i think you'll really like it i think the main reason i lost a little low end power is because of the dual 2.25 pipes but i wanted the look and sound and got a little of it back with my superchips so im happy now haha

 

you guys realize none of this even matters right? The original post was about a guy with a 4.7 stock everything. There is absolutely NO NEED to get this technical with a stock engine. It doesnt ****ing matter. If this guy plans on just cutting out the muffler, and replacing it with another muffler, he can get whatever he wants and odds are it wont change a thing except for the sound.

 

I've lost low end power from day one when I've started messing with my exhaust on the Ford. That's why I say just don't mess with the cats, keep a single pipe, and keep the diameter down (like 2.25, 2.50 inch).

The I6 has decent low end but I imagine the V8 has just as much. Like I said, I think you would be happy with a mere glasspack!

 

I just put a spintech muffler on my 4.7 durango. Stock piping with just a muffler swap and the truck sounds like it has a dual system on it. Its inexpensive and has similar flow and sound to a Borla. 2 weeks after i installed it my cat managed to clog because of the increased flow helped clean some gunk out of the engine (along with the lucas treatment) so i swapped that to a magnaflow and i couldnt be more impressed with the sound. all through a single 2 1/4 pipe

 

yea, dont mess with cats and pipe size and you wont do anything except change the exhaust sound. Once you start ripping out cats,, getting larger diameter pipe...etc thats when you can mess up low end. I had a 3" catback on my 3.9 for about 4 years and i noticed a slight loss in low end. Now I have a knockoff magnaflow with 2.5 inch pipe dumped before the axle (because the catback I had on rotted away) and its just like it was when I had the stock exhaust.

 

http://www.youtube.com/watch?v=JZ6xYVamjDk

 

your pipe size does very little to the back pressure unless you change it by 1/2" or more, then your getting too much or none. Your cat is the most restrictive part of the exhaust system.

Leave the stock size but get a hi flow cat and you keep a balance. You gotta make sure you open up the air intake first or it does very little good

A CAI from K&N is the best thing you can do for the money with the 4.7 cause the stock air box is inefficient. I made the swap and i got more low end power and better MPG at the same time

 

Precisely!
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