2005 S60 What Octane is Best to use with 2.5T?

whistlebird · Post by **whistlebird** » 27 May 2014, 12:35

Since I got my car a month ago, I have read many different articles about what gas one should use in the car.

Mine being the 2.5Turbo model, the service advisor at my Volvo dealership told me that I could get away with Regular as long as the engine doesn't knock or ping. Others have told me Mid-Grade, and some even Premium.

I know the manual states 91 Octane, and here in the USA, we only have 87, 89, and 93 or 94 if you consider Sunoco Ultra.

So far I have put in Premium, and now started to use Mid-Grade. I noticed no performance difference or knocking or pinging as I know the computer will compensate.

For best performance and longevity, what would you all recommend or better yet, what have you been using?

Thanks.

Post by **marshallh** » 27 May 2014, 13:01

The user manual recommends 91 octane, so that's what I use.

They'll run fine on 87, but mileage is worse. I did some calculations a while ago and found that the worse mileage basically offset the decreased cost per gallon. So both octanes cost the same in the end. Better to use 91 then.

Whether you have 91 or 93/higher depends on your state and the ethanol subsidies in play. Higher concentrations of ethanol in gas cause worse mileage.

whistlebird · Post by **whistlebird** » 27 May 2014, 14:21

I just came across this article on the web concerning the blending of Mid-Grade. It sounds like a rip-off, if only a small percentage of Premium is blended with the Regular to make Mid-Grade.

http://hyperbear.blogspot.com/2006/05/d ... grade.html

In other words, if I am reading the article correctly, mid-grade is not created using a 50/50 mixture, more like 60/40.

That being said, the clear choice seems to be use either Regular or Premium. It seems there are too many risks with the Mid-grade.

Thoughts?

benrk · Post by **benrk** » 27 May 2014, 15:39

As I knew that there are different methods of measuring octane ratings I once again looked it up on http://en.wikipedia.org/wiki/Octane_rating

The manual for my '01 XC states AKI87 or RON91, AKI is the number commonly given on pumps in North America while most of the rest of the world uses RON & I believe I once read something about ROZ though the wikipedia article doesn't mention the latter.
However, it is regular automotive gasoline in most markets, interestingly I thought I remembered contemporary reviews complaining about these cars requiring premium.

whistlebird · Post by **whistlebird** » 27 May 2014, 17:13

Based on your commentary the best grade of gas according to the manuals is one with a minimum octane of 91, which here in the US we do not have, or 93 Premium for the best performance.

Post by **osman** » 29 May 2014, 19:59

Turbos need premium fuel because of the higher pressure and heat which (when used with low octane fuel) can cause pre-ignition and ultimately burned intake valve(s).

Post by **MoVolvos** » 30 May 2014, 01:13

marshallh wrote:
The user manual recommends 91 octane...

Whether you have 91 or 93/higher depends on your state and the ethanol subsidies in play. Higher concentrations of ethanol in gas cause worse mileage.

Have 3 older cars with 175K, 200K and 245K and they all run on 91 (Chevron). Can notice the difference running a lower grade and/or fuel with more ethanol.

Blessings,
BKM
_