40 + mpg out of a mid size truck?

[JRMichler]

I think I could get my Canyon to 40 MPG (summer only) if I did the following:

Air dam
Belly pan
Wheel covers
Alternator delete
Possibly 3:42 rear end ratio
Possibly wheel well skirt mods

BTW, I run all season tires year around. Nokian WR's at 52 PSI.

[EcoCactus]

The 1984 Toyota Diesel Pickup 2wd got 44hwy and 4wd got 36hwy. These are hard to find today though. No 2014 trucks get more than 28 mpg. But by 2025 there light trucks must get 36.5 mpg average.

[aerohead]

Originally Posted by JRMichler

I think I could get my Canyon to 40 MPG (summer only) if I did the following:

Air dam
Belly pan
Wheel covers
Alternator delete
Possibly 3:42 rear end ratio
Possibly wheel well skirt mods

BTW, I run all season tires year around. Nokian WR's at 52 PSI.

Could you tell us your:
* target speed ?
* rpm in top gear now at that speed ?
* does GM use full-synthetics all around ?
--------------------------------------------------------------------------
Your '06 probably has a better BSFC than my '94 T-100.I've hit 39-mpg once,at 55-mph,mostly downhill from Cloudcroft,NM,to Artesia,NM,only a 85-mile run.
I have a fairly complete aero kit,including 30" of boat tail at the time.In 2012 I was seeing up to 37 mpg at 65 mph.
I kinda think the Canyon might hit 40,but you'd really have to do extreme aero mods.Weight doesn't seem to be an issue on the highway.And I'm running Hankooks at 38-psi,so your 52 psi tires ought to give you a little R-R edge.
It would be a really interesting project but you'd be looking at a few thousand man-hours of your time.You'd have to be as nuts as me!

[JRMichler]

My target speed is 54-55 MPH. The nearest 65 MPH speed limit is about 80 miles from where I mostly drive. A typical 70-75 mile trip has about 55 miles with 55 MPH limit, with the rest at speed limits 25 to 45 MPH, and four miles of narrow twisty gravel road. My average mileage on such a trip is about 5% better than MPG at a steady 55 MPH. My kill switch gets a lot of use.

My tires are 2% oversize, so current gearing is 1800 RPM at 55 MPH with a 3.73 rear end ratio. Most summer highway driving is at 6 to 9 PSI MAP, which is why I think a taller rear axle ratio would help.

I've never looked up the lubricant specs. Engine oil is whatever the 10 minute oil change place puts in.

The factory air dam is well above the low points. Underneath is a collection of huge holes, with the transmission cross member a couple inches lower than anything else.

And agree on the BSFC. When I do frontal area / Cd / rolling resistance calculations, I need to use less than 0.40 lbs/hp/hr to get calculated MPG to match real world MPG.

I doubt I'll ever do it all, but I'm sure thinking about it!

[aerohead]

Originally Posted by JRMichler

My target speed is 54-55 MPH. The nearest 65 MPH speed limit is about 80 miles from where I mostly drive. A typical 70-75 mile trip has about 55 miles with 55 MPH limit, with the rest at speed limits 25 to 45 MPH, and four miles of narrow twisty gravel road. My average mileage on such a trip is about 5% better than MPG at a steady 55 MPH. My kill switch gets a lot of use.

My tires are 2% oversize, so current gearing is 1800 RPM at 55 MPH with a 3.73 rear end ratio. Most summer highway driving is at 6 to 9 PSI MAP, which is why I think a taller rear axle ratio would help.

I've never looked up the lubricant specs. Engine oil is whatever the 10 minute oil change place puts in.

The factory air dam is well above the low points. Underneath is a collection of huge holes, with the transmission cross member a couple inches lower than anything else.

And agree on the BSFC. When I do frontal area / Cd / rolling resistance calculations, I need to use less than 0.40 lbs/hp/hr to get calculated MPG to match real world MPG.

I doubt I'll ever do it all, but I'm sure thinking about it!

I tried to run some numbers for the Canyon,but the lower speed mix complicates things.Taking a simple average of your winter/summer mpg increase we're looking at a 35% mpg gain.
If this were all done a steady 55-mph,we'd have to see a 70% drag reduction to explain it.
If the Canyon started at Cd 0.40,then you'd be at about Cd 0.12 according to the formulas.
If you're seeing north of 37 already in the summer,40 seems doable.
The T-100 responded really well to the nose and airdam.With the current tires,no headlight covers,none of the bellypan,and no boat tail,I'm seeing 29.6 mpg @ up to 75 mph,turning 2850 rpm.
At a maximum 70 mph,she's 30.4 mpg.She turns 2,000 rpm @ 55 mph.A sixth gear would be nice.Taller gears would probably help the Canyon as well,just as you've mentioned.The lower airdam I'm certain would help.
Some cardboard and duct tape mods might show some results as it did on the Dodge truck and CRX,and other member projects.With the OBD-II electronics it wouldn't take you long to see any changes.

[JRMichler]

My rolling resistance goes way up in winter. Because of that, aero improvements won't do a lot to improve winter mileage. I have not tried to track down where the cold weather rolling resistance is coming from. Something about crawling around underneath in below zero temperatures is just not appealing to me.

In summer, my MPG drops about 20% from 55 to 65 MPH. I've never run at 65 long enough to get good numbers.

I do have a spare front bumper that I could use to build a conveyor belt air dam. I'm trying to decide if I should go down as far as the front cross member and A-arms, or as far as the transmission cross member.

[user removed]

Originally Posted by EcoCactus

The 1984 Toyota Diesel Pickup 2wd got 44hwy and 4wd got 36hwy. These are hard to find today though. No 2014 trucks get more than 28 mpg. But by 2025 there light trucks must get 36.5 mpg average.

US EPA (old version) is 30 city and 30 highway for the highest rated 84 Toyota diesel pickup. New EPA is lower. To get 44 MPG in that truck you would need to be going 30 MPH in top gear with no traffic obstructions.

Compare Old and New MPG Estimates

regards
Mech

[aerohead]

Originally Posted by Old Mechanic

US EPA (old version) is 30 city and 30 highway for the highest rated 84 Toyota diesel pickup. New EPA is lower. To get 44 MPG in that truck you would need to be going 30 MPH in top gear with no traffic obstructions.

Compare Old and New MPG Estimates

regards
Mech

This sounds right.In 1986,while helping build a college chum's home near Colorado Springs,we spent a lot of time in his Toyota Diesel p'up.At the old double-nickel speed limit,at altitude,I believe we never saw north of 33-mpg,And we were trying hard.He's driving a Prius today.

[kozaz]

I did not read the entire thread, but if you decide on a mini-truck, look for a old Dodge Rampage, it's front wheel drive and you could swap in a VW Turbo-Diesel. And of course, do all the other eco-mods you can. Only down fall I could see beside carrying/towing capacity, is it has no rear end so your re-gearing options are very limited (trans swap would be your only option, besides taller tires).