1997 850 Premium Fuel

[jblackburn]

I always used 89 unless it was 80+ in the summer.

They do run like total crap on 87 though. So much bog.

[diggler30]

I always use the highest octane available, especially in a turbo. I just find the benefits are well worth the money. My tank is 18 gallons so if i fill up with with a lower octane and save $0.10 per gallon I am only saving $1.80 and getting worse performance and economy. Is that really worth it? I definitely don't think so.

[jblackburn]

I always use the highest octane available, especially in a turbo. I just find the benefits are well worth the money. My tank is 18 gallons so if i fill up with with a lower octane and save $0.10 per gallon I am only saving $1.80 and getting worse performance and economy. Is that really worth it? I definitely don't think so.

Try 60 cents/gallon difference here

[polskamafia mjl]

I always use the highest octane available, especially in a turbo. I just find the benefits are well worth the money. My tank is 18 gallons so if i fill up with with a lower octane and save $0.10 per gallon I am only saving $1.80 and getting worse performance and economy. Is that really worth it? I definitely don't think so.

+1 That's always been my logic. The "savings" are so small as to make no difference.

[diggler30]

I always use the highest octane available, especially in a turbo. I just find the benefits are well worth the money. My tank is 18 gallons so if i fill up with with a lower octane and save $0.10 per gallon I am only saving $1.80 and getting worse performance and economy. Is that really worth it? I definitely don't think so.

Try 60 cents/gallon difference here

$0.60/gallon! Wow! Next to my house is currently $3.59 for 87, $3.69 for 89 and $3.79 for 92. Only $0.10 differences around here for the most part.

[jblackburn]

I have seen 3.29 for 87, then 3.89 for 93. Ridiculous.

[scot850]

I used to have a 93 850 N/A. We don't do a big mileage and mostly for running around the city. Had the car for 6 years and covered about 45kkm (30 kmiles) mostly on 87 without starting problems or anything else. I don't rev the nuts off my cars, or drive hard. However, if I was to do any highway driving at higher speeds I used premium as the engine had to work harder. In Canada, the gas is about $10-15c/litre (about 38c/gallon) difference in Alberta province.

One consideration for up here though is that a lot of the 'Regular' 87 gasoline have little 'cleaners' and can freeze easier at low temps we get. Now that I do little mileage (2000 V70R has done 3000km in 18 months) I only now use 91 in all 3 Volvos, especially as they are all turbos.

Bottom, line, I'd only use premium in turbos and regular in N/A ONLY in town driving. Not very scientific, but in town driving out 850 N/A showed little difference in mpg, and as we don't drive like crazy folks, pick-up was not an issue.

Neil.

[instarx]

I doubt you will save money by using 87 octane. i am a engineer-type and I do carefully controlled experiments, and two years ago I measured a significant boost to fuel efficiency when i tried a few tanks of 91 octane. It probably resulted from the engine management system being able to use more efficient settings with the higher octane. When I did the math it turned out that the extra money I paid per tank was being balanced by the extra miles i got per tank. As a result I had the same overall fuel costs whether I used 87 or 91 octane - I could pay less and go fewer miles, or pay more and go more miles. But because the car runs so much better with 91 octane I switched over and now use only 91 octane even though i am a cheap b*. I suspect using 89 octane would fall in the middle, but I did not test it.

If the manufacturer says use 87, then use 87 - there will not be any savings by going to 91. But if the manufacturer says use 91 then the car needs 91 to run at peak efficiency and it probably isn't costing you any extra to do so.

There is an old thread here where I talked about the numbers in detail.

[davolvo]

Well, I did up grade to premium from the midgrade and I put some Lucas cleaner in with my last two fills. My mileage went from 20 normally, to 22 on the second fill and 24 and the last fill. Wow, what a difference!

[jblackburn]

If the manufacturer says use 87, then use 87 - there will not be any savings by going to 91. But if the manufacturer says use 91 then the car needs 91 to run at peak efficiency and it probably isn't costing you any extra to do so.

There are some engines "rated" (read "de-tuned") to run on 87 that will run better on higher octane. Toyota's V6 engines and my Chevy 1.4T are a good example. They'll run on 87, sure, but they do it by pulling timing and throwing away MPG and midrange power. They, like the Volvo, will run much better on something like 89 or 93. Why are they specced this way? Because people would throw a hissy fit over having to use more expensive gas in a non-luxury car.

Well, I did up grade to premium from the midgrade and I put some Lucas cleaner in with my last two fills. My mileage went from 20 normally, to 22 on the second fill and 24 and the last fill. Wow, what a difference!

Yep, your car is able to fully advance timing and make the most out of each combustion stroke. The higher octane pre-ignites much less than 87, which makes a difference in power AND fuel economy when the car isn't constantly having to combat knock.