OZ ATV :: The Australian ATV Forum

[wa5]

apart from the higher octane, would all other benefits come down to water/ alcohol content?... would a water/ alcohol injection system offer similar benefits?

[HaggLE]

The power comes from the added octane but mostly the cooling aspects that alcohol fuel have.
We have found that there is no or minimal difference in ignition timing from an unleaded setup to E85.
Personally, if you arent racing then dont worry about it.

[bullet]

e85 makes about the same power per litre as petrol.
Your engine will make more power because you get to use more of it in each combustion stroke.
Basically you'll be pooring 27% more fuel in each time.
There are other reasons that e85 is not as good, so you wont get 27% more power.
Depending on how perfectly you can set your engine up for the e85, you might get 5% to 10% more power.
But it will run heaps cooler.
Some turbo engines claim up to 20% more power in "some" situations, but i don't think they are realistic, and not for your quad anyway.

I think this is what they call 'playing with fire'
_________________
Can-Am X Team
Bullet #Y12. MrsB #Y18.

[HaggLE]

Anyone in the goulburn area on Sunday? Come to Wakefield park and check out some bikes running e85. Talk to the "motolite" owners.

[Dino]

I wouldn't run it in anything unless it was all that is available, OR I had the motor professionally tuned to run on that fuel all the time.
Likewise with LPG.........
In our car, with 10:1 compression and computer controlled ignition and injection with all the knock sensors etc, the cost saving at the bowser was cancelled by the increased running costs. Specifically fuel consumption. Same with the previous car. Neither has given any indication of bursting into flames.
Both our boat and whipper snipper ( 2 strokes ) perform better with a premium mix also.
Our bike, 500cc carby single with 10:1 compression performs best on premium.
Fuel going stale and impurities seems to be a bigger problem now than 20 years ago.
Regardless of all the hype, I have to change filters more often and I am so over the BS surrounding fuel.
BTW....
In Brissie, we have 2 fuel refineries who supply all the fuel for a big distance around, regardless of brand of retailer. The oil is sourced from Malaysia, paid in US dollars at that time, shipped here and refined over 6 weeks later and distributed.
And if a camel farts in the Middle East, the fuel cost goes up instantly at the bowser.
_________________
Remember. We elect politicians, but we have to deal with bureaucracy.
Notice that crazy in the bureaucrats.

[triple"A"]

hLooking for more power? It's as easy as filling up with some racing fuel... Isn't it?

Words: Alan Swanson

'High Octane' is a phrase that conjures up images of fast cars. It's also a phrase that is bandied around by nearly all of the petrol companies in advertising slogans, along with products described as 'ultimate', 'racing' and 'extreme'.

So, high-octane petrol must be the fuel of choice if I want my car to go faster... After all, petrol companies refer to 'improved performance and acceleration' and racecars use it -- it must have a performance advantage!

Not necessarily...

Let's have a look at what an octane rating is and what it does.

In Australia petrol uses an octane rating called RON (Research Octane Number). The RON number is achieved from the results of lab tests in which the fuel is run through a test engine which varies its compression ratio under controlled conditions.

The results of the test are compared to results for a mixture of iso-octane and n-heptane. For example, if a fuel is found to perform in a similar way to a mixture of 95 per cent iso-octane and 5 per cent n-heptane, it is given the rating of 95 RON.

When a fuel mixture is compressed there is a point at which the extreme heat and pressure will make the fuel explode, or spontaneously combust. This is the process that diesel engines rely on. However, in a petrol engine the point of combustion is controlled and the fuel mixture is ignited by the sparkplug.

Basically a high RON fuel will have a higher resistance to pre-ignition (also called knocking or pinking or pinging). This is because the higher octane rating means that the fuel has a high activation energy. In other words the fuel needs to be subjected to more extreme conditions before an explosion will occur, either by high levels of compression or high engine temperatures.

So will high octane fuel give a car better performance?

Let's look at the case of a normal road car. Most road cars have a recommended octane number of the fuel which should be used. The compression that takes place in the combustion chamber and the internal engine temperatures while running are suited to work efficiently with the recommended fuel rating.

If a lower octane fuel is used then it's possible that some problems may occur. Pre-ignition (also known by the terms noted above) can damage the engine internals in the worst cases.

If a higher octane fuel is used what happens? Well, nothing. The engine is already able to perform at its highest efficiency on the recommended fuel. The extra octane rating has no effect.

So why do high performance cars or racing cars use high octane fuels?

This is because their engines are designed to take advantage of the properties of high octane fuels. High-performance road cars tend to make their extra power from generating higher pressures in the combustion chambers of the engine, either by having high compression ratios or by using turbo or superchargers.

To avoid pre-ignition due to the high pressures, high octane fuels are used and, in the case of road cars, recommended by the manufacturers.

What clouds the issue is some of the 'smarter' engine management systems used by car manufacturers today. As well as being able to measure when pre-ignition occurs and alter the ignition timing, boost (in turbocharged cars) and other factors to stop it, these engines can also 'tune' themselves up to take advantage of the extra octane rating and potentially make more power.

One example of this is Saab's BioPower turbo fours. By taking advantage of the higher octane number of ethanol rich fuels such as E85 (85 per cent ethanol, 15 per cent petrol), the turbocharged 2.0-litre engine offered in the 9-3 Sport Sedan increases its turbo-boost and tweaks ignition timing automatically to increase its claimed output from 129kW/265Nm on normal fuel to 147kW/300Nm on E85.

Okay, but if the octane rating typically doesn't improve performance, why do premium fuels claim better power and acceleration? Well, such improvements are possible, not because of the octane rating, but because the chemical composition of the fuel may be capable of producing more power.

It's a matter of how much 'bang' each drop of fuel contains. Looking at the chemistry of the fuels in question, Carbon-to-Carbon bonds actually contain more energy than Carbon-to-Hydrogen bonds. Therefore a fuel which contains more Carbon-to-Carbon bonds will give more power, regardless of the octane rating.

It's more likely that a premium brand fuel will contain more Carbon-to-Carbon bonds and boast a high octane rating.

So yes... Premium fuel with an octane rating higher than recommended by the car manufacturer may well be able to improve the performance of your car, but it's not necessarily because of the high octane rating...

The myth 'High Octane fuel will make a car faster' is therefore -- Busted.

there's a little light reading

[bullet]

I like how they said they busted the myth, but generally yes, a premium fuel is more likely to have more carbon to carbon bonds and produce more power.

It is also fair to say that higher octane fuels are usually more refined (or taken off higher in the refining process) therefore they are usually cleaner and more pure fuels...
Well that used to be the case, but now days i'll bet they are just beefed up with addatives.

I would say that high octane fuels generally don't make any more power... but, they definitely do allow you to run a higher compression engine in a more demanding environment, and the higher compression engine will make more power.

Years ago Zoom Magazine did some great testing on about a dozen different octane boosters... Most of them increased the octane (fuels stability) but only 2 of them actually improved engine power.
The best was Nitro-methane, it gave the highest octane point boost and best power increase.
Back them it was about $80 a litre but you only mix it at 10%
_________________
Can-Am X Team
Bullet #Y12. MrsB #Y18.