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High octane fuel and the truth

wraith

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Wraith

Your claims are not credible. You are telling us that your 94 Buick engined VR increases its fuel economy by 50% just by using premium unleaded?

Unless your engine has a much higher compression ratio than standard, or is supercharged, (in which case your economy would go the other way), I can't see any way it's "tuned for 98 already."

But, it's your story and you're entitled to believe it.

Yeah believe it if you will I have people that will back my claim but yeah. Maybe it's my cop chip:dance:
 

greenfoam

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I'm not too fussy on octane on low compression engines but if you have a look at the filter baskets in the injectors on a car that runs on premium rather that 91 octane there's a huge different in how clean they are so don't agree with both fuels being of equal quality as far as keeping things clean goes
 

kane88

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I can only go off personal experience which is by no means scientific. But when I run 98 I get 600 km's to a tank on anything else it's 400 km's. Although I suspect my car is tuned for 98 already as it refuses to run properly on anything else.


That seems a little bit too unbelieveable... If everyone could pull those figures in a controlled environment then nobody would buy 91 RON, ever.
Considering most of the information I have come across suggests a few percent benefit, and the fact that the difference in price between the two fuels is a matter of cents, for you to get a 50% improvement is huge, even if tuned for 98 RON fuel. If the premium stuff really did give these sort of results we'd be paying well over $2.00 per litre for the stuff.

What are the variables here? Is that city travel compared to a highway cruise? Did you flog it for the previous tank?

I suppose grandmas can't afford 98 or 95 any way. Good point.

Also, are you calling VY/VZ grandma's cars?
What does that make your VR? :smoking:
 
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ephect

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With so many guys on here talking about using 95 RON, 98 RON and higher, and claiming to make up to 30% difference in power output, and so many others asking whether this more expensive fuel is going to benifit them I just thought I'd start a thread to help educate people and dispel some common misconceptions.

1. If your engine is not designed to use premium fuel, it will not benefit.
When I say 'not' I mean in any noticeable way. Sure, you may get a 0.2 or 0.3% change in fuel use or power output, but it is barely measurable, and certainly not noticeable.

2. Premium fuel is not 'better quality' or cleaner than normal unleaded.
Believe it or not, all fuel comes from the same place. It is all refined and then put into storage containers. Chemists then add chemicals to this fuel to determine what it will be called ie. Premium, ultra, regular etc. In fact, premium fuel has more chemicals added to it than regular unleaded.

The deciding factor for which manufacturers designate the engine to use, is DESIGN. The design of the engine (generally the compression ratio of the combustion chamber) decides whether the engine will NEED high octane fuel, or not. Engines wil compression ratios of 8 or 9:1 do not need premium fuel, nor will they benefit. It's not a choice that manufacturers they make, it's a need.

Standard Commodore engines do not need premium fuel, nor will they benefit from it.

I just hear so many stories of people wasting their hard-earned money on premium fuel and not realising that it's no better than regular. Their mate told them that they got an extra 50 km or 100km from a tank, or they think their car 'feels' better with it. One-off anecdotes unfortunately do not make good proof.

There's one main reason fuel companies push it onto consumers (apart from those few that actually need it), because it is more profitable. More $ for the same product. They don't lie, a 0.08% fuel consumption decrease is a decrease, but they happily leave this data out of the marketing dribble.

If you want to know more about it, then I recommend you read some engineering books, or peer reviewed documents (not a forum or manufacturer's website). Please don't waste your money.

I am happy to answer any questions/comments/disagreements that you may have.

how can you say your commodore will not benefit from higher octane fuel and not have facts to back it up? think about it, more fuel, more fire, more intense explosion.. less work = more milage. the delco can adjust to a higher octane fuel, not as much as a car tuned to it but oranges and apples.

hmmm... nothing that I'm allowed to publish online. All too complex and long winded anyway.

I have heaps of books, articles and journals that I studied from, but, being on a forum, this post was more to educate people than to proove or justify my words.

I will, however, answer as best as possible.

why aren't you allowed to publish the facts? how can you educate us just by dictating; this is the truth but im not allowed to back it up with facts?! just believe me...... so your saving that avgas, which is a higher octane, just because it comes from the same refinery will gain you no noticiable results? regardless of tune?
are we talking efficiency of engine or fuel efficiency or just tyre fryin fun?

Me personnally see no reason to pay 15c extra all the time, i'll run a couple a tanks here and there on trips.
 

v8commie

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Yeah believe it if you will I have people that will back my claim but yeah. Maybe it's my cop chip:dance:

hey cop cars never had a chip i dunno where people got that from they probly feel quicker because they have an lsd they came out with fe2 and lsd thats it
 

moose man

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how can you say your commodore will not benefit from higher octane fuel and not have facts to back it up? think about it, more fuel, more fire, more intense explosion.. less work = more milage. the delco can adjust to a higher octane fuel, not as much as a car tuned to it but oranges and apples.


why aren't you allowed to publish the facts? how can you educate us just by dictating; this is the truth but im not allowed to back it up with facts?! just believe me...... so your saving that avgas, which is a higher octane, just because it comes from the same refinery will gain you no noticiable results? regardless of tune?
are we talking efficiency of engine or fuel efficiency or just tyre fryin fun?

Who said anything about more fuel?
Dude, do you even know what an octane rating is?


Heaps of people are talking about a 'tune', whatever that is. If you are talking about eeprom/ECU programming, then you should know that you can't change the compression ratio of the engine this way.

Remember, a higher compression ratio is the only reason that you would ever need to change from regular fuel to premium...no other reason. A tune will change how much fuel is injected, when it's injected and a host of other changes to increase performance, but it won't need premium fuel to do it. The power increase comes from the fuel and ignition mapping changes, not the fuel octane rating.

I should have expected the sheep on this forum to trash my thread just because they don't like what I'm talking about. That's fine, but tell me why so we can all learn instead of just calling bullshit. Go and do some reading on what a knock sensor does, and why it does it.
 

one_and_only2004

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I thought this was common knowledge? I've been running mainly standard 91 through my car ever since i got it - the few times i have used premium i've actually used more fuel.
Admitedly i'll have to start running 95 octane to compensate for the added compression from the supercharger, but untill then standard 91 will do the job.
E10 is 95 octane isn't it?
 

moose man

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RON - Reasearch Octane Number, is a rating given to fuel that describes it's resistance to pre-ignition, or pinging. Fuel pre-ignites for two main reasons:
1. When there is a hot engine component that flashes off the fuel mix before the spark plug can,
2. When the engine compression is too high.

RON has nothing to do with a fuel's energy output or flame heat.


Who I am doesn't really matter, but I'm lucky enough to have worked alongside many different types of engineers, programmers, designers and industrial chemists with many different car manufacturers as part of my job. I don't profess to know everything, but I've seen what happens behind the scenes and why they do things the way they do.
I have simply written this thread to share the knowledge I've learned, not to stir trouble...but take it as you will.
 

BowTie

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Your entire perspective seems to to be focused in regards to pre-detonation or pinging.
The big picture includes performance, emissions and residual deposits.
Your claims are accurate only in regards to preventing pre-detonation.
Dyno would show the truth.
I am happy to pay 7% extra for a 3-4% performance gain.

Unleaded is for tightarses with woolies dockets.
 

sik_dose

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It was obvious you where going to get upset people posting crap right from the start. As soon as you tell people they have been wasting money on something that is only better in their head their going to winge. I only run 95 RON when I put injector cleaner through my tank other than that, S pack tune VN runs smooth as on 91 RON.
 
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