Premium Unleaded is "less dirty" than Standard Unleaded.

True or false?

I tried premium for a month and I'd rather unleaded, my car sucked the premium I got barely any distance out of it compared to unleaded, I've also tried e10 and that's s**t my car sometimes won't start on e10 and my car uses so much, so yeah for me unleaded is the best

I'm a chem engineering student and have been told by a few lecturers, in a car which is not tuned for 98ron (ie e-series falcons) performance difference will be minimal, however there should be a small economy improvement, BUT they recommended running a full tank of premium just once a year because of the extra cleansing properties...they said there's no need to run it all year in a car which is designed for regular..


As for e10.... I work at a shell servo part time and am a chemical engineering uni student full time...and I'm against E10, it is both less economical AND makes negligible difference to the emissions...it's just a government ploy to appear as if they're doing something about the environment...

So here's the chemistry approach, for fuel economy:

Combustion of Ethanol:
C2H5OH + 6*(O2) ---> 3*(H2O) + 2*(CO2), this reaction produces 1368kJ per mole of ethanol heat energy.
1mole of ethanol is ~46grams. So Ethanol produces 29.74kJ heat per gram.

Normal petrol is a mixture of hydrocarbons ranging from 5-carbon chains to 12-carbon so we'll take an average of 8, octane.

Combustion of Octane:
2*(C8H18) + 25*(O2) ---> 18*(H2O) + 16*(CO2), this reaction produces 5430kJ per mole octane.
1mole of octane is ~114g. So octane produces 47.63kJ heat per gram.

You can see that octane produces a lot more energy per gram than ethanol...

In terms of emissions:
So octane creates 678.8kJ of energy per mole of carbon dioxide evolved, while ethanol generates 684.0kJ. But then consider, ethanol is less efficient so more will be used meaning more tankers to transport more ethanol meaning more emissions from them. Then I guess you could go into a whole life cycle analysis which I CBF doing but you get the idea, this is why Prius's etc suck a**, because their whole life cycle analysis gets pwned during production and during recycling.


My fairmont is tuned for 98ron, however i couldn't tell a difference because during tune i also had a cam done and gained over 15rwkw, dunno if any was due to 98ron tune...it does run more economically now though despite the extra power

If I run regular, my car will ping under load when warm, if I run 98 it doesn't, it also runs smoother and i get better milage.

I have also been told that by the end of next year you won't be able to buy regular it will be replaced by E10, some states are already phasing it out.

Difference is about $5 a tank. don't be a tight a**

Get a tune to suit Premium and reap the economy and torque gains!

Full disclosure: I sell these tunes

yeah my 98ron tune was a j3 done by paul at cve...

but yeah like i said not sure how much of it was just due to the tune, because I did cam at the same time, but it did give a solid >15rwkw gain throughout the midrange

98 is way claner than norman unleaded. Iv proved it wen i changed my fuel filters after normal unleaded and there full of crap and after 98 it barely has any dirt at all!! I have to run 98 in my car anyway coz it pings with normal unleaded and runs like crap

well i dont supose you can run on av gas anymore i used to use it in the 60s and 70s for street use and cheaper that super for me at that time

i run nothin but pulp (premium) in my cars , if i run ulp the cars run ruff ,idle ruff ping under load and use a s*%t load more fuel

I went to the v8 supercars one year. Bp was sponsoring an fpr car and they had an exhibit with two bf gtp's on a dyno. They claimed they were both identical except one was running 91 and the other was running 98 ultimate. There was up to 20% difference in power, but they didn't let on that one car was auto and the other a manual. Hard to see but I could see one guy shifting and the other guy had both hands on the wheel. I am kicking myself now for not pointing that out in front of the crowd. But they gave me a $25 98 ultimate voucher for answering the question right.

So which station would have the best quality Premium Unleaded?

BP? Caltex? Shell?

imo, bp...........

I use shell or Caltex for PULP, only as I get a discount thru the vouchers there lol.
With a J3 tune and the AU motor I had it'd ping on 91 or 95, but not on either of those 2 98 ron stuff.

if i run 91 for a while my car misfires and all the injectors stuff up, i run 98 it goes well and doenst drink as much, also i ran e10 for a while and it stuffed my fuel pump, ill never use the stuff again