Fuel saver mode, engaged. Well not really, but a man can dream can't he? Fuel efficient F350?

In case you didn't already know, I'm fixing to make a longish trip. 3400 miles worth. I'm making this trip in a 1994 F350 dually with a gas 7.5L chunk of iron under the hood.

I love this truck. It's quiet, smooth, fairly simple, and it drives good. I love the 460. It pulls like a train from 1000 to 4000 rpms. I don't have to listen to it, I don't have to deal with the stink of a diesel. That said, it's a gas hog. This 3400 mile trip is going to burn $1000+ in gas.

So as a mental game I'm thinking engine swaps. No diesels, gas only. It doesn't need to move the world, just a 7000 pound truck with a camper in the back and towing a boat or the Samurai. Call it 10K pounds, maybe 12K.

What's out there that will get 18-20 mpg unloaded, 14-15 loaded, and get the job done without any fuss. No screamers please.

I know this is a pipe dream. I know I should buy a new truck, I know it should be a diesel. Not happening. I am not a fan most diesels. I hate the rattle of the older ones and stinking pumps and the oily mess that they are.

I know it's blasphemy, but LS?

You have a shot at the unloaded goal, but no hope of the loaded goal without a diesel.

Cummings turbo diesel and 8 speed.

In reply to DaveEstey:

Yeah, I know.

I had a van with a 5.4. It would achieve 13-14 empty but loaded sucked badly. I've heard the Ecoboost suffers the same fate.

You know, the price of a new diesel F250 will buy me 16000 gallons of gas.

Back when I was a kid, we camped on our semi-annual drives across the country. Similar distances. We had a 460 with a camper in the bed, too.

My dad realized that it would be a lot cheaper to do the same trip with a decent 4 seat sedan (that we needed anyway) and stay in hotels. Generally, more comfortable, too, as I recall.

Your truck is an auto?

I wish we had a good swap candidate, but nothing like the LS1. A truck version of that would be a pretty easy swap- shoot for similar power, and powertrain match well with the trans, and you will be well set.

ecoboost package from ford? or you could go the salvage route and get a complete ecoboost f150 and swap in the tranny and motor.
package tune will get you 400 rwhp ish and better gas mileage.

not entirely sure you'd get the mileage you want though but it would have to be better than teh 460.

ala http://www.garagejournal.com/forum/showthread.php?t=147380

heck even teh coyote has to be better for fuel mileage.

In reply to alfadriver:

There aren't any hotels where I like to stay.

The Ecoboost is still a long way from ever being a swap candidate, isn't it? What are the chances of anyone ever cracking the ECU reliably?

My 91 F350 with a 7.3L IDI would get 17-18 mpg unloaded, probably close to what you listed towing, but I didn't tow with it much. A 94 7.3 IDI turbo would be an easy swap (no ecm to deal with) in your truck. Yes it is a diesel but would be closest to your goal.

Ford sells an ECU package and a motor for swaps. http://www.roadandtrack.com/car-culture/buying-maintenance/news/a24602/ford-racing-really-wants-you-to-mod-ecoboost-engines/

EDIT: google foo says only the four cylinder is sold as a crate at this time from ford racing.

From what I understand the ECU is not locked. Not sure what you mean.

Toyman01 wrote: So as a mental game I'm thinking engine swaps. No diesels, gas only. It doesn't need to move the world, just a 7000 pound truck with a camper in the back and towing a boat or the Samurai. Call it 10K pounds, maybe 12K. What's out there that will get 18-20 mpg unloaded, 14-15 loaded, and get the job done without any fuss. No screamers please.

Here's an out-there idea. Forget large displacement, what you want is a smaller engine that needs to run at or near WOT just to cruise. Then cruise at stoich and run EGR or water injection to cut down on knock. Water's a lot cheaper than fuel.

Or you could figure that the 460 is probably built and tuned to be detonation-free even with a complete moron behind the wheel, towing an overloaded trailer up a mountain in the high desert in August. You're not going to be punishing it that badly and you have mechanical sympathy. Try cetane enhancer for Diesel engines. Think of it as a combustion accelerant and a kind of anti-octane booster thing. Some people have good success with it, I noted a MPG gain in my low-compression piston engine but the gain in economy almost exactly offset the $9/two tanks that the cetane enhancer cost. Your situation will be different, maybe to the worse but maybe to the better. Won't know until you try. What's $9 for an experiment in the face of possibly saving a few percent of a $1000+ fuel bill?

Wikipedia says that your 7.5L powerhouse made 245 hp and 395 lb-ft of torque the day Ford made it; I assume it makes a bit less now (no offense meant.) Since the torque numbers in the FRPP catalog for 351-based 427 ci competition engines range from 520 to 545 lb-ft, I bet you could come close to the numbers you need with a more ordinary truck-type 351. Less displacement = less gas, right? (I believe the 2.7L twin turbo Ecoboost puts up comparable numbers too.)

Getting those numbers in an old 1 ton truck is going to be very difficult without a diesel.

Megasquirt the 460 and see how lean and advanced it will go?

Or suck it up and buy a used diesel.

I drive Diesel Ford F350 CC (6.4?) 200 miles into the desert and for work about once a month. It never stinks and the sound is as un-noticeable as its gas counterparts. It's stock and maintained by the USAF. It gets great milage in my opinion. In that 400 mile round trip it still has lots of fuel left in the tank.

I wish I could afford to buy it. Cloth seats and fits 5 adults comfortably while carrying whatever you want in the bed or behind it. I'd rather drive it over my 1.6 eco-boost fusion on family trips. But, I'm a poor ass, I have 3 old Mercedes and a Starion, and I'm trying to wiggle my way into a cpo 911 in 2016 or 2017.

Lean doesn't always mean less fuel. Interesting lesson I learned with fuel economy tuning a bridge ported rotary. It might just mean lean. The trick is to tune for whatever makes the engine happy, meaning lowest injector duty cycle for a given speed. At some points this meant 12.5:1 on highway cruise for THIS engine in THAT car under THOSE conditions. Play with what you got. Your mileage, as they say, may vary

But hell, the sucker did 29mpg once and did 24mpg average on a 975 mile trip, when it was new. That's like spectacular for what it is.

Nowadays I run leaner than that, because I am lazy and I will trade off a few MPG for not having to change the oil so often. I was diluting 5 quarts of oil with an additional quart of gasoline in under 1000mi running that rich all the time.

Read this: http://performanceunlimited.com/projectmpg/

I did most of the tricks involved except the gear vendors overdrive (I have a E40D transmission) and the bigger throttle body.

I also added a full Banks Powerpack system to my 1990 460EFI because it includes the K&N filter, headers and I ditched the cat and smog pump.

It gets a bit better mileage now, 15-ish mpg empty and 12-ish pulling a trailer.

If I have my slide-in camper, I get 10 as long as I keep it under 100kmh.

It will do 120 all day long with the camper on but you can watch the fuel gauge move. With a horse trailer 120 all day is no issue.

I takes fuel to do a job, I've learned to not watch my fuel mileage and just put gas in the tank.

Up here in Canada, diesel is more expensive than gas and I can buy a hell of a lot of gas for the price of a new truck.

Would a GearVendors OD unit stacked on the back of the trans help at all?

In reply to Stealthtercel:

Where is the torque peak on that 2.7L?

I bet it's nowhere close to 2000rpm like it is on a 460.

HappyAndy wrote: Would a GearVendors OD unit stacked on the back of the trans help at all?

THAT will entirely depend on the engine and existing gearing. Lower RPM doesn't automatically equal better fuel economy. The vehicle will always need a certain amount of power to be propelled at a given speed, and gearing for economy is a matter of matching that to the engine's BSFC map. You can gear tall enough that economy drops.

Another anecdote: I bought a Subaru from someone who said it always got him 24mpg. When I drove it, I never used 5th gear since 5th gear was too damn tall, and I got 27mpg.

Just like leaner sometimes just means leaner, less RPM sometimes just means less RPM.

If you got 18-20 instead of 9-10 you will still burn up $500+ worth of gas so it is really only costing you $500+ extra. Just enjoy your ride and pay the extra $45 per day.

All I know is that with about 75% of max towing capacity on my F350 I get 6mpg with the 5.4.

3400 Miles at say 7 mpg with 3.35$ cheap gas 1627$ Ouch. Still cheaper then a swap.

Came here to post project mpg. Got beat.

You're not gonna pull that kinda MPG in a truck that heavy and have any power to tow with a gasser. Physics doesn't work that way. The Ecoboost struggles to pull its rated numbers in its home application, let alone a truck much much heavier. Also having driven a few, they're not that impressive power wise if you're used to a big block.

On the RPM thing. Best fuel mileage will happen by keeping the engine running at the RPM it is most efficient.

I know it's a motorcycle but on a recent 1000km trip with my Stelvio 1200, chugging along at 2000-ish rpm on the tach nets me 5.9L per 100km. If I keep my cruising rpm at 4000, the mileage jumps to 5.2L per 100km.

Streamline it like you're heading to Bonneville.