Slant Six Forum
https://slantsix.org/forum/

What kind of gas mileage should I expect?
https://slantsix.org/forum/viewtopic.php?t=14233		 Page 1 of 2
Author:  CStryker [ Thu Sep 01, 2005 5:39 pm ]
Post subject:  What kind of gas mileage should I expect?
Ok, my dad and I are having a little debate here... I've got an 82 dodge ram w/ a 225 slant six, 727, and 3.21 gears in an 8 1/4 rear. It has the factory e-beam welded single barrel intake and a hunk-a-junk rebuilt 1945 from Advance Auto (never again, will I buy one... long story). Anyway, I've seen several people here claiming to get 20ish mpg in their cars, but I'm only getting 13-15 on the highway. Is my truck simply that much heavier, or is the crappy carb killing my gas mileage as well as my performance?
Author:  Dennis Weaver [ Thu Sep 01, 2005 5:45 pm ]
Post subject: 
That'a about what I'd expect for that truck. It's the fact that it's a truck and your rear-end ratio killing your mileage, but if it had anything higher, it would be a real turd power-wise.

D/W
Author:  Craig [ Thu Sep 01, 2005 6:41 pm ]
Post subject: 
My 1987 D150 ran 15-16-17 on the highway. Once a tank ran 18.2 on a long over the road trip. This was with 3.21 axle gears and P235-75R15 tires (factory installed tire size on this 6050 GVWR truck).

I changed to 3.55 gears a couple years ago but don't know what it does now for gasoline mileage. I've been running it on propane during winter and it is parked during the summer while I'm driving my air-conditioned 1979 D150 with V8.
Author:  SlantSixDan [ Thu Sep 01, 2005 7:39 pm ]
Post subject: 
I feel your pain, brother. I just filled up my '89 D100 (long bed, 318 with factory throttle body injection, donno rear axle ratio).

86 litres of regular at $1.139/litre (that's $3.61 in US dollars per US gallon).

430 kilometres travelled.

That's 269 miles and 23 US gallons, for a wallet-screaming mileage of 11.7 .

Ow. Image
Author:  62savoywagon [ Thu Sep 01, 2005 9:09 pm ]
Post subject: 
Jeeze, my old '70 W200 Crewcab got 15 average. 383 2bbl and 6000 pounds.

Still miss that beast!
Author:  Slant6Ram [ Fri Sep 02, 2005 8:55 am ]
Post subject:  Yep, mileage stinks
Mine is an '85 d-150 with super six, lean burn removed in favor of standard electronic, 727 auto, 2.94 rear, and 235-70r15 tires.

I believe the block/head are 1971 model, with solid lifters, and I'm pretty sure the compression is weak. Bet it needs rings and valve seats. (Guy who did the pollution test last year said it was really bad and that the valve seats was easily the big cause) Lots of miles on this pig.

I just drove to Harrisburg and back yesterday and I think I got around 13 mpg over the 370 mile trip. All highway travel and loaded with 2 slant six motors in the bed comming home.
Quote:
Is my truck simply that much heavier, or is the crappy carb killing my gas mileage as well as my performance?
I'm getting very afraid of gas prices, since even a well tuned and rebuilt slant six won't get much better than 18 mpg pushing that heavy brick of a truck. I keep hearing that the 727 kills mileage as well. Worst of all, a brand new full size truck barely does any better. So, yes, heavy, non-aerodynamic, RELIABLE truck = poor gas mileage.

Crappy carb might not be helping, but a new carb won't be any magic bullet that gets you into the 20 mpg range. A lighter foot is the best medicine at the moment. When I super sixed from a worn out holley 1920, I saw almost no change in mileage, but a slight improvement in power.

On the plus side, I can start charging more for 'weekend moving' nobody is willing to loan out their trucks any more because they are so expensive to operate and NOBODY around here is keeping their old work trucks going any more.

I recently saw a whole truck on ebay for $75!!! In 5 years, all these trucks will be in the crusher for the price of their weight. If you like yours, hang on to it because this is why they'll become valuable classics 10 years from now.
Author:  CStryker [ Fri Sep 02, 2005 1:37 pm ]
Post subject: 
"valuable classic" may be an overstatement...

These are some of my favorite pictures:
Image

Image

Image

Image

The splatter paint (no, that's not bird poop) and dents on the bed were "features" when I bought it, but the "body work" (pulling the radiator support out w/ a come along so the new fender would fit) was a result of me learning that my braking system needed to be overhauled. I replaced the doors because one window frame was cracked in half from an accident the PO had, and the other had a huge dent/crease in the lower skin, and into the bottom sill.
Author:  Dennis Weaver [ Fri Sep 02, 2005 1:48 pm ]
Post subject: 
Cool truck.

D/W
Author:  emsvitil [ Fri Sep 02, 2005 1:51 pm ]
Post subject: 
Quote:
............. but the "body work" (pulling the radiator support out w/ a come along so the new fender would fit) ...........

And I thought you were trying to pull the tree over onto the truck for the insurance money...................

:wink:
Author:  CrAlt [ Tue Sep 06, 2005 2:26 pm ]
Post subject: 
Cool truck!

I always have my eye out for a /6 4sp OD shortbed truck. I love my 91 318/727 D150 but it SUCKS down gas..10mpg.

Once you get the truck going i would look out for a 4speed OD setup. The 727 is good truck trany but its heavy. Ive been told it take 30hp to run. I know when i swapped the weak 904 out of my D150 and put the 727 in milage and seat of the pants power went down.
Author:  Slant6Ram [ Wed Sep 07, 2005 6:09 am ]
Post subject:  Classic!
Quote:
"valuable classic" may be an overstatement...
:) :D :lol:

Mine is not picture perfect either, but as long as the frame isn't rotten, all that other stuff bolts on and off. I love my truck! Sure, I'd like better mileage, but have you seen the price of a comperable new truck :shock: :shock:

Luckily my old dodge will last until I can afford a new one. Might be a really long time. :wink:
Author:  slantvaliant [ Wed Sep 07, 2005 6:31 am ]
Post subject: 
Wow! Your truck is so mean, you have to keep it chained to a tree?
"Beware of Ram!"
Author:  SlantSixDan [ Sun Sep 11, 2005 8:29 pm ]
Post subject: 
Check them tire pressures, folks! I sometimes get lazy and forget to check. Found all four of mine down to 30psi. Pumped them all up to 38 and drove carefully, and just filled up again tonight. Much better average this time, of 13.4 mpg. Still rotten, but 15% better than before.
Author:  emsvitil [ Sun Sep 11, 2005 9:59 pm ]
Post subject: 
Quote:
Check them tire pressures, folks! I sometimes get lazy and forget to check. Found all four of mine down to 30psi. Pumped them all up to 38 and drove carefully, and just filled up again tonight. Much better average this time, of 13.4 mpg. Still rotten, but 15% better than before.

Hope you're talking about truck tires and truck mileage... :shock:
Author:  SlantSixDan [ Mon Sep 12, 2005 8:03 am ]
Post subject: 
Yep, still talking about my '89 D100 pickup with TBI 5.2 and (as it turns out) 2.76 rear axle.
Page 1 of 2 All times are UTC-08:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/