Fuel Consumption

[andyc]

In the reports in the Magazines,on Boats and engines,the writers put in fuel consumption figures,mpg etc.How do they do that?
I assume they use some sort of fuel flow meter or they just use the gallons per hour figure given by the engine manufacturer.

Any one know of a fuel flow rate meter that can be fitted in the fuel system?

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[Talbot]

If your engine is petrol (or engines) and you have a Navman 5500 or 5600 chart plotter, you can attach a fuel flow meter which will do just what you want. If your engines are diesel it doesnt work because of the fuel return line!

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[rickp]

<A target="_blank" HREF=http://www.floscan.com/ModelSelection/series6500.html>Floscan</A> and others do fuel monitors, that can deal with subtracting the returned fuel from the fuel feed so do work on diesels.

Not sure that the magazines go to such lengths to get their figures. I suspect they note the speed at a particular RPM and then use the engine manufacturer's fuel consumption figures for that RPM. Be interesting to find out if that is what they really do

Rick

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[jimg]

I was on a boat during a magazine test recently and the diesel engines were of the of the "electronic" kind. They noted the fuel used on the engines display and GPS speed for a range of revs.

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[jfm]

The magazines often state that they have used manufacturer figure, which I think means they note the speed then use gph from manufacturer data sheets.

The navman systems will not cope with returned diesel but plenty of others will incl floscan as mentioned.

Volvo EVC engines have flow and return sensors already fitted, so you can just buy an electronic display to get fuel flow data. I suspect Caterpillar is same. You don't even have to run a wire between helm and engine, the fuel consumption display just plugs in under the dash with daisy chained CANbus wiring. I think the same applies to Volvo EDC except there's no CANbus, so you have to wire it traditonally.

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[Divemaster1]

Magazines use manufacturers figures, or do so on new boats with all the gadgets installed ...
Bad news to retrospectively install one of those in my books ... people and SWMBO may actually realise how much this thing really do use of the fossile fuel stuff..... Better to have a good feeling yourself for calculating range, and leave others in blissful ignorance and marvel over the speed, luxury, handling or whatever.... The minute I say 90 - 100 L / hr ... everyone say "WHAT!!!" ... easier to be evasive and just state the range of 250 Miles or whatever ... the fact that it cost you £ 300 in fuel to go the 250 miles is just the way it is ..

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[tcm]

i agree. Some bloke asked me the fuel consumption and i said no idea matey, i never work it out. swmbo pays the fuel bills, i just reckon on about 400 miles range. Bloody cars these days (mercs anyway) have this fliping display in the speedo that shouts how the mpg is 9.2 or whatever, so i have changed to l/kilometre which doesn't mean anything to me.



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[Deleted User YDKXO]

I think where they can, the mags use flowmeters and where they cant they give manufacturers figures. Even so, you often see discrepancies between mag tests of the same boat so everything has to be taken with a pinch of salt. Then there are things like sea state, boat loading, hull cleanliness, water temp and salinity which all have an effect on mpg
There are a few rules of thumb.
Sterndrive boats are usually more efficient than shafdtdrive so use less fuel
Planing boats use less fuel at a given speed than semi displacement boats
For planing shaftdrive boats, the following wont be too far off for 20knots
30footer 1.5mpg
40 footer 1.0mpg
50 footer 0.7mpg
Extrapolate in between

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[jfm]

[pedantry] you mean interpolate, shurely? [/pedantry]

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[Deleted User YDKXO]

Yup

Still would have got A Plus Double Star in my GCSE 'coz they dont care about grammar nor spelling no more

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[EME]

Oil Price ..

Wasn't the FIVE point 2 in that machine of yours? . Between you and JFM you are destabiling the whole Western economy.

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[PhilF]

shurley you mean surely

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[jfm]

Re: Oil Price ..

Hmm yes. Gotta say though, the new M5 is very oil-price ecofriendly. At start up, bhp is only 400. You have to press a button on the dash (to remap some engine settings or summink) to increase it to the full 508bhp. So when you're just bimbling around the shops and are quite content with just the 400bhp, you can be deliberately eco-friendly by NOT pressing the button, so saving fuel.

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[EME]

Re: Oil Price ..

OOh , I stand corrected. !!

400 bhp , so about the same as 7 Smart cars then ? Come to think of it .. I prefer your eco-friendly option.

Envy is a very sad (if rather obvious) trait of some.

Now if it was a DB9 .. nuff said, or even one of those nice 997 which are fetching a 15% premium in SoF .. much more friendly machines....

i.e. envy = criticsm ( mixed with hypocrisy )

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[ArthurWood]

Re: Oil Price ..

Wot's the point of 400 or 500bhp when most UK driving is stop/go, stop/go nose to tail? /forums/images/graemlins/smile.gif

 

[BrendanS]

Re: Oil Price ..

Good grief Arthur, where on earth did you dig this old thread up from?

 

[qetoo]

Re: Oil Price ..

I have a Floscan that came with the boat. It shows both rate of fuel consumption (gallons per hour) and total fuel used. I use it mostly to determine just how much to refuel the tanks; I find it quite useful for that. It seems to be quite accurate.

 

[jfm]

Re: Oil Price ..

"most UK driving is stop/go, stop/go nose to tail"

I dont think it is, at least not for someone like me who doesn't commute to work by car. There are loads of times when the road is open and you can use 500hp. My 6am to 6.25 am blast to Luton airport most Saturday mornings is pretty traffic free, frexample /forums/images/graemlins/grin.gif

There's no real logical reason of course. It's mostly just for fun, like boats. This week's Autocar test of the M5 vs Ferrari 430 is recommended reading - the 'rari just couldn't keep up!