Unleaded vs Premium Unleaded

Hello all,

I'd be interested in your opinions on this subject.

I drive a Subaru Forrester (bought new) not quite 12 months old with 20,000klm on the clock. I use an injector cleaner periodically. I notice a fairly significant increase in power if I use Premium unleaded fuel vs ordinary unleaded. I know there's about 5 or 6 whatevers used to measure octane rating difference between the two (and thus a bigger bang) but I'm wondering if that's all there is to it?

Also, is it worth paying the extra 10c or so per litre for the extra performance? Is it a cleaner fuel? Does it have any other herbs & spices that the ordinary one doesn't?

I notice from other posts that some of you have worked in the petroleum industry and so await your opinions with interest..:confused:

Cheers,
Keith

I don't know about the techo side of things as far as fuel is concerned but I drive an XR6 ute and definately notice you get more bang for your buck with premium!!
I think in the early XR6's it was the recommended fuel, not sure if it is these days.
Jack.

Keith, we too have the forrester. In the handbook is a supplement which says the vehicle must be run on premium except in Australia. This is based on the assumption that ULP in Aus is 90.9 or higher which it aint. We get at least 60 to 100 km more out of tank of premium so you do the sums. Add to that the cars runs better, doesn't stall and generally has heaps more power. Some BP servos have three types of ULP with the middle one being 91 octane which is less expensive than premium but the forrester runs well on it.

My brother is a mechanic and has had a number of forresters in with complaints of stalling, poor economy and low power. Problem solved by changing to premium.

Cheers

I've found that I get better mileage with premium too. It probably works out about the same price over a long distance, so is worth the extra few cents per litre in my opinion. Our mechanic told us that we should use premium because it extends the life of the injectors. I always fill up with premium.

Have heard that not all premuims are created equal though. Not sure what the story is there, so I await info from the informed.

Thanks for that. Btw, the last lot of premium I got was from a Woollies outlet. You don't suppose that they'd use inferior quality petrol do you?

The premiums like the Shell Optimax and Mobil 8000 have adatives to clean your injectors as well as being higher octane. You also get better combustion at the higher end of the rev range with a high octane fuel. Definately more bang for your buck.

Not available in tassy.
had to sell my Honda Integra Vtir
before moving here. Broke my heart.

im not in the petro industry but my understanding is that when they boil crude oil it seperates - all the more viscious stuff sinks to the bottom and the less vicious stuff rises to the top. they then skim all the stuff off in layers to get the various products. examples are bitumen at the bottom and fuel at the higher end - avgas etc at the top... I also understand that the stuff at the top is more volatile thus "more bang for buck" - therefore the premium must be lighter ? ??? :confused: :confused:

feel free to correct me here - i'm happy to be wrong. I'd like to know if i'm right ..

cheers

Quote:

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Originally Posted by keith53

the last lot of premium I got was from a Woollies outlet. You don't suppose that they'd use inferior quality petrol do you?

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I have been getting the premium - the new Caltex stuff from Woollies and it seem to run my Subi just as good, but I still like to put a tank full of BP in every third or fourth tank.

My car has run almost exclusively on Optimax since I bought it new 5 years ago. At a recent service the guys said it showed. Very clean inside. I can't compare to the regular because I've never put it in there but my son pays the extra for Optimax in a 1990 TRX and says he gets more kms out of a tank so it doesn't really cost any more.

Quote:

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Originally Posted by Zed

im not in the petro industry but my understanding is that when they boil crude oil it seperates - all the more viscious stuff sinks to the bottom and the less vicious stuff rises to the top. they then skim all the stuff off in layers to get the various products. examples are bitumen at the bottom and fuel at the higher end - avgas etc at the top... I also understand that the stuff at the top is more volatile thus "more bang for buck" - therefore the premium must be lighter ? ??? :confused: :confused:

feel free to correct me here - i'm happy to be wrong. I'd like to know if i'm right ..

cheers

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So, the premium is lighter, therefore, the car is lighter with a full tank, hence the better mileage. :D

I've got an AUII - anyone tried premium in one of them for normal driving? Personally, I can't see how it would help your average beast in normal driving because most of the benefits are at the top end of the rev range, but I'm happy to be corrected.

The MG runs on premium, but she's been hotted a bit and isn't a happy beastie on standard dishwater. Mind you, I tend to be a little ... er ... spirited when I drive her.

Cheers
Richard

The higher the octane rating the better the fuel, but it has nothing to do with the actual amount of "octane" in the fuel. Check here for more info http://www.prime-mover.org/Engines/G...es/octane.html
If you put a low rated fuel in a car that needs the high rated juice then the engine will start knocking (igniting at the wrong time) and if you do it long enough you'll stuff the motor. But you can put the better fuel in a regular car and not have a worry. You also used to be able to buy an octane booster to mix with your fuel (probably still can) but from memory the good stuff was $30 for every tank

I have a V6 2002 Vectra ... its said in the manual to only use premium unleaded .... so that is what I do.

I find I get more k's when filled up with the Shell premium (stuff) .... I get it from Shell as they have the 4c off with the docket and it only makes it 6c dearer than the regular.

I have filled up time to time at the local APCO who has its premium at about 4c dearer than regular unleaded and find that the performance and milage is lower than the Shell premium.

My mechanic said that BP has the highest octane and is the best of the premium brands .... no discount docket and no flybuys means that it is Shell for me.

I've got a newish honda accord euro and it runs exclusively on premium. I ran a tank of normal unleaded through once and there was about a 10% drop in fuel economy and a noticeable drop in power.

If nothing else, it is better for the environment too (so I am told). Something about burning cleaner and having less pollutants. Or something like that.

I use optimax most of the time - sometimes the ampol stuff (but it's not as good)

Trav

The octane rating refers to the amount the fuel can be compressed before spontaneously ignition occures lower the octane rating the less you can compress it before it ignites by itself .Not good when it hapens
I run my forrester ( this is the second one) on normal unledded around town , with all the stop & starts economy is at its worst .
But when on a trip or towing the Camper always use optimax more power better economy




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