That's what I heard too: your engine's got to be capable to handle the
advantage of premium.
The '57 Dodge owners manual says on page 19:
"A WORD ABOUT FUEL - The D-500 engine requires premium fuel. The Red
Ram, Super Red Ram and Get-away Six engines deliver highly efficient
performance with regular grades of fuel."
Now, that says it all, not?
In the Engine Data on page 49 and 50 I read the D-500 has higher
compression (9.25, the others have 8.5) and uses different Spark Plugs
(not hotter, but longer/shorter?).
We know it has a different carb, with larger jets.
And when I look up the tune-up specifics, the D-500 requires different
timing, centrifugal and vacuum advance.
Now, this all is clear to me: I ONLY use Premium.
The guy I bought this car from, always said "it needs a little fine-
tuning", because he couldn't get to operate it properly. He ALWAYS
used (cheapest) Regular. He laughed about me when I told him he should
only use Premium.
And since I feed Mr. Greene Premium, it spins like that big cat that
I've recently received pictures from!
My daily drivers are a Volvo V70 and a BMW K1200S motorcycle. These
new transporters have computers in them to run the engine, and they
can take (almost) any fuel. I drive about 625 miles a week and simply
found out that using Premium gives about 10% more milage and so
actually is cheaper in use. I also found out that not every brand is
the same. Especially a motorcycle engine is critical and I found out
that the one brand Premium gives more milage then the other.
But the latter is not FWLK...
End of story: use Premium when your manual says so, AND have your
engine tuned to handle so! Also: whenever possible, use the same brand
ALWAYS!
Jim.
----- Oorspronkelijk bericht -----
Van: David Homstad <dhomstad@xxxxxxxxxxx>
Datum: woensdag, mei 25, 2005 6:17 am
Onderwerp: Re: [FWDLK] Driving Miss MoPar....
> Neil,
>
> Why not run some premo thru a couple of tanks and do a live
> comparison? Let
> us know.
>
> One of the reasons premium gets better mileage is that you can run
> morecompression and ignition advance, both of which make the
> engine more
> efficient. But if you don't change these, you may not even see a
> difference.
> I also remember reading something a long time ago that regular gas
> is made
> of heavier and denser molecules. (The article talked about measuring
> specific gravity as a way to identify better gas brands for
> racing. Lighter
> is higher octane.) This makes regular slightly heavier per gallon,
> providingmore hydrocarbons and thus more fuel mpg. Because high
> octane has less HC
> weight per volume, slightly larger carb jets are needed for high
> octane to
> get the same air to fuel weight ratio. This slight increase in
> fuel volume
> flow can be offset by the advantages of higher compression and
> more ignition
> advance. So, a properly prepped engine with balanced c/r, advance,
and
> calibrated carb, can achieve high mpg on premium. To put premium
> into a
> regular gas engine ForwardLook car without these mods gains little
> but a
> higher price per gallon.
>
> Oxygenated gas just has alcohol in it, usually 10%. Required in
> this farm
> state. Because alky has less HC per gallon (about half), the net
> effect is
> to lean out the mixture about 5% and thus reduce HC emissions. To
> restoreyour carb's balance and car's power (and HC emissions) you
> need to increase
> the jet size slightly. Alky also evaporates easier, cooling the
> mixture and
> simulating a higher octane for reduced knock.
>
> Some modern computerized cars can automatically advance the
> ignition and
> control the fuel-injected mixture by using feedback from sensors
> (knock and
> oxygen sensors) and achieve some improvement from premium. My
> son's 87
> T-Bird has a switch on the dash for regular or premium.
>
> Back in 1948, or so, Oldsmobile road tested their new Rocket V8 with
> compression ratios as high as 12 to 1, or more, to determine the
> effect on
> gas mileage. They found that even though mpg improved, very high
> compressionratios (over 9 or 10) required more expense to make the
> gas than the
> improvement in mpg paid back.
>
> Dave Homstad
> 56 Dodge D500
>
>
> -----Original Message-----
> From: Forward Look Mopar Discussion List
> [mailto:L-FORWARDLOOK@xxxxxxxxxxxxx]On Behalf Of eastern sierra
> Adj Services
> Sent: Tuesday, May 24, 2005 2:08 AM
> To: L-FORWARDLOOK@xxxxxxxxxxxxx
> Subject: [FWDLK] Driving Miss MoPar....
>
> Ok, So, Fearless Leader doesn't want us to discuss the raping that
> Big-Oil is perpetrating on us (billions is profits, in just the last
> quarter-
> year).....
>
> So.....Jim Hoekendijk has written, to say that he believes that
> PremiumGrade gasoline might produce around 10% better fuel economy
> (& better
> performance, etc.) than Regular Grade gas.
>
> I live @ 4k' elevation, so can run a leaner fuel mixture (I
> believe) and
> lower octane-rating, than a car, residing @ sea level.
>
> At any rate, I've put Regular grade (87 octane) in Horrie, (9.25:1
> c.r.) during the cooler-months, and Mid-grade (89 octane) during 100
> degree summer months, without any apparent engine damage (his 325
Hemi
> did/does not have hardened valve seats,like the CHRY-Hemis have).
>
> Does anyone have any real-world documentation, as to the
> improvement in
> MPG, that might be produced by a higher octane rating?
>
> I do know that "Brand-name" gas is supposed to have mo-better
> additives(anti-knock/detergent, etc) than the "no-name" generic
> gas dealers.
>
> Now, here comes the interesting (Urban-myth??) part: Regular gas,
here
> costs $2.38; Premo costs $2.58 ($.20/gallon more).
>
> If my car "normally" gets around 13 MPG, a 10% increase (from El
> Premio)would be about 1.3 MPG.
>
> For a 20 gallon tank-full, my car would travel ("on average") about
> 20gal x 1.3 extra-MPG =
> 26 "extra" miles.
>
> The Premium gas would cost $.20 extra/gallon, or: 20gal x $.20 =
> $4.00 ( "extra").
>
> BUT, with the Regular-grade gas, it would take 'exactly' 2
> gallons to
> travel that same "extra" 26 miles.
>
> And, 2 gallons of 'Regular', @ $2.38 = $4.76 , or, $.76 MORE than
the
> cost of the Premium grade of gas!!!
>
> So, the equilavent cost of Premium gas is actually about 4
> cents/gallonless expensive, than it would appear to be ($.80
> (approx-savings
> divided by 20 gallons), plus
> your car would benefit from whatever additives/octane that the
Premium
> grade would provide.
>
> So, again, has there been any research, or testing-results published,
> OR, has anyone 'here' done a grade -vs- grade driving comparison,
> regarding the increased performance that might be expected, in a
> 9.25:1c.r. engine??
>
> I do recall the axiom that a higher-octane gas will not benefit an
> engine that was "designed"
> for a lower grade of gas.
>
> Finally, divide your present cost-of-gas by eight, & see what the
> "late1960's" price of your gas, would be (amazing; about $.30,
> for $2.38-
> price, now)
>
> Neil Vedder
>
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