Need some advice: calculating how much fuel is needed

And that could be because of not paying attention to details and/or making the effort and spend money for the right things to make it happen.

Exactly!

And have you done the math on it if you got 9 mpg. Fuel cost for 120K miles a year with 4$/gal fuel @ 6.7 mpg = $71,642.....@ 9 mpg = $53,333....difference $18,309 that is a lot of money to buy mods to get there and probably more than half of the annual salary of the typical company driver.

Mine has a CAT 3406E that averaged 9.3 mpg last year, but it is not stock by no means.

 

Just search IFTA. Here was a recent thread http://www.thetruckersreport.com/tr...-owner-operator/241719-working-with-ifta.html

You are correct that each state gets its share of fuel tax for the miles you drive in their state and it's based off of your fuel mileage. So you can't do anything to change what you will pay in fuel tax (IFTA) except to improve your fuel mileage. See the thread above and search IFTA for other threads. People misunderstand and argue about IFTA ad nauseam.

 

Probably right about that, but again that's a choice we make on what engine to have.

 

I'm up from 5mpg from last year. I only drive 55k a year doing air mile work so I sit idle a lot with lots of downtown work. I don't see much gain for me unless I keep shutting my truck off all the time but I don't want to keep putting in starters.

 

Just make sure you mark on your trip sheets those empty miles because anything over 8 mpg triggers an IFTA audit. I know. Been audited 2 years in a row (2012 and 2013) and everything in line and accepted.

 

I never tried to understand it,but remember one particular quarter I was running through SC a lot getting that cheaper fuel and at the end of the IFTA quarter I owed $300. Normally,I had a credit.

 

As a former O/O I can also insure you that any fuel savings realized from no idling versus APU will more than be spent on maintainence of APU. The road salt is brutal on those things.