Improves Engine Performance

Your local gas station probably offers you 3 levels of gasoline, like
gold, silver and bronze. These typically have different levels of
octane in them and you will generally get a little better mileage for
the more expensive type.

In addition to different octane levels there are many different
additives that can be in a companies brand of gasoline and this
differentiation can have a big impact on your vehicle.

One type of additive is a detergent which generally cleans your
engine. Without some level of detergents engine deposits form and this
causes reduced fuel efficiency, acceleration and power as well as
increasing emissions and rough idling. read here..
http://www.zone-car.com/?gasoline-detergent-improves-engine-performance.php

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used car resources

 

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This is not my experience. I have found that there is essentially no
difference in fuel consumption using any of the three grades in my
typical mixed city/highway driving.

 

I find moving to mid grade improves economy, but between that and premium is
not any improvement I can measure. Depends on the car, higher compression
engines will benefit more in general.

 

Out of curiosity, what is the typical spread in price over these three
grades?

Here in Finland, we have two grades, called '95' and '98'. (I don't
think they correspond exactly to American 95- and 98-octane because that
would be some pretty high-quality fuel.)

Tax is much higher here, of course. The 95 presently costs about 1,36
euros per litre, with the 98 at 1,40. At today's rate of exchange,
that's about US$7.02 and 7.23 per US gallon.

If I put 50 litres in my '95 850T (which has a 73-litre tank), the
difference in cost between the 95 and the 98 is only two euros!
Translating again into American terms, it means the difference between
$92.89 and $95.62 for a 13-gallon fill-up.

With such a tiny margin of difference, it doesn't make any sense to try
to 'save money' by using 'cheap gas'.

cheers,

Henry

 

Last I checked, regular was about $2.65/gallon, mid grade was $2.89, and
premium was $2.97, so about a 30c/gallon price difference between regular
and premium is typical.

 

Thanks. That's interesting: 2.65 plus 30 cents is more than 11% higher.
Here the price difference between regular and high-test is less than 3%.

cheers,

Henry

 

$3.09 for regular unleaded to $3.49 for premium hereabouts.

 

Thanks for the data-points. That's an even greater margin -- almost 13%.
I can see that with a spread like that it might be tempting to try to
get by with the lowest grade that works. But, as I noted in my earlier
post, here in Europe such considerations don't really apply as the
difference is between $94 for a typical fill-up with regular versus $96
for the premium.

And now I get a chance to quote my favourite old-Volvo-geezer line:

NOBODY EVER BOUGHT A VOLVO FOR THE FUEL ECONOMY.

cheers,

Henry

 

Wow. Roughly $44 for a fill up here at $3.09.

My 1990 240 gets significantly better mileage (about 23 mpg in mixed
driving) than the 1988 Ford Bronco II it replaced (which got about 18
mpg in mixed driving).

I am also a bicyclist and ride that to work when the weather is
congenial for it. At $94 to fill up the tank, I'd ride to work even
when the weather wasn't congenial!

 

I did, well among many other reasons. I've gotten over 30mpg in my Volvo a
couple times and average around 24-25, that's a lot better than the trucks
and SUVs that swarm around here.

 

My personal experience with gas is that the highest grade gave me
better mileage when doing highway. In city, I couldn't notice any
difference.

I don't put too much belief in the additives added to the gas. Get
something to clean the valves, injectors, etc, every few years and
you'll be better off. That's my personal experience.

 

here down under fuel is @$1.20 a litre and was up to $1.39 which
multiplied by 4.56 gives us @ $6.33 cents a gallon imperial or @$5.56
au $4.55 us a us gallon .What you call gas we call petrol which was 8c a
litre when I started driving 32c au a us gallon and my morris mini got
53.4 mpg 998 cc my mums mini 850 got up to 63 mpg so it was cheap
driving .All high way driving.

 

As for grades of fuel my Turbo loves the expensive mix but pings on normal
fuel .So if I turn up the wick I must use good fuel and its goes much better
so much so I find I throttle off a bit .

 

Here in Toronto the three most common grades are 87, 89, and 91 octane
with Sunoco offering "Super 94" as well. Lately the prices for 87 have
been hovering around $0.97 per litre with a 10-13 cent spread between
87 and 91. The "Super 94" is about the same price as other stations'
91 but it's a bit harder to find Sunoco stations.

I used 87 in my 95 850 (NA) and had lots of detonation so I switched
to 91. Since then I've replaced the engine head and am wondering if a
step back to midgrade might still be ok to save a few $.

blurp

 

If you're getting detonation on even the lowest grade, I suspect there's
something wrong. The engine should have a knock sensor that will retard the
timing in the event of detonation.

 

There was an article on Sympatico.ca about car myths, and better
ileage from premium blends is a MYTH!

RTFM -- read the fine manual -- the book that came with the car, and
match the recommended octane rating to what you're purchasing.

I also remember that the on-board systems with Volvos will adjust
engine timing to compensate for fuels with lower octane.

Best determinant of great gas mileage: steady driving speeds, lighten
up the old lead foot for starting and stopping, and keep the speed
close to the limit.

I'd be driving a diesel Volvo (looking at 50-100% increase in range
with the current crop of auto engines) if they sold them in North
America.

Two years ago, I wound up with a brand new Saab 95 diesel when in
Western England for two weeks. 40 litre tank (standard size), 1000 KM/
600 mile range on full tank, passed just about everything on the road
except those white cars with stickers and blue lights on the top.

OK, knocka-knocka-knocka in the morning and when idling.

 

Been reading this tread, and I can't believe someone hasn't responded
with more facts.

Higher octane fuel, in itself won't help gas mileage. It will, however
allow you to advance ignition timing (if your car's ignition timing is
in fact adjustable.)

Advanced ignition timing WILL increase your fuel mileage and power
significantly.

I learned this back in 1980 when the highest octane available was about
87. My '71 164 would ping its brains out with the timing set to spec.
With the timing retarded to the point where the ping went away, the car
was a total pig. No power and about 13 mpg.

I installed a vacuum controlled water injection system which allowed me
to advance the timing beyond spec and the car ran super and the mileage
went to over 20 mpg. The only drawback was that I had to refill the 1
gallon water tank about every 25 miles when I was going uphill.

My present car is an '84 245 and with mid grade gas it gets a full 10%
better mileage than it does with regular. That means that if the price
differential is less that 10%, I'm saving money with mid grade. Premium
gas has no effect on this car beyond what mid grade does. If I advanced
the timing more, I assume the mileage would improve with premium fuel.

This is not a myth. If you set your timing to the most advance without
pinging for whatever fuel you're using, your car will have more power
and better fuel mileage with high octane. Try it.

 

I added water injection on a crysler valiant with success. I made it so the
microswitch came on to the water injection when I put my foot down only .on
the MG I cant remember if it helped but on the big six it did .