Jump to content

first small road trip. terrible MPG

ct_corey

Recommended Posts

SMJ24 Enthusiast

SMJ24

Posted
Posted

Every Sunday my son plays in an indoor lacrosse league, it is a 39 mile one way trip with approx. 35 being highway. Last Sunday I was early so I set the cruise control to the posted speed limit of 55 and 60 mph and maxed out at 24.1 mpg for the trip. This week I drove it like normal, still using cruise control but set at 70-75 mph and maxed out at 19.1 mpg.

  • Replies 40
  • Created
  • Last Reply
thewhitestallion Senior Enthusiast

thewhitestallion

Posted
Posted

Well there are a lot of variables that come into play. Could be the gas, could be the terrain, could be the drag from your lift, could be your speed. In all honesty in my opinion it is all of those factors.

 

When I am on a road trip, if I go over 70mph then I know not to expect great gas mileage out of the truck. Sometimes the truck surprises me but between the wind resistance, terrain and higher rpms your chances of good mileage drops tremendously!

diyer2 Senior Enthusiast

diyer2

Posted
Posted

Cruise works well on flat roads, not so well on hilly terrain. On flat it will not down shift as much trying to keep up to speed.

Krusty Enthusiast

Krusty

Posted
Posted

In my Duramax 2500HD 4x4 CC Standard box I saw 19 mpg avg overall on empty hwy trips hand calc driveway to driveway. A perfect trip at 65 mph and 1,600 RPM peak torque would net 20-21 mpg.

 

But these V-4 switching engines ain't no Duramax - I know that going in - and don't expect the same outcome.

 

:chevy:

Heavy 5.7 Enthusiast

Heavy 5.7

Posted
Posted

Every Sunday my son plays in an indoor lacrosse league, it is a 39 mile one way trip with approx. 35 being highway. Last Sunday I was early so I set the cruise control to the posted speed limit of 55 and 60 mph and maxed out at 24.1 mpg for the trip. This week I drove it like normal, still using cruise control but set at 70-75 mph and maxed out at 19.1 mpg.

If it's "normal" for you to drive 10-15 mph over the posted speed limit you may want to invest in a watch or day planner. lol.

Brian S. Enthusiast

Brian S.

Posted
Posted

Nothing is "killing" the "fuel economy", that's just the way it is.

 

I did a year with the 4.3l Ecotech and got 17.4 mpg on a 3.42 geared 4wd dbl cab.

 

I've done over two years with two different 5.3l Ecotech 3.42 geared 4wd dbl cabs and got 16mpg overall.

 

The only time I've noticed you can get 20mpg (or more with the 4.3l) is cruise on 60mph.

 

I think these "Yes! I'm getting 20mpg with my half ton pickup truck (any brand) are basically lies or people posting about trips on flat road at 60mph with cruise on.

 

It's also intuitive that levelling trucks would lower mpg, they have big, flat fronts that would drag more with pitch adjusted to perpendicular to the road. It's no mystery why every sports and racing car on the planet has a pointy front end and sits low to the ground.

tnchevy Senior Enthusiast

tnchevy

Posted
Posted

The OP is driving near 80 mph and has a 1.5 inch level ( and probably more aggressive tires to go with it) in a V8 truck and is complaining about fuel mileage in the mid teens???? Drop your truck back to the factory level, quite driving well over the speed limit, and if you have bigger/more aggressive tires then put the factory size and style on it and you will get around 20 mpg.

Z45 Senior Enthusiast

Z45

Posted
Posted

Once you get over 65 mph the mileage is going to go down, more wind resistance. On a recent trip I drove 300 miles on 2 lane blacktop at 60-65 mph and I was getting 23.4 mpg. The next 280 miles were on x.way and I was doing 70-75 and mileage dropped to 22.1.

ct_corey Enthusiast

ct_corey

Posted
  • Author
Posted

The OP is driving near 80 mph and has a 1.5 inch level ( and probably more aggressive tires to go with it) in a V8 truck and is complaining about fuel mileage in the mid teens???? Drop your truck back to the factory level, quite driving well over the speed limit, and if you have bigger/more aggressive tires then put the factory size and style on it and you will get around 20 mpg.

Stock tires. If they were larger I would have mentioned that but thanks :nopity:

truckguy82 Senior Enthusiast

truckguy82

Posted
Posted

I drove 330miles back and forth a couple times a year, I set the cruise control on almost exactly 75mph on 65mph highways. I average 21-22mpg there and back like clockwork. Stock '14 6.2

Havvkeye Enthusiast

Havvkeye

Posted
Posted

If it's "normal" for you to drive 10-15 mph over the posted speed limit you may want to invest in a watch or day planner. lol.

 

Why? Are you assuming people only speed when they are late for something? That is pretty ignorant.

FreeAmerican Enthusiast

FreeAmerican

Posted
Posted

Wind resistance is exponential. Winter gas sucks too, as well as it takes longer in the winter for your truck to reach operating temps. Also have you checked your tire pressure. Cold weather impacts that too and can cost you some mpg as well.

 

Add a level and you have your answer.

 

I do notice I get better power (butt dyno) and def better mpg running higher octane gas and I turn the grade braking off.

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,842
    Total Members
    8,960
    Most Online
    CaptainDad
    Newest Member
    CaptainDad
    Joined

  • Who's Online   5 Members, 0 Anonymous, 487 Guests (See full list)

  • Latest Articles

  • Posts

    • asilverblazer
      Slate Electric Truck

      By asilverblazer · Posted

      I like the idea.  I would pick diesel if I had a choice. I need pictures though.
    • newdude
      Help purchasing a touch screen digitizer

      By newdude · Posted

      I've installed cheap eBay new aftermarket digitizers before.  They work.  Did a bunch of Cadillac CUE (aka Cadillac's MyLink) for someone years ago.  They all worked fine after the repair.    That number 22740886, that is a component part # for GM.  You can use it to search, but its not something that's obtainable at the dealer level.     So pretty much any of these will work - 2015 Colorado Digitizer for sale | eBay
    • asilverblazer
      give me some tips to make my truck look better

      By asilverblazer · Posted

      Black bumper and the later years Z-71 style color matched grille.
    • fondupot
      Exhaust heat while towing!

      By fondupot · Posted

      You can install tailpipes that direct the exhaust sideways vs the OEM one that goes straight back. There are several on the market, do you own research. HOWEVER, you need to make sure the Venturi vents are still intact, otherwise it will throw a engine code. There is a sensor somewhere that detects back pressure on the exhaust. And if it doesn't collect the correct metrics, it will throw the truck into limp mode. 
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      "Teardown" is complete. Head surfaces are clean and ready, new intake is prepped and ready. Coolant drained and water pump is removed, radiator is removed, new hoses and pump are ready.   The replacement intake is also from a '95 (with I think 260k, the odometer said). Noticeably less pitting where it covers the rear coolant passages. I'm not sure if that's a tribute to more frequent use, more frequent coolant changes/upkeep, or if the intake was machined at some point. But it appears I found a good one.   My coolant hoses were original, and the lower hose still retained the factory spring inside. It's not really rusty, but it's got deposits all over it. Unsure if I should re-install it (will thoroughly clean it first). Someone said hose technology has gotten better since 1995 (has it?) and I don't need the spring. I think modern EPDM is what made those hoses last from 1995-2026, so it's a question of how much suction can the water pump really pull, and will it collapse the hose without a spring?   I'm stopped and waiting for parts, however.   When I first brought the truck home, the fan was intermittently hitting the radiator shroud. I could see someone had monkeyed with the shroud (put a bunch of cardboard as a spacer between the upper/lower shroud halves. Someone said the motor mounts have likely failed and the engine has sagged. I wasn't sure I believed that. The engine is really solid in its mounts: To remove the old intake I *just* nearly permanently welded to the heads with freshly cured RTV and gasket snot two weeks ago, I literally had to use the arms on my lift and a chain with a bolt attached to the intake to pull it loose. It almost picked the front of the truck off the ground before ....scuuuuuuuuuuup.... I could actually hear the gaskets tearing and it broke loose and the whole truck settled back down. Motor barely moved.   SO, those parts I'm waiting on... The lower radiator mounts/bushings had completely failed. The radiator needs to be insulated from the rad support, and the bushings help the rad stand at the correct height. The plastic "baffle" was also destroyed at some point. Someone had attached the shroud to it incorrectly, overlapping a joint that should have been underlapped, creating another suspect issue potentially causing things to hit the fan. Broken tabs, side is busted off, and it's perma-formed/bent where it was jimmied incorrectly.   The baffle? Unobtainum. Long since discontinued from GM, of course. Aftermarket/capa/chinese? Also unobtanium. In GM's infinite wisdom, it appears there are at least two different variations whether the Blazer is 2 or 4 door, and I can't yet tell if they shared the same part with the S-pickups. Plan B, if I can't find a viable used one, will be to create a bracket to re-assemble the critical joint I need to seal a gap with the shroud. But that will bug me, it won't be...perfect.   The water pump bolts appear to have been installed with...plumber's putty. I guess, sure, if it works...? I've found a few "backyard fixes" like that. Someone's been here before....   If I can't find someone to jam bamboo under my fingernails to fill my free time this week I think I'll install the driver's power window motor and replace the rear door speaker that's inop. I've got a genuine GM "9.5" ohm working replacement. Why GM used a non-standard resistance....nevermind. Of course they did, you can get more sound from a cheap factory amp that way.   And the saga goes on...

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...