[Topless 335i]

I'm planning on buying either the RR or AR catless downpipes but was wondering if there were any negative long term effects of removing 2 cats? Is the 5-10 hp difference between catted and catless downpipes noticeable?

[Sniz]

shouldnt be any long terms changes, the turbo's should actually have a little less stress on them.

the increase is noticeable, especially the quicker spool and better throttle response.

[shpirate87]

Originally Posted by Topless 335i

I'm planning on buying either the RR or AR catless downpipes but was wondering if there were any negative long term effects of removing 2 cats?

I have to assume you mean other than it being illegal and the risk of a $5K or more fine.

[ragingclue]

Planning on running catless in Cali? Do you know a smog tech or something?

[jadeddjay]

how about global warming?

[Kelvin1000]

The cabin will eventually smell like an old Chevy truck

[midlife]

Originally Posted by Kelvin1000

The cabin will eventually smell like an old Chevy truck

had my catless dps on for 1 year = no smell at all.

far as global warming... i plan on quiting smoking within 2 months

[SteveMD]

On a serious note, here in MD, we have to take an emissions test every two years. If you do too, how do you get around it?

[ar design]

Benjamin is usually a pretty convincing guy

In other news, downpipe long term effects usually include miles of smiles, giggles, and a sudden need for new rear tires

[scottp999]

Originally Posted by SteveMD

On a serious note, here in MD, we have to take an emissions test every two years. If you do too, how do you get around it?

I'm in MD. I'm probably going with the catted version of AR's. I don't even think they will look around if there is no catless smell. They will just plug into the port, find no codes, and pass the car.

If they do fail your car they give you time to correct it and bring it back.

If you are not throwing any codes, you will be fine:

"What is the Right Test for Your Vehicle?

On-Board Diagnostics (OBD) Test
1996 or newer model year vehicles weighing 8,500 pounds or less and equipped with a computer controlled engine and fuel system

Instead of testing your vehicle’s exhaust, your emissions test will involve scanning your vehicle's computer for emission control malfunctions. During an on-board diagnostics scan, a lane inspector will connect to your vehicle's computer through a connector under the dashboard to determine the presence of recorded “trouble codes” that illuminate the “check engine” light on the instrument panel. Vehicles with an illuminated “check engine” light automatically fail the emissions test."

http://www.marylandmva.com/MVAProg/VEIP/veipinfo.htm

[Sniz]

Originally Posted by scottp999

I'm in MD. I'm probably going with the catted version of AR's. I don't even think they will look around if there is no catless smell. They will just plug into the port, find no codes, and pass the car.

If they do fail your car they give you time to correct it and bring it back.

If you are not throwing any codes, you will be fine:

"What is the Right Test for Your Vehicle?

On-Board Diagnostics (OBD) Test
1996 or newer model year vehicles weighing 8,500 pounds or less and equipped with a computer controlled engine and fuel system

Instead of testing your vehicle’s exhaust, your emissions test will involve scanning your vehicle's computer for emission control malfunctions. During an on-board diagnostics scan, a lane inspector will connect to your vehicle's computer through a connector under the dashboard to determine the presence of recorded “trouble codes” that illuminate the “check engine” light on the instrument panel. Vehicles with an illuminated “check engine” light automatically fail the emissions test."

http://www.marylandmva.com/MVAProg/VEIP/veipinfo.htm

yeah here in MD you'll be fine most likely running fully catless assuming your not throwing codes. They will just plug into your OBDII, find no codes and your on your way.

[Qmax03]

Originally Posted by ar design

Benjamin is usually a pretty convincing guy

In other news, downpipe long term effects usually include miles of smiles, giggles, and a sudden need for new rear tires

LOL ..

+1 ..... All my cars ive ran Full Cattless exhaust systems with out any problems or smells.

[Panoz]

Originally Posted by jadeddjay

how about global warming?

This is one of the effects for sure...but it seems that this is Inevitable (but not because of our catless DPs)


The other effect is that your wastegates will live longer.

[///M ichael]

Originally Posted by jadeddjay

how about global warming?

Global warming is a myth!

[Panoz]

Originally Posted by ///M ichael

Global warming is a myth!

I hope you are kidding...

[Nikolas]

Originally Posted by Panoz

I hope you are kidding...

Well the polar caps are shrinking for sure. He may be referring to the concept that global warming is cyclical and happens regardless of man's contribution. There are many scientists that believe this to be the case and that global warming as a result of man was spawned by politicians.

Regardless of which global warming is happening.

[inthemiddle]

Originally Posted by Nikolas

Well the polar caps are shrinking for sure. He may be referring to the concept that global warming is cyclical and happens regardless of man's contribution. There are many scientists that believe this to be the case and that global warming as a result of man was spawned by politicians.

Regardless of which global warming is happening.

+1000000 on research/science - the idea of figuring things out, rather than blindly believing in "manbearpig"

- content to not know the answer, but do agree, that regardless of the actual reason, cleaner emissions are good overall....

[ragingclue]

I am here to educate you about the single biggest threat to our planet. You see, there is something out there which threatens our very existence and may be the end to the human race as we know it. I'm talking, of course, about Manbearpig. It is a creature which roams the Earth alone. It is half man, half bear, and half pig. Some people say that Manbearpig isn't real. Well , I'm here to tell you now, Manbearpig is very real, and he most certainly exists—I'm cereal. Manbearpig doesn't care who you are or what you've done. Manbearpig simply wants to get you. I'm super cereal. But have no fear, because I am here to save you. And someday, when the world is rid of Manbearpig, everyone will say, "Thank you Al Gore—you're super awesome!" The end.

And California's answer to manbearpig is to ban black cars. I wonder if any conclusive, impartial research had even been done on their part before diving into this idea.

[bmwzimmer]

Catless downpipes with stock Catted exhausts will pass smog. In fact, there is no odor once the car is warmed up... 4 CATS is overkill, 2 is plenty

[ragingclue]

Originally Posted by bmwzimmer

Catless downpipes with stock Catted exhausts will pass smog. In fact, there is no odor once the car is warmed up... 4 CATS is overkill, 2 is plenty

I agree that four cats is overkill, but your hands are really tied in the visual inspection states.

[bmwzimmer]

DP's are well hidden. You would have to remove the underbody cover to reveal the downpipes. No inspector's going to do that. They're just going to do a visual and see the rear Cats and run the smog test. It should pass as long as you don't throw any codes.

[ragingclue]

Originally Posted by bmwzimmer

DP's are well hidden. You would have to remove the underbody cover to reveal the downpipes. No inspector's going to do that. They're just going to do a visual and see the rear Cats and run the smog test. It should pass as long as you don't throw any codes.

Good point.