[jazzy]

Originally Posted by Gothy

wow i really didnt expect this many posts so soon. lol.

I went through a stage of only using 98, in my 400.
Its amazing the difference it makes to pulling power, but i stoped using it when the fuel prices rocketed upwards.

But in my car it doesn't really make any difference.

so i guess it depends on the particular engine.

also why do your numbers get lower for higher octane ratings?

Have a look at the Wikpedia link.....its a little complex but understandable...I got NOOOOOO chance of even trying to explain it

See for me here fuel prices are dirt cheap..costs me 10€ for a tank of fuel

[bladeracer]

Originally Posted by jazzy

See for me here fuel prices are dirt cheap..costs me 10€ for a tank of fuel

How does that compare to our A$1.15 per litre?
I think it's about the same?
18 liters for A$20.

Edit: I'm curious - do US fuel prices include tax or do you get charged tax on top of it?

[jazzy]

Originally Posted by bladeracer

How does that compare to our A$1.15 per litre?
I think it's about the same?
18 liters for A$20.

Edit: I'm curious - do US fuel prices include tax or do you get charged tax on top of it?

Sorry Larry, I was basing mine on 15litres (light-on time to fill up). Its about 87cents ...more or less

[bladeracer]

Definately no complaints out of you then :-)

[WyoJames]

Originally Posted by jazzy

Sorry Larry, I was basing mine on 15litres (light-on time to fill up). Its about 87cents ...more or less

thats it, I'm movin to lanzarote

[MelScrilla]

i always run premium 91

[Doomwitha929]

here 87,91,93 and 106 for camII .
All gas produces the same power when burned.
Additives do not enhance power they aid in clean combustion and deposit build up prevention. If you use a fuel that has an additive that aids in atomization etc then it can make more power then another fuel of equal octain rating in an engine whos state of tune/compression etc requires it.

"Gas" is normally composed of Isooctain and normal heptane. The higher the octain the HARDER it is to burn the fuel. Octane rating is the fuel resistance to combustion, it is less volatile. In an engine that does not require high octain fuel using high octain gas may produce LESS power because of incomplete combustion (also worse milage)
In an engine that requires high octain fuel to run best EX: an engine with high compression or a combustion chamber geometry that causes high combustion speeds or a boosted engine using lower then proper octane fuel will cause the fuel to burn too fast which is detonation.
using too low or too high octane fuel in a car with a cat can damage the cat also.


I always run high octane fuel in my bike although I probably do not have to. I just feel better about it.

[bladeracer]

I've never noticed any difference in power between 91RON and 98RON and I doubt there is a measureable difference.
I regularly notice the extended mileage though running the 98 over 91RON though which is the only reason I run it.

[slickwill]

In the US any of the gasoline brands that have the "Top Tier" rating have the exact same additive package no matter which grade you run. Whether you buy 87, 89, 91, or 92 you get the same additives package. So you can buy whatever grade is recommended for your car and know you are getting the same additives.

WYO - at the elevation you are at you could easily drop a grade and it wouldn't make a difference. With the increased elevation you get decreased O2 which lowers the octane requirements significantly.

[jazzy]

Originally Posted by slickwill

In the US any of the gasoline brands that have the "Top Tier" rating have the exact same additive package no matter which grade you run. Whether you buy 87, 89, 91, or 92 you get the same additives package. So you can buy whatever grade is recommended for your car and know you are getting the same additives.

WYO - at the elevation you are at you could easily drop a grade and it wouldn't make a difference. With the increased elevation you get decreased O2 which lowers the octane requirements significantly.

Hi slickwill, what about heat as in warm air....here in the Canary Islands its always hot. Make much difference???

[bladeracer]

Originally Posted by slickwill

In the US any of the gasoline brands that have the "Top Tier" rating have the exact same additive package no matter which grade you run.

So, what is the point in having different brands and how do they compete if their products are identical?

[dicknose]

Originally Posted by bladeracer

but I'm talking about _not_ changing the engine characteristics at all.

But pretty much all fuel injected engines these days run knock sensors and have an ecu that can do this adjustment.

So sure - it wont do much for engines from the 70s or even most from the 80s.

But any modern performance engine that is designed to make use of high octane fuel will get a power benefit from running it. This power gain is due to the octane rating.
The additives may help, but the big gain is from adjusting timing and on turbos boost.
Basically the car is tuned for high octane - run it on lower octane and you get less power.

[dicknose]

Originally Posted by bladeracer

So, what is the point in having different brands and how do they compete if their products are identical?

You do know that in most Aussie cities there is only 1 or 2 suppliers of unleaded. Depending on your city - I think Perth is only 1. Sydney and Melb are 2 (but different 2)
So Sydney has Shell and Caltex - so any 91 unlead fuel you buy from BP or Mobil has come from either Shell or Caltex.

Ok - googled - Fuel Industry Background
Perth has one major fuel supplier - BP

[bladeracer]

My Suzuki Swifts, 929, ZX6R and GSXR's don't run knock sensors but all exhibit better fuel economy on higher octane fuels. It's more noticable in the cars than the bikes but the bikes tanks are so small even another 20km a tank is well worth it for me. In the cars we get around 50km more per tank.

[bladeracer]

I was aware that we only have a single supplier over here. Doesn't shell modify it to their own spec though for retail?
I was referring to the statement about the US market that all fuels regardless of octane rating are identical. Doesn't make any sense to me at all.

[WyoJames]

Originally Posted by slickwill

WYO - at the elevation you are at you could easily drop a grade and it wouldn't make a difference. With the increased elevation you get decreased O2 which lowers the octane requirements significantly.

thanks slick, i didn't know that, I'll give it a shot on my next tank

[slickwill]

Originally Posted by bladeracer

I was referring to the statement about the US market that all fuels regardless of octane rating are identical. Doesn't make any sense to me at all.

Chevron might have different overall additive package than Shell, which may be different from Conoco so there is difference between brands but all of their individual grades have to have the same additive to be counted as top tier. It prevents the lower octane gas from being cheap crap. It only applies to gasoline with the "Top Tier" rating so there are still other brands out there that don't have the rating.

So Chevron 87, 89, 91 will all have the same additives.
Conoco 87, 89, 91 will all have the same additives.

But they will differ from each other, however they both still have to meet minimum (but strict) requirements to get the rating.

So I buy 89 octane for my bike (F4i) because it's the cheapest here and yet I know I'm still getting just as many additives as if I paid for premium.

However, my XR650R was built with the full HRC kit by Precision Concepts and was tuned by them to run on race fuel. So I put 93 octane in it from the one station in town the sells 93.

Here's the list of "Top Tier" fuel manufacturers.

Top Tier Gasoline

[slickwill]

The standards developed by the four automobile manufacturers (BMW, General Motors, Honda, and Toyota) for TOP TIER Detergent

That's who came up with the required standards for "Top Tier."

[bladeracer]

Originally Posted by slickwill

So I buy 89 octane for my bike (F4i) because it's the cheapest here and yet I know I'm still getting just as many additives as if I paid for premium.

To clarify, you're saying that regardless of brand all the fuels have to have the same _minimum_ additives?
So they could add a whole bunch of other additives as well as the minimum?
If that's the case then all the fuels can hardly be considered the same.
So, when you say that you're getting just as many additives regardless of the octane rating you're implying the fuels are identical except that the one has been refined to a higher octane?
My understanding is that the higher octane fuel has several further additives that the lower octane doesn't have to improve its overall quality as a fuel and make it appeal to a much larger market. If it _only_ had a higher octane rating the only people using it would be those running factory engines built to use higher octane and modified engines, both of which are a tiny market compared to the number of vehicles designed for regular. The price would be right up there with race fuels I would think.

[BigBassTurd]

Like the commercial says buy Chevron gas with TECHRON(Chevron's fuel additive). They all have thier SPECIAL receipe they add so they are all basicly the same but way different.

[slickwill]

Originally Posted by bladeracer

To clarify, you're saying that regardless of brand all the fuels have to have the same _minimum_ additives?
So they could add a whole bunch of other additives as well as the minimum?
If that's the case then all the fuels can hardly be considered the same.
So, when you say that you're getting just as many additives regardless of the octane rating you're implying the fuels are identical except that the one has been refined to a higher octane?
My understanding is that the higher octane fuel has several further additives that the lower octane doesn't have to improve its overall quality as a fuel and make it appeal to a much larger market. If it _only_ had a higher octane rating the only people using it would be those running factory engines built to use higher octane and modified engines, both of which are a tiny market compared to the number of vehicles designed for regular. The price would be right up there with race fuels I would think.

Go to the website and read it. For any of the fuels to meet the "Top Tier" specification they HAVE to meet it with ALL grades of fuel. So you can drink the "premium is better" Kool-Aid all you want but for certain fuels that isn't the reality. Now down at the local "Joe's" gas station then there might be a difference between the additives in whatever they are stocking but if you go the companies on the "Top Tier" list then you don't need to buy premium unless your engine was designed to run on it. There isn't anything preventing them from putting even MORE additives above and beyond the strict requirements that it takes to get the "Top Tier" rating but I'm not going buy that the fuel companies that are already meeting the extra strict requirements are going to that much trouble. Some of the local stations here have quit selling premium because no one buys it so it was just sitting in their tanks collecting water and junk. At many of the stations they only have 87 and 89 available. If you pull into many small town stations you don't want to buy the premium because it has been sitting there forever.

[bladeracer]

As I've said numerous times I run 98 octane purely for the extra mileage.
Have you tried the various octanes yourself to see if you get any difference in mileage?
If there's no mileage benefit then I can certainly understand why nobody uses it in the US.

[slickwill]

I've tried it on a lot of different occaisions. With some of the cheaper brands of gas I have had better mileage than with their low grades but never enough better to justify the difference in price. With the name brands that I've tried I haven't had a measureable difference. Definitely not enough to justify the extra cost. The one product that I have used that gave me very measurable results was Lucas Oil Products fuel additive. That stuff always gave me and extra four miles per gallon. It costs about ten dollars a bottle. The math probably works out to be worth it but my new car specifically warns about fuel additives not being good for the metal coating on the injectors so I don't use it anymore.

[dicknose]

Originally Posted by bladeracer

My Suzuki Swifts, 929, ZX6R and GSXR's don't run knock sensors but all exhibit better fuel economy on higher octane fuels. It's more noticable in the cars than the bikes but the bikes tanks are so small even another 20km a tank is well worth it for me. In the cars we get around 50km more per tank.

Sure - there are additives in the 98 that can give better economy.

And you might also get a bit more power.
But if the extra power was purely due to the additives then it would be about the same amount for all engines, when its not.

Personally I find the extra fuel economy not worth it - its costs more per distance due to the 10c extra cost of the 98.

Do you get Shell 100RON in Perth?
Last I looked it was about 20c more than unleaded but is great in the turbo car.

[bladeracer]

I get around 5% better economy out of my bikes and closer to 10% in the Swifts. In the Swift it's actually cheaper than 91RON and on the bikes the difference is negligable so the extra mileage is worth it.
I'm not aware of 100RON at the pump anymore but I used to buy it in drums years ago when fuel was crap.

[dicknose]

Originally Posted by bladeracer

I'm not aware of 100RON at the pump anymore but I used to buy it in drums years ago when fuel was crap.

Shell only offer it at a few locations - when it started it was at about 10 locations each in Sydney and Melbourne.

I think they stopped it a few months ago - Im guessing it wasnt selling well, having a 10c markup over 98 fuel.
From their blurb I gather it was just the 98 with 5% ethanol (which has a higher octane rating)

[CoenieL]

Hi there. I can get my hands oin some cheap 112 octane fuel. Have a 2007 Blade. You guys know if I can use this in the blade? Bike is standard, except for Leo Vince slip on.

[lanbrown]

The bike is not designed to use it and will provide no gains. If you could advance the timing to use it and raise the compression, then you could be making more power from it.

All you will do is waste your money. Higher octane does not mean higher power. When an engine is designed for it, then to make that power it was designed for requires the fuel to allow it.

[bladeracer]

As above.
You may find some improvement in fuel economy but it'll depend on the brand and what economy-improving additives they've put into it.

[imcamod81]

Fuels 101

Octane is the resistance to detonation or spontaneous combustion not caused by the spark plug.

There are two common methods to determine the octane rating of a fuel. The research method and the motor method. These methods are listed as RON - Research Octane Number and MON - Motor Octane Number. There is a third rating called PON - Pump Octane Number. PON is RON+MON/2.

The possible reason for some discrepancy in RON numbers is that two fuels can have identical RON and perform substantially different in the actual engine. Hence the reason for the PON. It takes the average of the two testing methods.

This came from Shell Oil in the years after WWII. They had the guys they called the Shell Answer Men. One of them was a professor of mine and explained all this stuff to me. He created the PON.

You see he was drafted into the army in WWII and spent his time researching fuels for all types of army vehicles, including supercharged airplanes. They were having reliability problems at the beginning of WWII with their supercharged engines. They felt it was fuel related and later proved it with tests.

The MON test is pretty cool. They use a variable compression engine and increase the compression until the engine emits an audible ping or knock. At least that is how they used to do it before knock sensors came around. I have worked on a variable compression engine and it was a piece of art work.

As has been stated, if the engine isn't knocking on a particular fuel, then solely increasing the octane is unlikely to increase performance. In the case of an engine that is adjusting itself to fuel capability, then yes more performance is possible. Different fuels can contain different heat contents and can produce more power, but this really has more to do with additives than raw octane rating. The following link will take you to VP fuels page on fuel info. Click on the octane tab to learn more there.

VP RACING FUELS - SPECIFICATION SHEETS LIST

Here is a link to an octane researcher's listing of octane engines, like the Waukesha that I worked on.

John's Octane Engine Page