S-80 fuel

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PERRY BROWN

I have a 2000 S-80. The owners manual says that I should use 91 Octane
fuel. Where I live fuel comes in 87, 89, and 93 Octane strengths. Should I
continue to use the 93 Octane fuel or will the 89 Octane suffice?
 
I have a 2000 S-80. The owners manual says that I should use 91 Octane
fuel. Where I live fuel comes in 87, 89, and 93 Octane strengths. Should I
continue to use the 93 Octane fuel or will the 89 Octane suffice?
Click to expand...
IMHO, you should keep using the 93. Do you have the Sunoco brand? They have a
91 octane in our area (NH). The other option is to do a tank of 89 and a tank
of 93. My son does that with his 850.
 
For obvious practical reasons (marketing/advertising for a start) it's
in the best interests of Volvo Corporate to provide cars that return the
best possible mileage and performance numbers. Even when the gasoline
recommended is somewhat more expensive, those interests are still being
served.

The highest octane "premium" fuel most widely available in North America
is (U.S. rating) 91. For them to say ". . . or higher if you can get
it" adds unnecessary confusion, but should be obvious. For some years,
Volvo Owner's Manuals have stated that 87 octane is the minimum
acceptable. The cars will run on this fuel without damaging the engine,
but both economy and performance suffer as the computer backs off
ignition timing and advance to prevent knock.

Bottom Line: If Volvo could market quality vehicles that would run on
kerosene (not a good example of l-o-w price anymore, just low
performance) it would be in their best interests to do so. *So,* if a
pricier fuel is recommended, it's because they know that, overall, their
customers will be happier.

bob noble
Reno, NV, USA
 
Thank you for your thoughtful response. I will continue to use 93 octane
gas and see what happens. I know that as the car ages I should utilize
higher octane fuel.
 
I think that 89 is the way to go***as long as you do not get 'knock' during
normal operation--not during hard accel, but during normal use if no or very
small knock...will be fine.
 
I think that 89 is the way to go***as long as you do not get 'knock' during
normal operation--not during hard accel, but during normal use if no or very
small knock...will be fine.
Click to expand...


The car should have a knock sensor that will take care of it (though
this necessarily compromises efficiency), but I can't agree that *any*
amount of knock is fine. What you are hearing is the result of a
shockwave being created in the combustion chamber.

Using a lower octane fuel than the engine is designed for can result
in it not buring progressively as it should, but instead it responds
to the pressure inside the combustion chamber by detonating with a
flame travelling at supersonic speed. This not only stresses the
engine components, but is inefficient. You may get away with it, but
it is not fine - it can be very destructive.

For best efficiency, use a fuel with the octane rating the engine was
designed for. If this is not available, use the next higher.
--

Stewart Hargrave


For email, replace 'SpamOnlyToHere' with my name
 
I wouldn't have thought that a good idea as the ECU 'learns' a set of
operating parameters over time. If you keep changing the parameters by using
different fuels it will never settle on an optimised calibration...... I
would have thought it much better to stick with one or the other.

If you want a DIY solution to unobtainable octane ratings check this
out.....

http://www.vtr.org/maintain/gasoline-octane.html
 
The non turbo has a knock sensor?




Stewart Hargrave said:
The car should have a knock sensor that will take care of it (though
this necessarily compromises efficiency), but I can't agree that *any*
amount of knock is fine. What you are hearing is the result of a
shockwave being created in the combustion chamber.

Using a lower octane fuel than the engine is designed for can result
in it not buring progressively as it should, but instead it responds
to the pressure inside the combustion chamber by detonating with a
flame travelling at supersonic speed. This not only stresses the
engine components, but is inefficient. You may get away with it, but
it is not fine - it can be very destructive.

For best efficiency, use a fuel with the octane rating the engine was
designed for. If this is not available, use the next higher.
--

Stewart Hargrave


For email, replace 'SpamOnlyToHere' with my name
Click to expand...
 
Virtually all modern electronic engine management units have knock sensors
these days...
It helps them to get optimum economy and performance from the engine.
 
Please answer the question, a general statement is not an answer.
Does the non turbo 2.9 have a knock sensor?
 
Yes, the 2.9 non-turbo does have a knock sensor fitted - as does just
about any car that's fitted with an onboard computer. This allows the
advance curve to run at the optimum for power and economy.

bob noble
Reno, NV, USA
 
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