FYI: just to add to the 3 ft rule; Some drag racer in the past doing research on scavenging wanted to know the ideal length to cut a straight pipe after the header. They would paint the pipe white and cut it off where the paint was not burnt off. usually 3 ft...

 

[QUOTE=otto457;811257]I know the 2009+ trucks have the "hybrid" type muffler. I consider it a hybrid because while you can see through it, it still has the chambers that do the sound deadening. The stock systems have come a long way from what they use to be, but still aren't perfect.[/

That depends on what you are trying to accomplish, sound or performance gains. For me sound is more important, so I replaced my stock almost 3 ft boat anchor with a much smaller lighter 2chamber 40 series flow master si/do.I seriously doubt there is very little horsepower gains difference on a stock behind the cats system whether straight through or chambered. I have not noticed any power loss,IMHO. But to each his own

 

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very good write up on exhaust. helped me alot!

 

awesome write up dude good info thanx..!!!

 

Of course it does because you're running wide **** open the whole time and don't have emissions standards to comply to...

 

Another update in the exhaust world. Finally got to see the insides of a 2011+ muffler, and here are the pictures. Ford is now going with a double chamber style with a third chamber that uses a packing much like many of the straight mufflers use. Good step in the right direction IMO still keeps a fairly quiet volume for every average driver, but still provides pretty good flow characteristics. The muffler is definitely not the plug in the system that it was in the years and years past.

 

Ford has added a double scavaging system/ballance tubes, for its V6's for better power and mpg. Muffler looks like a semi glass pac.

 

I was checking the driveshaft repair when I noticed the exhaust pipes on my truck. This looks pretty high tech to me. To get over 300 hp from 3.7l, I think this exhaust has to be highly efficient right from the factory.

 

Hello to all,
For my first post I would like to direct you to the best technical explanation of exhaust science I've read. This theory is optimized in the products they produce. I don't know if it's practical on the street, but in the lab it is mind boggleing.
WWW.Impulsengines.com/how/header.shtml