Pete 379 with Cat C-15 mpg?

if you live in pa area i don't think mr haney is too far from you. i would try to hook up with mr haney 1st and i think you'll get more return for money spent. been trying to make contact with him myself

 

Like others say your first order of business should be to make sure everything is right before ecm tunes. Would drive it stock for a while to get a feel and have a good baseline but that's just me. Haney is the man for CAT's.

 

Before you spend any inheritance I can tell you I dropped the catalytic mufflers, Bullydog tune, after market manifold, and absolutely no change in mpg. However it does not know what a load is. My quarterlies are in the 5.3-5.5 range. I'm going with the conversion soon. Your buddies are right. I did not want to believe it but insurance gave us a loaner (ugly old Volvo) gutless, and got 6.5 mpg for the week doing the same work. Made me just sick. Buddy who is a mechanic said keep the Cat as the Volvo will take the fuel savings back from you every time. Who is to say.

 

Do some looking around in the KW forum, I posted some pics in there on how to eliminate the under the cab mufflers using most of what you already have, you just need to cut and weld the y-pipe to be able to use it. An Acert is not that loud with straights, the jake will bark, but you can still carry on a conversation with it on. If you ever see me on the road holler, mine is straight piped with 7's.

 

TMC had similarly speced trucks except we could only go 63ish. My Mpg was low 5's most of the time pulling flatbed. If I got a long flat haul i might get up to 6, but average was low to mid 5's. Now your going 7 mph faster ad those cats eat fuel above 1400 RPM. I know no one wants to slow down, but how fast can you go at 1400 RPM? You may get way better MPG by only sacrificing 1 or 2 mph.

 

Slowing down... Whats that worth? My truck goes 90+ but only time it see's over 68 is going downhill.
98% of time is at 62-65 mph.

 

I agree that slowing down is the best for getting fuel mileage, but as a former livestock hauler myself people need to understand that slowing down is typically not an option in that end of the business. These guys aren't almost always in the left lane because they think fuel is cheap, they REALLY do have to go.

 

Just FYI, you can but those same mufflers that PP is selling, they're a Donaldson muffler, from Ryder truck parts for about $100 or less a piece. And when I put them on, my truck was actually quieter, even with the jakes.

Speed makes a big difference, it's like a 5-8% fuel difference between 65-70.

 

I went thru all 14 pages didn't see it

 

I'll do some digging and see if I can find it for you.