I just want to see what everyone else is getting. I am thinking about getting a new truck after the first of the year. I do a lot of pulling with my truck. I haul a 3-4 car hauler and stay loaded all the time. I have had no probs with my 6spd G-56 in my '05.

I have hauled with other guys with autos and they get a little better fuel milage than I do pulling the exact same trailer and load.

I want to know what is the best in fuel milage and in long run as far as repairs a good solid built auto for pulling or the tried and true manual. The only thing I have done to mine is a clutch and all the other goodies at 208K miles. Will I get that kind of life from an auto under heavy pulling conditions? Any input would be greatly appreciated!

 

I also haul a 3/4 car trailer (Countryside) I have the NV5600 though so the gear ratios are a bit different than yours. Fully loaded I get just under 12MPG I dont have much either only the Volant intake and my cat is MIA otherwise stock. As of today im at 311,994 miles.

 

The best I've got with my 06' auto pulling 14-15K is 12mpg.

 

Trick is, they changed the final ratio on the 6 speeds for 08, so you will be geared much closer to what those Auto guys are running in OD.

The 05/06/07's usually run about 2000 RPM's at 63-63 MPH, should be more like 1950 with the "new" 6th gear in the G-units.

I would stick with the manual, as you said, you've had no trouble with it!

 

waam here, I get 12 to 13 most of the time, pulling my 10,000 lb fiver. At 65 mph my rpm's are always just below 2000 rpm's but I have a 3.55 rear axel ratio, and I pull in overdrive most of the time. In windy weather and in hill country I don't always get 12 mpg. waam Holland, Mich.

 

fully loaded i get 8-9 mpg. Dang 6.7. I also have 3.73s, bout to do 410 or trade up though

 

If the final drive ratio is the same, it is possible to get better mileage with the manual. There is less internal resistance in a manual than an auto. You can also anticipate better than an auto. A lot of people with the manuals have a tendancy to lug the engine thinking that they will get better fuel mileage and it actually gives them much worse mileage.

It looks like next year, the new trucks will have very similar final drive ratios so the manual should get better mileage driven properly.

 

I agree. The overhead guess-o-meter set on instant MPG is very useful for me to determine my relative fuel consumption and will show worse mileage when lugging the engine. Hand calculated mileage also confirms this. Seems counterintuitive, but revving the engine at 2,000-2,200 RPM in the next lower gear uses less fuel than chugging along quieter at 1,600 RPM with a load--even though the engine will do it with no problem.

 

If you are towing at the same speed as the auto guys and they are claiming better mileage you need to consider that they may be lying. It happens sometimes.

 

Now I was wondering a lot of people state that 1600 RPM's and lower when towing is lugging the engine (which I can see) BUT what I want to know is with no load what is considered lugging?

 

Everyone of my stick trucks averaged better milage then the auto's. I had a 5spd '02 with 3.55's and 35" tires that got 18mpg empty. All of my auto's averaged around 17mpg empty. With 285 tires or smaller the stick trucks would average right around 20-21mpg.

 

Lugging is when your rpm is too low for the power that you are putting out. When the rpm is higher, the number of cylinders that fire increases for a given time interval. Therefore, each combustion event must produce less power at higher rpm to give the same total power output of the motor. When lugging, since a lot of fuel is being injected during each injection event, a lot of stress is put on components like bearings. Also, the fuel burn is less efficient which leads to decreased fuel economy.

As far as how to drive to avoid lugging, you are correct that 1600rpm at no load is not lugging. The more power that you need from your engine, the more rpm you should run. If you don't need any power, you should be idling(or turn the thing off). The most efficient power versus fuel consumption generally occurs at torque peak or slightly above it so something like 1900rpm for these motors. The most efficient power output for all other throttle settings falls somewhere in between.

 

Most "efficient" power happens at lowest BSFC. That's 2K rpm for a 24V (VP truck) and 1600rpm for a stock 12v. I have no idea where it is for a HPCR truck, but it's probably right around 2K, maybe a hair higher.

jh

 

10 mpg is the best I have gotten pulling a 10,000 lb 5th wheel toy hauler.