I'm Still confused about which Octane to use?

[John Wilson]

I have an 08 G8/V6. Do I use 87? Or go higher? Any benefits from high Octane? Better MPG? More HP? Is there a Guru in the house! HELP!! John Wilson

[Chewy]

I would go by the manual personally. If you were to tune it I imagine you would benefit from a higher octane.

Cheers

[John Wilson]

I would go by the manual personally. If you were to tune it I imagine you would benefit from a higher octane.

Cheers

Thanks 4. My dealer put afull tank of gas in the day I bought it...low gas warning light was on. He put in 93 Oct. At a quarter tank I added 87 Oct. I hope nothing got scewed up? JW

[BlueJacket]

You will be fine. I am using 87 until I get a turn and then I will only use 93+.

[Mashko1]

I bought the car, it seemed alright. I put 89 in it and felt a nice improvement, also slightly better mileage. I just filled up with 91 today, so we'll see how that goes. The car is just about 2 weeks old. 89 is probably the sweet spot but with gas prices dropping so rapidly, I figured I would try.

[-Ray-]

John, now that the temps are getting lower, using 87 will not hurt your G8 in any way. 93 octane in a G8 tuned for 87 only helps with reducing spark knock. Spark knock reduces timing in turn reducing performance.
I ran 87 until my G8 was tuned for 93. Now I look for gas with no ethanol.

[John Wilson]

I bought the car, it seemed alright. I put 89 in it and felt a nice improvement, also slightly better mileage. I just filled up with 91 today, so we'll see how that goes. The car is just about 2 weeks old. 89 is probably the sweet spot but with gas prices dropping so rapidly, I figured I would try.

Got 19.84 MPG with the 93 octane.Top it off after a 1/8 tank with 87 octane.. 18.9 MPG. Now down a 1/4. Just found in the manual " 3.6L V 6...87 octane. For best performance or trailer towing 89 octane." I'll stick with 89 for a while. Mine also is two weeks old. We sould also see a improvement at 10K to 15K miles. John Wilson.

[Blackrider]

I was very supprised in the performance jump when I went to 91 from 87.

[Chewy]

Remember that he's talking about the V6 here folks! Not saying it wouldn't benefit either though...

[-Ray-]

My answer still stands.

[Mashko1]

Still feels better at 91. The car is still being broken in so that may have to do with it. Only 700 miles so far.

[chuy_copey]

87 or better per manual. One of the reasons the car is a good hit worlwide is because the engines for the v6 and v8 were modified to use regular unleaded 87 octane. This is due to gas prices I assume. I am using 89 thinking octane during different season might be lower than it is specified at the station. Note that we don't want to put the least sold gas in the car for it has been sitting at the station the longest. I will read the meter for each octane and if 89 is used more than the 93 I will stick to 89. Otherwise I will start using 93 to test it out.

[menace]

The lowest fuel here in Oz is 91, then 95, 98 and 100.


How much difference is there in price between 87 and 91?

[Chewy]

The lowest fuel here in Oz is 91, then 95, 98 and 100.


How much difference is there in price between 87 and 91?

We rate ours differently here.


In most countries (including all of Europe (http://www.answers.com/topic/europe) and Australia (http://www.answers.com/topic/australia)) the "headline" octane rating, shown on the pump, is the RON, but in the United States (http://www.answers.com/topic/united-states), Canada (http://www.answers.com/topic/canada) and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, the octane shown in the United States is 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US (http://www.answers.com/topic/united-states) and Canada (http://www.answers.com/topic/canada), is 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and some even deliver 98 (RON) or 100 (RON).
It is possible for a fuel to have a RON greater than 100, because iso-octane is not the most knock-resistant substance available. Racing fuels, AvGas (http://www.answers.com/topic/avgas), LPG (http://www.answers.com/topic/liquefied-petroleum-gas-1), and alcohol fuels (http://www.answers.com/topic/alcohol-fuel) such as methanol (http://www.answers.com/topic/methanol) or ethanol (http://www.answers.com/topic/ethanol) can have octane ratings of 110 or significantly higher - ethanol's RON is 129 (MON 102, AKI 116). Typical "octane booster" gasoline additives (http://www.answers.com/topic/gasoline-additive) include tetra-ethyl lead (http://www.answers.com/topic/tetra-ethyl-lead), MTBE (http://www.answers.com/topic/methyl-tert-butyl-ether) and toluene (http://www.answers.com/topic/toluene). Tetra-ethyl lead (the additive used in leaded gasoline) is easily decomposed to its component radicals (http://www.answers.com/topic/radical-chemistry), which react with the radicals from the fuel and oxygen that start the combustion, thereby delaying ignition, leading to an increased octane number.


87 here is 1.79 per gallon and 91 or 93 is 2.05 or so.

[menace]

Ahh thanks for the info.

$1.79 a gallon. Man that is so so cheap!!!

Fuel is currently 0.70c a litre for Unleaded or around $2.90 a gallon

[HoldenMan21]

I use 91 Shell V-Power, I'm getting 21-22 mpg city in regular driving conditions. When I'm pedal happy... I get 18 mpg. I used 87 on my first tank...never again ! I will stick with Shell also, better MPG !

[schwartz]

I was using the 89 octane for the longest time since it was the cheapest then decided to try the 91 and it seemed to give it better performance off the line and at WOT.After 2 tank fulls of the 91 I went back to the 89 and it seemed to run slower performance wise.Definitely sticking with the 91 regardless of gas prices.I could care less about the gas mileage,its all about the performance for me.There is a station out here that has 94 octane which i think i'm gonna try next to see if there is a difference.But right now the 91 for the V6 seems to be the way to go.But thats just my opinion.:Canada: