05 Screw 5.4l

Has anyone looked at their stock exhaust before removing to upgrade? It doesn't look like there are an crimp bends in the exhuast system until after the muffler. Also, how many cats do these engines have? On my truck I can see two coming off the headers before going into a Y-pipe. Also, that stock muffler is huge, there must be a lot of restriciton in there.

 

They are decent for stock, and my 00 had stock for the first 2 years (60,000km's) and it still just looked dirty and slight coloring from heat. Upgrade was worth it with the sound. Your truck should have 4 cats. Upgrade because the stock muffler/tailpipe is a bit restrictive unless you want quieter.

 

Wow, four cats? This engine must put out a lot of pollution to need all four of those. I'm going to wait on my exhaust until I can redo the entire system. Including removing the cats. I know some people say that it doesn't help performance or mpg to remove the cats, but I aim to find out for sure. I'm guessing that with four of them, there would be a huge difference in both perf and economy.

 

meow meow

 

actually they run pretty damn clean.with the 4 cats mine only put out co2 for 2 or 3 years and then put out .01 on hc or co one or the other.you will notice a big difference in goin to 2 high flows