Hello

I am in the process of redoing our exhaust system do to a cat failure and started to think about not running any cats at all.
Have any of you done this and what pro and cons have you come across.
I am not worried about any testing and yes there will be a check engine light which I can live with and one advantage is no heat soak into the front driveshaft meaning longer life.

Thanks

 

I guess a pro is no expensive cat's to replace. Cons? Permanent SES light and codes, impossible to pass sniffer emissions if your state/country/whatever does that, possibly louder more obnoxious sound. (I know you mentioned some of these but still cons)

Personally the ses light would do it for me. I'd get annoyed thinking something was wrong even though I knew what the problem was.

You dont need to buy LR specific cats if that is your issue. Just get some standard ones that any muffler shop can fit in 10 mins.

The drive shaft argument is weak at best. Grease your u-joints even semi regularly and they'll outlive you. The original ones came unsealed in that area and last over 100k without issues. With the occasional greasing then rusting through the yokes would be more of a concern than baking grease in the joints.

 

Good points above. To add.

Cons: Your exhaust is going to smell horrid since you will be dumping out unburned hydrocarbons, black soot. I'm going to skip the environmental impacts.

Pros: healthily exhaust flow. Although, you may have to install an X-Pipe to help maintain adequate back pressure. No need for SAI (if equipped) so, you can get rid of that system.

You can fabricate O2 sensor bungs into your new downpipe and add spacers on the O2 sensors which will pull the sensor up out of the exhaust stream enough not to throw a code. I run a high flow cat set-up in my Audi with this set-up. And I pass through emissions testing. You just need to keep the ngine tuned and running properly to avoid the code.

 

The smelly exhaust is a good point, as I removed the cat on my VW Golf and the wife complained about the smell. She also pointed out the environmental impact issue and with us being outdoors folk it makes no sense. I have made the decision to just replace the cats.
Thanks guys

 

https://landroverforums.com/forum/he...t-codes-56712/

 

Are you a BC boy as well?
I just your thread about the spark plug spacers, are you currently running no cats?

 

cons: against federal EPA laws.

 

Yes I live in the Greater Van area. I ran my D2 without cats for just over a month. I did not notice any smell and mine wern't even welded. As I said in my little write up though the only real plus with no cats is the money you get from you old factory cats. I found no gains with HP or MPG, only noise and codes.

 

I did it in my S60R for a year or so without issue, but the smell was annoying so I had one welded in.

 

TooFarOffRoad has it right.


If your engine is running right, there will be no smell, no MPG gains, no nothing.

Heck, it it weren't for the SES light WARNING the inspector that it is gone, chances are you will pass emissions as well. The CAT is most effective for early emission control, not after the car has warmed up (hence why everyone recommends taking warm car to inspections....your emissions are better).


If your exhaust smells bad and you have black soot coming out when a CAT is removed, then you have other problems. Welding a CAT back in is not going to solve them. That black soot is incomplete combustion and it is going to coat your catalyst and your CAT will fail. Then you will have loss of power due to back pressure and eventually your CAT will get so clogged you won't get over 2,000 RPM and 30 miles an hour.

Ask me how I know. .


Welding a new cat in a poor running engine may net you 30~40k miles, it will be a slow death, but it will die.


Back on topic, there really is not "gain" and with aftermarket CATs being reasonably priced, it just makes sense to put it back. For resale value, if nothing else. My area does not test for emissions, but I always replace the cats when one fails.