All,

I searched on this subject but couldn't find anything. I'm using the N-tech high-flow cat and I've retained the air pump for obvious reasons. After looking at the factory manual, there is supposed to be a check valve in line with the hose that connects the mid pipe to the intake system. However, this check valve was part of the OEM tubing that is discarded when you put on your new cat. (There is a flange attached to one side of the pipe...)

But without this valve, exhaust gasses can flow back up the pipe into the intake system. This is a bad thing, right? What should I do? Is there an aftermarket check valve, or do I have to butcher the OEM part and reuse it? Any help would be greatly appreciated,

-ch

 

I would suggest to "butcher the OEM part and reuse it".

 

Agreed...

 

I have a similar question.

I have a Random Technologies Hi-flow cat. Does it have to have the air supply?

 

It's debateable. Most people agree that the air pump will allow the cat to last longer (even though Random and other places say the air pump is not needed).

If you care about your air pump lasting (and have emissions testing), you'll want to have the air pump connected.

 

In my experience, you will fail emissions horribly with the air pump disconected. I had a high flow with no bung for air pump and was failing emissions by 2x to 3x for both HC and NOx. After having a bung welded onto my cat I passed with about 1/2 the allowable emissions.