Tripmeter MPG vs Actual MPG

[OB_Tangram]

My meter reads KM/Liter (YUCK!) I'm in the UK, so we buy fuel in literes rather then gallons, but we still travel 'miles' not kilometers, so the trip meter fuel calculations mean nothing to me anyway. Bloody Europeans!

 

[OB_Hayabusero]

You ain't kidding! I have noticed the exact same thing. The meter is about ten miles different than the actual MPG. I have tested it a lot of times and it's the same thing, I get more mileage from my Corolla than I do from my Busa. I ain't complainting, I mjust think that they shouldn't even bother to put the meter if it isn't gonna work.

 

[OB_JohnC]

That’s a bigger difference than I expected. My Vette does the same type of thing, using injector pulse duration, for fuel measurement. But, the Vette is only off 1 to 2 MPG(always on the optimistic side). I figured the Busa would be as close. If we ever get enough good weather to put some miles on, I'll give it a test.

 

[OB_ROR]

Hayabusero, I'm glad to get some confirmation on this. I wasn't sure whether something was wrong with my bike.

The big problem it causes is trip planning on fun lonely roads out West where having 30-40 mile less range on a tank can mean a long, lonely walk.

 

[OB_JokerJ]

ROR, good heads up on the trip mileage. I suspected it was off as well. Now I know for sure. I'm sure Suzuki could come up with a ECM upgrade but that's a bit costly for something so minor. I'm just glad the fuel gauge isn't some how effected by those calculations. but considering my truck only gets 15 mpg at it's best...(10yrs old). I can't complain.

J

 

[OB_Badagindo]

The MPG reading you see is not derived from the MilesTravelled / GallonsPumped. It is a calculation based on the fuel use, speed, etc at the time the computer takes the reading. Ride 1/2 mile in 2nd at 6000 RPM and check your MPG. Then ride the very next half mile in 3rd at 3500. You will see a big difference.

Bascially at any given reading, it shows the MPG you should get if you continued at THAT speed and THAT RPM for the entire tank of gas.

 

[sherm]

I usually get 41 to 45 mpg actual and the tripmeter mpg usually reads about 2 mpg more.I'm pretty sure the mpg is supposed to be an average over the length of the trip, not instantaneous mpg.

 

[OB_boneman]

I would think that how long you warmup would also have an impact on your actual mpg as opposed to the computer calculated.

Do long warmups and you burn more gas thereby get a false impression that you're hogging more fuel in relationship to the actual miles placed on your bike. Make sense?

Just a thought.

 

[rotts4u]

One more thing to remember is since your stock speedo is running fast (even if you have not changed your gears) your actual MPG is being overstated even when you use calculated MPG based on fillups and mileage traveled

don
rotts4u@aol.com

 

[OB_stu]

Never gotten more than 32 MPG.
Gauge is pretty close, maybe off by 1 or 2 miles.

Apparently I need to slow down if everyone is getting this great mileage.

 

[OB_CanuckBusa]

ROR, your bigger problem is that you may need a different pillion passenger (won't go over 4000rpm?). :-)

My pillion gal hangs on, no problems to 10,000rpm wide open in 2nd! True love.

 

[OB_ROR]

CanuckBusa, I hear ya. Actually in 10 months of ownership, this weekend was only the 3rd time she'd been on it and the first time for a ride of any length. She found it a fairly uncomfortable bike, as I could tell from all the squirming around back there. I don't think she'll ride again.

Fortunately I taught her how to ride several years ago and she's got her own bike (a Suz GS500), so she doesn't need to ride with me and when I want to go fast I go riding by myself anyway. By the way, she celebrates her 56th birthday later this week and would absolutely kill me if she knew I put that on the web! I don't think she's doing half bad at all.

 

[OB_CanuckBusa]

ROR, no she's not doing bad at all. The only other 50-something lady I know who will ride on a Hayabusa is my mother-in-law.

 

[OB_ROR]

Is anybody else finding that the miles per gallon displayed in the tripmeter (tripmeter 1) doesn't match the mileage derived by dividing the number of miles traveled by the number of gallons pumped?

Here's my last three experiences:
Distance = 77.7 miles, tripmeter mpg 40.4 gallons pumped 2.611, actual mileage 29.5. Mostly freeway, some city streets, mostly 4,000 rpm or less.

Distance = 62.2 miles, tripmeter mpg 42.1 gallons pumped 1.685, actual mileage 37.2.
Nearly all freeway/highway, mostly 4,000 rpm or less.

Distance = 105.6, tripmeter mileage 44.7, gallons pumped 3.214, actual mileage 32.8.
Freeways/mountain highways, mostly 4,000 rpm or less.

Factors. California bike, '99, 5,981 miles. Stock tires. Distances traveled are approximately accurate. I tried to eliminate uneven refills as a factor the last two times by filling only to bottom of filler restrictor tube in the California tank (1/2 gallon less capacity for evaporation controls). Stock engine with Two Brothers slip-ons, ECU originally set at +5 +5 +10 with Yosh box when slip-ons installed last fall, but quickly reset to zero (or at least that's what I asked dealer to do) when bike ran worse than stock. Dealer did do something because bike ran better and got better mileage on the tripmeter. Bike still runs fine. (It will go over 4,000 rpm but pillion passenger won't.) Fuel filter recall done about 3,000 miles ago. Not checked since.

My Suzuki manual says the tripmeter uses ECU signal for injector time plus speed sensor signal to calculate miles per gallon. There is no evidence of fuel leaking, nor gasoline odor. The fuel filler cap whistles when bike is in sun, apparently from evaporation escaping, which dealer says they all do. (It didn't when it was newer.) But all of these measurements were done within hours of each other this past weekend, so how could evaporation be a significant factor?

 

[OB_busTa Kaw]

I agree with Badagindo. The fuel consumption meter takes readings at various intervals although Im not sure how often. You can go downhill for awhile and watch the meter go up. I dont think it is an average of the trip. Just displays miles per gallon you were getting at the last reading it took.