WOW! Full size diesel truck, gets HOW much mpg???
 

My neighbor has a full size GMC pickup truck, with the extra door for passengers. He said it is the type that has a chip, and he got a special chip where he can change the horsepower the truck puts out. I think he said he can put in 70 HP, 90, 110, or 135 HP.

He has it set at 110 HP, and he has a special muffler for the truck too, that might help some.

Mind you, I talked to someone with a similar size gasoline truck just yesterday, who gets 7 mpg when towing a backhoe, and 10 when not towing, and maybe 12 on a good day on the hwy.

My neighbor's diesel truck gets....

are you ready for this........

24 mpg on the highway!!

That's amazing!!

He said when it was stock, he got about 17 mpg.

Could you imagine what my 1991 300d would give, if there were a way to tweak it? (though there's probably not much HP to play with on a car). If he can get that on a full size truck, and my stock MB gives 36 hwy, I'd probably get 55 mpg.

I guess it's not impossible
 

However, I was just wondering if your neighbor deals in any real horse manure

My dads V8 300+ horsepower 2003 chevy silverado gets 24 mpg highway. Premium or midgrade gas, taking good care of the truck, synthetic oil with a clean filter goes a long way it seems. Its stock everything too. Its in mint condition too :D

24mpg sounds kinda high, my friend with a large Cummins truck (1998 Ram 2500)... mind you its the PPump, so its all mechanical, but he told me he is getting 17 on the highway. I thought it would get better then that. My dads 88 F350, that weighs 8500Lbs (full tool box and huge bumper) gets 14 on the highway, and hes got a Banks Turboed N/A 7.3L.

I'd have to see it to believe it, but I don't seriously doubt him.
I'd think bumping the HP would downgrade the MPG's but who knows...

I do something similar with my 300SD. I just turn the ALDA screw CCW half a turn when I go into "power mode" which hauls very nicely, specially in mountainous terrain, getting around 20-22 MPG, and turn it back to normal half a turn CW for "econo-mode" getting about 25-30 MPG. I love these old diesel Benzes :)

I have a 2001.5 Dodge 24 valve, 6 spd. 3500 Dually with the Cummins. I can get over 20 MPG. But, I have to be real light on the pedal with 900 ft. lbs. of torque on tap (several mods). Over 65 and it really drops because of the aerodynamics and tires (dually).

That is actually pretty believable. I have some friends that drive the D'max in different varieties. That is not an average. But he probably might get a tank or 2 with those MPG's. I have seen it. Not bad for a truck weighing in at over 7,000 lbs. Over time his average will drop if he is tracking every tank and "averaging all of them".

I have a 2000 24 valve with 410 gears & a 5sp. Average since I've owned the truck has been 16. I get more in 5th gear with < 10# of boost. A chip and injectors would help perhaps 3 mpg. It takes a long time to make up the cost at the price of the hardware but that doesn't count the fun factor or an extra 100 hp. Truck is to haul, SD is comfort, Datsun Z is for fun. Really all are for fun.

My 2000 Dodge Ram 2500 --- MPG
 

I have the extended cab, L O N G bed version (it's over 8 foot long) and I can get about 24 MPG

IF

I drive it on the interstate
I keep the speed under 68mph
No towing.

I get about 18.5MPG just driving back and forth to work everyday; I would classify my drive as light, small city type driving; about 12 traffic lights and 40mph most of the time.

I towed a broken 123 home from east of Seattle when I first got my Dodge/Cummens, she got 23 MPG on the 240 mile round trip, The PO, a friend of mine went with me, I had to admit "not too shabby". Those engines are only 160 HP but he needed more plus duels for the camper he had :D

Its legit, he gets 24 alot of the time. I don't know how but he does get 23-24 mpg lol.:cool: We drove like 220 miles and he used less than half a tank of a 20 gal. tank.

And holy crap 900 ft. torque? Good luck keeping tires on it! :P

I have a 2006 Duramax (lly) with the Bully dog chip and i can get 22 out of the truck on the highway with the chip turned to the second highest level and unloaded.... 24 is a little bit of a stretch i am thinking but i have seen 25 from time to time if i am really light on the throttle and going mostly down hill but as soon as you get to a traffic light you are right down to 18-19. Idle time kills the millage.... Can watch it right on the economy/flow meter gauge.

My stock 95 CTD gets 17 on local Vermont driving, rarely out of 4th gear and I have not run a full tank on the highway to figure that yet.

I have been commuting 10 miles each way to work and I have been getting a whopping 14.55mpg on B20 but that's because it's stop and go on hilly backroads lugging 6000lbs around.

Gas engine? I call BS!

If he is honest he does not know how to calculate it or has a problem with his odometer.