Returned yesterday from a week-long, 2,200 mile RV trip to the Outer Banks of North Carolina (OBX). Our route took us through the mountains of WV - at one point, I was pulling our 9k lb travel trailer up a 7% grade that was 4-5 miles long -- which is the point of this ruminating post...

I'm quite happy with the way my '12 modified E-350 performed. Changing out the rear 3.73 for a 4.30 was simply the best pairing for my V10 that I could've hoped for.

I held that 7% grade at 55mph under almost WOT with the engine RPMs pegged at about 4,250 (which is max hp according to Ford). The engine temp never rose, and other than the engine noise, the powertrain never complained once. (But boy, resetting the fuel econ gauge during the ascent showed I was getting 3.9 mpg. I figured I nullified the carbon benefits of 38 Toyota Priuses.)

I would've liked to have a trans temp gauge, as I'm sure my tranny was probably cooking at times... but the constant air flow kept it under control (I hope).

Loved that tow/haul mode, too. Nary touched the brakes as I descended down the backside of that same hill. What a great tow combination.

My truck was running Mike's 5-Star tuning for 87 octane, but under heavy loading (ie: hard acceleration) I discerned a little pinging in the first part of our trip. So I began using 89 or 93. The pinging was gone and fuel economy improved slightly. I did not re-tune the engine for 93 octane.

On flat land, I averaged about 7.8 mpg (I was hoping for 9), in the mountains I averaged about 6.2 mpg. Unloaded, my truck can get as much as 12.x mpg freeway.

I checked my engine oil every other fill-up and it never seemed low. My truck's got 49k miles on it and I religiously use Mobil 1 5w20 with a Motorcraft filter. I was really pleasantly surprised that there wasn't more burn off. ?

Anywho... for those pondering the benefits of a lower rear diff -- I'd like to whole heartedly recommend the 4.30 if you've got a V10 and tow a large trailer. The improvements in towing performance are massive, yet the penalty in fuel economy isn't as bad as you might think (ie: very small, IMHO).

Lastly... having owned an '02 E-350 7.3 diesel, and an '05 Excursion 6.0 diesel, I can say unequivocally that diesels rule as tow vehicles -- uphill, downhill, flatland, whatever. As good as my modified gasser is, it's still not nearly as good as a turbo diesel.

I understand Ford is introducing 5 "new nameplate" trucks in the coming few years. One is bound to be the re-introduction of the Bronco. I hope one of the others is an aluminum-bodied Excursion with a turbo diesel and Ford's new 10-speed automatic. Talk about being a happy camper...

 

That's good story and I appreciate the details.

I towed about 200miles yesterday (mine is a 07 E350 with V10; pulling 3,500lb enclosed trailer with about 3,500lb inside). I'm looking forward to filling it up today and checking the fuel "economy."

So yours was staying at high rpm under WOT? And it was at the speed you wanted? Seems like it would have shifted or sped up... I've never been in the situation.

 

When I used cruise control, the computer tried to hold the grade in fourth gear with RPMs struggling around 3200 RPM -- which is near max torque. But I steadily kept losing speed and rpm's. So I manually shifted to third gear and held rpms at 4,250. that way I never lost speed

 

180 miles on this tank lol. Pulling race car trailer at 62-70mph.

25.47 gallons fuel. 1.5qts oil lol

 

why are you burning so much oil?

 

^^^ With the check engine lamp lit.

>>>>>>>>Action

 

Check engine light is from my hollowed out catalytic converters.

All the V10 owners report a bit of oil consumption. Mine is a quart per week (about 800-900 miles).

I guess the extra workload increases it some.