33mpg is my GSA Broke
- Thread starter davidblythe
- Start date
A fantastic theory!
Alps or any altitude riding produces better fuel returns because the bike adjusts the mixture to get the correct burn. Less oxygen = less fuel required.
What a brilliant idea.....but flawed I am afraid! If there is less Oxygen in the air that may well have to be 'mixed' with less fuel BUT you will need more of the mixture to produce the same power.
Alps or any altitude riding produces better fuel returns because the bike adjusts the mixture to get the correct burn. Less oxygen = less fuel required.
What a brilliant idea.....but flawed I am afraid! If there is less Oxygen in the air that may well have to be 'mixed' with less fuel BUT you will need more of the mixture to produce the same power.
Dellis
Registered user
However you can only get the same volume of mixture in the cylinder for any given revs as the engine is naturally aspirated. Therefore you end up with less oxygen and thus less fuel. I agree you need more mixture to get the same power but you have no means of getting any additional mixture in there and I didn't mention power.
In fact if you've ever ridden a bike with carbs at altitude you'll know that the bike runs too rich as it draws the usual amount of fuel for any given revs but there is less oxygen. The fuel saving only applies to fuel injected bikes as the mixture is adjusted by the ECU in conjunction with the lambda sensor.
Dave
Its pretty simple
Just open the throttle....and you will get more mixture and use more fuel. (believe it or not I WAS a rocket scientist)r
Just open the throttle....and you will get more mixture and use more fuel. (believe it or not I WAS a rocket scientist)r
Dellis
Registered user
I accept that you can open the throttle more but it won't and doesn't make sufficient difference to make up for the lower amount of fuel taken into the cylinder. I always get better fuel economy in the mountains and the vast majority of other also do.
I'm really not sure what being a rocket scientist has to do with the workings of the internal combustion engine.
Dave
You have a petrol engine. This has a throttle. When the throttle is closed virtually nothing goes into the cylinder head, which is why you have a pilot air screw to stop the engine cutting out completely on a closed throttle.
Brian is correct.
Simple thermodynamics
"I'm really not sure what being a rocket scientist has to do with the workings of the internal combustion engine. " No, you are right, it is not essential! However where a rocket goes there is not much oxygen as you will realize. You therefore pour masses of fuel (it was paraffin in my day!) and masses of (liquid) oxygen into the motors. Fuel consumption is somewhat heavy.
"I'm really not sure what being a rocket scientist has to do with the workings of the internal combustion engine. " No, you are right, it is not essential! However where a rocket goes there is not much oxygen as you will realize. You therefore pour masses of fuel (it was paraffin in my day!) and masses of (liquid) oxygen into the motors. Fuel consumption is somewhat heavy.
ianp5uk
Registered user
Ever noticed you get more mpg in Europe compared to the UK even when riding the same....
We always get about 10% more mpg.....UK fuel is not as good!
Could it be a higher octane than the shite we normally use?
don't argue the toss, try it next time you go to Europe!
I always put that down to being on holiday and chilled out. Less aggressive riding etc.
no they dont,usable fuel capacity,approx 33l,reserve,ie when last bar on guage shows,approx 4 l until empty,so total cap approx 33l,not 33l plus 4,unless i cant read of course,and i havent been actully filling my last 2 gsa s every time ive filled up
I don't know about 37 litres but I have managed to put 35 litres in mine many times.
FFS.................is this thread for real
All getting a bit ott about a bit of petrol
All getting a bit ott about a bit of petrol
Dellis
Registered user
For any given throttle opening you will allow less oxygen into the cylinder the higher up you are resulting in less power and less fuel used.
I'll be more than happy if you can come up with another explanation why motorcycles use less fuel in the mountains/at altitude. My understanding is that it's mixture related.
Dave
'It is a well known fact .??????'
"......explanation why motorcycles use less fuel in the mountains/at altitude."..... you should rephrase that and ask "do motorcycles use less fuel in the mountains/at altitude ?" and if someone says 'yes,' ask how did they measured it.
"......explanation why motorcycles use less fuel in the mountains/at altitude."..... you should rephrase that and ask "do motorcycles use less fuel in the mountains/at altitude ?" and if someone says 'yes,' ask how did they measured it.
must be me then,perhaps next time i will see how far i can go till i run out,with a can on the back obviously
FFS.................is this thread for real
All getting a bit ott about a bit of petrol
Who cares what you think.
Anyway back on topic.
My computer thingy stays on average at 47 mpg during normal riding and has never dropped below 40 mpg. Has never taken more than 33L at refuel even with the miles to empty at zero.
Dellis
Registered user
I know my bike uses less fuel in the mountains, a number of people on here say their bikes use less fuel, including the one I have quoted from this very thread, and others that I know say their bikes use less fuel in the mountains. Using myself as an example I measured it by the standard measure of fuel economy, calculated miles per gallon. I normally return around 44mpg and in the Alps it's always much nearer to 50mpg.
Dave
Blasting down the motorway v. the twisties
There is nothing like a vertical drop of a few hundred feet at the side of the road to dramatically lower your fuel consumption. You don't need to look at your computer -or anything else except the tarmac in front of you.
There is nothing like a vertical drop of a few hundred feet at the side of the road to dramatically lower your fuel consumption. You don't need to look at your computer -or anything else except the tarmac in front of you.
Dellis
Registered user
Not every Alpine road has a drop at its edge. Oh and I made no mention of a computer.
Dave
pathfinder
Registered user
A small number of the 2010 bikes have had a problem with fuelling,mine did.Can you smell petrol when on tickover or when you have just switched off.The bike will also have a very rough tickover.
midnitemo
Registered user
fuel efficiency
I'm no scientist but i've found my bike is pretty good on fuel in the mountains..i alway's assumed it was down to a mix off things , aerodynamic's not being as big a deal at lower speed , BMW's supposed very advanced engine management calibrating superbly for the change in altitude and the fact you usually have gravity helping you for 50% of the time
I'm no scientist but i've found my bike is pretty good on fuel in the mountains..i alway's assumed it was down to a mix off things , aerodynamic's not being as big a deal at lower speed , BMW's supposed very advanced engine management calibrating superbly for the change in altitude and the fact you usually have gravity helping you for 50% of the time
pathfinder
Registered user
Look at my post number 58
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