Howdy. I have on 05 SRT6 ATM, and I'm debating straight piping it... this has not been a rash decision, no split second nonsense. This has been something I've gone over countless exhausts and through much debate landed with the preferred sound of it Straight piped with the 4 cats... my question is, could this harm the car? Besides the straight pipe drone and slightly decreased fuel mileage I can't think of a way ot could hurt? Also how does this affect the SC with the back pressure?

 

With only removing the muffler and leaving all four cats, you should not have any problem with back pressure.
I am running 2 cats and a muffler and would have less back pressure then four cats and no muffler.
Converters are alot more restrictive that a muffler.

 

Been running my SRT with the rear cats and "H" pipe deleted and have a "X" pipe in their place. Also have the muffler deleted and left the resonator in-place for back pressure. No drone because of "X" pipe and fairly mild sound until WOT. Been this way for over a year with no problems what-so-ever!

Back Pressure should be of no concern. If it was then the NeedsWings down pipes that replace the cats would be a no-no. The "X" pipe I used only helps in the scavenging effect and is therefore beneficial to the SC. Naturally I went to a smaller pulley to increase the SC pressure!

I've seen systems that used the downpipes (no cats) into a dual system with a "X" pipe integrated and straight flow muffs used with no problems.

See here: https://www.crossfireforum.org/forum...aust-help.html