no cats?
Le Mans Master
Joined: Dec 2004
Posts: 5,492
Likes: 808
From: West coast CA
No. Running catless does not increase CO2 emissions. Catalysts prevent CO, HC and NOx emissions - i.e. regular old air pollution.
A city full of cars without modern emissions controls suffers from considerable and obvious air pollution with real, measurable consequences.
A single catless car pollutes the immediate vicinity and is an irritant to those unfortunately enough to be behind it. The performance benefit is negligible.
A city full of cars without modern emissions controls suffers from considerable and obvious air pollution with real, measurable consequences.
A single catless car pollutes the immediate vicinity and is an irritant to those unfortunately enough to be behind it. The performance benefit is negligible.
Burning Brakes
Joined: Nov 2009
Posts: 1,114
Likes: 42
From: California
Cats prevent CO2??? You know how much those cost the manufacturer?
Nothing personal...but they definitely do cut down on emissions. Don't get me wrong I'm all for all out race setup...but the smell is terrible! On pump fuel anyway!
Nothing personal...but they definitely do cut down on emissions. Don't get me wrong I'm all for all out race setup...but the smell is terrible! On pump fuel anyway!
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Safety Car
Joined: Sep 2007
Posts: 3,502
Likes: 82
For what it's worth I don't think you get a guarantee of "no stink" with a cat'd system. My car was virtually odorless when new. When I added headers with high flow cats I picked up some exhaust smell even with a re-tune and correct AFR verified by my wideband o2. When I added the cam the smell increased even more even after another re-tune and the proper 14.7-ish to 1 AFR.
I think the fact is that the aftermarket high flow cats just simply are not as efficient as the OEM stuff and there should be some expectation of increased odor if you change the configuration whether you choose cat'd or cat-less.
I think the fact is that the aftermarket high flow cats just simply are not as efficient as the OEM stuff and there should be some expectation of increased odor if you change the configuration whether you choose cat'd or cat-less.
Last edited by Motorhead-47; Nov 28, 2009 at 10:32 AM.
Safety Car
Joined: Nov 2007
Posts: 4,537
Likes: 1,403
From: Bethesda MD
With headers,the cats are relocated further away from the engine. It takes them longer to warm up and do their job. After the car has been running for a few minutes, aftermarket should be showing good results.
Safety Car
Joined: Sep 2007
Posts: 3,502
Likes: 82
The first couple of minutes of my startup are kinda stinky but it gets much better as the car warms up but never completely goes away. My pipes burn clean and no residue on the rear fascia of my car either. Just comparing the location and physical size of OEM to the post long tube header location pretty much tells you they are not going to be as efficient as the factory stuff but have to be better than no-cats at all.
Last edited by Motorhead-47; Nov 28, 2009 at 10:44 AM.
Thread Starter
Advanced
Joined: Mar 2009
Posts: 95
Likes: 0
From: Wakefield Rhode Island
Pro
Joined: May 2006
Posts: 670
Likes: 1
From: Wellington Florida
Some folks over exaggerate, I'm running with no cats for 2 years now, no bad smell, nobody behind me complaining, If anything, people are always on my tail for some reason, I'm not sure if they are admiring the car or they really like the sound of my bullets, but nobody is fighting to stay away from me. I have no complaints whatsoever.
Race Director
Joined: Oct 2005
Posts: 14,555
Likes: 1,255
From: Saint Albans, WV
Some folks over exaggerate, I'm running with no cats for 2 years now, no bad smell, nobody behind me complaining, If anything, people are always on my tail for some reason, I'm not sure if they are admiring the car or they really like the sound of my bullets, but nobody is fighting to stay away from me. I have no complaints whatsoever.
Safety Car
Joined: Sep 2007
Posts: 4,359
Likes: 6
From: Los Alamitos California
St. Jude Donor '09
Some folks over exaggerate, I'm running with no cats for 2 years now, no bad smell, nobody behind me complaining, If anything, people are always on my tail for some reason, I'm not sure if they are admiring the car or they really like the sound of my bullets, but nobody is fighting to stay away from me. I have no complaints whatsoever.
San
Burning Brakes
Joined: Nov 2009
Posts: 1,114
Likes: 42
From: California
And some over exaggerate and just don't want to admit the odor is present. BTW...just how do you know the drivers behind you aren't complaining and cursing you the whole way?? There is absolutely nothing to gain with the offroad x-pipe other than sound volume. It's common sense, if you don't have cats you're going to stink. A lot of us have been there and went back to high flow cats for a reason.
I think we should hold ourselves to a higher standard...my dad always used to say if you don't have anything nice to say...
Besides all of us on here drive one of the best cars around! I think we should all be grateful
Just so you know I'm an engine builder on a road race team, and when an engine is actually tuned right and not pig rich...which is usually over done for safety. It actually doesn't smell very much.
Advanced
Joined: Oct 2009
Posts: 82
Likes: 0
Some folks over exaggerate, I'm running with no cats for 2 years now, no bad smell, nobody behind me complaining, If anything, people are always on my tail for some reason, I'm not sure if they are admiring the car or they really like the sound of my bullets, but nobody is fighting to stay away from me. I have no complaints whatsoever.
