Difference between 4" and 5" exhaust??
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Tuned
Joined: Mar 2007
Posts: 342
Likes: 1
From: South central kansas
Difference between 4" and 5" exhaust??
Hey fellas, I am looking at buying an A/M exhaust , and have a few questions.
1. What is the performance difference between a 4" and a 5" system?
2. I have looked at several of the big brands of exhausts and most of the 4"
systems allow you to keep the stock cat, does the 5" allow this??
I am also wondering about the difference in performance of a turbo-back with stock cat versus a cat back system?
Any info on this from those of you who have run different setups of been around trucks set-up the same with different exhausts would be appreciated.
Thanks
1. What is the performance difference between a 4" and a 5" system?
2. I have looked at several of the big brands of exhausts and most of the 4"
systems allow you to keep the stock cat, does the 5" allow this??
I am also wondering about the difference in performance of a turbo-back with stock cat versus a cat back system?
Any info on this from those of you who have run different setups of been around trucks set-up the same with different exhausts would be appreciated.
Thanks
Hotshot
Joined: Nov 2006
Posts: 11,288
Likes: 269
From: North of Greenville
Tuned
Joined: Mar 2007
Posts: 365
Likes: 0
From: Alberta, Canada
Theoretical flow of the 5" is substantially more, however unless you are planning on making obscene amounts of power and running your 6.0 ridiculously fast you would likely see next to no difference between the 4" and 5" setups.
The elimination of the cat makes a substantial difference; although I have seen reports that the cat provides little restriction in the exhaust; this is only true of new, unobstructed cats. As the cat collects particulate is does indeed provide substantial restriction. I've seen older trucks that literally were barely able to run due to obstructed cats. Simply by removing the cat and muffler from my truck and maintaining the stock 3.5" pipe I saw a reduction in EGTs in the order of 100 degrees and an increase in fuel mileage of 0.5 - 0.7 mpg. I also like the enhanced turbo sound that the elimination of the cat and muffler give. The truck is not obnoxiously loud unless I'm really on the throttle hard.
I would recommend going with a 4" complete turbo back kit if I were in your shoes. If you have to keep the cat I would recommend gutting the inside of it before you reinstall it.
The elimination of the cat makes a substantial difference; although I have seen reports that the cat provides little restriction in the exhaust; this is only true of new, unobstructed cats. As the cat collects particulate is does indeed provide substantial restriction. I've seen older trucks that literally were barely able to run due to obstructed cats. Simply by removing the cat and muffler from my truck and maintaining the stock 3.5" pipe I saw a reduction in EGTs in the order of 100 degrees and an increase in fuel mileage of 0.5 - 0.7 mpg. I also like the enhanced turbo sound that the elimination of the cat and muffler give. The truck is not obnoxiously loud unless I'm really on the throttle hard.
I would recommend going with a 4" complete turbo back kit if I were in your shoes. If you have to keep the cat I would recommend gutting the inside of it before you reinstall it.
