How many miles per gallon?

[hotrodpc]

Took my $100 truck that I rebuilt the T400 in, 84 3/4 ton with the 454 out for its first long ride today. Been poking around town in it. Today I had to go out to my dads about 70 miles east of here and pick up my ATV to bring it home for some repairs. So I took the old truck. Filled up one of the tanks for an mpg test. About halfway back home and 101 miles on the ticker, which seems to be accurate, it took 7.6 gallons to fill it back up. That's 13.29 mpg. I had the cruise set at 75mph all the way there except for a 5 mile construction zone @ 60mph (Speed Limit 55), and on the half way back home, cruise was set @ 70. Traffic was bit thicker for the holiday weekend. Not bad for an old 3/4 HD with a Fo Fitty Fo. Do remember, this truck is the one that has all the heavy duty everything but it has that grandma station wagon rear gear ratio of 3.21, but hey I got the 4.10 spare rear end for it this week.

[hotrodpc]

My 93 E-350 Box Van gets 7-9 mpg. EFI 460, Overdrive Auto and 4.10 Dana 70 rear end. It gets that loaded, unloaded, city or highway, no matter what. I have finally figured something out about this truck. And if you can figure out anything out about this wierd math, then please fill me in. I can drive the truck LOADED heavy moving my duaghter and son in law to Abiliene, TX and got 7 mpg @75 mph. Coming back empty I got 9 mpg @80 mph. Then I drive the truck to Abilene EMPTY to pick up my $100 truck and tow it home, at 75 mph and got 7 mpg. Doesn't make sense right? I got 7 mpg going Abilene, both empty and loaded. So on the way back towing the 3/4 truck I am expecting to get about 5-6mpg. Would you beleive I got 9 mpg towing that truck back @75 mph? Bottom line is, I get 7mpg going to Abilene loaded or empty, and get 9 mpg coming back loaded or empty. I think have a good answer to that, just wondering if anyone else has a suggestion??? Now earth is round, so going south down hill, I should get better than going uphill to the north right???? Whats up with this???

[Crmzendrgone]

I get about 14 city and 17+/- highway depends on how much lead I have in my foot.

[vansdonk]

'69: 8-12; '04: 12-15; '74 MG 28-32 (very lean)

[USAFGM]

Well I got a 2007 GMC Sierra 2500 HD with the 6.0L and the best I have gotten on the highway is 16.3 MPG that's empty and without hauling a trailer. The average is about 12 MPG.

[LAH]

I drive a '98 Chevy K1500. The truck is completely stock, 305 V/8, auto w/OD, and 3.73 gears. Running empty on the big road I do 21-22 MPG if I keep the RPM at 1800 [63MPH]. Around town, empty, not pushing it's 17-18.

[gmctrucks]

Now this last time that I went on a trip on my 1993 F/S 5.7 GMC made 14.9 but I was getting after it now on my trip back pulling a U-Haul I used a whole tank in 240 miles somewhere in that range it sucked up that gas BAD my brothers HD-Diesel was making 17 miles per gallon pulling the same U-Haul and getting on it I also felt the U-Haul he didn't.


I will also add that coming back on the trip I did a lot of stop & go taking off and I was getting after it from each red light pulling that U-Haul which I know ate up that gas big times. I figure that it dropped down to 10 mpg because when I put gas again I did fill it up im just taking a guess. But my baby did ok.

[hotrodpc]

That is about the norm JeemC. Diesels are sleds as far as hp, but they are raw power and torque. Exactly what they are designed for is to pull and get decent mpg while doing so. I bet he also has 4.10's you have probably 3.42's. That in itself will make a differance. You really do not notice gear ratio much on an empty vehicle but you sure do when you are pulling something. My box Van has 4.10's and a Ford 460 gas multi port injected. It does not make alot of hp, but it'll pull a house off its foundation. Although it gets a mere 8mpg average. I can get 11 towing my 84 3/4 ton from Abilene, but I'd only get 7 going there. Wind drag affects the truck bad with the box on it. Same mpg loaded or emply, towing or not, but depending on which direction I am driving is what determines the mpg. As far as torque, you do not notice the wind at all. You do not know it was windy or your were fighting wind until you gas up and realize it drank though 8 straws. 1 for each cylinder.

[gmctrucks]

Hotrod your so right I do have 3.42's gears I was thinking of changing them to 3.73's when I have this buddy put on my Auburn posi-unit but im fine with what I have my truck is too heavy to be racing around maybe once and a while but really it's no race truck even thou I beat a 5.3 truck.

[BernieB]

3.73's would have given you better low end power though, which is just what a heavy truck needs.