jguy94@sprintpcs.com

OKay so I want duals on my 06, and I have read every exhaust post in the forum but i still have a question. What I want is to but some flow AT of 40's and have the shop fab me up an H pipes and go true dual.

My question is if i do this wont I need another cat some where?? It doesnt seem right that I should be able to run a single cat and I know if I take the cat off the CEL will come on as soon as i get if off the lift, not to mention the O2 sensors I'll start burning through.

Anyone can help this dual thing has me puzzled.

chidrock

Our cars already have 2 cats on them. They come back together before the exhaust and then split at a y.

Wicked Pony

Our cars already have 2 cats. All you need to do is bolt the custom H-pipe to the stock cats the O2 sensors are already on that part of the stock cats.

Derf00

X pipe is what you want, not H. At higher RPM the H pipe does nothing.

You don't need a second cat anywhere. As long as your state does not check the underside of the car you should be fine. Just make sure they have Hiflo cat(s) in there. They are slightly bigger round than stock and allow better flow while the larger diameter makes up for some of the lost catalyst of the second cat. The only thing that causes the CEL to come on is if you're missing O2 sensors. Get O2 sensor deletes in place of the ones that you take out and that should solve that problem.

jthorn9

You won't need, nor do you want anymore cats. Are you sure you don't have 4 cats like the rest of us do or did, two upper cats that are just behind the headers, and two lower cats, that sit about 4" behind the upper cats?

jguy94@sprintpcs.com

I think its better for me to leave that question for the more experienced than me. My stang only has 300 miles on her not bad considering she had 4.3 on friday when i took her home, and I havent got a chance to get under her yet!

Puerto Rico 4.6

One again jthorn, the 05s are very different from pre 04s. The only have 2 cats after the headers , thats it, not 4 like the 99-04 and not 6 like the pre 99s. So jguy , u already have enought cats ......get a dog...coulnt help myself ...sorry.

Wicked Pony

4 cats! Holy Cow. But why?

sonicblue05

h pipe sounds deeper though. and x over h is only like 2 hp maybe

WindVeil05DropTop

Here's the correct answer for you:

You have two cats, one coming off each exhaust manifold. Each cat has two 02 sensors. After the cats, the two pipes join together at a Y and go back to the stock muffler via one long pipe.

So, have the muffler shop cut off the Y after the cats and weld in an X or H. then run an over-the-axle pipe for the driver side muffler. You can reuse the passenger side over-the-axle pipe if you like.