OK guys, your driving them, what's the real world MPG like. Also, if I'm reading it right the differential ratio is pretty high (thought I heard something like 335), hows that impact the raw pulling in power situations? Anybody got a comment. thanks from a 6.4 owner who is thinking about the scorp.

 

CrewCab short box XLT, 4x4, 250 w/10,000lb GVWR, 18" wheels, and 3.55 gears. I have 800ish miles on it and have these results from the dash. (if you don't like those numbers, stop reading now, I trust them to be within my level of accuracy concern) First 300miles were towing an empty car trailer(well, it had a 14' pipe gate on it) on the highway at 72mph. Got 16.5 ave. Next couple hundred were running back and forth to town(I farm about 15 miles outside of an eastern Iowa city) and got 17.5-18. Next up was some light towing with farm wagons weighing <7,000lbs and in and out of fields, lots of idling, and short runs. Got about 12-13. lastly I've been pulling my 3horse bumper pull with one or two inside for short runs to the polo field. (about 7 miles) It's getting 16ish.

In all, hard to get a real good feel in only 800 miles, but I'd say that it will average out about 2-4 mpg better than my similar '04 6.0 I just traded off. Closer to four better running to town(mixed 60mph, and stop and go suburb type stuff) and more like 2 better on the highway pushing a lot of wind, and when towing.

mikE(in the ballpark anyway)

 

there was a table of effective ratios somewhere recently..

the rear axle ratios are 3.31, 3.55 and 3.73, and are compensated by lower 1st/second gears and new 6th od gear at 0.67

from your sig, the 4.30 down to 3.31 is a 28-29% change.. that would lower the RPM.. probably in the 15-20% mileage improvement..

Sam

 

f350 drw
empty on high at 70-75 19-19.5 mpg

pulled 15000 5th wheel this weedend running 65-70 8.5-9 mpg

 

what gear ratio?
and those numbers are from the mileage meter in the dash, right?

Sam

 

all DRW f350's have 3.73's and f450's have 4.30's

they are off dash, i haven't had calculated anything yet...i know its reallll close from putting fuel in

 

thanks.. do you remember what the RPM looked like on your hiway 70-75 cruise? 1800ish?

19ish would certainly be an improvement over my 14.5 on the hiway at the same speeds.

Sam

 

at 70-75mph it was around 1800
pulling the 15000 it did a great job pulling in 6th gear

Feels like your going 50mph going 75. lol That something to get used too! Its like" are we going any where.lol"

I was running 75mph down some hills and didn't feel out of control at all
Rode really smooth, wasn't for the jerk from time to time, from the road and of course the weight when going up hills. I would honestly say, you hardly new it was back there.

I drove in 5th gear on the way up, it like 45-50mph, going 65 mph seemed to really work it. I was a little worried thinking i didn't have enough truck. I really was thinking, holy crap...wonder what 6th feels like...little scared.
then i pulled in 6th on the way home....it loved 6th gear!! going up hills, just give it just a little extra pedal and it will climb it. Going 70mph pulling 15000,some fairly long hill gradual climbs, just give it a little and it didn't slow down, on the steep shorter hills, i would give a little (no much) and it wouldn't go below 65mph going up.

When i go to the UP on I-75,will be a good test.
its constant long tall hills on the way up to the mack bridge.

When i used to have a 28ft tritoon and 2004 f150, the one day where coming back from UP on I75, the wind was blowing from south so hard, going down long tall hill's, i would let off gas and i would litteraly feel being pulled backwards! I would slow down so fast..i had to give it 1/2 throttle to go down the darn hill.... then going up...it was a long trip thru there, top of the hills i was going like 30mph multiple times on couple of them hills. lol

I will post after i go thru there later on this summer!

 

thanks.. yes those hills on I-75 will be a good test..

used to camp right there at mackinaw

Sam

 

How about the Urea?
How often do you have to re-fill?
What's it cost to re-fill?
What happpens when it runs out?

 

If you tab to the Trip A/B page it will show you the actual gallons of fuel used.
I have 1286 miles on my F450 with 4.30's and have used 81 gallons thus far for a real 15.8 mpg. this is all varieties of driving, i.e. city, highway, loaded, unloaded and just plain idleing. This is about as real as your going to get.

 

Reports are that the 5 gallon tank will take you approximately 7000 miles. The computer will let you know when you are about 800 miles away from running out. Don't let it run out, if you do the truck will default the trans and the truck will not drive. About $2.39 a gallon is what it will cost and is becoming readily available.

 

I'm sure not an engineer and I don't doubt what you say, but it seems counter to everything I know about gears. It just don't seem possible that changing the tranny gearing can compensate for lost differential power. There just ain't no free lunches. In fact if you could do that all diffs would be the same and power would be gotten by adding a lower gear to the tranny. Right?

 

Ive got the 3.31 and about 550 miles... Getting 14-15 in the city.. That would have been 10-11 or less with the same driving in my '08

 

yes sir, you don't have to tell me how bad my mileage is, I get that. I'm just wondering if you gave up some power to get it. don't get me wrong, i bought my truck used, had i ordered it I would have at least the 410 instead of the 430. But my 5er weighs 17,500 on a good day and I sometimes need all the torque I can get. I'm thinkin about the 2011 but wondering where the right mixture would be of torque vs economy. I haven't seen any literature, does the towing capacity change as you increase the ratio of the differential? In the eariler years ford just didn't make the 373 available on the DRW truck. It was 410 or nothing, then on the 08 it was 410 or 430. Now if I'm reading these posts right I could get a DRW 350 with a 331. If that's right seems like the towing rating would change. Not that I ever payed much attention to that anyway, I'm just courious.