WWDiesel wrote:
The Flowmaster 942542 Series 40 Delta Flow Muffler is an exact replacement for the stock muffler.
2.50 Center In / 2.50 Offset Out
That's assuming the exhaust is stock. There have been modifications so I need to measure to verify.
Quote:
Just remember, a CAT diminishes Turbo performance some and also raises the exhaust gas temperature coming out of the engines combustion chamber due to the higher backpressure due to the restrictive nature of the CAT honeycomb. It's not there for noise control or to enhance performance. If your want better performance, fuel mileage, and lower EGT's, get rid of it unless you have to withstand a visual emissions inspection.
Elevated EGTs are not nec a bad thing. Sustained 1300* pre-turbo....different story.
While the CAT is not intended for noise control it does give that benefit. Better performance and MPG by removing the cat is debatable but quantifiable. A good example is in the Cruze Diesel, there are 2 cars I'm aware of that have hit 1,000 mile range on single tanks. One is fully deleted and the other is 100% stock. Where the deleted cars see their advantage is town driving with no regens.
The turbo design can have more effect on back pressure than a clean CAT. Another example was my 2000 6.5TD. The GM turbos have a very poor designed exhaust housing causing excessive drive pressures regardless if a CAT is installed. When I finally replaced the stock exhaust on my truck with a 4", including a 3" DP and mandrel bent x-over there was no measurable gain in MPG and I still had to drive by the EGT gauge as max sustained #s would be too high towing.
Now if someday I decide to do a full hot tune I could see where that may overwhelm a stock CAT but would a high flow aftermarket unit handle it?
FWIW, we don't have emissions testing but I still have the stock CAT and exhaust on my Dmax too. It gets rid of the haze and being a DD/tow rig I like it that way. Want smoke and haze? Have a couple 12V cummins in the yard for that, lol!