the part I am talking about is the tube that comes out of the stock cat and goes to the air pump from what I can gather from the service manual.

Ok so I installed my hiflo cat last weekend and obviously it did not have anywhere for this to go. I plugged it, but just wanted to see what you guys had done with it.

I was thinking of putting one of those small K&N style breather filters on it, but didn't know if it made a difference.

Thanks,
-Josh

Oh and I did a search and damn sure didn't find anything on it.

 

That pipe runs from your airpump to your cat and suplies your cat with air so it can function properly. Without it attached to your cat you will run the risk of cloggs.

 

errr ok then why was the one on the hiflow cat sealed off? (serious question not trying to be a smartass)

 

Hi-flow cats come with an air supply bung that is plugged. Certain vendors sell a hi-flow that has had the plug removed and the tube for the air pipe welded on (rx7fashion, rx7.com). There has been much debate about whether a modern hi-flow cat will fail without an air supply. One thing's for sure, you won't be passing emissions without the air pump hooked up to the cat.

Rip the pipe off of your old cat and have an exhaust shop weld it on to your new hi-flow.

 

got ya. thanks for the advice.

 

What should I do if I don't have a cat? I should I plug the pipe, or should I just leave it open? I don't want to remove the air pump, because I have to go for emission tests once every 2 years.

PS sorry for bringing up this old thread...

 

wow four years, almost five