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What Octane number do you use inyour gas tank?

  • 91-93, Yea Baby!!

    Votes: 112 36.7%
  • 89, does the job, no complaints.

    Votes: 64 21.0%
  • 87, I'm poor, only wish i could use the high stuff.

    Votes: 129 42.3%

  • Total voters
    305
121 - 140 of 195 Posts

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reddevil said:
I use 91 octane and add a gallon of tolulene (114 octane) into everytank A gallon of tolulene bought in bulk is about $6 per gallon, so the average price per gallon I am paying is about $2.60 per gallon, and at 15 mph it is getting spendy. However, I don't want to blow ahole in another piston. I am pushing about 7-8 psi on a 1990 NA 2.2 via an Eaton m62 supercharger, walbro pump, MSD rrfpr and an AWIC.
:eek: :eek:

How many miles u got on the engine? Maybe you wouldn't detonate if you had some MSD ingnition and/or timing control in the mix...just a thought. Always been a MSD fan....or was it LSD? Whatever :screwy:
 

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Just to clear up the confusion between US octane rating and Australia and (I suspect) the UK. In Australia fuel octane is quoted in RON (Research octane rating). In the US it is the average of RON & MON (Motor octane rating), which results in a lower number for the same fuel. RON is the octane rating at low revs and MON is taken at high revs. I'm not sure what the MON octanes of our fuels are in Australia so I don't know how it actually compares but I have consistently heard that Australia often gets detuned versions of cars due to our low grade fuel.

Available in Australia from the pump are:

Unleaded 91 RON
Premium Unleaded 95 RON
Lead replacement petrol 96 RON
Ultimate/Optimax/Synergy 98 RON

You can also buy drums of Avgas (100 RON) for rally cars etc.

Generally the BP ultimate costs about 7 cents a litre more than standard unleaded. I have found that I get between 50 & 100km extra out of a tank by using it (depending on how I drive) and the extra kick you get at 4000rpm and above seems to be a little bit more pronounced. (MY02 Impreza RS).
 

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Z1Auto.com
MY00 2.5RS SRP
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483 Posts
I use 89, the engine is stock but I don't want to put that 87 piss in my car and get shitty gas but I also to want to put 93 in and have it running too rich. Plus the price for 89 is finally coming down, I found it for $1.99 a gallon which definitely works for me considering that last month I was paying $2.25
 

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1999 2.5RS WRB
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CWC.02 said:
I'll start, I use 91-93 Octane, and Texaco (now known as Shell) and 76 seem to be the better grade of gas over here in Wenatchee, Washington. But I am thinking of going down to the 89 Octane, just to see if I can notice a difference and save a couple bucks.
Dont u mean Texaco and Chevron are the same company? Shell is separate
 

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02 Impreza RS2.5 with no mods. Average mileage with Shell V-Power (91) is just over 20mpg. With 87 from various vendors I get 17-18mpg. The car also pulls better > 75mph with the roof rack on using 91.
 

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I'm at about 5,000ft where I live, and that's where my day-to-day driving is. You can get higher than 91 in CO? I used to get 93 in WI, but not so much here in AZ.
 

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Audi Fondler
2000 Silverish 2.5rs Sedan
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there's some places that sell up to 100... but stock you won't benefit much more than 93... with a lot of n/a mods up to 95 is useful... usually you find 93/94 or maybe a 97 or 100... so you gotta mix or use a good concentrate booster for your tank size... the place that sold 100 nearby closed... the nearest place that does 94 is kinda far now so I only get it if I'm planning on a track day or if I'm in that area... I hope the place that took over Larry's Amoco on Wadsworth will continue to carry 100 once it re-opens
 
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