OK, I am not technical at all. I have been reading a lot here and most of it looks like spanish. Here is what I had done on my last truck. It was a 97 Extd. cab, 4.6 4X4. I had the muffler cut off and a y-piece welded just after the cat and then two pipes out the back with tips. Sounded great.

I now have an 02 Fx4 Lariat ext. cab Fx4. 5.4.
I was thinking about having the same thing done. I am reading about things like back pressure and what not. I don't have a clue. What to do?

thanks

 

Back pressure is the pressure load on the engine due to the restriction of the exhaust pipe. The engine is pushing exhaust gasses out, but they are contained by the exhaust pipe.

If you go too big on the exhaust pipe, you lose the scavenging effect of the pipe and lose your low RPM power. If you go too small on the exhaust pipe, the backpressure reduces engine performance.

For the 5.4L engine, go with 3" pipe for single exhaust, or 2.25 to 2.5 for dual exhaust. This, of course, is unless you have extensive engine modifications (supercharger, turbocharger, ported/polished manifolds and heads, etc...)