I have been reading a lot of info on modifications to do to improve MPG's.
Would it be unrealistic to hit 25MPG on my truck?
6.9 4x4
I can not say what I get right now as I still have not been able to put this truck to the test yet, still at the shop. But I hear the average MPG for a 6.9 is 16-18?

So far I have:

1. Banks turbo which i hear increases about 2MPG in your truck.
I keep reading something about adjusting the PSI? How would I be able to do this, can you share your turbo settings and why you have them the way you do? What about EGT?
Increase: 2MPG.

2. Gear Vendors. I hear this only really helps for long trips. Cruise 70MPH at 2000 RPM.

Increase: 2-4MPG ( i have read that some guys got 6MPG increase but ill assume they got lucky or lying)

What im looking to add...

3. Fastback bed fairing.
Increase: 1.5 MPG

4. Flat Tonneau: Chances are I wont use this, I do furniture delivery half the time, so it would get in the way. UNLESS some of you know IF and where I can buy one that say... Rolls in and out. Maybe made out of vinyl and permanently attached to the front end of the bed? (not the tailgate end obviously). Maybe this roll out has tiny hooks every foot until its hooked to the back? Any suggestions would be appreciate it. I can not put a hard top/permanent one.
Increase: 1.5MPG

5. Air Dam? I have a grill guard i dont know If i could get this mod. But maybe someone here knows a good Air Dam for an 86 F Series.
Increase: ? I would assume at least 1MPG.

6. OEM-size tires (Original Equipment Manufacturer). I don't know what tires I currently have, but i know they are new. I will have to look up what size the Originals were and see if i have the right currently installed.

7. I have stick shift, which I read adds about 2 MPG. Should have added this at the top but too far down to edit.

8. Belly Pan? This would help with aero dynamics but dont know how it would look on the truck, and if its leaking oil, it will be a mess in no time. I will see what can be done about this. Probably spend hour after hour researching this.

Dont want to add wheel well skirts, that would just start to look funky.

Is 25MPG on a 6.9 Diesel possible?

 

On a 4x4 truck I doubt you will ever get 25mpg unless you drove it like a grandma would. If it was 2wd, it would be more doable. 4x4 makes it heavier, and higher up in the wind. Another problem you are going to have is the fuel. In the old days if you were careful, you could possibly get 20mpg. With the new fuel, 16mpg would be very good for your truck.

 

Especially so with a diesel, I'm gonns say unlikely. I know Cummins diesels putting out 13 mpg empty. These trucks are not boosted up. I also know a cummins thats been dynoed several times and have over 1000 ft pnds torque at the the rear wheels, and like 500-600 hp.

 

I have to agree with Franklin. With the fuel they used to sell in the 80's it's more feasable.

With todays fuel especially with gasoline, (I know we are talking diesel), the ethanol they add, the type of crude they use, and the fact that the fuel can be stagnent when you pump it at the station, are all factors that hurt fuel mileage.

 

With 2wd, two doors and steep gears (2.75 or numerically lower..) with preferably a manual transmission you should be able to put down 25mpg on the highway. A turbo and custom built non crappy exhaust manifolds would also help. Throw in an electric radiator fan too. Forget about the gear vendors, if it's a project then throw in a ZF5; it will be cheaper; lighter and better.

If you want to spend a lot of money then throw in an Isuzu 4BD1T or Cummins 4bt.

 

Electric radiator fan? Ill look into it as Ive never heard of it (yeah new to auto mechanics in general). My truck already came with a gear vendors so I won't be spending extra money on it. The ZF5 is something I want to get. just need to see the prices and so on. Kinda broke after these mechanic fee's. I think ill pass on the Cummins and Isuzu.

Thanks again.

 

Where is it all at now?

 

How much have i spent you mean?
$1400 for Truck.
$100 fuel.
$400 Towing
$1500 Mechanics
$325 ARP studs and victor reinz gasket
Total: 3725.00 YIKES i had no idea, i thought i was at $3200....

 

No, I meant are you back on the road again (head gaskets, oil in water etc)?

 

Oh, no its still at mechanics, they said it will take about 10 days... you know mechanics...
Im going to call them tomorrow and ask how much to fix oil cooler. I want to get the parts myself though, at a local autozone, do you know what i should ask for? Oil Cooler Repair kit? Still havent enjoyed it =( but im dying to drive that sucker. Been in my room researching, seeing what I can add to it (mobile fridge, dvd/gps/cd unit) Im not too worried about getting it back. If it was ready today i would not have the money to get it =D.

How much can i expect to pay for the oil cooler repair? Dont want to get ripped off.

 

Oil cooler repair is a real hassle. So I am figuring it's going to be expensive. It's hard to get to, and you have to take the engine loose and jack one side up on most trucks to get it out. Mine was leaking at the cooler to engine connection, so I took the cooler loose and cleaned it up and replaced the gaskets without taking it completely out. That was the messiest job I have ever done on a vehicle, oil and antifreeze dripping everywhere including on me.

 

Would it matter if the mechanics already have the heads off since im currently doing a head gasket repair? Or will the truck still need to jack one side up to get to it?

 

Dont buy parts and bring them to your mechanic to have them put them on. That is like going into a diner and handing them eggs, bacon and bread and telling them to cook it for you

As for 25MPG, not going to happen, you should be thrilled giddy to get 20mpg

 

Not exactly. I saved about $225 by providing my own parts and they had no problem giving me a quote for the labor only. Had they seemed bothered by it I would have either paid the extra $225 or shop around for labor only. The comparison is a bit exaggerated as I know people have taken their specific/custom parts in to mechanics, but never known a single person to provide their ingredients to a restaurant.

Maybe 25MPG wont happen and I believe that but I want a high number to try and hit. If I fall short 5 miles i'd still be happy.

 

Youve got to figure and run a CBA on the savings of a diesel. Getting 20mpgs at 3.80 a gallon (diesel) is 190. Roughly equivalent to getting 16 mpgs in a gasser.