Hey Doug, you sound like a pro already. I would say you are driving it perfect. This motor loves working the low end like you are doing. After towing some you will be able to tell where it likes the best rpm. Probably around 1800 towing. Great question. Some of the experienced 6.4 manual guys should have some real good input for you. You are making me wish I had the manual again. Enjoy!

 

so what do you cats with a manual get for gas mileage? Is this with duallys?

 

Depends on high up the food chain you want to go. I do not think you can get a manual with a KR package or HD package. I think I read that the manual transmission eliminates the center front console and also eliminates some non related items, worth checking out if ordering new.

 

You can't have a manual with the center console. So that eliminates KR, and Leather FX4's.

My dually with 3.73's gets 17-20mpg highway, and 13-15 city.

 

My dually is up to 10.5 if I do not touch the throttle. But, I picked up 80 - 8" blocks yesterday, and drove home, about 15 miles, on I - 75 with 10 boost, and was happy as all get out. Almost forgot, also had 3 bags mortar, 75 pounders. I just wished I had someones loaded trailer to pull. Idling a 6.4 is unfair. So my 4.1's are not the best, but I am happy.

 

[quote=SouthTexasDiesel;6020613]Making a corner at 800 rpm's is fine.
For the best mileage I normally shift below 2,000 rpm. Not using the low gear, start out in #1 till 10 mph, #2 to 20, #3 to 30, #4 to 40, OD ++++. Not too hard to remember. Normally I don't accelerate too fast, keeping the boost below 20 psi.quote]

I was trying this strategy yesterday, and it seems to work pretty well. At the half way point, I actually started seeing the MPG average inch up. I don't yet know how accurate the display is, but half way on my first tank I'm sitting at 14.3 right now with a pretty even mix of city and highway. If it's accurate, I'm already 1.0MPG better than my Titan was doing, and just about offsetting the increased cost per gallon of the diesel fuel. As I understand I can expect another 3-4MPG once the engine is broken in, I'm feeling pretty good all in all!

Thanks for the tip, SouthTexasDiesel!
Doug

 

Thanks for the tip, SouthTexasDiesel!
Doug[/quote]

Hopefully more guys will listen to the great advise SouthTexasDiesel has. Hind sight I am wishing I went with the manual. A day late and and a dollar short now. Just have to peddle to the Gym now to save those dollars for camping this summer. Wonder how the Manuals do towing around 17k for fuel milage? Might not be too much of a difference?

 

Once you get up over 10k the mileage between the manual and auto evens out. That 20' horse trailer I was towing weighed about 7k and I got 12-13 on flat ground @ 1900 rpm, thats including the 4 regens I went through in 1000 miles.

I can't with to see what I'll be getting once I get the Cat and DPF off, full 5" strait pipe from the downpipe back into 6" stacks!! I don't think 22mpg is too far out of the question. And the manuals sound awesome without the DPF, pulled mine off for a few days and the turbo noise you get when you hit the clutch sounds like a blow-off valve.

 

I'm sorry but I just can't let this comment go. What is your statement based on? The breaking in of a diesel has the same effect for both. So if the manual gets a couple miles a gallon better mileage over the auto with a tight diesel, once the diesel breaks in and gives better efficiency, then the gap will essentially be the same and actually slightly better. For illustration purposes if the average friction losses through the auto is 10% and the manual is only 5 % then once the diesel is broken in, 10% of the larger mileage number will actually make the gap grow. For example, let say the diesel sees 16 miles a gallon new. All else being equal (rearend, wind resistance, etc.) 16 miles through the trannies will be 14.4 with the auto and 15.2 with the manual, a .8 mile per gallon difference. If after breaking in, the diesel improves to 18 miles a gallon. mileage through the trannies will be 16.2 for the auto and 17.1 for the manual a .9 mile a gallon difference, which is a tenth of a mile improvement, not an " evening out".

 

Umm, how about you read the comment before the one I posted. Clearly we were talking about towing weight and not mileage on the odo.

Pay attention next time instead of picking out random numbers and showing everyone that your computer has a calculator on it.

 

drove both today, just on my test drive, the lie o meter gave the stick about 2mpg better, drove the same road, same distance and reset them right when I took off.

 

Wow, someone is a little sensitive. I have read and have posted to this thread through and though several times and was fully aware of the towing portion of the comments. But you are right, your unexplained 10K was interpreted by me to be mileage on the odometer in relation to towing, not the amount of towing.

So I have reread your comments and my comment still applies using the clarification that all things being equal. To better illustrate for the towing situation:

If you are towing a weight that drops mileage in half, then the mileages will be about 7 for the auto and 8 for the manual. This assumes that the change in friction losses in automatics and manuals is equal under heavy loads, which I seriously doubt. They both have bearings and shafts and gear interface related losses. But the auto also relies on friction and and the generation of heat to work. The recent gains in automatic efficiency have been made in lockout technology. These gains are seen under light steady loads, which is far from the case when towing.

What I think you may be responding to is if we assume the above comment about friction is not an issue, the smaller gap of 1 mile per gallon could be perceived as a closing up of the gap. In reality it is the same percentage loss. One mile a gallon difference at 7 miles a gallon is 14% difference while 2 miles a gallon difference at 14 miles a gallon is also a 14% difference.

 

Yes CATANG misunderstood that we were talking about towing weight milage. To his comment. After 5,000 miles including 2,000 miles towing my MPG increased. Part of that I believe would be to the Auto loosening up a little. It is so tight to begin with, That is why the 2mpg difference between the manual and auto. Breaking in the auto might be 1.9mpg difference. No calculations just my thoughts. Hopefully some other manual guy out there is towing around 17k to give us some closer comparisons.

 

Do a little research. The manual is geared slightly different than the auto. Friction in the tranny doesn't mean anything when you've got several tons behind you.

Manuals run at slightly higher RPM's at speed than autos, when empty there is basically no effect, but while towing it creates higher boost and more fuel is used. Thus evening out the mileage when towing.

Believe me, I've probably done more research than just about anyone before I bought my truck. While there is logic in what you are saying it basically has no effect on these trucks. I've told people with autos to drive like me and magically their mpg increases to within 1mpg of mine. Honestly it's more of a physiological difference than a mechanical. People who drive manuals tend to be more patient and pay more attention to what is happening with their vehicles.

 

Well I doubt I am going to change any minds here. But I can assure you that all other things being equal (truck, axle ratio, load, destination, etc.) when one system performs better than the other, the difference is efficiency. They both have one-to-one final gears so they are even equal, rpm wise except that the auto is going to see higher rpm due to the friction slippage mechanisim that all auto trannys rely on to operate. Now if there was terribly designed spacing of the interanal gear ratios between shifting speeds for the auto or manual tranny there might be some possiblity of slightly different efficiciency for small amounts of time at between-gear situations. But I can assure you that Ford has been making autos and manuals for quite some time now and with the number of gears available now, things are pretty darn good in that department for both trannies.

The auto is similar to a manual with respect to the transfer of power from the engine to the driveshaft using shafts and bearings. No difference in lossening up over time. They are nothing like motors and after the first 10 miiles have the ideal clearances for effieiency. After that, any additional play is contributing to misalignment and efficiency losses. But where the auto losses more mileage is in its difference of using friction bands and slipping torque converters versus meshing gears. The design relies on slippage and friction to work. The resulting by product is 100% heat and loss of efficiency. In fact it is so great that the auto requires a cooler to keep it from burning up.

When a truck is carrying a greater load more work is required in the driveline and the loads go up. This produces more friction and heat losses in both the auto and manual tranny. BUt the auto system, relying on a friction generating system to work, generates even more more heat under load to work.

Hence the reason autos under load always sound more wound out than manuals for the same ground speed.