Since your truck is a '05 it already has a 4" exhaust from the turbo on back from the factory. I'd recommend either chopping off the muffler completely or replacing it with a free flow direct replacement muffler. Also, I'd look into either the Smarty or the Smarty Jr. for programmers. Put on a cold air intake of your choice(please never use a K&N) and switch to synthetic fluids from front to back.

Scott

 

Good thing you don't drive a duramax, mine killed me. My 06 Dodge is getting about 19-20 mixed driving.

 

Likewise here too. Had my truck since new '06 w/ 38,000 miles on it now. I have a Magnaflow 2x" muffler, and no cat, with a K&N drop-in. Why the no-go on the K&n? Just curious, don't want to hurt it, but still let it breathe/ get better mpg.

-SS

 

No on the K&N because it is known for doing what is called "dusting" the turbo which means when the turbo is dusted, it needs to be replaced and they are not cheap. Go with aFe or Amsoil for an air filter. Or you can do what is called the BHAF mod. That stands for Big Honkin' Air Filter. Go to your local NAPA auto parts and order air filter part number 6637. It is basically a poor man's cold air intake.

Scott

 

Smarty

 

With the 6637 less dusting than the K&N will occur with a closed air box?

-SS

 

The 6637 will filter air better than the K&N.

EDIT: Here's what the 6637 looks like installed on a 7.3L Powerstroke.



Scott

 

Another vote for the smarty/smarty jr. The only way to go, IMO.

The napa isn't oiled, it's a dry paper filter, so it won't deposit the film on the turbo blades...

For that reason, I also liked the aFe pro guard 7. It was oiled but had a finer fabric and filtered nearly as good as paper filters but flowed nice.

 

Alright, I pulled my K&N out and they actually gave me a refund at the O'tooly's when I told them the dealership wouldn't honor my ext. warranty unless I replaced the K&N. So the 6637 filter from NAPA, what do I ask for as far as manufacture name? Thanks guys.

-SS

 

You just ask for part number 6637.

Scott