exsaust
Former Vendor
Joined: Jan 2006
Posts: 3,849
Likes: 1
From: Seattle
The cel (check engine light) comes on and stays on, you fail your emissions inspection at license time and end up having to put them back on anyway. Not worth the time, bother and expense. It won't give you any noticable increase in power and may have a negative (bad) impact on your fuel economy as the computer uses input from the o2 sensors to control fuel and emissions. There are o2 sensors before and AFTER the cats. Dan.
Junior User
Joined: Jun 2008
Posts: 76
Likes: 0
From: Ft Collins Co
If your o2 sensor is after your cat you might have problems but if it is before you should be fine. I cut mine off and got about 10 hp gain and it will sound a lot better too but you will not pass emissions.
Senior User
Joined: Dec 2007
Posts: 325
Likes: 0
From: Lower Hudson Valley, N.Y.
You might want to try it the other way: lose the muffler and leave the cat. I'm going to this spring. I got positive comments a while ago when I asked this question.
Later...
Brewster...
Later...
Brewster...
Junior User
Joined: Jun 2008
Posts: 76
Likes: 0
From: Ft Collins Co
if you take the muffler off you many or may not get more power if you take the cat off not only will you get more power but if your cat is clogged you can loose power. So if you cut it off you would get your stock power back and more.
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Elder User
Joined: Oct 2008
Posts: 519
Likes: 7
OBDII became mandatory for all vehicles sold in the U.S. in 1996. So no Super Duty is OBDI. I think most OBDII vehicles have a downstream (after cat) O2 sensor.
And, why not just get a high-flow cat? You will see increased performance, but will still pass emissions and retain economy.
And, why not just get a high-flow cat? You will see increased performance, but will still pass emissions and retain economy.
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Junior User
Joined: Jun 2008
Posts: 76
Likes: 0
From: Ft Collins Co
If you want to sped the money go for it but you will not get as good of a sound from it but if thats not what you are going for then that would be the way to go. You may get some power from a high flow cat but not as much as you would with no cat. so it depends on what you are going for sound or power or both and how much you want to spend. just cutting the cat off will cost as little as $30.
Prolocutor
Joined: Jan 2009
Posts: 13,618
Likes: 1,245
From: Western MA
I remember working on my buddies Mustang a few years back. At inspection they sometimes looked under the car to verify the cat's were in place. We decided to "gut" them instead so no one could tell. Pulled the dual exhaust and used a long piece of brake line to knock the insides out and reinstalled. The amazing thing was that the car still passed the emissions test at inspection. Not just the visual, but the probe in the pipe. Makes you wonder why they were on there in the first place...
Senior User
Joined: Jan 2009
Posts: 419
Likes: 1
OBDII became mandatory for all vehicles sold in the U.S. in 1996. So no Super Duty is OBDI. I think most OBDII vehicles have a downstream (after cat) O2 sensor.
And, why not just get a high-flow cat? You will see increased performance, but will still pass emissions and retain economy.
And, why not just get a high-flow cat? You will see increased performance, but will still pass emissions and retain economy.
Check out this thread about it.
https://www.ford-trucks.com/forums/236756-cat-less.html
Hotshot
Joined: Mar 2007
Posts: 10,101
Likes: 40
From: Pa
Wrong, trucks over a certain weight had an OBD2 plug but were basically OBD1, I think 2004 is when the OBD2 change occurred for 3/4 ton and over trucks. I have a 1999 F350 with no after cat O2, Never did have one.
Check out this thread about it.
https://www.ford-trucks.com/forums/236756-cat-less.html
Check out this thread about it.
https://www.ford-trucks.com/forums/236756-cat-less.html
No O2 after the cat, no problems.
Junior User
Joined: Jun 2008
Posts: 76
Likes: 0
From: Ft Collins Co
Ya one of my friends told me that one of his friends went to get his car tested with no cat and it failed went home took the insides out of the cat and put it back on and took it back and it pasted.
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 421
From: Long Island USA
https://www.ford-trucks.com/forums/5...t-come-on.html
The Superduty is over 8500lbs GVWR, so it was not required to go to OBD-II until something like 2007. However, they did go OBD-II in 2005 with the fly-by-wire setup. So, any 2005-up gasser SD is going to be OBD-II and require catalytic converters to NOT get a check-engine light.
There ARE, however, some Superdutys that have an O2 sensor after the catalytic converter. Especially the Excursions. They are usually California emissions spec. They also might have an EGR valve. '99 Superduty, all V10's had EGR and I'm assuming so did the 5.4.
Elder User
Joined: May 2003
Posts: 818
Likes: 0
From: Mobile, AL
Mine is a 2008 5.4, and I have both cats and no muffler. My truck feels better with my current set up over stock, Flowmaster and a Magnaflow knock off. I'd leave your cats on and ditch the muffler.
Here is mine.
Here is mine.