gas mileage of an 80 in sand dunes: Yikes!

e9999

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did a bit of calc'ing:
over about 100 miles of dunes play - with quite of bit of bogging down going up steep dunes, I averaged out to...




















































5.6 mpg!!!! :eek:

(close to $50... :rolleyes: )



Odd thing, though, is that some of these oldtimers in LRs seemed to manage to cross the Sahara desert with only 4 or 5 jerry cans on the roof. How the heck do they do that?
 

Jim_Chow

 
 
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Yep, diesels, and probably manual trannies, so no slipping torque converter, and more torque at the lower end, so you don't have to gun it often. You can get tremendous range in a LC78 w/ factory 25 gal sub-tank..that's about 50 gal of diesel minus any jerry cans. If you stick to the roads, drive 45-50mph and get 20mpg, that's 1000 miles between fill-ups! Let's face it...in true offroad environments, diesel is the way to go. Even at $3/gal here, if you get 50% better fuel economy over gas w/ the diesel, it's like paying $2/gal for gas. In just about every other country on this planet, diesel costs a fraction of the price of gas. After all, it requires less refining, and you get more gallons of diesel than gas per barrel.
 

cary

 
 
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Based on my experience with motorcycles, I would estimate the mileage to go up significantly on cross desert treks. Once you hit about 35-40mph, the vehicle gets on a plane when going down sand roads and sits on the sand rather than cutting through it. Just like a boat on plane, efficiency goes up a great deal once you are up on the plane.
 

e9999

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I am wondering about mileage in Hi vs Lo. In Hi, which should in principle have better mileage cuz fewer gears involved (I assume) the engine was bogging down in soft sand, but with relatively high rpm for the low speeds achieved. Probably significant slippage at the converter? Whereas in Lo, it seemed like I was doing about the same rpm as in Hi at not much lower speed. Meaning less slippage? So wonder if it would not be better to do it in Lo in soft sand, mileage wise...


and yes, of course, there should be a huge difference between soft dunes and flat "roads" at speed
 

hoser

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cary said:
Once you hit about 35-40mph, the vehicle gets on a plane when going down sand roads and sits on the sand rather than cutting through it. Just like a boat on plane, efficiency goes up a great deal once you are up on the plane.
And since you are at speed, you could also run a slightly higher tire pressure for less resistance?
 
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Jim_Chow said:
Yep, diesels, and probably manual trannies, so no slipping torque converter, and more torque at the lower end, so you don't have to gun it often. You can get tremendous range in a LC78 w/ factory 25 gal sub-tank..that's about 50 gal of diesel minus any jerry cans. If you stick to the roads, drive 45-50mph and get 20mpg, that's 1000 miles between fill-ups! Let's face it...in true offroad environments, diesel is the way to go.

Funny. A lot of truth in this that we like to overlook.

So these things are really overbuilt mall-cruisers (hint of sarcasm).
 
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I'm pretty sure that you always get better mileage, gas or deisel, if you aren't looking to climb every steep face or drive through every loose pocket of sand or mud but instead are only intent on getting across with the least difficulty in as little time as is comfortably acheived.

Deisels do make a difference but not necessarily in such an extreme manner. The difference is only a mile or two per gallon.


Kalawang
 
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