You will likely lose your Jeep if you get caught.....

 

Why would you remove it anyway?
BTW, if you require an air emmisons test down the road in order to renew your plates...you will rightfully fail.

 

ummm......... can we say federal offense.

 

This motor is so efficient that the catalytic converter hardly does anything. All it does is restrict airflow. Maybe this is just the thing to do where I'm from but everybody who installs an aftermarket exhaust on their vehicle takes out the catalytic converters if it won't trigger an engine light. There is no way to visually tell that my cat is hollowed out. It looks completely stock from the outside.

Hitzy: Who's gonna take it from me?

Keeping Fingers Crossed: In Alberta there are no emissions tests.

ilterzo84: Older cars don't have a catalytic converter and it isn't illegal to drive them. But if it is a federal offense then this whole thread was for information purpose and didn't actually happen

 

ilterzo84: Older cars don't have a catalytic converter and it isn't illegal to drive them. But if it is a federal offense then this whole thread was for information purpose and didn't actually happen

Federal law states that a catalytic converter can not be removed from a vehicle for 15 years unless it has failed. with in those 15 years it must be replaced with a stock replacement. pre-1976 cars didnt have catalytic converters because it wasnt invented yet and not required by federal law.

so any vehicle that is over 15 years olds can have the cat removed unless stated otherwise by state law.

 

I had a supercharged 2003 corolla, that I removed the cats from (Yes there were 2). It definately helps with performance, and give the exhaust that "hotrod" smell. Unless I was putting some form of Force Induction on the patriot, I would never do this. Higher RPM horsepower will be gained, but You will likely lose a lot of low eng torque with the decrease in backpressure.

To each their own. We only have the OBDII check here so no check engine light = pass.

So there is no downstream sensor on the patriot? Thats interesting.

 

There is no such thing as exhaust backpressure!

The speed of the exhaust is important, so a specific CFM through a 3" pipe is slower than a 2" pipe.

I have not investigated the MK cat to judge, but hollowing it out should improve flow and performance at any engine speed.

 

There is not such thing as exhaust backpressure!

The speed of the exhaust is important, so a specific CFM through a 3" pipe is slower than a 2" pipe.

I have not investigated the MK cat to judge, but hollowing it out should improve flow and performance at any engine speed.

In this case you have 4 cylinders that converge into one pipe. The restriction that the converter creates, causes the exhausting cylinder to force a small amount of pressure against the closed valves of the other 3 cylinders.

Now obviously all engines run different. Clearing that restriction would be a good thing for exhaust flow. The problem is, the ECU is tuned to run with that restriction. Maybe even allowing a small amount of exhaust to flow back into the cylinder for fuel economy, and emissions.

With proper engine tuning, no doubt you would see a power gain. Without proper tuning, it could actually create a loss.

Im not trying to argue with you APT so dont get the wrong impression. Im just saying there more to it.

 

Well, it won't void the warranty on the stereo.

There are plenty of legal reasons in the US to not gut the cat or remove it, way more costly then lack of vehicle warranty.

As I said, let each person do his own research.

 

Very interesting. Thanks for the Link. :smiley_thumbs_up:

 

I see you have Manaflow listed in your add ons, is that a cat-back, or just a muffler upgrade? Also what subs do you have? Pics?

 

i thought that was a resonator, the cat is part of the exhaust manifold no??

 

there are two cats on the 4x4. one that is part of the manifold and one abit further down stream. chrysler says that it is two halves of one cat.

 

An excerpt from one of the articles disproving the back pressure myth.

" Thumbs up Exhaust theory and design
Exhaust theory and design

Dispelling the "backpressure" myth...

The following excerpts are from Jay Kavanaugh, a turbosystems engineer at Garrett, responding to a thread on www.impreza.net regarding exhaust design and exhaust theory:

"Howdy,

This thread was brought to my attention by a friend of mine in hopes of shedding some light on the issue of exhaust size selection for turbocharged vehicles. Most of the facts have been covered already. FWIW I'm an turbocharger development engineer for Garrett Engine Boosting Systems.

N/A cars: As most of you know, the design of turbo exhaust systems runs counter to exhaust design for n/a vehicles. N/A cars utilize exhaust velocity (not backpressure) in the collector to aid in scavenging other cylinders during the blowdown process. It just so happens that to get the appropriate velocity, you have to squeeze down the diameter of the discharge of the collector (aka the exhaust), which also induces backpressure. The backpressure is an undesirable byproduct of the desire to have a certain degree of exhaust velocity. Go too big, and you lose velocity and its associated beneficial scavenging effect. Too small and the backpressure skyrockets, more than offsetting any gain made by scavenging. There is a happy medium here."

My question does backpressure exist and does it effect engine performance?

Answer the question your self after you read and understand the facts.

 

I think the turbo guy stated this pretty clearly. It does exist, but you don't want or need it. Scavenging is the name of the game for N/A cars. You want to really get into exhaust tuning, look up reversion dams.

 

Who cares what it does, if you remove it, you will get a fine and a court date!

 

funny how it turned from a question to the deputize sherriffs/lawyers to tell you it i illegal.Who ever doesn't believe global warming isn't real is living in denial or is just plain ignorant.Snow doesn't melt unless it gets warmer and even the south pole is melting

 

That engine was designed to run with a Cat!! ---Just leave it alone--!!!!

 

he probably wants a little more power and sometimes gutting out the cat does give you more power geez give the guy a break I like cheap horsepower too.Like someone else said no check engine light=pass on emissions only older cars get tail pipe checks or if they pop open your hood and say no way(I have had that done)I had a 69 camaro highly modified pretty much pro street and as soon as I would pull up to an emission place they were like no way were passing you lol (it was very loud even with mufflers it would rattle your windows and you can smell how rich it was 5mpg hehe)

 

One can spend money on a replacement cold air intake (we already have a pretty efficient one), replacement cat back exhaust system (we already have a pretty efficient cat back system), or making your car illegal by disabling or removing the catalytic converter (federal felony in the U.S). But, you won't see a power increase except for maybe when you have your foot to the floor and are above probably 4,000 RPM or so. Otherwise, the slight maybe increase in engine intake and exhaust capability is just along for the ride and it's effect on your credit card and/or bank account.

Unless your foot is flat to the floor with the RPM above 4,000 RPM, you have free power available just by pushing the loud pedal farther and/or revving higher. What percentage of your driving time is spent with your foot to the floor above 4,000 RPM?

My statement about our effective stock cold air intake is based on my Scan Gauge II comparisons of ambient air temperature and intake air temperature. When moving, the difference is usually under 10 fahrenheit degrees.

Of course, if you want noise, and perceive that noise equals power, and want to spend money on noise, then have at it.

FWIW and YMMV.

 

How are you all keeping your check engine light off after removing the cat? I've seen a method using a spark plug non-fouler that worked for some but not for all. Check out the diagram on this site it looks pretty intriguing.
zero-signal.org/o2/O2bypass.html.htm
I've seen this resistor/capacitor setup on a few other sites as well but no success/failure stories. Just wondering if anyone's tried it...

 

I'm extremely glad Al Gore made it to jeeppatriot.com but that was not my question. Damn, I'm all for treating animals good too but is PETA or gonna come in here and trash this thread next? Maybe the Catholic church? I'm here for Q&A not for a morality check. Somebody please ban this guy.

 

Anyway, back to what I was talking about a few days ago, I just completely removed the second O2 sensor on my 08 pat and so far so good. CEL went off and has stayed off 3 days now. I'll post again with any news.

 

Cutting the Catalytic Converters

ilterzo84 wrote:
Federal law states that a catalytic converters can not be removed from a vehicle for 15 years unless it has failed. with in those 15 years it must be replaced with a stock replacement. pre-1976 cars didnt have catalytic converters because it wasnt invented yet and not required by federal law.

so any vehicle that is over 15 years olds can have the cat removed unless stated otherwise by state law.

Just want to add on this...

Federal gov't vehicle pollutants control legislation requires that practically all vehicles built and/or sold in USA come geared up with a catalytic converter. And we can’t lawfully remove your catalytic converter as we may well become subject to rigid fees and penalties.

 

some of you guys are making to large a deal of this cat nonsense...

 

nevermind...

 

This thread is old... just realized...

 

Just an FYI, cars contribute only 5% to global warming the other 95% comes from factories. If the goverment really wants to crack down on global warming they should go after the factories and leave us car guys alone.

 

+1 ...

 

Just regarding the carbon footprint comment... Catalytic converters reduce NOX emissions mainly.

 

There is no such thing as exhaust backpressure! I have seen plenty of dyno sheets for a corolla XRS engine that lost mid range torque after the exhaust was opened up. It gained about 10 hp at redline, but lost about 5-6 ft lbs of troque in the mid range.






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