exhausted...

[jbrown1132]

my 2005 lly is stock. thinking about a new turbo back exhaust. should i go 4" or 5" what difference can i expect from either one. how loud would it be straight pipe with out a muffler. i'm mostly interested in improving mpg over brut power.

[n0useforaname]

4 inch is fine. A 5 inch won't give you any better performance, just a louder drone. Plus the 5 inch doesn't come in Stainless. Either way, you will get lower EGT's and a better sound...plus for me, I gained some extra MPG by letting it breathe. But all trucks respond differently! Straight piped with out a muffler? It would def. be loud....but it won't be as loud as a Cummins or PowerS. The Dmax is a pretty quiet diesel....but it will scream.... And also, don't expect brute power from an exhaust.....main gains are EGT's, MPG, and noise...but you HAVE to go turbo back to get all those benefits. The CAT is the weak link there....

[n0useforaname]

Also...you need to remember that the LLY has cooling issues....and there are ways to fix it. Search the threads on here for some good info. on LLY cooling issues.

[Durallymax]

as stated 5" isnt necessary mostyl for looks sound and bragging rights or compensating for other things

[big block 88]

4" will flow as much air as your D-Max can shove through it. 5" inch is louder and bigger that is about it.

[KSL667]

i have a four inch and it is hardly noticeable in the cab. maybe 5 to 8 decibals louder in cab but much louder outside truck. inproved cooling

[jbrown1132]

thanks guys you give great advice. i'm gonna go with the 4" turbo back.

[DuramaxOnTheBrain]

You will be happy with the 4" I just installed mine and it sounds incredible. I bought mine from Tyler here on the forum. Meyer Performance and Fabrication. Look him up for a good price and great customer service.

[Meyerperformance]

Thanks Brian, and ya you will be more than happy with 4". I run 5" because i like mine loud, and like to be different.

Tyler
MPF