I need some help here
I am trying to get more mpg and I am getting from 5.1 to 5.45 now.
here is my info
2005 kw t 800
c-15 475 hp
10 speed
I keep a clean air filter and try to stretch my fuel.
my truck tops off at 70 mph.


any suggestions?

tks

 

What size tires do you have and what is your rear axle ratio ? Do you have a full sleeper with a roof fairing or a flat top with nothing ? If your truck tops out at 70 is that how fast you run or do cruise at a slower speed ?

 

The driver probably has more to do with your mpg than any other signal factor. One thing you could do is slow down and try to plan your stops. Drive like you have an egg under your accelerator pedal. Speeding up and slowing down can eat up your fuel. If you pull a van and own the trailer you could install a bubble on the front of the trailer. There are also wind deflectors that are also supposed to help with wind resistance.

 

Your definetly right Gman. I wonder other things too though. If a driver has 3.90 or 4.11 gears and 22.5 tires and they're running down the road at 70 mph then their mileage is probably not going to be good because of the high RPMs. He probably has a more normal setup but I just wanted to find out. You do see a lot of drivers burning through the gears with their foot to the floor just to race to the next red light.

 

I see that a lot, TK. Some of these drivers like to wind through the gears even though they know they will need to stop at the next light. As to the above poster, if he has low gearing that could have an impact on his mpg. Where he runs and what he hauls will also have an impact on fuel economy. It would be good to have more information.

 

Having a BIG Cat engine is your biggest problem. A big fuel waster. Air filter has nothing to do with it. A dirty air filter gives you the same MPG as a dirty one, since engine is computer controlled/compensated. The only thing that happens with a dirty filter, is you start losing power.

Try progressive shifting through the gears; 1st shift @ 1150 RPM, then 1200, then 1250, then 1300, etc. It will save fuel.

 

I have heard air tabs help with fuel mileage. I have a intl coe that has always gave me real good m.p.g. mine tops out at 70-72 m.p.h. at 1850 rpm's it still gets 6 min m.p.g. if I drop to 62-65 m.p.h. I will get 6.5-7.2 m.p.g. min. I have never known why at 1850 rpm's mine gets the good m.p.g that it does. it just does.

 

I get fairly good fuel economy with CAT engines. The gearing and how you drive has much more to do with it than the engine you have under the hood. I have always found that a dirty air filter will not only affect power but fuel consumption. When demands are made on an engine and it cannot breathe or get enough air then it will compensate by using more fuel.

 

Nothing wrong with a "big Cat engine". Mine is tuned up to 550 HP 2000 lb-ft torque at 1425 RPM and I get 6.5 MPG (US) with heavy loads and 7.3 with light loads all day long. But I cruise at 62 MPH 99% of the time and thanks to 3.42 ratio the CAT spins at 1,325 RPM only. Having an aero truck helps too: 2004 International 9400 will push less air than the T-800.

 

you probably have a slight leak in the air-to-air turbo system and at high rpm the leak has less effect on the engine performance due to high pressure inside the hoses. rutherford mentioned this once on his radio show.