Octane preferences

[Dave T]

My Saab specifies 87 octane (The US uses the R+M/2, which is about a 4-5 octane lower number than in Europe, Australia, Singapore; European 98 is about the same as 93 in the US) and recommends 90. Octane requirements are higher in hot weather.

I mix premium and regular to reach 90 in the winter. In the summer, I run it a bit higher than 90.0. Some of the last customer's choice remains in the hose so if they bought regular and you buy premium, you get some regular. One motorcycle forum said this was significant for motorcycles if they just buy a gallon. I first buy premium then pump regular second.

I found that gas mileage is slightly higher with 93, but that the increased costs cannot be justified by increased gas mileage. The US EPA tested a 2005 9-3 and published highway mileage is 1 mpg higher with premium. I'm not sure whether it was 0.6 or 1.4 mpg higher.

I found that in hot weather, the car has slightly more pep running on 93 than 90.

I rented a Dodge Charger a few months ago. The owners manual said the Hemi engine should use 89, 87 for the other engines. It also said not to use higher octane, just the correct octane.

In California, the highest octane that is readily available is 91. That might be why some cars specify 91, not 93. In Seattle, 92 is the highest found. 94 is available in Vancouver, BC.

[nordwulf]

Saab specifies a minimum of 87 for the 9-5 but at least 90 is recommended for the 2.3t LPT and 93 for the 2.3T engine. I experience using 87 really affect performance and I noticed engine pinging. Gas mileage decreases as well so it is a no-brainer for many 9-5 owners (in the US) to use premium only. The difference is only a few dollars per tank so it doesn't make sense to use regular gasoline. As with engine oil, only the best gas for my car.

[Aaron]

I think the 2.8T asks for 90+ in the manual. Around here different stations offer different options, examples of the two I visit:

• Hess: 87, 89, 93
• Sunoco: 87, 89, 91, 93.

With Sunoco I tend to pick at random whether I want 91 or 93 since they tend to only make it a 2-3 cent difference, Hess is always pretty reasonably priced so I pump 93.

[sab]

I only ever use 98RON here in both my Saabs. And only buy it from BP, with maybe Mobil being second preference. never use Shell as had all sorts of problems with their 98RON mix.

sab

[jlrSAAB]

I was using 95RON during the first year and I my exhaust pipes got very black smoky due to water condensation...
in resume to be short.. right now, I am using "OPTIMA 98ROM" ten cents more expensive than 95RON.

[jlrSAAB]

RON, MON or PON?

Or how do you grade petrol/gas

What do you think about these equivalences?.

[SaabKen]

In California, the highest octane that is readily available is 91. That might be why some cars specify 91, not 93. In Seattle, 92 is the highest found. 94 is available in Vancouver, BC.

I've been using "mostly" 87 for the past 9 years on my 2.3FPT with the occasional splurge to 89 or 91. I might have filled once or twice (ever) with 94. In the past 2-3 months I've "seen the light" and gone up to 89 steady. Matilda likes it. she purrrs.

Dave, we're running about Cdn$1.15 for a liter of 87 these days, or about US$4.30/gallon

[Burnsside42]

In our 9-5 we run 89OCT regularly with an ocasional 93OCT tank to "clean things out" - but the 89 seems to work well for the GT17. If we had an Aero we'd prolly run more 93.

In my 9000 with the Aero turbo and Stage 4 tune - that car has not seen less then 93OCT more then once or twice.

My 86' 9000 I run 89OCT as well as the 90' vert. Stock cars can deal with the lower oct better. I never run 87 in ANY turbo car - that gas is dirty and produces too little power the car just feels unsafe to me. Not a fan of pinging...

[SaabScott]

Dave, we're running about Cdn$1.15 for a liter of 87 these days, or about US$4.30/gallon

And I haven't read a single thing to explain this either.

Still, my Saab only gets 91 or 94 octane regardless.
The savings I get from increased fuel economy with the higher octane make up for the difference in cost.
Especially as it starts to creep up there.
$0.85/L + $0.14 for the higher octane = 16.5% increase in price
$1.15/L + $0.14 for higher octane = 12% increase
When I am getting a return of 10%, the higher gas goes, the closer I get to break even!

[SpecialTool]

I mix premium and regular to reach 90 in the winter.

Dave you are a sick puppy.

Like sab I'm a BP ultimate (98RON) devotee. Who cares about a few extra bucks, it's simply the best.