Have any of you completely straight piped a 4.0? Like cat delete and everything? I'm thinking of doing it just curious as to what it sounds like...
Check out my YouTube channel, MrHyperlyte. There's a video of my 4.9 with an empty cat, thrush muffler, and downturn pipe. FYI, sounds like **** if it dumps under the truck... I currently have the exhaust removed pending re-work. In my video you can hear how the empty cat causes a rice burner revurb... Not ideal... My state has inspections so I have to have the cat, and I have a Jet chip in it normally. So during inspection I take it out and it runs very lean. Otherwise it would fail every time.
Here's a link to it:
I have not gotten a MIL with the empty cat, but the O2 sensor is still installed. The lower back pressure helps her run cooler I have found, but am waiting until I explode the welded thrush muffler from fuel fume backup while descending hills.