Higher Octane Gas, Mileage & Gas Prices.

[eskimo2]

I was looking at gas prices today:
87 octane was $2.29 a gallon
89 octane was $2.39 a gallon
93 octane was $2.49 a gallon

With such high prices these days, and relatively little difference in price, is it worth spending about 9% more to get about 9% more octane?  Will the higher stuff produce better mileage?  
(I have an 89 Volvo and a 97 Ford Van)

Thanks,
eskimo

[Lizking]

Basically, you should just get rid of both.

[superpug1]

Ya, the Higher Octane gas would be better. It gives u most power and gas milage because it will burn hotter and more violently. this means that u have to use less of it. I use mid grade in my truck and it gives me one or two more miles to the gallon. lol so now i get 10 miles to the gallon booya:aok

[rabbidrabbit]

You won't have any benefit of higher test gas unless you have high enough compression to use it.

[RightF00T]

What rabbit said...higher octane is only useful if you have pinging in your engine(gas burning off too quickly)  Higher octane only means it has a higher boiling point.  

With that said, there are some engines that require high octane.  I doubt your Volvo or van are set up this way.

[Masherbrum]

Originally posted by superpug1
Ya, the Higher Octane gas would be better. It gives u most power and gas milage because it will burn hotter and more violently. this means that u have to use less of it. I use mid grade in my truck and it gives me one or two more miles to the gallon. lol so now i get 10 miles to the gallon booya:aok

You will not reap ANY benefits from using a higher octance than your engine is rated to use.  You're only damaging an engine.  

Karaya

[JTs]

find out if summit racing on I76 east of town still has their weekend tuning clincs

[RightF00T]

Karaya?  It has no benefits but I don't believe it damages the engine.

[Leslie]

My 1973 Olds 98 runs well on the 93 octane, but has a tendency to ping a little on shutdown.  Maybe a carb problem though.

Not sure what gas it was designed for, leaded or not, but it does ok with the 93 octane unleaded.  It's a road cruising machine.  This is the low compression  455 engine 10.5 to 1.

One of the few pleasures I get outta life is driving that car, so gotta pay the price for gas.  My philosophizing is it would give a little more than average protection in a fender bender.  Justifies the gas price.

 But we all know that a car like that is just plain 'ol cool.


Man I saw a 1972 or so Buick Centurion couple days ago and that car looked good.  I love old Buicks and Oldsmobiles.  Those cars need the 93 octane to run and perform like they were meant to.





Les



 

[SFRT - Frenchy]

I don't know what u are complaining about.

Los Angeles:

87 $2.45ish to $2.55
89 $2.60ish
91 $2.70ish to $2.80

Gas could still be $3,00 I would still keep  my 1973 455 engine as a daily driver runing on 91. I don't care. I pick a car on the fun factor, not on gas mileage.

It's now or never, because when u will be old driving your electric car, you would have wished you would not have wasted gazoline on a Honda Civic.

[mipoikel]

I wouldnt whine about those prices.

Here 1 liter 95 octane (0,26 gallons) costs about 1,40 eur.

So 1 gallon costs about 5.3 eur = 6.2 dollars

[rpm]

The Volvo might be the only one I'd consider running higher octane in. Unless you are having a problem with ignition knock or clatter run the 87 octane and use a bottle of good injector cleaner in your gas every time you change oil.

[storch]

Originally posted by rpm
The Volvo might be the only one I'd consider running higher octane in. Unless you are having a problem with ignition knock or clatter run the 87 octane and use a bottle of good injector cleaner in your gas every time you change oil.

or add a quart of diesel fuel to your tank at every other fill up.  it will do the same.  Ive never had injector problems since an old mechanic suggested that years ago.

[Captain Virgil Hilts]

The only thing gasoline with too much octane will do for your vehicle is make it less efficient. SOME of the high octane has a lot of additives in it that will create excessive deposits when they are not burned.

Older vehicles can be ajusted so that they perform better and are more efficient with more octane, but it takes serious tuning to make the most of it, and the gains aren't worth it unless you just like to fool with it.

Newer vehicles will sometimes adjust to the high octane gas by SLIGHTLY leaning the mixture and increasing the timing. However, they are designed to require less octane with the same compression ratio and timing as older vehicles.

Increased timing lead actually creates NEGATIVE torque, by firing earlier in the stroke, before the piston reaches TDC, actually trying to force it down. It does increase cylinder pressure though, making it more efficient. But even more efficiency can be had by increasing the copmression ratio to gain cylinder pressure, and decreasing timing lead. You get the same cylinder pressure, with no negative torque. That's why you see increased compression ratios these days.

[rabbidrabbit]

Originally posted by Leslie
My 1973 Olds 98 runs well on the 93 octane, but has a tendency to ping a little on shutdown.  Maybe a carb problem though.

Not sure what gas it was designed for, leaded or not, but it does ok with the 93 octane unleaded.  It's a road cruising machine.  This is the low compression  455 engine 10.5 to 1.

 But we all know that a car like that is just plain 'ol cool.


Man I saw a 1972 or so Buick Centurion couple days ago and that car looked good.  I love old Buicks and Oldsmobiles.  Those cars need the 93 octane to run and perform like they were meant to.

Les

 

I sincerely doubt your unbuilt 455 runs 10.5:1 stock.  Pretty sure stock for those was in the neighborhood of 8:1 which has no use for high test gas.  I don't have the book and maybe someone else knows for sure but I'll bet a neener neener on it..!