Gas Milage, 2008 F350, 6.4

[kmh3212]

Dave take the K & N filter back. These filters have shown to pass too many solids (dirt) into your engine intake. The small benefits aren't worth the risk. There are aftermarket filters out there that work as well as OEM but they are expensive. 2-300 dollars. Stay with stock and protect your warranty and engine. Go to thedieselstop.com for infomation on ford diesels.

[kmh3212]

"I have very little experience in putting together a power package Iam looking at F350 SRW PSD but the Rear end gears are confusing me. they offer 3.55 Non Slip 3.75 Lim Slip 3.55 Lim Slip. Which would be the best all around fuel mileage, towing and not towing. Thanks for all the knowledge.
Bob"

Bob the 3.55 rear end will give you the most mpg but the poorest towing performance especially in the hills and mountains. If you are towing and hauling more than about 12,000lbs I would go to a 3.73 rear in a Ford. Ford's Navistar diesel is a high revving motor making horsepower and torque at a little higher rpm than GMs or Dodges. You can really wind these engines out without damage. To take advantage of the horsepower you'll need the rpms of a 3.73 hauling more than about 15,000 get a 4.10. You can damage a motor by lugging it (too low rpm for the load). Also remember vehicle load is weight of trailer, all the stuff in it, water, sewage, passengers, fuel, tools, hitch and the stuff under the seats.

[gregh9999]

I have a 2008 SD KR 4x4 short bed, 3.73LS gearing. Empty mileage is 15-18, with the 18 being straight Interstate driving. Towing the new 2955RL, I'm doing high 11's. Of course, this is towing in Virginia...

[bsmeaton]

I have the 3.73 here in Colorado with my Ford 6.0. If anything, they could be a little deeper. This 3400 is heavy at 12,000 ft.

[billhoover]

quote:Originally posted by bsmeaton

I have the 3.73 here in Colorado with my Ford 6.0. If anything, they could be a little deeper. This 3400 is heavy at 12,000 ft.

The advantage with a turbo diesel is that the diesel does not know it is at 12,000'...as long as it keeps pumping air in that engine, there is very little difference in power betweeen sea level and anywhere else.

[PowellsMonty]

Drove to Louisville, once out of the mountains got 18-20mpg not towing. Happy!! Doors unlocked twice after about 2 hrs. of driving, and twice when I nailed it passing someone, it bogged and white smoke out the tail pipe. Went to Charlotte twice this week and neither of those things happened.
Will see. Love the truck though!!

[kmh3212]

quote:Originally posted by Bob & Lee

I have very little experience in putting together a power package I am looking at F350 SRW PSD but the Rear end gears are confusing me. they offer 3.55 Non Slip 3.75 Lim Slip 3.55 Lim Slip. Which would be the best all around fuel mileage, towing and not towing. Thanks for all the knowledge.
Bob

Bob, The 3.55 rear gear ratio will provide the highest fuel mileage with the worst towing performance. It would be okay for flatland towing but would be undesirable in the mountains. Your transmission would be downshifting going up the hills. The 4.3 rear gear ratio would give the lowest fuel mileage with the best for towing in the Rockies and mountains of the east. If you will be towing the 3400 most people are buying the 3.73 or the 4.10. I have a 3670 RL loaded pretty heavy with lots of gear. I chose the F450 4x4 dually with a 4.30 rear end. Empty I am getting 12.95 mpg. I can handle most any mountain pass in the country with this truck. The F450 is in a class by itself. The 3.73 will probably get 14-16 mpg empty depending on how much lead is in your foot. Great truck looks and comfort!

[Dave Couch]

Hello,
Hey you guys are doing pretty well I have a 2000 Dodge 5.9 I don't know what rear end I have the best I've got is 17.6 and towing is about 10. I was reading about the air dam is that those wind defelectors and is the biggest one the best we just got our Monty it is a 3575 model.

Thanks

Dave Couch

[richfaa]

"The advantage with a turbo diesel is that the diesel does not know it is at 12,000'...as long as it keeps pumping air in that engine, there is very little difference in power betweeen sea level and anywhere else."

Actually they do. Do some homework on that issue. Diesel still needs the proper air/fuel mixture.Diesels that operate at High altitude on a regular bassis are adjusted differently. The power loss is much less that a gas motor..but there is a difference..

[c5racer]

An air dam is the part under the front bumper.