3FE MPG in -30 C (1 Viewer)

[JakeVII]

It's been a bit colder lately, so here we go-
What kind of fuel efficiency can I expect in -30 temperatures with a 3FE?
What kind of fuel consumption can I expect while idling?


My last fillup was about 36 L (9 ish gallons) to 68 miles. So...bad. Last fillup before that was about 11 mpg. So, not too bad. I usually get 12-14 mpg in fair weather.

That said, it did a lot of idling in the last few days. Probably not enough to explain the discrepancy.

All that said, shorter trips (10 minute drives) in -30 would probably make the engine run rich until it got hot.


Thoughts?

 

[scottryana]

The engine actually runs extra rich until it warms up. Lots of little short trips and it will not warm up and be efficient. Not to mention you might not be burning off the condensation, etc in your oil. At least try and drive it until it's up to operating temp.

It's been a bit colder lately, so here we go-
What kind of fuel efficiency can I expect in -30 temperatures with a 3FE?
What kind of fuel consumption can I expect while idling?


My last fillup was about 36 L (9 ish gallons) to 68 miles. So...bad. Last fillup before that was about 11 mpg. So, not too bad. I usually get 12-14 mpg in fair weather.

That said, it did a lot of idling in the last few days. Probably not enough to explain the discrepancy.

All that said, shorter trips (10 minute drives) in -30 would probably make the engine run lean until it got hot.


Thoughts?

 

[JakeVII]

Yeah, I think I'll do a long range test this weekend and see what the results are. I'll post back the results for comparison.

 

[SUMMIT CRUISERS]

Your gear box fluids are also a huge drag in very cold weather. Dino gear oils almost turn into a grease/goo like substance when in very cold temps. You might look into changing to synthetic gear oils. I would at least do it in the transfer case and the rear third. The front may be contaminated with moly from the birfields and changing it out may not help. If not contaminated, then change it as well.

 

[JakeVII]

Your gear box fluids are also a huge drag in very cold weather. Dino gear oils almost turn into a grease/goo like substance when in very cold temps. You might look into changing to synthetic gear oils. I would at least do it in the transfer case and the rear third. The front may be contaminated with moly from the birfields and changing it out may not help. If not contaminated, then change it as well.

Turns out I am running all synth from my latest change in the transfer case and rear...

 

[LINUS]

I would be far more concerned with my antifreeze / cooling system than my MPG in -30* weather.

I hope you're factoring wind chill in that number, that's frickin COLD!

You may need to block a portion of the grill if you're in that temp just to get to operating temp, esp if you're doing highway runs.

Just me though.

 

[JakeVII]

I would be far more concerned with my antifreeze / cooling system than my MPG in -30* weather.

I hope you're factoring wind chill in that number, that's frickin COLD!

You may need to block a portion of the grill if you're in that temp just to get to operating temp, esp if you're doing highway runs.

Just me though.

Yeah, I've got a block on the grill. It makes a huge difference on the highway. I didn't last winter- big mistake.

What would most worry you about the coolant at those temps? I try to run a 60% coolant 40% water mix and it seems to work okay when coupled with the block heater.

 

[LS1FJ40]

Winter mix fuel = bad mpg
Short trips/engine not getting to temp = bad
Cold weather causing oils to thicken = bad
Heavy truck that already gets poor mileage = bad

You've got the perfect storm for bad gas mileage. I live in Iowa. I feel your pain. There were times last winter when I was seeing 6-8 mpg in my 1992. I'm seeing 10 so far this winter but I'm driving it longer distances and getting it up to temp every drive. Last winter was a lot of 1-3 mile trips. 50/50 on getting it up to temp.

But they are beasts in snow! And we are going to get dumped on today and tomorrow!

 

[Bigsky80]

When the mercury drops below zero my MPG has dropped as low as 8 around town (for reference I see 11-12 in good weather). However, I do allow my 80 to idle longer so I can sit in a warm truck so I'm sure that is a factor.

 

[Alleycats]

I think I'd be running some 0w 30 in weather like that.

 

[nukegoat]

Quick tip: just drive around in L to maximize rpms

 

[JakeVII]

Yep, it's all worth it to play around with this thing in the snow. It's almost unreal how good this thing is compared to a lot of other trucks.

I predict that during a longer drive tomorrow I'll average about 9-10 mpg.

 

[JakeVII]

Followup:
At -20 C

Short trips, lots of idling, speed below 40 mi/hr:
34 mi travelled, 6 gallons consumed
About 6 mpg.

Highway driving, speed between 50-60 mi/hr:
36 mi travelled, 4 gallons consumed
About 9.
Could be better, but with low temperatures and winter blends...maybe as good as it gets in the conditions.