Getting Better Fuel Mileage

In my time in a cat acert if you lug it down to 1000/1100 rpm like cat suggests your truck will be a dog in the slow lane and sucking fuel! If you can top the hill at that so be it but if you have to down shift you cant get on top of the turbos they wont build much boost and you will be back at 1100rpm looking at another gear. If you have to down shift do it at 1250/1300 rpm get the turbos going and get up the hill. Your cruise rpm has to be low 1300 to 1400 max maybe lower if your running flat ground. Never tach above 1750 even pulling a hill. It also seems best if you never put your foot to the floor always trying to see how little throttle you can give it. I run local same routes all the time some 2 lane with a 45mph speed limit and some 4 lane that you can run 65. I have tried lots of differant ways of driving in the 4 years I've had this truck and thats what seems to be the best. I have a W900L day cab 550cat 18spd 3.555 rears 11r24.5 open sholder tires. Pulling a flat bed sometimes running heavy 110,000 gross to light 60,000 and some empty miles at 30,000lbs get at best 6.5 worst 5.8mpg. Hope that rambling makes sense. If running a cat acert just remember this the softer you drive it the better it likes it.

 

For 2 weeks i change my 2 mufflers from my c 13 engine i put the straight pittsburghpowermufflers
and iam very very happy i gain 0.5 miles more p gallon.before i spend money for turbo 3000 and aircell nothing works only losing my money now with the mufflers i have doble exhaust iam ok and happy i fixed in a shop in pa i-80 ex 29 is a small shop only the guy have mufflers and boxes and fass system and teh labor is only 55 us for a hour the best investent what is do for mi engine is now a little louter only the engine rund smoother thanks pittsburghpower iam happy whit this

 

Not if you have an Eaton manual transmission. They say do not lug it below 1200rpm. They claim this is the cause for input shaft breakage and will not honor their warranty if you break your input shaft, guess how I found this out.

Funny how mine broke and I've never lugged it below 1200rpm, but guess who had to pay the repair bill?

 

Hi maxeffort , this is a great thread , I have a question for you if your still checking in, dose the ride hight make a differance? I know it has made a differance on my half ton truck after I lifted the front 2 inches.

 

So how did that prediction work out for you?

 

I CHANGE MI MUFFLERS AND NEVER DRIVE MORE WITH THE CRUISE CONTROL ME SPEED IS 65 TO 70 AND I HAVE NOW A VERY BETTER MPG THEN BEFORE,BEFORE 40000+, 5 or less now 5.7 ,light before 5,6 now i pass easy the 6,last run ca-me with stops 5400 miles, 6.4.iam very happy with the cat c13 never troubles and never i drive more with cruisecontroll,drive with cruise is losing mpg

 

Very informative post. Thanks. Tough to go slow though, makes me wanna sleep. I try not to speed Anything under 70 on a long haul is positively sedating.

 

Great job on your explanations ! Just to back up your thread, a scania r730 (which is 730hp) together with a close coupled trailer and side skirts for aerodynamics ( the norm over here ) are constantly returning up to 11 mpg @ 97,000 lbs, high torque - low revving engines is the way here now along with good aerodynamics that coe's provide, thats as long as your trailer is very close to the cab! High torque means little gearchanging so those engines operate at 1000 rpm alot of the time!

This just shows a big engine and good aerodynamics and of course a good driver really does save alot of fuel, you do need all three working in harmony to make it work , theres no point saying "well this thing only saves x amount of fuel so I ain't gonna bother doing it" it's the combination of all these little things that makes the difference,

 

I like that! Only wish I could still do 70!

 

Don't know how relevant this is to your situation; I've had low ride trucks in the past, they are called megas here, the bumper would have been 4 inches from the ground, they got small tyres, kinda like a goose neck without the goose neck ( you know what I mean? ) the truck wheels were not much bigger than the gooseneck trailer wheels, this means you gotta change gearing etc etc and NO , actually worse on fuel, side skirts are far more effective, get the airflow around the truck without upsetting the gearing besides it's much cheaper to put a few skirts on rather than lower the whole truck where u would have to replace tyres, suspension, diffs and trailer landing legs