Best Grade of Gasoline

[MrAl]

Hello there,

What do you think is the best grade of gas, the low priced, medium priced, or highest priced at the pump?
I ask because someone said that the high octane gave them better gas mileage.
Question is, is it worth it to buy the higher octane, like 93 ?

[FlyingVolvo]

Fuel grades, like oil, can open a can of worms. The general consensus is that if you have a turbo, you should be running higher grades. Most Volvo manuals state that 87 is minimum, but 91 optimum. Any slight increase in MPG you will get from higher octane will likely be negated by the additional cost. That being said, on a per-tank basis, the difference in cost is pretty minimal, so why not just go for what the engine was designed for?

There's a lot of misconceptions out there about fuel grades. Most people believe that "higher octane = MORE POWER! BIGGER BOOM!" while it's sort of the opposite that's true. Octane rating is basically a measure of the fuel's ability to resist compression (and pre-detonation a.k.a "pinging"). Higher octane fuel is in a way "less explosive" because it can be compressed higher and resist detonation better until the spark plug actually does the job.

[oragex]

It has been already discussed in a thread somewhere on the forum. Looks like the turbo must use Premium gas, while the non turbo IF it is in good condition will work perfectly fine on Regular without pinging. You may loose a few mpg using regular on the non turbo but the gallon cost difference should make up for it.

I would however pay more attention about the place to fill up: in the US and NJ is not an exception, it's not rare for gas station owners to allow mixing some Regular inside the Premium underground tanks when the truck comes to refill so the Premium they sell is not really 93 octane.

http://www.nj.com/news/index.ssf/2011/1 ... charg.html

[rspi]

Owners manual recommends 91+. I only use Top Tier stations when possible.

http://www.toptiergas.com/

[sleddriver]

It depends......
The gas I buy here in Tx. isn't the same as what you buy in NJ. Second, ambient temp. is another consideration. It's very, very hot and humid here during the L-O-N-G Summer. It can hit 100°F here on May 1 and Sept is often as hot & humid as August.

[MrAl]

Owners manual recommends 91+. I only use Top Tier stations when possible.

http://www.toptiergas.com/

Hi,

Thanks for letting me know about that octane issue. I must have missed that.

I dont think we have any "Top Tier" gas stations in this geographical area but i could check.

[abscate]

Remember you have to be careful to sort out if the manual is referring to US or EU octane, read the fine print

[mrbrian200]

My car, MY06 2.5T, seems to like Marathon premium. Throttle response is a bit zippier and it gets the best consistent econ from varying Marathon stations. It also likes Shell premium, but only Shell purchased in Illinois/Chicago area. It does not like Phillips 66 and Shell purchased in Indiana: Those are both listed as top tier, but I get noticeably lower econ with their fuels.

[June]

Owners manual recommends 91+. I only use Top Tier stations when possible.

http://www.toptiergas.com/

Spent time on YouTube looking at Top Tier gas and the Shell premium is. Amazing the difference if you have not looked. One of the short newscast for Detroit tested the 87 and 93 gas for amount of detergent. Shell 93 came in at 31g per 100ml as the highest detergent for 93 grade compared to like 8g per 100ml. Exxon 87 had the highest detergent content for 87 grade at 20g per 100ml.

In the link provided to Top Tier gas is a link to AAA independent study of non Top Tier gas and Top Tier gas with astonishing results. On YouTube the intake valves from the test engines can be seen. I truly thought all gasoline had the same detergent maybe a little more in 93. This link was a eye opener. June

[abscate]

Not too many differences but just remember to never mix Shell And Mobil products..