Help!! C15 twin turbo MPG...

because it's worth it to look cool

 

Those oil temps are about 10-20* high. But remember the ACERT motors don't have a actual oil temp sensor. The temp is guess-timated throught the ECM with the help of air and coolant temp. The only way to get a true temp is with aftermarket gauges.

My guess for the mileage lose is still a boost leak. It sounds like you are about 5-10psi low on boost. Check over the hole intake system while it is pressurized with some soapy water...you will be surprised at all the little leaks that add up to a big one.

 

Because as most of us with non-aero trucks will tell you the shape of the hood and skirting have very little to do with actual fuel mileage. Take the worlds smoothest most aerodynamically designed truck (you can even add the goofy trailer skirts) and put the wrong driver it there and all that plastic junk doesn't amount to anything other than added maintenance. Honestly, I'm as greedy as anyone and I'll keep my W900L's and my happy drivers with a 6.2mpg fleet average, all local stop and go.

 

I have essentially the same truck and started out at 4.8. After reading the CAT threads and following the advice I now get 6.2 overall avg. I'm told this equals a savings of about $1,000 per tenth per year, so it is a big deal to me.

Biggest changes:
Slowed down to 64MPH + or -, cost = FREE
Learned to progressive shift, cost = FREE
Tested and repaired a leak in the air to air at a clamp, cost = FREE
Bought cheapest Donaldson mufflers, took an air grinder and cut out the bottom baffles, cost = $124
Upgraded fuel filter head from 90GPH stock unit to a 120GPH unit from CAT, cost = $40. These engines are famous for sucking air at the filter head and the ACERT needs lots of fuel flow. Also began using a higher flow fuel filter, a FS1212.
There are other tips and tricks to be found on here, just get 'ta reading!

 

Aero makes a big difference! I can get half to one full mpg better than my dad's W900B running the same road and him even following me taking it easy. I even get better mpg's than his Classic with a 3406E 550 and a standup sleeper. The W9 and my FLD120 both have B's in them. Mine has full skirts and a wing, his has a big hood and a bumper that almost drags the ground...

 

Might ask a Cat dealer about the oil drain line from the valve cover aria. Marten just this line in all of our trucks with C-15 Accert engins. I had the fuel filter housing crack on my truck recently and the truck was looked at by 3 shops befor someone put a clear fuel line on it and saw the bubbles in the fuel.
Driving style makes a big difference with this motor, keep your RPMs as low as you can during cruise 1150-1350. While accelerating keep it under 1500 and skip gears as much as possable (drive it like a nine).
My current truck (T600) governed at 65 MPH with 3.36 gears cuises at 1350 RPM and gets 6-7 MPG reliably pulling loads gossing 60-80,000 lbs.