Is cheaper fuel a false economy?

[avgas]

What most people don't know is that petrol JDM vehicles are designed to run on a much higher octane fuel than our 91, so even low performance bikes and cars are often more expensive to run on 91 than on 95. People don't generally look at the big picture, and want immediate savings (from cheaper fuel).

Not to mention they have 104 at the pumps.......I miss Japan.

[Ender EnZed]

My car is cheaper per km on 95/6 than 91, 98 is more expensive to buy which cancels out the benefit. The DR gets the furthest out of a tank of 91 so that's a pretty easy decision. The VFR gets about the same out of a tank of anything but feels smoother on 95/6.

I don't worry about where I fill up so I can't comment as to brand differences, but I never use ethanol and I'd prefer it if stations with 98 had 95 as well.

[avgas]

http://www.stuff.co.nz/business/indu...biofuel-claims
Seems that high ethanol fuels give lower economy...
There was a thread on the rgv forums talking about how the higher ethanol fuels damage the rubber in the hoses and carbs

Ethanol has always has lower fuel economy..........but it has its advantages

[Asher]

Ethanol has always has lower fuel economy..........but it has its advantages

Its all about the tune i guess

[SMOKEU]

At least ethanol fires are easy to extinguish with water.

[p.dath]

FYI, our the Automobile Association in NZ ran a test like this a while ago for cars.

They found for engines designed for 91 octane using a higher octane rating made no difference.

On engines designed for higher octane, they found that on short trips it didn't help. They found on longer trips (and probably when the engine is running at a constant RPM) it improved the fuel economy.

[bogan]

You may be right, but that isn't why I take note of fuel consumption. I just want the most riding pleasure for the least dollars.

Changing my riding habits would probably lessen my riding pleasure. Riding economically? That would increase the number of speeding fines. Ride less often? Then why bother enjoying motorcycling at all.

I intentionally used drive instead of ride there... Bikes use less fuel than cars anyway!

[SMOKEU]

Bikes use less fuel than cars anyway!

My GSXR600 uses more fuel than the Honda City Turbo I used to have.

[ducatilover]

yea ^
Thinking it would be interesting to see the results of a higher octane engine (95 std) running the different grades tho. I've seen these 91 engine tests before, same result you're just pissing away money by running higher octane.
But I haven't seen any where they try to downgrade the octane of a 95 engine be interesting to see just what effects it has, if any

Take a 5.7 Gen3 V8 Dunnydore out for a blat on 91, then fill it up with 98.
The difference is massive, we're talking 15-20rwkw...

Personally, my bikes tend to run smoother on 95/8, so I put that in them.
If you're worried about fuel costs, buy a fucking pram and a paddle.

[98tls]

Take a 5.7 Gen3 V8 Dunnydore out for a blat on 91, then fill it up with 98.
The difference is massive, we're talking 15-20rwkw...

Personally, my bikes tend to run smoother on 95/8, so I put that in them.
If you're worried about fuel costs, buy a fucking pram and a paddle.

Ive tried both in my XR8 but didnt notice any difference at all.Have always run 98 in the TL.

[cs363]

Well assuming it's the same model - looks like Bob has been chucking away more than 40 quid a year on high octane petrol, as according to the owners manual (apparently the least read book in the world according to Top Gear) the GSX650F is designed to run on a minimum of 87 octane (R+M)/2 which is the US octane rating, that equates to around 91-92 octane in the European/NZ ratings if my memory is correct.

Source:http://www.scribd.com/doc/39634165/Gsx650f-Manual

All the magazine/TV etc., tests I've ever seen on octane ratings always conclude that there is no advantage in using a higher octane fuel than the engine is designed for. In these tests there have never been any conclusive increases in power or fuel economy (certainly not enough difference to warrant the increased cost). The exception of course is with forced induction motors which do perform better on high octane fuel.

Individual results may vary..........

[Ender EnZed]

All the magazine/TV etc., tests I've ever seen on octane ratings always conclude that there is no advantage in using a higher octane fuel than the engine is designed for. In these tests there have never been any conclusive increases in power or fuel economy (certainly not enough difference to warrant the increased cost). The exception of course is with forced induction motors which do perform better on high octane fuel.

I see on TardMe that a lot of the auctions for Leagcy GTs claim "Only ever run on BP 98" or similar. Anyone know if there's any reason that this would be better for the engine (wear and tear etc.) than lower octane? Rather than just making a little more power and going on further on a tank (generally the best case scenario).

[cs363]

I see on TardMe that a lot of the auctions for Leagcy GTs claim "Only ever run on BP 98" or similar. Anyone know if there's any reason that this would be better for the engine (wear and tear etc.) than lower octane? Rather than just making a little more power and going on further on a tank (generally the best case scenario).

Legacy GT's are forced induction (turbo in this case) so running high octane fuel prevents engine damaging detonation as well as improving overall performance (especially as most of the boy racers will have the boost wound up). Most Jap import petrol turbos are designed to run on 100 octane or as close as possible.

[Flip]

What a load of twaddle.

The caloriphic value of all petrols is the same. The higher the compression the more eficient the motor is its called volumetric efficency. You could also say a high compression performance motor makes more HP than a standard low compression motor.

I put the cheapest fuel I can get in all of my vehicles, its all out of spec crap in this country anyway.

[avgas]

The caloriphic value of all petrols is the same. The higher the compression the more eficient the motor is its called volumetric efficency. You could also say a high compression performance motor makes more HP than a standard low compression motor.

Your theory would be perfect if the engine dissolved the energy from fuel. Not burnt it out.
There is a bit more to engines than volumetric efficiency......as we have learnt in the last 80 odd years.