[JPaige5408]

Hey guys - i have XRT Pro for my dpf delete on '08 Cummins 6.7L. i bought it in May of 2012. i've updated it about 4 times over the course that i've owned it. When i first got it, i was knocking out almost 24mpg's on flat hwy at 70mph unloaded. 4 updates later, i'm knocking out about 18mpgs under the same conditions.

all other variables have remained the same - except one. Good clean K&N air filter, 5" TBE exhaust, same size tires, no lift or anything else, hell i even buy my fuel from almost always the same 2 stations. However, i ADDED the transmission tuning software, but i still adjusted the shiftpoints back to stock.

After e-mailing the guys at H&S, they said there was no way to revert the software on the tuner and "downgrade". Coincidentally, i've noticed i hardly blow any smoke anymore at all. Not that i like to "roll coal" as some of the overzealous diesel bombers do, but i just thought it was odd.

My question is, has anyone else experienced this or have any solutions? would the overdrive tuning reduce fuel mileage? maybe i should look at a different tuner?

 

[3brorce]

Could always add MCC and some custom tunes.

 

[jwcarguy]

I noticed that my mpg never went back up when I had in "tow" mode then went to 'Street" now back to "tow"
only getting around 15mpg ??

 

[JPaige5408]

Same here. I did notice an increase in mpg from "street" to "performance", but on a mostly stock truck I don't like running that all the time. And I dropped close to a grand on the tuner, another $300 on the tranny tune, and now it seems my only option is to pay for MCC tuning that I know nothing about. So why are the broad updates leading to continually worse performance? Was it truly inadvertent, or intentional for MCC revenue? Any H&S guys care to comment? Lol

 

[JPaige5408]

May need to jump over to the H&S boards for this...

 

[jwcarguy]

maybe that has something to do with it?

I did the "trans tune" when switching from "Street " to " Tow" modes, then the mpg went down

I didn't mess with the shift points ( left in "default" selection)

 

[jwcarguy]

May need to jump over to the H&S boards for this...

It would be worth searching for sure

 

[JPaige5408]

maybe that has something to do with it?

I did the "trans tune" when switching from "Street " to " Tow" modes, then the mpg went down

I didn't mess with the shift points ( left in "default" selection)

I might try taking the trans tune off and see if it helps the mileage. any idea how to return to stock on tranny only?

 

[jwcarguy]

I might try taking the trans tune off and see if it helps the mileage. any idea how to return to stock on tranny only?

Have no idea??
Still learning about this