In preparation for installation of a chip one of the restrictions to additional power in the powerstroke equipped trucks is the factory downpipe. As you can see from the pictures it is a flattened tube which hinders the flow of the hot exhaust gasses thereby creating higher backpressure so the turbo can't produce as much boost. In the brilliance of the engineers at ford someone though that it would be a good idea to design this piece of the exhaust such that to remove it in one piece you would need to remove the transmission. So since I'm not ever going to put this back on the truck the other option is to introduce it to the sawzall. :evil: I started the project with the 6" blades I had on hand hoping I could skip a trip to the hardware store but In the end I had to make a trip and get some 9" blades.
I ordered my downpipe from DPP based on information from others who have done the same install and ease of installation, be aware that some manufacturers require you to bend the floorpan to clear their pipe this one cleared even my pinchweld with no problems. It is also designed to bolt directly to the catalytic converter that is on these trucks which is beneficial if you are not replacing the entire exhaust system at the same time. My future plans are to modify the exit of the catalytic resonance chamber to exit directly to a 5" pipe which will be the diameter for the rest of the exhaust system. This option allows me to pass possible future visual emission inspections.
Once you get the factory downpipe out you will need to install the lower portion of the downpipe and get someone to hold it in place while you slide the upper 1/2 into the lower. Once the lower portion is loosely bolted to the rest of your exhaust system you will find it easier to line up the pieces. The places that you need to check for clearance are the pinchweld indicated and the up-pipe going from the manifold to the turbo. Once you get the pieces lined up tighten the clamp that attaches the downpipe to the EBPV. Tighten the exahust band clamp on the mid pipe joint very tight. Tighten the bolts to the catalytic converter. Start the truck, let it idle and feel for any exhaust leaks, the exhaust pipe will remain touchable, but warm, for about 3-5 min if you allow it to idle only be sure to start at the top and work your way down.
One side effect of the insallation will be increased turbo noise or whistle especially when under heavy load when combined with an open intake which is also recommended prior to chip installation. EGT's were lowered by about 100? cruising and peak EGT dropped almost 200?.