We just returned from a trip out west. Here is some info and a report on how the V10 did.

V10 with 100,000
5 Star Tune with 5 Star Y-Pipe.
New K&N Air Filter.
Tuned for 87 Octane.

Route...Northern Indiana West on 80 to the Tetons North to Yellowstone out the Northeast Gate to Cody picking up 90 through the Black Hills, Badlands, South Dakota, Minnesota, South through Wisconsin, Chicago, and home. The Biggest troubles seamed to be the Bighorn National Forest/ Mountains of Montana just East of Yellowstone.

I ran it in 87 tow tune the entire trip.

Trip Total Averages...8.1 mpg.
Best 9.6
Worst 6.5

I had hoped for better with a tune but I did experience a noticeable difference in not jumping out of my overdrive and not downshifting and not losing cruise on every incline as it was in Indiana prior to the tune. I will say that if you are going out west with a gasser beware...many stations refer to 85 octane with 10% ethanol "regular unleaded".

 

Sounds like a good trip!

 

SW Montana resident here. I can attest to some of our mountain passes and what it takes to pull something over the top of them. Where I live, the passes have a maximum limit of 25mph for commercial trucks and the LEOs are always watching. You didn't mention what you were pulling or how much it weighs, but a gasser is going to struggle with just about anything out here if you don't have the proper gearing. Even running empty, my 2000/V10 will downshift over these passes with 3.73 gearing and the 5Star tuning. Can't say that I notice a difference in the way it runs with 85 vs 87 octane in performance mode, but its a complete dog in Econ mode. I've tried the 91 Tow mode once when pulling about 8k lbs, but all that really did was hold each gear longer.

Prior to purchasing the Ex, our family hauler was a 2wd Durango with the little 318 V8. It had 3.92 gearing and towed sooo much better than my Dodge 1500 with the bigger 360 V8 and 3.55 gears. Having the extra power didn't help that truck in any way. It was a complete dog, as well. I no longer have either of those rigs and really miss how comfortable the Durango was. My daughter cooked the head gaskets about the time I upgraded our camp trailer, so it was time to go big or go home. If there was one single improvement I could make to the Ex, I'd swap out the gears with the first $2000 that started burning a hole in my pockets. If I new anything about setting backlash, I'd do it myself.

 

x2 on gearing. 4.30 or better if towing heavy, especially in the mountains. I had a somewhat similar trip back in June/July from MI, out to central CA (southern route), then back to MI on a northern route through NV, ID, MT, SD. On the entire trip, I averaged just under 7MPG. My TT is just under 12k loaded.

 

I have 3.73 gears in my X and I was towing about 7500-8000#.

 

a lot of really good guides on the internet......gears are scary until you do them, then they are just tedious because it is a lot of fine tuning if you are like me and want perfection

 

85 octane fuel at above 6000 ft ish is the same as 87 octane below 6000 ft. ish.

Due to less oxygen availability, less octane needed. A 300 hp motor at sea level is only 240 hp up here. So 85 octane is normal here, I would treat your 87 tune the same with 85 octane if your above 5000 ft or so. But if you fill up with 85 octane and head east to below 5000 ft or so be careful as lower elevations need better fuel.

It sucks, my NA V10s are 20% down on power. That like having a 5.4L at sea level.

 

My biggest losses showed up between in Western South Dakota. I would not have expected that.

 

Did that trip last year. My X has the 4.30`s and I also have the SPD Y-pipe and 5star tune but with 89 octane towing tune. towing a 9300lb loaded trailer. Set the cruise at 75 on some stretches. only dropped to 60 on one back road grade coming out of Jackson. but it was very steep and I was still able to go faster than some of the traffic. I averaged 7.2 on that trip.

I would change the gears to 4.30`s or better yet 4.56 even though you are towing lighter. when I went from 3.73 to 4.30 I picked up .5 mpg towing. the gears alone will make you wonder why Ford ever offered 3.73`s with a motor that needs to rev to make its power!

At Buffalo Bill Reservoir in Cody WY.



And Badlands SD.