there if your car is running dirty that's when they actually so their job. It doesn't really give you an exact yes or no answer but just an idea lol.

---------- Post added at 01:18 PM ---------- Previous post was at 01:15 PM ----------

We dont have smog in mississippi but both my stangs have gutted cats with x pipes and if you have to pass smog emission there then i can honestly say you would probably fail. Most ppl cant stand by my cars long because the smell is so rich. But man it makes the exhaust sound wonderful!
You would b surprised some of the stinkiest exhaust I have seen pass emission like to the point you felt like you would pass out lol n others u couldn't even smell fail. Smell isn't always a bad thing lol.
 

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GReese87 said:
This is a tricky question because it depends. Here in nj we don't have smog but we do have emissions testing and I use to work for the inspection station years back and I have seen cars with cats fail and cars that have straight pipes pass, it mostly depends how your car is running how clean it runs. Basically what I mean is the cats are only work when they have to if that makes me sense if your motor is running clean the cats are just there if your car is running dirty that's when they actually so their job. It doesn't really give you an exact yes or no answer but just an idea lol.

---------- Post added at 01:18 PM ---------- Previous post was at 01:15 PM ----------



You would b surprised some of the stinkiest exhaust I have seen pass emission like to the point you felt like you would pass out lol n others u couldn't even smell fail. Smell isn't always a bad thing lol.
I can believe it. If you can pass with it its worth it
 

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Discussion Starter · #16 ·
Gotcha Greese87. It's an F250 with a built 460 that has passed CA emissions with flying colors since it was new. I've heard that, running correctly, they will actually pass with all of the emissions equipment removed. Just not the visual inspection. Lol. I guess I'll find out at the next test. Thanks for the input everyone!
 
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