Stelvio NTX Fuel Gage and MPG Info

[biking sailor]

I have had my 2013 Stelvio NTX for 2 weeks and now have 1000 miles on it.  Had the breakin service done at 600 miles.  Bike runs pretty good but has a little surging around the 4K RPM.  My question is concerning the fuel gage and MPG that other owners are seeing.

Gage, looks like I am loosing approx one bar (of the six total) for each gallon of gas burnt.  This is based on how far I've ridden and when the bars go out.  The last bar goes away and I fill up with around 6.5 gallons.  The low fuel light comes on when about 6 gallons are used.  What are you guys seeing?  About the same?

Fuel milage, the dash says my average MPG is 42 to 44 and when I fill up and figure it, I have been getting 36 to 38.  I didn't expect it to show perfect, but that is quite a big difference.  The 1200 Sport average MPG on the dash was usually not as high as I was getting figuring it at fill ups.  If it showed 42 MPG, I would find 44 at fill ups.  Again, what are other owners seeing?

Disclaimer: I deal with statistics in my profession and that fits my personality very well.  Not complaining about the bike at all, so far I am very happy with it.  Just wanting to compare what I am seeing with other owners that have the same statistical OCD.   ;D

Thanks, Darren

[Kev m]

I have a bit of statistical OCD myself and I notice these sorts of posts on EVERY vehicle forum that I frequent that HAS an on-board trip computer.

I posit that the problem ISN'T THE COMPUTERS.

I suspect the computers are better at determining how much fuel is being used at any given moment and collectively over a tankful than WE ARE at determining just how well we've refilled the tank.

Problems can include:

1. How level the bike/car was when filling
2. Ambient temperature when filling
3. How well calibrated the pumps are (I believe we had a board member here who used to work for a state bureau of weights and measures chime in on this once)
4. How exact we matched the fuel level from the last time (see #1 and #2, as well as those intangibles - how far up the filler neck the fuel goes or doesn't).

Now the computers aren't perfect either, I suspect there's a small amount of uncalculated loss from EVAP system operation too, but I hardly think that outweighs factors 1-4.

I know that I see fluctuations too sometimes on my vehicles that have trip computers (that I always compare by manually calculating trip meter reading/gallons at fillup) but as hard as I try to be consistent with my fillup, I recognize those factors are likely the largest part of any discrepancy.

I chalk to rest up to a zen-like acceptance of my own OCD.  :BEER: :D

[kirb]

My dash vs. actual is high on the dash by about 5mpg. The low fuel light comes on with about 2 gal left. I have gone 60 miles past the light with no issues at all. I think the most I have put in the tank was 7.5 gallons. I would go as far as 80 miles before I started to worry.

Human error isn't going to be off by that much with the calc. Fill the tank on the side stand all the time and you MIGHT be off by .1 gallons or ~1mpg. Most fuel pumps (in my state) are tested twice a year and have to be pretty damn close to pass muster.

I usually get in the mid 40's all the time, low 50's if I am on two lane back roads all day under 65mph.

[ChuckH]

My '12 NTX has 12K miles on it.  Initially, when my fuel gauge went to the Yellow Light I would fill with just about 6 Ga, so I had about 2.5 Ga in Reserve.  More recently I'm seeing the gauge go to the Yellow Light a bit earlier, when I have only used about 5 Ga.  

As far as fuel mileage, I average in the 40-42 MPG range on the road.  That's measuring miles run divided by the fuel used.  I never look at the dash reading, have no interest in it.

Hope this helps.

[Kev m]

My dash vs. actual is high on the dash by about 5mpg.

<snip>

Human error isn't going to be off by that much with the calc. Fill the tank on the side stand all the time and you MIGHT be off by .1 gallons or ~1mpg. Most fuel pumps (in my state) are tested twice a year and have to be pretty damn close to pass muster.

Well, I might be more skeptical if I regularly got that big a fluctuation on my calculations - but from the Breva to the Mini, a couple of Jeeps, Juke, Impreza etc all the trip computers I've used have regularly been within 1 to sometimes 2 mpgs. It's VERY rare that they go outside that variance for me. But I am pretty darn retentive about filling routines (and even stations that I use).

YMMV of course

[biking sailor]

But I am pretty darn retentive about filling routines (and even stations that I use).

YMMV of course

Yep, that's me!   ;D

Have kept track of each tank as well as recording milage and gallons since new (only guessing the dealer delivered it full but know it was close).  Last filled up at 980 miles and have put 26.8 gallons, according to odometer and gas pumps.  Works out to 36.6 mpg. 

Must throw this out, the difference between a Salesman and an Egineering?  The Salesman works to the left of the decimal point and the Engineer works to the right.   ;)  I had to force myself not to carry the mpg figure out to 4 decimal places!

Darren

[Kev m]

Darren, I take it that you, like me, are resetting the dash indicator at each fillup (is it the same as the Breva, resets when you reset the tripmeter?).

[biking sailor]

Darren, I take it that you, like me, are resetting the dash indicator at each fillup (is it the same as the Breva, resets when you reset the tripmeter?).

Yes, similar data available.  It has two trips, 1 and 2, with each trips stats (riding time, mpg, avg speed, top speed...) except the Breva had the trip milage constantly displayed and you could see it at the same time as the avg or current mpg.  The Stelvio dash will only show trip miles or others one at a time.

Darren 

[spmoto]

No disrespect KevM but I'm experiencing the same discrepancies with my NTX. Odd, because my '09 which I traded for the NTX had no such issue. My reserve light comes on at around 225 miles and all bars are gone at  around 240 mi. At this point I can get just over 6 gal. in the tank. Each tank full I have been pushing it a bit further and yesterday went 70 mi. on "reserve" and still only got 7.2 gal. at fill up. BTW I reset trip 1 after each fill-up. MPG is also consistently off by about 6-8 mpg. This is not such an issue for me but I sure would like a better idea how much fuel is actually in the tank due to varying riding conditions, loads, etc.
Steve M

[biking sailor]

Thanks for the data point, Steve M. Sounds like our bikes are very similar.

Darren

[Zoom Zoom]

Would it be safe to assume that since you are self professed OCD on this that you are using a GPS for your actual miles run, divided by the gallons at the pump?

I ask because my '09 Stelvio is pessimistic in the odometer department. About 3.5 miles per tank. (My per tank includes the aux tank from Stucchi, giving me 8 to play with.) Having said that, my actual mileage is slightly better than the dash indicates.

Next, with only 1000 miles on the bike, you are not even close to having it broken in. You should still be under a recommended rev limit until you hit 2500 miles. Then you can flog it more, but you still are nowhere near having it fully worn in. I mention this because early on, as things seat and wear in, the engine balance will change more rapidly, and valve lash will change more rapidly. Valves are pretty easy to adjust. TB balance and TPS reset requires some additional equipment.

Several trips the last few months have netted me 41 mpg + or -. This past weekend, I did all the things I mention above. The bike runs better than it did prior to readjusting things. Therefore, it would be safe to expect a slight increase in mpg's. How do I know it is running better you ask? Well, the valves needed adjusted. The TB's were a little out of balance. Resetting the TPS is part of that process. Next, I can reach down and put my hand on my aux lights. (Mine are on their own mount on the front of the engine.) Anyway, the vibration I could feel in the body of the aux lights have diminished drastically. That tells me the engine is running smoother and therefore more efficiently. 

In summary, with your engine so new, I don't think your numbers are far out of line. I would also expect you to see an improvement as miles rack up on the bike.

John Henry 

[LowRyter]

Congrats on the new bike, Darren

[biking sailor]

"Would it be safe to assume that since you are self professed OCD on this that you are using a GPS for your actual miles run, divided by the gallons at the pump?"

Actually, since I don't generally listen to music when I am riding, except for the voices and tunes in my head, I calculate and think regularly about statistical things when I am riding any significant amount of distance/time.  Hence the answer to your question.

The trip home from the dealer was approx. 100 miles on old route 66.  I figured good for break in with varying speeds and going thru towns and such.  With the GPS running and comparing it to dash values, over the three 100 mile trips, i found the speedometer to be optimistic by ~4% (this calculation was less accurately done as the speed numbers reported on the dash and GPS were dynamically changing and calculation had to be done post observation).  The odometer on the other hand was pesimistic by 0.4% (had static numbers to do the math with).  I told you I was OCD, or CDO which is in the proper order.   ;D

Therefore the MPG calculations are being done using the odometer readings that have less than 1/2% error, of course changing due to tire wear.

Darren

[azccj]

My Norge's Trip Computer is always on the low side. It will say I'm getting 43 mpg when I'm actually getting 46. My BMW K1200LT's trip computer is always spot on. When it says I'm getting 51 mpg that's what I'm getting when I do the math at the gas pump. The question with the BMW is, how does something that weighs 800 plus pounds, uses an engine design which dates back to the early 80s, and has a huge frontal area, get better gas mileage than my scooter? ???

[Kev m]

Interesting discussion guys, thanks for the data points.

I'm baffled by the discrepancies.

[Boulder Ed]

I have a bit of statistical OCD myself and I notice these sorts of posts on EVERY vehicle forum that I frequent that HAS an on-board trip computer.

I posit that the problem ISN'T THE COMPUTERS.

I suspect the computers are better at determining how much fuel is being used at any given moment and collectively over a tankful than WE ARE at determining just how well we've refilled the tank.

Problems can include:

1. How level the bike/car was when filling
2. Ambient temperature when filling
3. How well calibrated the pumps are (I believe we had a board member here who used to work for a state bureau of weights and measures chime in on this once)
4. How exact we matched the fuel level from the last time (see #1 and #2, as well as those intangibles - how far up the filler neck the fuel goes or doesn't).

Now the computers aren't perfect either, I suspect there's a small amount of uncalculated loss from EVAP system operation too, but I hardly think that outweighs factors 1-4.

I know that I see fluctuations too sometimes on my vehicles that have trip computers (that I always compare by manually calculating trip meter reading/gallons at fillup) but as hard as I try to be consistent with my fillup, I recognize those factors are likely the largest part of any discrepancy.

I chalk to rest up to a zen-like acceptance of my own OCD.  :BEER: :D

My mpg gage is 19% optimistic on a 2013!  If I limp it to 50mpg, it will turn out to be 40 when I fill it. 

[Demar]

My 2012 NTX is close to the OP's. I show about 42mpg and I get about 38mpg actual. As soon as the fuel gauge bars are all gone I fill up with about 6.0-6.5 gallons. I don't pay much attention to the mpg. I pay A Lot of attention to the 13.4v charging display.

[pyoungbl]

With our 8.5 gallon tank the actual MPG is only important to the point that it tells you how far you can go when the low fuel light comes on.  On mine I think that I have about 2 gallons left before I'm walking.  OK, that means somewhere between 60 and 80 miles of searching for gas.  That after going about 250 miles already.  Let's face it, you can never have too much gas.  Nevertheless, you will be hard pressed to find another motorcycle with greater range than the NTX Stelvio. 
Peter Y.

[canuguzzi]

Known fuel usage also is useful to determine if the engine is running as it should. Just because you have a large fuel tank doesn't mean fuel economy isn't important. If your fuel usage goes down significantly it can point to a performance problem.

Minding fuel usage is as important as monitoring anything else on the bike, like oil consumption. Being lulled into complacency because you have a large fuel tank leaves you vulnerable to potential problems you might catch before they become big problems.

[pauldaytona]

The big tank stelvio reading and the moment the light goes on can easy be adjusted, just by bending the sensor arm in the tank, I have it so that the light goes on when 60 miles fuel is left. Stock most of the time the light was on and no use. When you get used to the yellow light, you don't pay attention.

[Kiwi_Roy]

When you gun off at the lights the fuel milage must suffer, how do you account for that in your head.
Whenever we go on a trip we have a competition to see who will get the best milage, I always lose, I suspect it's something to do with the grin factor.

Sorry I should add I don't have a Stelvio or bike with the readout.
My friend with an NTX told me he gets better milage by selecting a lower gear and piling on the revs, how do you guys find it?
What is the most economic rev range to operate at, I'm sure it transfers to other FI Guzzis without a readout.

I imagine the computer uses injector open time and ground speed to calculate the mileage.

[pyoungbl]

OP's original question:
Fuel milage, the dash says my average MPG is 42 to 44 and when I fill up and figure it, I have been getting 36 to 38.  I didn't expect it to show perfect, but that is quite a big difference.

NP's observation:
Known fuel usage also is useful to determine if the engine is running as it should. Just because you have a large fuel tank doesn't mean fuel economy isn't important. If your fuel usage goes down significantly it can point to a performance problem.

Minding fuel usage is as important as monitoring anything else on the bike, like oil consumption. Being lulled into complacency because you have a large fuel tank leaves you vulnerable to potential problems you might catch before they become big problems.

The issue is that the Stelvio computer gives bogus mpg figures.  The actual mpg is, in my humble opinion, less important than knowing how far you can go before you are forced to walk.  If the low fuel light normally comes on at 245 (as happens on my Stelvio) I know that I have about 80 miles of range left.  If the low fuel light comes on at 220 I can consider a few factors (wind, temp, rain, speed, etc) for that tank and maybe I don't have the 80 miles left but actually only 60.  If the light comes on at 200 for the next tank I can see that there is a trend here and maybe time to look at the machine.  Thus, I'm aware of the fuel being used....not so much the actual mpg number but rather the miles per tank. 

Peter Y.

[Demar]

Having the largest tank in your group of riders usually means you never have to worry about running out. 

[Spuddy]

My Stelvio's computer has similarly inaccurate as described.  But I want to know what the actual fuel capacity v the specified one.  So, I guess it's time for the 1 gal. can in the saddlebag...

Spud

[pauldaytona]

it holds 32 litre.

Only the warning light comes on way to early.  Just bend the thing a bit until it fits you. My light goes on when 6 litre is left

[Cool Runnings]

Would it be safe to assume that since you are self professed OCD on this that you are using a GPS for your actual miles run, divided by the gallons at the pump?

I ask because my '09 Stelvio is pessimistic in the odometer department. About 3.5 miles per tank. (My per tank includes the aux tank from Stucchi, giving me 8 to play with.) Having said that, my actual mileage is slightly better than the dash indicates.

Next, with only 1000 miles on the bike, you are not even close to having it broken in. You should still be under a recommended rev limit until you hit 2500 miles. Then you can flog it more, but you still are nowhere near having it fully worn in. I mention this because early on, as things seat and wear in, the engine balance will change more rapidly, and valve lash will change more rapidly. Valves are pretty easy to adjust. TB balance and TPS reset requires some additional equipment.

Several trips the last few months have netted me 41 mpg + or -. This past weekend, I did all the things I mention above. The bike runs better than it did prior to readjusting things. Therefore, it would be safe to expect a slight increase in mpg's. How do I know it is running better you ask? Well, the valves needed adjusted. The TB's were a little out of balance. Resetting the TPS is part of that process. Next, I can reach down and put my hand on my aux lights. (Mine are on their own mount on the front of the engine.) Anyway, the vibration I could feel in the body of the aux lights have diminished drastically. That tells me the engine is running smoother and therefore more efficiently. 

In summary, with your engine so new, I don't think your numbers are far out of line. I would also expect you to see an improvement as miles rack up on the bike.

John Henry

Ride it like you stole it.  Not a believer in easy break-ins. I know, there are two schools of thought!