The "Sweet Spot" (best MPG)

We all witness time stoping when we arrive at the shipper or receiver...,,

 

I know the SPEED LIMIT in TEXAS as well as all the other states , but there are times / places / conditions that the OP likely cannot run in his SWEET SPOT.

 

I'm experiencing that now.

 

I discovered this while fiddling about in CA. I don't use 13th unless I'm above 61-62 mph. High rpms = low boost and low boost is what gives me decent mpg. My shop manager still has a hard time believing that I get better mpg (at least in CA) by cruising at 1430 in 12th instead of 1250 in 13th.

 

Pyro temps are not something one typically needs to worry about on Electronically Controlled engines. The computer will not let you over-fuel the engine. So you won't see exhaust temps that are too high.

And yes, it's all about the amount of boost.

 

Well, that depends on where you are, in some places it is 85 MPH, in other places 20 MPH.

 

This is silly. You will always get better MPG going slower. The difference at most between running in the sweet spot and not is about 2-3%. Yet running fast will cost you more than that. It's simple physics.

The sweet spot is there so you match it to your cruising speed, not to justify running faster.

 

Pyrometers might even be a thing of the past with the newer EPA-regulated engines. An acquaintance of mine with an '09 Peterbilt with one of the last CAT motors to be put in a truck (with all the fancy emissions stuff) said they wouldn't put a pyrometer in the truck, they didn't want you to know how hot the exhaust was. I personally like 'em, one of the big 4-inch gauges.