Hello,
I was just wondering if anybody is running with out a cat on there truck.
on my 99 im going to install banks headers and y-pipe, then a 50 sereies flowmaster 3 in 2.5 dual out, have custom tailpipes made. I got a 3 inch pipe to do with out the cat, but i was wondering if i can really run with out it, will the check engine light come on? there is no 02 sensor behid the cat, and i dont have emission tests here in illinois. and i do believe that the original cat is starting to get puged up.
just wondering thanks
Shawn

 

I know I don't have a V-10, I got a 5.4, I took my cat off, no problem! A little
deeper\better sounding exhaust and a tad more power, the cat was as clean as ever though, the same as my vics cats when I took them off, I hear they get cloged, but everyone I have ever taken off has been as clean as new?! I had my flowmaster on and couldn't even hear it, got the cat off and then you could tell it was there. You will be happy that it's not there! No check engine light or anything funny, I have yet to hear of a problem wih the V-8 or V-10, as long as that O2 sensor is in front of the cat you are great!

 

can't run properly with out a cat on a obd2 motor. the o2 sensers take readings before and after to control the fuel mix. there is not much gain with out any more. not worth looking at the flashing lite telling you shut off the motor

 

Nor is it worth the stiff fines and penalties imposed by the government if they catch you without a cat.

 

There is no O2 sensor behind the cat of the '99-'04 gas SD's, and the motors run great without them!

 

My 03' V10 has a 02 sensor after the cat. Mine truck has 3 02 sensors total. One on each downpipe before the ypipe and one after the cat.

 

wrong again mr. miller. 1 each bank before and 1 each bank after . every car and light duty meaning 1 ton and under have to have them for obd 2 to work. some are in the manifold some in the cat right at the start of it and right after some times right in the shell. get caught altering a system now even for the owner is stiff fines.

 

With these truck being pretty new you should keep the cats on them. You are just putting more bad chemicals in the air and smog, like we don't have enough anyway. I don't have a problem with what ever you want to after that with you mufflers.

 

We found no significant difference on the dyno cat on or cat off. FWIW my 01 only had 2 O2s before the cat.

Clean air is important... more than our rights to modify our motors.

I am against all laws that fundementaly restrict our freedomes. But I am adult enough to know that most of the laws are intended for the better good of all citizens.

The current (under inforced) laws specifically forbid us to change or modify ANY emmissions component.

If too many of us do so, and very pubically announce that act, and deliberatly tell others publically that it can be done, "you won't get caught" .... well all I can say is we are inviting the government to get deeper into our freedoms.

 

agree with fred again. the way the cats a built now they do nothing to harm performance in any way.since 1995"obd2" the cars started useing 2 o2's 1 before and 1 after they do several functions including measureing the cat temp. and emmissions out to adjust the fuel mixture and to ensure the cat functions correctly. the cats are smaller now then ever before showing how well they now function.
maybe back in 1973 or 4 we could prove they hurt but not now.here is where old school thinking is false. we are useing computers and they work very well. not carbs any more.
my 05 has a pair of small ones"cats" right by the manifold and 2 sensers each side. cailf. spec system.
taking a cat off now gives no gains and only helps throw more bad emmissions into the air. todays motors need back pressure to work correctly. every thing up front is a very balanced system and it shows in the horse power gains we again see with every motor. when i started out in the feild forty plus years ago 1 hp per cubic inch was huge now we see 100hp per liter fairly common.

 

Just to clarify some things...

Regardless of whether your city, county or state performs inspections, it's a violation of Federal Law to tamper with a vehicle's emissions system. You can't even 'legally' replace your cat unless you have over 100,000 miles or it is physically damaged.

There are two different emissions systems offered on gas engine Super Duty trucks- at least through the 2002 model year:

The "California" emissions system includes an EGR setup and apparently three (or more?) O2 sensors. I've never seen a CA truck, so I'm just going by the info you guys have provided.

The "non-CA" emissions trucks have only two 02 sensors (both before the cat) and no EGR. I can post pics of the non-CA system for you unfortunate souls that have to put up with that extra "stuff".

"Heavy duty" (believe it or not, the F250+ fits this class) trucks are exempt from some of the emissions requirements set for cars & "light duty" trucks. Read the emissions certification label under the hood and you'll see that it states the engine is certified for use only in HD vehicles. This might mean that some of us do not have FULL OBD-II functionality/certification. But, it's good enough for the Government.

And, as a bonus FYI, 1997 (non-CA emissions) 460CID-powered trucks are still OBD-I. Again, HD trucks were exempted from the 1995 deadline for OBD-II. I'm not sure about the HD trucks with the 351 engine. Since it was offered in the F150, Ford may have just used the OBD-II setup in the HD trucks too???

Please correct any glaring errors that you see.

 

For those who are interested your best friends right now are SEMA (hell I forget the acronym meaning) they are the aftermarket folks who spend great oodles of money trying to convince Congress that we American Vehicle owners are entitled to modify our cars and trucks. The EPA, NHTSA, and a few other pollution and safety organizations have feverishly been trying to pass laws that lock the HOOD to any but Qualified Certified Emissions specialists. I am not BSing here they want you the OWNER to be prohibited from working on your vehicle...PERIOD

Now this is very serious stuff and each and EVERY time they get to EXPOSE some nimrod who is running down the PUBLIC roads with a VERY loud exhaust and MY o MY NO catalytic converter also...well they have a field day writing up the IMPLIED statistics of how many of us deliberately circumvent the LAW...

Think about that a little

And think about this... I challenge any 1999 or newer V10 owner to dyno with cat on and cat off and prove that there is any measurable HP or Torque to be gained above the margin of error that all dynos have....NO I am not talking about a old corroded screwed up and plugged Catalytic converter (few and far between in my experience).

Todays cats are full flow and represent very little restriction... The crappy "Y" pipe is the only real bottle neck in 99-04 systems and if you want to make your 99-04 much.....MUCH better get on your back and duplicate Fords 2005 design.

And for NoMo and others that understand OBDII implications... I seem to see on the Truck and Body builders web site where that have full OBDII compliance indicated for all 2005 gasoline motors now. My truck has 4 O2 sensors, an redesigned fuel system and fully compliant evaporative emissions system and a whole host of new doodads that I can not begin to explain hanging off the intake system

Late edit correction.. The MotorCraft site has the full OBDII compliance certificastion and if you are an insomniac it will take you all night to read all the sensors, logic and tests.

 

All I know is I have never seen a '99-'04 SD that had a O2 sensor after the cat. I am not saying that it isn't possible or that some of the trucks have them, but all the ones I have seen have never had one. My vic didn't have O2 sensors behind the cats either....

 

is that true that these motors dont have egr's? that seems hard to believe.

 

I have heard some California-emissions trucks do have EGR, but my 04 California-emissions truck does not It does have an o2 behind the cat.