Removing a catalytic converter?

[bunduguy]

So I overheard someone in a muffler shop;
Saying that if you remove the CC you'd get more power and better mpg.

so besides the downside of emitting a buttload more CO2 and whatever else, has anyone done this. Just curious. I'm about to replace mine (after a test tomorrow), and the rear muffler too.

 

[WoldD90]

You can also get some money as the Catalytic Converters have Titanium in them.

Removing the CC will not get you more power unless you will be able to reprogram your ECU, as without them your sensors will sense a problem.

 

[CA-RJ]

You'll get a check engine light and that will not allow you to pass inspection.

 

[Street Wolf]

Removing the CC will not get you more power unless you will be able to reprogram your ECU, as without them your sensors will sense a problem.

Wrong.

You'll get a check engine light and that will not allow you to pass inspection.

...and wrong.





I PM'ed you a cheap solution to throwing a code with the o2 sensor. Other solutions would be purchasing a o2 emulator or of course the best way would be to get into the computer if possible.

 

[gotmud]

X2 what Street Wolf said. Losts of options out there. I've been running cat free for three years and have had no problems. Of course, my 80 is OBDI. However, I have done the mods Street Wolf is refering to on OBDII with great success.

 

[bunduguy]

Living in New Mexico, we have no emissions regs, but the naturalist in me (I was an African Safari guide for several years) feels super guilty at the thought. So it seems there may be a power difference after all. Any idea how much? And does it come at a mpg sacrifice?

Excuse the ignorance, but I'm not an engine-type guy! More of a birds-and-the-bees type......:hehe:

 

[haven]

Tampering with the emissions systems on your vehicle (such as removing a catalytic converter) is illegal if you plan to run your vehicle on the street. It also will make your vehicle fail its OBD-II smog test. It's legal off highway only.

It's against ExPo rules to use the forums to plan illegal activities. So if posts here talk about modifying emissions systems for on-highway vehicles, this thread will be closed.

Chip Haven

 

[Street Wolf]

Living in New Mexico, we have no emissions regs, but the naturalist in me (I was an African Safari guide for several years) feels super guilty at the thought. So it seems there may be a power difference after all. Any idea how much? And does it come at a mpg sacrifice?

Excuse the ignorance, but I'm not an engine-type guy! More of a birds-and-the-bees type......:hehe:

There is a MPG and 'power' difference between cat and no cat, however don't expect it to be a huge gain. Since I'm fairly certain you're not pushing the limits of your exhaust flow.

I'm currently running this little 'trick' on my Disco for the time being, which I PM'ed bunduguy

http://www.energeticforum.com/renew...odification-using-spark-plug-non-foulers.html

It works flawlessly though some may consider it a cheesy or rigged method, which it is. However I don't have a computer capable of digging into my Land Rover like I do on my car which allowed me to simply delete the SES codes when I removed the cat on it to allow better flow while running nitrous.

The second best way about doing this without throwing a code in my opinion is the o2 emulator. Though, little on the spendy side compared to just buying the required amount of those non-foulers and modifying them to work.

http://www.3800performance.com/Merc...de=O2-EMU&Category_Code=ES_H&Product_Count=17

The link above is really the only place I'm aware of to get the 02 emulator from, however it will work on whatever vehicle you install it on as long as you have the correct connector as shown in the photograph of it. I had one laying in the garage that I removed from my Grand Prix and made sure of that.

 

[Ursidae69]

Living in New Mexico, we have no emissions regs, but the naturalist in me (I was an African Safari guide for several years) feels super guilty at the thought. So it seems there may be a power difference after all. Any idea how much? And does it come at a mpg sacrifice?

Excuse the ignorance, but I'm not an engine-type guy! More of a birds-and-the-bees type......:hehe:

As a fellow New Mexican living 20 miles up the road from you, I'd ask you not be one of those people adding to the pollution please. Unless you're running some racecar, seriously, what is the point? Thank you.

 

[bunduguy]

Everyone seems to have missed the point - I did say I was replacing mine, not removing mine.

I was just curious as to the validity of the claim.

 

[luk4mud]

Replaced mine recently. They were 13 years old. When I cut them off, you could barely see light through either one of them, not good. With the replacement, it feels much more unplugged to me. I think there is a balance between being legal and having an essentially plugged up system.

 

[BlueBomber]

there are SMOG legal performance cats that flow more than stock cats. have you looked into that?

 

[bunduguy]

Replaced mine recently. They were 13 years old. When I cut them off, you could barely see light through either one of them, not good. With the replacement, it feels much more unplugged to me. I think there is a balance between being legal and having an essentially plugged up system.

Just took mine for test yesterday. While I don't understand the technicals, apparently one side had 4lbs of blowback, and the other had 5lbs. It's supposed to be around 1lb. So.....replacing the cats tomorrow, and looking forward to some regained power! They were 12 years old and had 120k miles on them.

 

[gwittman]

Restricted cats can cause a loss in power but modern cats flow well and work very well if clean. Yes, there are high flow performance cats that give a little more power but probably not noticeable in a stock engine.

BTW, there is no titanium that I know of in catalytic converters. It is the Platinum, Palladium and Rhodium that are the expensive catalyst precious metals in there.

 

[gotmud]

Also, beware of the cheap "universal" cats out there. There's a reason the OEM cats cost so much more - they have more precious metals (catalyst) in them. They are also more durable and are warranted for much longer than the aftermarket ones.

The hi-flow cats are a step in the right direction, however they can flow too well and not give the exhaust enough time with the catalyst to effectively lower the NOX. This in turn will trigger the CEL.

My advice would be to replace the cats with OEM and look at the pinch points in the rest of your exhaust. There is a bend near the rear axle on the 93-97 80's that is really restrictive.