4" vs 5" Exhaust

[shiprek]

I am looking at upgrading my OEM exhaust system. I plan on deleting the cat regardless but at trying to determine if the 5" has any more advantage over a 4" system. The downpipe connection will act as a restricter whether using 4 or 5 inch. The 4" will offer more resistance to exhaust gases but the gas velocity will be higher while the 5" will provide less resistance but the exhaust gas velocity will be decreased. Is the cost difference worth the extra money between the 4" vs 5"?

Thx in advance.

[colo_dually]

I'll put it like this, based on information I've gathered over the last couple of months as I get ready to do this same thing. There's a few different things that fall into the decision of an aftermarket exhaust. If you're keeping the CAT, stay with a 4" unless you want it loud. From the performance aspect, unless you plan on putting down a lot of horsepower (in excess of 500HP) you will be fine with a 4" system. Also if you're gonna be towing a lot, or push the EGT's you might consider getting a 4" DP, vise the 3.5" most systems come with.

[travisH3]

performance difference: none unless putting down serious power

resistance: turbo provides all the back pressure needed, with cat and muffler gone the egt difference will be slightly and i mean slightly better with 5 inch so there is no restrictive issues between the two

Sound: the 5 inch will put out a deeper sound vs a 4 inch

basically, pick which one you like the look of better and which sound you want. there is no real gains to the 5 inch staightpipe unless like was said before some serious power AND there is no negatives to a 5 inch. and if your looking for a 4 inch down pipe check brands because mbrp has 3.5 down pipe on both there 4 and 5 inch systems. i have diamond eye performance exhaust and it has a true 4 inch down pipe so just do your research on what you want
people who get the 5 inch is mostly for the look because seeing that piping running out from the back of you truck just looks bada$$. my dad has 5 inch to a 6 inch tip on his 6.4 and i have 4 inch to a 6 inch tip and his look is amazing. im definitely jealous

if you want i can get comparison pictures. our trucks are identical so you get a good comparison

[shiprek]

Thx guys,
I think I will go with the 4". I am OK from the sound level perspective as it is now and do not plan on needing additional HP. I will be towing but only a small cargo trailer, no 5th wheel/horse trailer...

[Dasaliac03]

I went with the 5", plan on making some power, it suits me fine

Since your in a 6.0l, a 4" exhaust does fine for all the boys locally, one 04 that is pretty loud has an 8" tip on the end of his 4" turbo back MBRP system.......when his gets into that infamous 6.0 GROWL, his is REALLY loud and thumping, really turns some heads when he lays in to the throttle

[scparrish]

I just ordered the diamond eye 4" duals with 4" down pipe can't wait to hear it

[shiprek]

You will have to post a note once you get it installed, maybe some pics? I was looking at the Diamond Eye also but the single. I have not crawled under to look yet, does the 6.0 have a 3.5 or 4 inch down pipe? I am new to diesels and very new to the 6.0L.
Thx

[njmudrat]

The 6.0 stock down pipe is 3".....

[shiprek]

Thanks for the update, I will keep this in mind when researching new exhaust systems. I second you opinion regarding Teachers/Cops/ and POS Celebs (in their own minds).

[travisH3]

But if you want a super smooth installation get mbrp or someone that has 3.5 inch down pipe. The 4 inch down pipe takes patience to get it in. It took me about 45 min to get it in just one person of top and one person on bottom twisting trying to get it. Patience is key