For my 09 3/4 cummins i put a new down pipe and hi flow muffler on it with the dpf Delete and well it's just as quiet or quieter as it was stock!
I was looking for a least a little louder..
Anyone strate piped a 09 6.7? I would loose low end tork I believe?

 

This is just my opinion but straight piped CRs sound horrible. I bet it is louder than you think while passing someone on a sidewalk. If you haven't already, have someone drive it by you while you stand outside and see what it sounds like.

 

Good idea.. But I can't hear any dif n the cab for sure

 

MINE DIDNT GET LOUDER TILL I WENT WITH A 5 INCH TURBO BACK.

 

The 6.7 will never be as loud as a 5.9l until you remove the factory vgt turbo and go fixed vane. The VGT turbo is one of the best mechanical mufflers that man ever created

 

^^^what scott said. take the muffler off i would never put a muffler on a 6.7 with stock turbo. for the reason stated above. and you wont lose any torque if you loose the exhaust. the turbo will hold the same back pressure with or with out a muffler untill you go to a bigger turbo back pressure will not change.

 

So in scraping the brand new muffler with just a pipe any noise change?

 

Yes it will change. it wont be loud like say a 07 strait piped 5.9 but you will hear it

 

i have 5 inch turbo back straight with an 8 inch tip and it roars and sounds absulutely amazing

 

i think straight pipes sound nasty