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Discussion Starter #1
I took my LT on a 300 mile run on Sunday (weather was finally decent). I was very concerned with my gas mileage. The OBC showed 34.2 mpg. After fill-up, I got only 150 miles until my fuel light came on (usually means around 25 miles to empty, right?).

Anyhow, I found myself running in 4th gear quite a bit (instead of 5th) at speeds around 60-75 mph. In the colder weather, I run with the stock windshield about half-way up.

The LT is stiil pretty new to me and I have been used to a 6 speed trannie. I ran around 4000 rpm at the 60-75 mph range and I'm thinking that it cost me the gas mileage that most report is more normally in the 40's.

What do you think?
 

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On my '05 LT, and also on my '99 LT that I used to have (55k), I found that cruising at 4 - 5K in 4th gear would often give me as good or even better mpg than running in 5th. Besides riding style, which has the greatest effect, the things I find that will also effect mpg the most are:

1. position of windshield (the lower the better the mpg)
2. position of the lower wind deflectors (flatter the better)
3. outside temperature (cold weather = less mpg)

Of these 3, the position of windshield seems to effect my mpg's the most.

The LT motor has a sweet spot in the 4k-5k range where it runs very efficiently and therefore gives the best mpg's.
 

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You are correct Mike as mine often runs the same...

When I am in the twisties in 3rd - 4th gear and in the R's I often get less MPG than when on the Fwy in 5th @ 55-70 mpg... There I often average 46-53 mpg.

When returning with the bike last March from coastal Oregon to Spokane WA in cold weather traveling **Way Above the posted speed limit I was showing on the BC " 34 " miles per gallon !!!!

Average for me is 46 - 48 on either regular or premium....

I ride for the most fun, not the gas mileage but thankful it is better than my old Hardley - Dangerous 2 cylinder...
 

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04 and older...

My '04 has that infamous buzz/rattle/grrrrrrrrr right about 4,000-4,200 rpm, so I'm not sure I'd WANT to ride in that RPM range...

Waiting for David Shealey to pipe in (miss ya, buddy, where have you been?) on this, but doesn't logic suggest that if you're in a higher gearing and ratio that allows you to ignite the gas and air mixture in your cylinders 2,500 times a minute at a velocity of say 60 mph, that you'll get better mileage than a lower one that requires 4,000 times per minute? (the reason c-5 and c-6 'vettes with their very tall 6th gear can pull 26 to sometimes 30 MPG at highway cruising speed, even with ridiculously powerful 400 HP v-8 engines)?

I'm currently playing around with the switch I put in between the "brown wire" since Tejas weather is currently below 80 degrees to see if "wire interruptus and higher grade gasoline" equals better mpg than "wire connected and mid grade gasoline"

P
 

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Discussion Starter #5
usmctpdog said:
You are correct Mike as mine often runs the same...

When I am in the twisties in 3rd - 4th gear and in the R's I often get less MPG than when on the Fwy in 5th @ 55-70 mpg... There I often average 46-53 mpg.

When returning with the bike last March from coastal Oregon to Spokane WA in cold weather traveling **Way Above the posted speed limit I was showing on the BC " 34 " miles per gallon !!!!

Average for me is 46 - 48 on either regular or premium....

I ride for the most fun, not the gas mileage but thankful it is better than my old Hardley - Dangerous 2 cylinder...
Hmmmmm,

Strange, when my low fuel light went on at 150 miles, I fuelled up (5.25 gallons) which indicated to me that I had about another 30-40 miles left in cruising range.

My reason for questioning the mpg is not because of anal-retentiveness with gas mileage, just that I'd hoped to have at least a 200 mile range per tankful on a big tourer. Hell, I was thinking I would get a 250 cruising range.

One other issue is that since changing to the full Remus exhaust (without re-mapping the fuel injection or installing the "chip") the bike seems to be running rather rich. Lots of sooty residue on the exhaust pipe tip . I know some sootiness is typical, but this seems more excessive than normal.
Near the end of my 300 mile ride I was experiencing some "sputtering" at lower RPMs indicating some fouling of the plugs.

Guess I will just have to see.... as they say.
 

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I took my LT on a 92 mile lunch run today and am happy to report that I did not fall over. :D Anyway, I played with the windshield position at an indicated 90 mph. It was like throwing a drag chute out as it moved higher. That has to have a major effect on mpg.
 

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Wow! I am amazed. I know it is anecdotal but my 99 gets consistantly 50 mpg. After decades of logging flight time I do the same with my motorcycles (neat to read during the snow and ice months) and can support these claims with thousands of miles. I love the FD gear ratio of the 99! I commonly fuel-up reading over 200 miles on the trip meter. The fuel low light comes on at about 225 miles. I use the BC for ambient air temperature. :bmw:
 

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<What do you think?>

Makes sense to me.

If you are using the center stand for gasing-up, you are not getting the tank full.

The BC will computer how many more miles left (I never trust it to go with in a few miles of getting gas).

Bob
 

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petevandyke said:
----------------------------------
Waiting for David Shealey to pipe in (miss ya, buddy, where have you been?) on this, but doesn't logic suggest that if you're in a higher gearing and ratio that allows you to ignite the gas and air mixture in your cylinders 2,500 times a minute at a velocity of say 60 mph, that you'll get better mileage than a lower one that requires 4,000 times per minute? (the reason c-5 and c-6 'vettes with their very tall 6th gear can pull 26 to sometimes 30 MPG at highway cruising speed, even with ridiculously powerful 400 HP v-8 engines)?-------------------------------------
Been right here, most every day.

Actually, fuel usage is not all that related to RPM, but instead POWER usage. In any given set of circumstances the bike needs a given amount of power at any one time. It is all thermodynamics, BTU in the fuel converted to Power output. If in a lower gear where the cylinders are firing more often you have the throttle more closed than if in a higher gear, thus burning less fuel each crank rotation. Basically, for any given power output you use nearly the same amount of fuel no matter which gear you are in. However, the engine's efficiency changes over the RPM range, so one would have to develop efficiency curves based on the torque/HP curves along with a fuel usage curve imposed on them. Then at any given instant you could see which would be the best gear to be in. As long as kept within the flatter part of the HP curves though, the gear selected has only minor affect on fuel usage.
 

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Now if you really want to have fun and give birth to a whole new line of forum chat, install a manifold pressure gauge and start comparing mpg with that. M.P. is a more accurate indicator of power being used thus mpg.
 

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Go read about pumping loss of gasoline engines. Unlike a diesel engine, the trouble with a spark ignition engine is that the throttle is so simple - yet so inefficient.

Relying on a manifold pressure gage will have us all driving around in 4th gear, wondering where the fuel economy went.
 

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Simple, really....

In town and around the burbs its just a 4 speed....

When you clear the last light and can stay at 60 mph or higher shift to 5th.... Otherwise its a 4 speed..............Pete
 

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Once above 30mph its 5th gear for me and leave it alone. Rarely get less than 50 mpg and mid 50s is more normal. Why would you ride along in 4th gear??? Mines a 03 model-does the later model use more fuel? I've just come back from a 3 week course in London doing a weekly commute and it was 152 miles door to door. I managed the return trip with about 20 miles still showing on the BC.
 

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BlackBMW said:
....One other issue is that since changing to the full Remus exhaust (without re-mapping the fuel injection or installing the "chip") the bike seems to be running rather rich. Lots of sooty residue on the exhaust pipe tip....
Mike, having "examined" my tailpipe for soot numerous times on both my LT and GT, I would say the bikes tend to run lean. Now, I can't say that with absolute certainty because I have never hooked an exhaust analyzer to my bikes. I think your soot, combined with low mileage is a good indicator, however. I would start by checking that fuel mixture.
 

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Hey guys, when speaking about rpms and sweet spots etc. keep in mind the BMW changed the overall gearing ratio to higher from ´05 models. (Meaning that engine revs about 400-500 rpm higher at 120 km/h, for instance)

Now I don't remember the exact gearing figures but somebody on the forum surely does.

When I was riding a pre-05 model I noticed a clear difference on how the bike behaved and run on the 5th gear. It was more like an overdrive (and more pleasant on the higways) than the current one. This must have some affect on the mileage as well.

Regards
 

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Gas mileage

your gas mileage will vary based on the following factors:
1. Year of your LT- ( i.e. gearing)
2. Octane of gas used
3. Altitude
4. Weight of your foot at any given moment
5. wind direction and speed
6. gear in use
7. speed driven
8. setting on the Motronic
9. geography of where you are riding
10. condition of engine and tuneup
11. air filter
12. condition of tires and air pressures

As you can see there are so many variables that everyone's average will vary but generally speaking you should get somewhere between 38-50 mpg. Remember that the "computer average" is usually not as good as calculating it manuallly by miles driven divided by gallons used. Ron Ray
 

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My experience has shown that the cold has the greatest effect on fuel mileage. Thin, hot air returns the best range. I typically get 48 mpg in the summer and 38-42 in the winter. This does not vary significantly with load or speed (mostly east coast speeds not the western open space speed).

I don't baby the throttle and I never run in any gear at less than 3,000. I read here that someone shifts to fifth at 35-40 mph. Wht would you do that? The bike would respond like a pig.
 

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Thin air

Were do you go in VA to get thin air? Mt Elliot Knob? :)
My gps reads 3100-5000+ on local roads....
I sure the choke has a lot to do with my lower (38-45) mpg for winter driving.
little jake
 
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