Today I was asked to help install mufflers without catalysts on a western star rig..
I had to weld up some melted clamps to custom, and they installed easily.
the catalyst original mufflers were destroying the engine and doing crazy physics. I laughed. I did the same chores to a doubled up subaru with 90 horses.
this truck goes in for one more valve job, and back to powerful, cool, economical, and brackets that can hold up mufflers weighing three times less, and 700 degrees cooler.
Challenge your automobile. "They" aren't quite right about alot of things.
I asked in the past to monitor a rig here...
1 mpg difference over a 100k mile year equals =