4" vs 5"

[Deuce's Wild]

This may have been covered before, but I thought I'd pose the question and see what everyone thought. I have and 03 CC Dually with the 7.3 and I am going to upgrade the exhaust. I am looking at a turbo back system, and both have a 4" down pipe and then 4" or 5" out to the tip. The truck is not a daily driver, but sees a lot of weekend use hauling the boat back and forth to the lake and the occasional race car trailer, along with trips to Home Depot for various things. I already have an Airaid Intake installed and a custom 6 position chip and gauges will soon follow the exhaust (when funds allow). So let me hear your thoughts. Thanks, Brian.

 

[powerboatr]

i ran a 4" magnaflow ss on my 7.3, egts went down several hundred
going with a 5" is probably not going to net you any gains unless you run WOT all the time
4" downpipe is a close fit , takes a bit of wiggling and tweaking of the body pinch weld.

do you have a cat on your 03?
some did some didnt
the magnaflow like the mbrp and oter is a straight flow through muffler nice tone.

 

[95_stroker]

Unless you already are or plan on being in the 500 hp class, you dont need 5". Ive got a 5" system and there are no useable benefits to having a 5" as opposed to 4" unless you like to tell people that you have a 5" pipe.

 

[crzycowboy]

Unless you have some serious mod's on your truck, I would think 4" would be ok. 5" systems will keep a cooler egt, and will alow the turbo spool quicker, but I've also heard some people say they lose top end power. I've got a buddy with a 5" system straight over the axel, he loves it to death...... All a matter of preferance.

 

[Deuce's Wild]

Yeah I am not really into WOT all the time, but the occasional foot to the floor at the light isn't unheard of......the price difference between the 2 is $100 so that isn't a big deal either, although that $100 could go towards the tuner......from what it sounds like the gains/loss with a 5" isn't worth it and that it's preference........thanks for the help

 

[95_stroker]

Yeah I am not really into WOT all the time, but the occasional foot to the floor at the light isn't unheard of......the price difference between the 2 is $100 so that isn't a big deal either, although that $100 could go towards the tuner......from what it sounds like the gains/loss with a 5" isn't worth it and that it's preference........thanks for the help

Perfect summary.