Exhaust cutouts before the cats?

[Coyotes55086]

Hey guys, so I was under the impression and even read somewhere that you could install the y tube exhaust cutouts before the cats in order to basically make it like an open header. I called a few muffler shops today and they said there are no room on the stock headers to do this. Is this correct? Does anybody know of any options. Because I would really like to do this with my stock headers I make it very loud

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[Copperhead73]

Even if you could, wouldn't you throw codes as soon as you opened them up?

 

[Nagare]

Here's a comparison pic of the ARH longtubes vs stock header:

There's no room there for it and this pic shows the bottom view to put it all together:

I guess there's a tiny bit of space right before each one, but I don't think that'd be really ideal for space and heat honestly.

 

[Coyotes55086]

Damn, I see what you mean. But then what comes right after the stock headers?

 

[ABPP2]

Damn, I see what you mean. But then what comes right after the stock headers?

Those are the cats

 

[EFI]

Damn, I see what you mean. But then what comes right after the stock headers?

The cats come literally like an inch or two right after the final Y merges...and that's where the o2 sensor is so there's no room for anything there.

Why would you want open headers though?

 

[Coyotes55086]

Because I want the car to be very very loud when need be

 

[Performance nut]

I believe it would be possible but it would take some custom work to accomplish. You would first need headers that basically incorporate the y-pipe into the collector so it would need to be purpose built. After that, you would need to put a flange on the new header and the stock catalytic convertors or go with an aftermarket catalytic converter. Once you got that all connected, you would then have to route the cutout to dump exhaust gases somewhere that won't burn up your engine compartment or overheat something.

Challenging, heck yes. Though if you can fit 2" headers in there, I have a feeling you can fit a custom built header with a dump that doesn't burn everything up. And you would need one heck of an actuator because that will be hot as heck in that area. Personally I would like to see someone do it with as much stock exhaust as possible as many have shown that cat deletes increase power rather significantly. You could probably do it easier with LTH's as it will position the collector in a more optimal position. The only way that would be beneficial is if you had a catalytic converter that really cleaned up the exhaust (and therefore giving restriction) that you could bypass when you are at the track. Then you get the benefits all around.

And yes, I would think you would need a tune to do this. The sensors would likely sense something is off when flow is diverted and flag it as I would think the two sensors would read the same thing and therefore concluding the catalyst has failed. If you somehow figure out how to do it without a tune, the pre-cat O2 sensor would have to come after the Y-pipe and the diverting pipe would have to be small enough diameter to restrict flow to allow some flow through the catalytic converter. Not sure if there is a minimum flow requirement through the catalytic converter (that it would be capable of cleaning the emissions) and if the O2 sensors would be able to distinguish there is less flow than normal.

 

[Coyotes55086]

Thanks for the help and thorough reply brother

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