S-60 Fuel Recommendation

Just took delivery of an S-60 2.5T. The manual recommends a minimum of 91
octane fuel, but the dealer says he drives his S-60 all the time with 87
octane and has no problems.

Wouldn't the timing be retarded under load and stress conditions all the
time with 87 octane? My Bonneville SSEi says I can damage my engine if I use
less than 92 octane. I realize that's because of the supercharger, but I'm
curious how similar the turbo's problems could be with the cheaper gas. I've
never owned a turbo before and could use some advice. Obviously, I'd rather
use the cheapest gas I can, but not at any risk to the engine.


Thanks for any advice,

Lee C. Carpenter
Landisville, PA

'04 Volvo S-60 2.5T
'00 Bonneville SSEi
'95 Grand Am SE 3.1

 

In my opinion, if the manufacturer says 91 octane, then use 91 octane. It says
that for a reason. However, I have heard from various mechanic sources that
whatever fuel you start ith, you should stay with, i.e. start with 87 then stay
with it. I had a Toyota Cressida several years ago and the book said 91, but
me being cheap ran 87. I got all kinds of knocking and sputtering and slow
acceleration until I went to 91. My son had a similar problem on his Volvo
850. Was running 87 and was having very poor performance. Now he runs a combo
of 93 and 89 (one tank of 93 and 2 of 89) and it seems to be running better.

Just my 2 cents worth.
Walter Wise

 

Thanks Walter.

The salesman couldn't tell us if the fuel they filled the car
with was premium or not. Therefore, I assume it wasn't. I'll put 87 in the
first fill up and see what happens.

Lee

 

The manual for my '01 S-40 also says to run 91 octane fuel. I ran an
extended MPG comparison between 91 and 89 (the mid-grade). On both fuels
the engine ran fine but gas mileage was lower with the 89 octane - I
computed the cost of the gas against the MPG and it turned out that the
actual cost difference of 91 octane gas was only 1 or 2 cents higher than
the cheaper gas - so I've stayed with the 91 octane ges ever since.

Rob MacTurk

 

The engine will have to compensate at all times with 87 Octane fuel... Why
not just go with the 91 that they recommend? My motto is, if you can't
afford the gas, then you can't afford the car, look elsewhere.

You are still getting much better mileage then an SUV ;-) Volvo's tend to
get pretty good fuel economy.

 

A common enough string on this NG, Lee.

My own extended (if not scientific) testing found that 91 gives about 5%
better mileage than 87. Performance is notably improved. As another
post suggested, you can do the math on this one.
bob noble

Reno, NV, USA