I just installed a Gibson Extreme Dual cat back exhaust on my '05 6.0 and before I reinstall the new muffler I shined a light in the cat. It has screen wire across the midsection , like window screen only slightly larger mesh. Can anyone explain how the cat. works? This has to be restricting the flow. The in/out pipes were cool to touch but the cat. was hot. Thanks, Alan

 

The CAT gets extremely hot...causing the un-burnt gasses that pass through it ...to be burnt off......IMO it does not impair the flow enough to make a measurable difference in performance. This…. no doubt can be an arguable point…..the flip side, if it does not hurt performance it helps the air we breath….now no flaming me about caring about the air we breath.

The little things that help emissions and do not affect the overall performance or cause me undue amounts of maintenances or rotten drive-ability ...like EGR valves that go bad...I do not mind having on any of my vehicles. Yea I know part earth guy and all performance lover.

 

Tim is correct it does not have much effect on exhaust flow, but it does raise the exhaust temp and as we all know this is a killer on turbo's. If your truck is running a stock program then you should leave it alone and if you have it running a program then just watch your EGT's, also note that your EGT's can get too high without the cat on also. The biggest exhaust restriction is the muffler I have seen one cut open and let me tell you "GET RID OF THE STOCK EXHAUST" you and your truck will be much happier. The parts shop above has some great bolt on kits!!!!!!!!

 

The muffler is a REAL bad...call MotorHaven and order one, like taking a girdle off.. ..only what I have been told!

 

I know there are high performace cats for gas burners. Anyone ever come accross one for a diesel truck yet?

 

The stock one is not bad so it is not really necessary to change. In other words and IMO there is probably not a market for it.