OK, so I have a Megan MP and a Universal High Flow Cat I'm welding into it. It has the inlet for the Catalytic Converter air tube so I will need to use some sort of high temp line (silicone?) to connect the cat to the air tube line, which is about 18 inches away. I know the cat gets SUPER hot, so any suggestions on what to use to accomplish this?

-- Anybody else HATE Emissions Tests?

 

I would get the stock air tube off the stock main cat and have it welded or attached with a small piece of silicone hose. thats what I did with my bonez hf cat and it works great with the air pump since you retain the stock air valve operation.

Jeff

 

I use generic auto store coolant hose. This hose is carrying cold air so it does not get particularly hot. I checked the hose recently and after 4k or so miles it still as flexible as new.

 

I have an extra set of the factory piping. PM me if needed/interested.

 

The thing about the stock metal hose is that the small flange has a valve that only allows air from the air pump into the cat, and stops exhaust from going up the air tube. If you can, it would be best to weld the stock piece to your new cat.

 

There is a check valve in the stock pipe. Make sure you incorporate that.

 

Unfortunately I don't have a stock cat, I wish I did so I could use the check valve. What happens if I don't use it?

 

In principle, hot exhaust gasses could be drawn back into the engine and cause damage. Not sure how likely this would be though. You could probably pick up a valve cheaply in the classifieds.