Diesel MPG test

[Neal]

Cummins ISL 9 400 HP Diesel Engine:
Pulling Chevy Colorado (toad)

It's been a long time since I did a check of the MPG of my engine. Long ago I think it was around 7'ish but never really cared. Now that I have near 55K miles and definitely broken in I figured I'd run a test again. This was carefully controlled, i.e. slow fill to full at start of test, slow fill to full at next fuel stop (to minimize foaming), at least 3/4 tank (per gauge) used, level terrain for most of drive. Now during this test I did perform a regen to test my Diesel Laptops Handheld which put the RPM at 1000 for an hour and 15 minutes. Not sure of the diesel consumption but I'll consider it negligible. Most of this drive was highway (freeway for lefties) and my highway cruise speed is typically 70-72 mph.

Result of test was 8.5 mpg

 

[Fish]

With or without toad? I think I got 6.5 to 8 mpg last year on my trip to and back from Florida.
6.5 was the fill-up after I had to run the generator a lot while parked at the truck shop awaiting repair and they had no electrical plug in.
If I drive over 65 it's because I've lost my focus.
2007 model isl400 pulling a full size Silverado.
My nerves won't let me get much below 1/2 tank before I fill up.

I know it cost me around $800 to get home from Florida and diesel is said to maybe start going back up again. Not that it actually went down much. Not looking forward to that upcoming expense.

 

[Neal]

I edited the OP, with toad

 

[stang37]

There is a setting on the Diesel Lap top that will give you total milage and total fuel consumed since mile one and will also show the average MPG. At 43K it showed my overall MPG average at 8.5. Performing the DPF regen at 1000 RPM for 75 minutes dropped my average at the first fuel stop to 5.5 on this trip. Normally it between 7 and 7.8 depending on highway conditions

 

[Texas Clodhopper]

I have found I get better fuel mileage at 70-72 which equates to about 1900 RPMs.

 

[MemoriesByTheMile]

Neal, which direction were you driving?
In our occasional tracking of MPG it has varied not only by speed but also the direction of travel. If traveling from west to east found that MPG is higher (or anytime when the winds are at our tail).

Very nice MPG though!

 

[Jim]

Result of test was 8.5 mpg

Nice! I barely get that with my Jeep!

 

[Neal]

Neal, which direction were you driving?

E.T. phoning home - east bound!