Which speed is the most fuel economic for cruising?

[avgas]

Most big bore bikes/cars are designed to get peak efficiency between 85-110kph.
However ironically the best economy I got in a V6 holden was about 140kph, as it seemed to be slightly more streamline then. At that point the computer said I was doing 6.2L/100kph.

So I guess there are exceptions to the rule.

[Gremlin]

It does depend on the bike and its gearing. My KTM is best around 130-140kph, as it doesn't really like 6th much before that. The CB900 is revving high at that, and is more fuel economical at 80kph or so.

[davebullet]

here's a question - my 1300cc bike at 3100rpm runs 15km/l at 100km/h. Will a 600cc bike doing 6200rpm at the same speed use about the same amount of fuel? half the capacity @ twice the rpm?

Depends on final drive ratio and air/fuel mixture required to generate the torque to maintain the speed of the bike given the total mass to push forward.

so all things being equal - yes. But things are never equal.

A good question. BTW - My answer has no scientific basis, I just use the dave bullet irrational thought process to draw up a conclusion

[Big Dave]

42

[nodrog:Me]

Bounce it off the revlimiter in second gear all the way. The limiter cuts out fueling to your injectors momentarily, thus saving fuel.

Fanny.

[slofox]

here's a question - my 1300cc bike at 3100rpm runs 15km/l at 100km/h. Will a 600cc bike doing 6200rpm at the same speed use about the same amount of fuel? half the capacity @ twice the rpm?

Good question...

My gixxer sixxer does best (as far as I have tested it anyway) at around 6000rpm in sixth gear. This is about as slow an engine speed as it is comfortable with. Less than this and it wants to drop down a gear. This equates to a speed of 103km/hr. At this speed I get around 18km/l or just under (50mpg in old money).

Increasing engine speed to around 6400 (110km/hr) makes eff all difference to fuel consumption and is more comfortable for the engine. So, if I really want to conserve fuel (not very often in reality), I sit between 103 and 110km/hr in 6th gear. Easy enough on a long trip and generally fits in with typical traffic patterns.

If, on the other hand, I want a more "interesting" ride the consumption can get down to around 14 - 15 km/l...that's 'cause the fuel gobbling imps get into the tank...

[The Pastor]

I get 30km/l on my GL, Do you want to buy it? One careful owner.........

[rastuscat]

42

Yeah, wot 'e said.

[imdying]

Bounce it off the revlimiter in second gear all the way. The limiter cuts out fueling to your injectors momentarily, thus saving fuel.

Only a womans logic

[avgas]

Bounce it off the revlimiter in second gear all the way. The limiter cuts out fueling to your injectors momentarily, thus saving fuel.

Fanny.

Didn't know it had a second gear.....

[porky]

here's a question - my 1300cc bike at 3100rpm runs 15km/l at 100km/h. Will a 600cc bike doing 6200rpm at the same speed use about the same amount of fuel? half the capacity @ twice the rpm?

got to be a bikers site. half of 1300 = 600 fact. then the next 20 posts agreed with it.

[Kermit250]

Except that engine displacement has nothing to do with how much fuel is pumped in.

Its all about the Fuel air ratio at the given RPM and how much torque is produced here (ie. heavy or light load) .

for example, why do somepeople want to put on power commanders, or jet their bike, usually to richen mixture up = more fuel used, but same engine size.


So my point is that unfortunately it doesn't quite work like that

[steve_t]

42

The meaning of life?

[AllanB]

I was going to say 'stop being a homo and ride it' but I won't.


Top gear sitting on 100-115 will be as economical as anything and through the hills use the mid range instead of thrashing the top-end.