Altitude Killing MPG
 

I have a 2000 TDI Beetle with 240K miles. I get on average 43-46 mpg. I drive 115 miles to work one way, 230 round trip. I live in Southeastern Utah and work in Southwestern Utah.

Anyways, I start out at 4700ft and over 45 miles work my way up to 7100 feet and then back down to 6800ft as my final destination...and then the reverse when I go home.

I keep my tires inflated to 40 psi and check them regularly, keep the speed below 65mph, but I still cannot crack 50mpg, as some others are with these TDI's. It is a beetle and does have some bad aerodynamics, I am thinking about an "Ernie" Wing.....but would this altitude and the multitude of hills decrease my mpg that much? Roads are quite rough in some spots as well.

Any help is appreciated.

AT or MT? If you're slipping your torque converter and downshifting on the hills, that will clobber your average mpg.

Try two days commuting while holding your top speed to 55 mph. That alone should get you up to 50 mpg for a tank.

230 miles at 55mph = 4+ hours a day every day.

Sucks huh, gotta have a job though.....

It is a MT with Redline Synthetic, engine has Mobil 1 TDT.

I am just thinking that the constant hills up and down are killing the gas mileage. Along with the lack of air???

Thanks

The Moab area is beautiful, and there's not much other traffic on the highways. Since the OP drives at 65 mph already, he's only adding 20 minutes to his drive time each way, looking at at the gorgeous scenery.

Air the tires to maximum sidewall pressure, typically 44 or 51 psi. That'll help a bit.

To answer your original question, I usually get better mpg in high altitude hilly conditions. I got 59 mpg for 165 miles from Gallup to Tuba City, and 51.5 mpg for 1213 miles from Gallup to the Bay Area. Last Summer I had 3 tanks >50 mpg driving around in SE Utah.

Welcome to ecomodder.

Is that a Beetle with a manual transmission ?


As most manufacturers, VW have some lightweight manual gearbox oil - lighter than what they previously used anyway.
If your car is due for a gearbox oil change, ask the dealer for it (and ask about its suitability) if they're not already putting that oil in it.

The lightest weight engine oil that's allowed for in the environment you run the car, will also give a small gain.

The manufacturers have put some research into this, use it to your advantage ;)


On the Volvo, I've swapped the gearbox oil for a compatible lighter weight oil after 90,000 miles and the difference can definitely be felt - smoother shifting and MPG are better than they used to be.

Wow, that's one serious commute !

Don't use cruise control on the way up or down.
Up
With these kind of elevation differences you're probably seeing some good length climbs ?
If driving with load (DWL / target driving) would probably see you slow down considerably, use a steady throttle.
(see the hypermiling tips at 100+ Hypermiling / ecodriving tips & tactics for better mpg - EcoModder.com , it's a good way down the page.)

Shed some speed when you can quickly regain it after the crest.


Do you have a fuel economy display in the car ?
You could experiment a bit using different speeds on the climb to see what suits the car best.
On steep hills, it's worth experimenting with different gears as well.


Down.
If the hills are not too steep you could put it in neutral and coast downhill.
My car will maintain 60-65 mph on 5 to 6 % gradients, in neutral ;)
(Extreme hypermilers will even shut down the engine - but you'd loose power-steering and more importantly, the power assisted brakes.)

If the hills are steeper so you need braking, let go of the throttle while in gear and use the engine for braking - if you don't already.
If it still picks up too much speed, brake (by foot) and change down.
In gear but without giving it any throttle, it won't consume any fuel.

Pick up extra speed on the downhill - as much as allowed or what you feel comfy with - if it's followed right away by a climb.

Are you using any of these techniques ?

Or you could find some inspiration here :
http://ecomodder.com/forum/showthrea...k-17012-3.html

Kamm-backs have been found to improve mpg on a range of vehicles.
Dieselbeetle's one-off improvement is too much for the modification he made, but you should still see some notable gain - especially as the Beetle isn't too aerodynamic at the rear.


The altitude also means thinner air, and less air resistance.
Diesels work on an excess of air, and I've never had any troubles with power or mpg while going thru and over the Alps in a diesel.
(A3 TDi, beating 50 mpg even without any effort at serious hypermiling).
You lose some MPG uphill, but can recover a fair bit downhill.

That's not helping either I'm afraid, but there's little to be done about it.

It's not the altitude. I would expect you would get better mileage with a manual, as I get mid-40s mpg with my automatic Beetle in Denver. Maybe your thermostat is worn, when my coolant was down at 160F I struggled to get 40mpg, that's 10% worse mileage.

Yeah, it's not the altitude.

I have noticed a difference in mileage at different altitudes in my Gas hybrid.

I live and do most of my driving around 5000 ft above sealevel.

On a recent trip to Nevada, I noticed the mileage increased 10-15%. Only change was lower altitude.

This may depend on how the car map changes by altitude.

Short of adding a turbocharger or a supercharger, there is only so much that can be done to improve efficency at higher altitudes.