Question about installing an X-Pipe.

its emissions stuff. capping it off is fine.

It pumps air into the exhaust for emissions stuff. The line goes up to the air pump system that's part of the accessory drive.

if you got a catted x pipe then ill assume the emissions stuff is important to you.
if not GET RID OF THOSE CATS!

Okay, prepare for a science lesson. The smog pump that came as stock emissions equipment on your mustang is not dead weight, nor was it put there for aesthetics. Automotive engineers are pretty intelligent. If you're keeping your smog equipment, the thermactor air pump pumps fresh air into the catalytic converters to aid in the catalyzation process. A three part reaction takes place in the catalytic converter, and the presence of oxygen is required (this is the role of the thermactor air pump).

A) Reduction of nitrogen oxides to nitrogen and oxygen: 2NOx → xO2 + N2
B) Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 → 2CO2
C) Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: CxH2x+2 + 2xO2 → xCO2 + 2xH2O

You'll notice above that oxygen is required for the chemical reactions listed. Without air supplied from the smog pump, the catalytic converters will overheat and eventually clog and fail, therefore severely increasing exhaust gas backpressure and limiting performance. You bought a catted X pipe, therefore you'll need to hook the air pump up to keep your cats alive and help pass emissions. I've heard that performance "high-flow" catalytic converters require less oxygen to operate, but this is heresay and hasn't been confirmed. Play it safe and hook the smog pump up.


Sorry for the novel, I was bored.

Is there an echo in here? Just kidding, Mike.

Mustang5L5 said:

Does the UPR pipe have the bung to hook the air pump pipe up to? If it does...connect it. If it does not, cap it off.

The air pump is to provide fresh air to the cats because certain types require oxygen to help the process. Since the pxygen is burned off when the engine runs, it must be provided through an air pump.

Modern cats do not require this, so the air pump can be eliminated in most cases. However, some companies still use the old style cats. In taht case, i just simply say that if the pipe has the provision for the air pump to be hooked up...then use it. If it doesn't then don't worry about it.

I actiually removed my smog pump quite a while ago, and now have reason to suspect my stock h-pipe is clogged. Now i'm in the market for the Magnaflow catted pipe

Click to expand...

My after market cat didn't come with the nipples to attach the hose to. So I just let it pump into the air. And the smog pump just siezed about a month ago. So now Im all good!