I have an 06 (4" from turbo back) and just replaced the muffler with a muffler elimination kit (straight pipe with proper bends) from Genos Garage. This actually produced the largest mileage gains for MY truck. That factory muffler is huge, restrictive and heavy. I left the cat in place, and the exhaust is really mellow sounding, maybe a bit louder than stock, but not hardly enough to notice. I think that is the most economical thing to do, unless you have over 500HP. Even then a 3.5 to 4" would still flow pretty well with a muffler delete. Plus, if you spend a little extra money and throw a nice tip on the factory exhaust you cannot tell the difference between that and a 500.00 exhaust. Scotty

 

Good to see fellow Edmontonians CDNDD!

Alright, so they cut out the cat. They told me (and billed me) for a 4" aluminized steel pipe, so on my 06 truck it is a 4". What did I notice...?

The truck sounds exactly the same. I do notice more smoke when I lay on the throttle. They told me at the shop that the cat for my model truck is "wrong", that it's not a good diesel cat, more of a gas engine cat, and so eventually it would becomes useless/ineffective.

At first, with normal driving I thought "Hmm...don't really notice much, if anything". Disappointed. But then I tromped on the gas and then I raised my eyebrows! No bad!

So my opinion: not a significant increase with regular driving, regular turbo spool. But when pushing the turbo...definately a good improvement. Worth the $150 parts and labour? Yes.

The other test will be milage. I will do my normal driving from now on in and post the numbers. In the interim, my gauges arrive tomorrow and so I will work on installing them. I'm quite excited, but it will be lots of labour. Hopefully the weather will be kind because my megacab is just a bit too long to fit in my garage!

After the gauges: FASS pump/filter installed and see what improvement that makes. Next, the upgraded manifold...then a new muffler...

Let the experimenting begin...

 

When i cut my exhaust out, I had only the quad box. I yielded 0MPG gains, and virtually 0 performance gain on low setting, however when I turned the box to 100 I think I could tell a diffrence.

I would say on a stock truck it does nothing, but the more mods you have them more it will pay off.

 

Yes I am still flying it, at loving every minute!!!

Thank You for your service.

 

And you for yours!!! Last trip over I rode Blackhawks and Chinooks all over Iraq, lots of flares going off in the Baghdad area!!! Beats the "H" outta driving though!!!