I am about to take a certain part of the exhuast system out (meow) and someone told me that he did this and his fuel milage went down the crapper. He has also done numerous mods to this truck and I would rather think the poor milage is do to these mods. Has anyone else heard of losing fuel milage with no kitty?

 

I would imagine your friends milage is suffering because he's got his foot in it all the time now.

 

Not I. I haven't heard of that. I have heard of gaining HP though. I would think it would get better MPG because its less restrictive. I removed mine when I put on 4" exhaust and didn't notice any difference. Just my 2 cents.

 

That's what I thought, and yes, he usually has his foot in the pedal. It sounds good that way

 

Why is there a cat in there anyway? There is no smog checks for these right?

 

My 2000 PSD doesnt have one. I looks like to me that it never came with one. I am the second owner, and it shows no sign of ever being removed. Just the same old rusty pipes it came with. I get about 17 MPG. I say about because I have taller tires throwing off my odometer.

 

In Nevada there are Smog checks now. They just started this about a year ago. I do not have a cat on my truck and it passes no problems.

 

smog checks for diesels are generally different anyways. in washington they do opacity checks. Test to see how much smoke you make

 

LOL Yea so go ahead and chop off the kitty and don't take it to get inspected with your chip on the highest setting!

 

it is not a cat, a cat is used to reduce hydrocarbons, non of which a diesel produce.

that is a smog canister that is packed with wire, guaze, and charcoal. it does nothing but ford put it there as a sorry excuse for reducing emmissions

 

From Ford 7.3L service manual:

"The Diesel catalytic converter is designed to only oxidize the "soluble oil fraction" of diesel hydrocarbons. Other hydrocarbons, NOX, CO, and particulates are controlled in the combustion process."

 

My F250 has dual straight pipes with no restriction and my mileage is around 16-18 empty. The Excursion is stock and gets about the same but has gotten as high as 18.9 once.

 

Opacity checks here in Nevada too.

 

okay, another question. How much more turbo whine will you get by removing the cat with a stock exhuast system?

 

noticable turbowhine, the more the better in my book. I did cat/downpipe and 4" all at the same time and put on a straight through muffler