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Armymedic
Posted on Friday, July 02, 2010 - 05:27 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Just got back from at 2000 miler on the Uly, out to California and back to Utah. I got only a measley 35 mpg on the way there. Once elevation was close to sea level then it went up to mid to upper 40s, sometimes up to 50 mpg. How much does elevation have to do with mileage? I was equally ham fisted going both ways. I loved the power of the Uly at sea level! Quite the difference. Suggestions or ideas?
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Froggy
Posted on Friday, July 02, 2010 - 05:38 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Altitude is a huge factor in fuel economy and power. I can easily get 75mpg (no hypermiling) above 5k'
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Armymedic
Posted on Friday, July 02, 2010 - 05:44 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Maybe I can get your ECM maps?!
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Froggy
Posted on Friday, July 02, 2010 - 05:50 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

They won't work with your bike (different intake and exhaust and ECM), and I am under agreement with the person that made the map not to share as he spent a lot of time perfecting it.

But yea, my stock 1125CR got 54mpg with a little hypermiling at high altitude. My Blast can get 85mpg at sea level, I might be able to break the 100 barrier in the mountains : )
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Royintulsa
Posted on Friday, July 02, 2010 - 08:23 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Typically fuel consumption is lower in internal combustion engines at lower altitudes due to high manifold pressure.

I fly for the Coast Guard and when we patrol at 500' AGL we get much better fuel burn than at higher altitudes.

Also, aviation speed races the planes that fly at the lower altitudes fly faster, with more power and longer endurance.
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Itileman
Posted on Friday, July 02, 2010 - 11:36 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I'm in the 50 + mpg's at higher elevations.
Getting 45 at 3k ft and over 50 at near 5k. Have hit the 60's when over 7k.
2009 XT
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Whisperstealth
Posted on Saturday, July 03, 2010 - 02:28 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

What is hypermiling???
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Froggy
Posted on Saturday, July 03, 2010 - 10:32 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Hypermiling is the term for attempting to achieve fuel economy thats is much greater than the EPA ratings via different driving techniques and modifications to the vehicle. For example, I can get almost 40mpg in a V6 Chevy Monte Carlo, and 100mpg in a Toyota Prius. I know people that get over 100mpg on a Ninja 250, 76mpg in a 96 Civic, and a 108mpg 1978 Mercedes diesel.
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Royintulsa
Posted on Saturday, July 03, 2010 - 01:59 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

From the Department of Energy doe.gov

Vehicles tuned up to operate at or close to sea level are less fuel efficient when they get to a higher elevation and vice versa due to difference in air density.

There are a lot of factors, including octane of the fuel burned, O2 sensor, lack of empirical data and difference in traffic patterns.

More air = more power. Humidity, increased temperatures and increased elevation rob you of power.
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Itileman
Posted on Saturday, July 03, 2010 - 06:44 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

That really doesn't explain why I get 50-60 mpg at 5k ft and above with no loss in power.
Stock 09 XT.
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Royintulsa
Posted on Saturday, July 03, 2010 - 08:36 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

In order to accurately measure fuel mileage, it takes 5 tanks. Throw out the high and the low and average the remaining 3, that is your true mileage. When you are at elevation do you go through 5 tanks?
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Mark_weiss
Posted on Saturday, July 03, 2010 - 10:17 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

My '08 gets notably better mileage at higher altitudes. My summer trips usually consist of "stay above 5k ft" as the goal. Riding between 6k and 9k feet, I'm usually in the middle to upper 50s. Tank after tank, it is a reproducible result.

As for "no loss in power", that's chemically impossible.

Mark
SE AZ
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Tootal
Posted on Saturday, July 03, 2010 - 10:34 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

There is less air to burn at elevation therefore less power. That's why Colorado police prefer turbocharged vehicles. I found that over 10,000 ft. the power of my bike suffered a lot. If I wasn't at 3000 rpm or higher it was a dog! I had to fan the clutch like a two stroke to get it to climb up a jeep trail. I have since lowered the gearing which will help but trust me, higher elevation means less power. As far as a vehicle tuned at sea level will get worse mileage at elevation, well that might be true in 1960! Modern fuel injection will learn and adjust to get better mileage. Even CV carbs will use less fuel at elevation due to less vacuum to raise the slide.
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Royintulsa
Posted on Sunday, July 04, 2010 - 11:37 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Hmm, I wonder why all horsepower tests, torque tests and quarter mile speeds are adjusted to standard elevation (sea level) and temperature (59 degrees).

Could it be because that is where the best performance is found? No, that would make too much sense.

Your comparisons are like comparing the fuel economy running up Pikes Peak to the fuel economy coasting down.

The only reason you may be getting more fuel mileage is because of lower temperatures at altitude, less humidity and a lot more coasting.

These engines make marvelous torque to get you up the hill more efficiently than other engines with more horsepower.

Speaking of climbing Pikes Peak, Buell took second and fourth in the annual hill climb. The new Multistrada took first and third.
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Froggy
Posted on Sunday, July 04, 2010 - 11:52 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)


quote:

As for "no loss in power", that's chemically impossible.




Agreed. Just because you aren't using it doesn't mean it is still there. Throw it on a dyno or take it to a drag strip and you will see the difference. I notice that it is much harder to do wheelies at higher elevations. There is a video of me doing a wheelie on my Uly a few years back, you can see the front end going up and down a bit as it was harder for me to modulate vs doing it the same way at sea level would have me on my ass.
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Bikelit
Posted on Monday, July 05, 2010 - 12:26 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I remember elevation power loss for a normally aspirated engine is 3% per 1000'
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Catalan42
Posted on Tuesday, July 06, 2010 - 02:46 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I live in San Diego, and it's nearly impossible for me to get less than 40 mpg (& I have a lead foot). I can sometimes get close to 50 mpg if I ride 55 on the freeway for 150+ miles, but that's boring. I just went on a vacation in the Sierras and I would say the power loss at 8000 feet MSL is at least 25% on the seat-o-meter.
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