Long Tube header advice???

[66nova]

So, I ordered a set of Doug Thorley Tri-Ys from Justin. Well after I ordered them I looked under the hood and realized my cats are built into my Y pipe, just below the manifold.

Texas has yearly inspections. Does anyone know if I can add a cat somewhere else and pass? I'm not trying to get by without running cats. That is/was not my plan. I want to be legal. Can it happen?

 

[Zembonez]

In order to run long tubes, you'll have to add cats past the Y. I believe Jarrod did on his white truck...

 

[Black02Silverado]

You should be able to hook up cats with no issues. Maybe ask Justin, he might know by selling a set up to someone else doing the same thing as you.

 

[daddy]

I hate cats; they make my eyes swell up and itch.

 

[66nova]

I hate cats; they make my eyes swell up and itch.

I do too! I really can't stand animals in general!


Digging around on performancestrucks.net last night I found where Thorley said their Y pipe has enough room to have the converters welded into place. We will see. While I may not want any cats in my house, I have no desire to go without them on my truck.

 

[Gunslinger]

Find some cats off a Workhorse motorhome with the 8.1 engine. They are super high flow and cats can be installed behind the headers. I think those cats would be cheaper than new ones. They don't shed either.

 

[66nova]

Find some cats off a Workhorse motorhome with the 8.1 engine. They are super high flow and cats can be installed behind the headers. I think those cats would be cheaper than new ones. They don't shed either.

Thanks man. I'll see how things go and I may look into that.

To start I'm going to cut out my stock converters and modify the Y pipe that comes with the headers.

 

[Black02Silverado]

Hooking up your cats should not be an issue, as you can see they are pretty flexible.

 

[66nova]

Hooking up your cats should not be an issue, as you can see they are pretty flexible.

Yeah, but they don't tend to be very cooperative.

 

[Bigredmariner]

Two choices really, find a good shop that can re-use your factory cats and fab a new Y pipe or go true duals with the factory cats.

Or, get a set of aftermarket cats and have the exhaust made up.

I would suggest sticking with the factory cats because you want to stay legal. If you go with high flow cats you will almost certainly need to have your rear O2 sensors turned off in the tune.

I left mine turned on and have battled trying to keep the P0430/ P0420 code from coming back. Such a pain in the ass... I've tried about every internet trick that I've read about and it works for a while and then the code comes back. I should have just had them turned OFF.

Leak tested the exhaust and all kinds of bullshit, new O2's and finally said screw it.