4" or 5"

[TGauger]

Did a quick search and really didn't find much on here about this so here we go. What do you all think? 4" turbo back or a 5" turbo back. Either way I will be going with a no cat, no muffler straight pipe and looking to do a 4" DP. I like the idea of the 5" just cause I'm a "Go big or stay home" kind of person, but I don't want to hurt any performance or MPG's either. To date I have had the motor rebuilt with crower rods, J&E slugs, O-ringed heads, etc. I have an edge with attitude programmer on there, and I'm really just looking to do an exhaust and intake upgrade and start on drivetrain. I appreciate your thoughts, and I hope everyone and their families have a wonderfull Christmas.

[HeavyAssault]

What other performance mods are you going to have done?? A 4" exhaust is plenty big enough for your mods.

[psd_va]

As stated above 4" is enough to support up into the 500hp. With that said I still went 5" and love it. The sound is great and I love the look of the larger pipe its kinda intimidating to others when they see it.

[jermcd]

5" is all about being heard. 4" is a great balance of sound but not loud.

[SelahPSD]

I have a 4" straight pipe with a 5" tip. When I open it up, my 2006 6.0L rumbles and roars like a '72 Oldsmobile Cutlass 442 (for those of you who have ever heard one). Yet at idle and regular throttle, it's much quieter and more pleasant sounding than the 5.9L or even the 6.7L Cummins. I am really happy with it, and would not want it any louder. The 5" tip is just right proportionally, in my opinion; a 6" tip is overkill aesthetically.

[jimmyz32]

4" exhaust is large enough flow for 800hp. all the tips do is change the tone of the exhaust sound and i have not found one that sounded good yet. also i have never been intimidated by some ones exhaust. Some of the dodge guys put 8" and 10" tips on there trucks it just makes me laugh And all the cops for miles can hear where they are when they get in the peddle. just my 2$

[psd_va]

^ yea i didn't mean intimidating to other diesel owners just some of my friends who are import drivers and people that don't know diesels. yes the 5" can be loud but normal driving and idle its pretty reasonable. my truck having a 10 blade MTW stg 1 turbo whistles it A** off at idle and light to normal acceleration, but when you get into to the throttle it is loud ill be the first to tell you but it doesn't bother me i don't get into the throttle much don't have to with tuning.

[89Foxbody]

I have the MBRP 4" turbo back straight pipe system and it's pretty damn loud. At idle it sounds like a jet and it lets out a lot of turbo whistle. Once you hit 2200-2500 RPM area it really starts to howl. Sounds incredible at WOT. The turbo whistle is really loud and sounds great. It's hard to resist flooring it under bridges or through tunnels.

[dieselburner21]

I like my 5", if you are considering both you will probably regret not getting the 5. Thats why I got mine

[TGauger]

Thanks for all the replies guys. I think I'm going to order the 5". I don't mind loud and would hate to have regrets down the road. As for future mods, who knows. Right now there is plenty of power for me, but opinions like that change fast. First time i get taken by a duramax I may be looking at nitrous and twin turbos!