Gas Mileage Towing Boat

[TBONE1904]

I have a 1986 GMC crew cab dually Q-jet 454 w/Turbo 400. I am only getting 8-9 MPG. It doesnt matter weather I am towing or just driving. I have done a tune up (spark plugs and wires), changed air filter, and it still gets the same mileage. Does anyone have any ideas that have worked to get better gas mileage?

[PHX ATC]

Pray for a tailwind. Go downhill alot. Turn off the engine when you can.
Seriously though, I think you're about stuck. Those big blocks will suck the fuel and if it's the same year as your truck, they didn't make them all that fuel efficient back then. 8 to 9 isn't really all that bad, all things considered...big truck, 6 tires rubbing on the pavement, etc.

[disco_charger]

4L80E, you need the extra gear. I had a 87 Burb with the 454. I put a 4L80E and went from 8mpg to 13mpg. However the 4L80E splattered itself after about 20K :burningm: It wasn't cheap either.

[fourspeednup]

You need overdrive. Swapping in a well built 700-R4 isn't too tough (pre-4L80E but basically the same). It's been done a lot so there would only be a min amount of fab work...do a little research and I'll bet you could find a kit of some sort :)
May want to go through the carb if it hasn't been done. Fixing an internal leak or two may get you a little more out of a gallon.
BTW--a Qjet has huge secondaries, try and stay out of them as best you can...I could pull 16-17mpg out of my 72 caddy that way ;)

[djunkie]

Get a Gear Vendor Overdrive. Not a cheap alternative but they are a lot stronger than buying a 700R4 or a 4L80. Should get you a couple more MPG. But I wouldn't plan on getting anything too great with those old 454's.

[sorry dog]

I had a 96 2500 454 truck for work a while back.
Pretty much got 11 unloading combined driving and 8 towing bobcats around. Sounds like you are doing OK.
It was one of the few GM products that I liked, but the $500 month gas bills caught the bean counter's attention...and that was with $1.25 gas.

[tahitijet]

i used to only get 7 towing with my last 98 chevy truck.. so I think your about par..
someone brought up tranny swaps so i'll throw out a shameless plug here but we have been manufacturing our own transmission cross members and conversion cross members for almost a year now. The most popular conversion we offer is a bolt on 4l80e swap into newer body style chevy trucks that had the 4l60E stock. This kit is fully bolt on and In conjunction with a friends shop this kit can be purchased as individual componets or the full deal complete with tranny, driveline, cross members,wire harness, and othe misc. parts. We can also build a cross member wtih just about any combination you could need to make a tranny swap a direct bolt in or for extra clearance on lowered trucks.
<<end shameless plug>> :)

[LAFD]

Dont Feel To Bad I Have A 03 Dodge Ram With The Hemi And Average I Get About 10 To 11 And On Freeways I Got Upto 16 17. Horrible. Trading In For Diesal.

[djunkie]

Dont Feel To Bad I Have A 03 Dodge Ram With The Hemi And Average I Get About 10 To 11 And On Freeways I Got Upto 16 17. Horrible. Trading In For Diesal.
Is that 16-17 when you are towing on the freeway? If so that sounds pretty good. I have and 05' duramax and I get between 16.5 and 18 when not towing on the highway. Granted itdoes only have 2500 miles on it so it should get better. But with the diesel you will have the power.

[H2OT PURSUIT]

Get a Gear Vendor Overdrive. Not a cheap alternative but they are a lot stronger than buying a 700R4 or a 4L80. Should get you a couple more MPG. But I wouldn't plan on getting anything too great with those old 454's.
Considering the price of a gear vendor overdrive it shouldn't take you more than 12 or 13 years to break even. Then you'll start saving money on fuel.

[LAFD]

Is that 16-17 when you are towing on the freeway? If so that sounds pretty good. I have and 05' duramax and I get between 16.5 and 18 when not towing on the highway. Granted itdoes only have 2500 miles on it so it should get better. But with the diesel you will have the power.
YEAH ITS BEEN UPTO 16 17 BUT THAT WAS ON MOSTLY LEVEL PORTION OF THE FREEWAY AT ABOUT 65.

[Trash]

Some things to consider as have been mentioned.
The Gear Vendors OD aren't cheap. It would take a long time to recoupe that money based soley on the difference in mileage.
My 351 Bronco gets 10 mpg towing. In fact, most small blocks (350 cid range) get about that towing an go up to 15-17 on the highway NOT towing. Most big blocks (i.e. 454 etc.) get about 9-10 mpg towing and might go to 12-13 mpg highway NOT towing. The big advantage is the big block is working a lot less than the same small block towing and will probably last longer under the same towing conditions.
Even a transmission change to one with an OD isn't cheap. Figure out how long it would take to cover the cost of the tranny change based on the change in gas mileage only. My guess is that it would again take a long time to recoupe those costs.

[CrazyHippy]

1st and foremost SLOW DOWN!!!!
I can go from 19mpg @ 60-65 to 12mpg @80-85
And under 10 @ 90mph.
BJH

[djunkie]

1st and foremost SLOW DOWN!!!!
I can go from 19mpg @ 60-65 to 12mpg @80-85
And under 10 @ 90mph.
BJH
So your that guy always doing 60 mph on the 10 east. The speed limit is 70. :D

[HammerDown]

Dont Feel To Bad I Have A 03 Dodge Ram With The Hemi And Average I Get About 10 To 11 And On Freeways I Got Upto 16 17. Horrible. Trading In For Diesal.
Trading for a Diesel huh...then you have to figure in the 5k or so option for the engine...and higher than gas fuel prices. This added cost will take some time to make up, if ever.
Something to think about.

[TBONE1904]

I stay at 65 mph and that still only gets me 8-9. I have to get in it to get up the hills, but on the flats I just set the cruise control and talk to all the drunks in the truck!! I think everyone one is right the payback is 20 years for the tranny or a gearvendors overdrive. next question whats the deal with the new chevy diesel will it get me some gas mileage towing? I have heard mixed things to be honest. My father has a 2000 crew cad dually with the 454 and O/D and he only gets a little better than 10. he is thinking of getting the new diesel with allison tranny, it is suppose to have ungodly power and good gas mileage.

[HammerDown]

My father has a 2000 crew cad dually with the 454 and O/D and he only gets a little better than 10. he is thinking of getting the new diesel with allison tranny, it is suppose to have ungodly power and good gas mileage.
Uh diesels don't get "gas mileage"... :rolleyes: :D Always cracks me up when I read this.

[CrazyHippy]

So your that guy always doing 60 mph on the 10 east. The speed limit is 70. :D
Towing it's still only 55 :rolleyes:
BJH :p

[Blownboat]

Your milage sounds great,coming back from havasu in the rain in december with a 98 454 I got 5 1/2 mpg... I think you just have to pay if you wanna play! ;)

[Norseman]

I have a 1986 GMC crew cab dually Q-jet 454 w/Turbo 400. I am only getting 8-9 MPG. It doesnt matter weather I am towing or just driving. I have done a tune up (spark plugs and wires), changed air filter, and it still gets the same mileage. Does anyone have any ideas that have worked to get better gas mileage?
Put a Gear Vendors overdrive unit under it. That's what I plan to do with my 86 Ford 460 powered Dually, if it doesn't get a diesel conversion first.
The Ford gets between 6 and 8mpg, and yea it doesn't matter if it's empty or pulling 15,000 lbs. The mileage stays pretty much the same.
Bob

[Lightning]

Assuming that you don't REALLY need a dually, the best thing you can probably do is go buy a new truck - with fuel injection and two less tires.