lim…@hamlet.uncg.edu (Funj) writes:
> Also cars outside the US seem more peppy. Perhaps less
> emmissions restrictions = more powerful cars .. or maybe
> the type of fuel. I know that in parts of Asia, cars run
> on 98octane leaded/unleaded w/o catalytic converters, the
> cars get an additional 10-15hp compared to cars in the US.
Contrary to popular belief, high octane gasoline contains no
more energy per unit weight than regular fuel does. The
purpose of increasing the octane level is to prevent knocking
by slightly slowing the fuel’s rate of combustion. There’s
less chance of knocking if the flame front reaches the piston
crown at a later point during the compression stroke.
Geoff
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Geoff Miller + + + + + + + + Sun Microsystems
geo…@purplehaze.Corp.Sun.COM + + + + + + + + Menlo Park, California
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Ian Meades (olee…@lafayette.unocal.com) wrote:
: So, does using higher octane fuel allow a higher compression ratio? And
: does using a higher compression ratio maybe provide potential for a few more hp?
Yes, it allows the designer to choose a higher compression ratio.
However, if your car is designed for low octane gas, putting high octane
in will accomplish nothing useful.
If you want to tinker, you could play around with advancing your timing
a little with the higher octane gas. You could gain a little power that way.
My old ’62 Benz actually had a mechanism on the side of the distributor
that allowed easy readjustment of timing to accomodate varying gasoline
octanes. (manual adjustment) But the primary purpose wasn’t to increase
power, it was to prevail in the face of inconsistent octane.
Ron Miller
In article <31p15q$…@jethro.Corp.Sun.COM>, geo…@purplehaze.Corp.Sun.COM (Geoff Miller) writes:
|>
|>
|>
|> lim…@hamlet.uncg.edu (Funj) writes:
|>
|> > Also cars outside the US seem more peppy. Perhaps less
|> > emmissions restrictions = more powerful cars .. or maybe
|> > the type of fuel. I know that in parts of Asia, cars run
|> > on 98octane leaded/unleaded w/o catalytic converters, the
|> > cars get an additional 10-15hp compared to cars in the US.
|>
|>
|> Contrary to popular belief, high octane gasoline contains no
|> more energy per unit weight than regular fuel does. The
|> purpose of increasing the octane level is to prevent knocking
|> by slightly slowing the fuel’s rate of combustion. There’s
|> less chance of knocking if the flame front reaches the piston
|> crown at a later point during the compression stroke.
|>
So, does using higher octane fuel allow a higher compression ratio? And
does using a higher compression ratio maybe provide potential for a few more hp?
——————————————————————————
Ian Meades Unocal Energy Resources Division
Email: olee…@lafayette.unocal.com Louisiana/Gulf Business Unit
Phone: (318) 295 6819 4021 Ambassador Caffery Pkwy,
Fax: (318) 295 6393 P. O. Box 39200, Lafayette, LA 70593
Ian Meades (olee…@lafayette.unocal.com) wrote:
:
: So, does using higher octane fuel allow a higher compression ratio? And
: does using a higher compression ratio maybe provide potential for a few more hp?
Yes!!!!
Brett Hamlin
Michigan Technological Univ.
bhham…@mtu.edu
olee…@lafayette.unocal.com (Ian Meades) writes:
> So, does using higher octane fuel allow a higher compression ratio?
> And does using a higher compression ratio maybe provide potential
> for a few more hp?
Of course. My point is that you won’t get more power out of a
given engine simply by burning higher-octane gasoline in it,
as many people believe.
The original poster seemed to be suggesting that any extra
hosepower from the engines of Asian-market cars compared to
their American counterparts was the result of higher-octane
gas being available:
lim…@hamlet.uncg.edu (Funj) writes:
|> > Also cars outside the US seem more peppy. Perhaps less
|> > emmissions restrictions = more powerful cars .. or maybe
|> > the type of fuel. I know that in parts of Asia, cars run
|> > on 98octane leaded/unleaded w/o catalytic converters, the
|> > cars get an additional 10-15hp compared to cars in the US.
Geoff
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Geoff Miller + + + + + + + + Sun Microsystems
geo…@purplehaze.Corp.Sun.COM + + + + + + + + Menlo Park, California
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
- Hide quoted text — Show quoted text -
In article <31rai9$…@jethro.Corp.Sun.COM> geo…@purplehaze.Corp.Sun.COM writes:
>olee…@lafayette.unocal.com (Ian Meades) writes:
>> So, does using higher octane fuel allow a higher compression ratio?
>> And does using a higher compression ratio maybe provide potential
>> for a few more hp?
>Of course. My point is that you won’t get more power out of a
>given engine simply by burning higher-octane gasoline in it,
>as many people believe.
>The original poster seemed to be suggesting that any extra
>hosepower from the engines of Asian-market cars compared to
>their American counterparts was the result of higher-octane
>gas being available:
While simply putting a higher octane gas into the same engine wouldn’t
increase power, with higher-octane gas you can *tune* the car to
increase power. The *tuning* of cars are different for each countries,
or even for different regions within the same country. This is why the
higher-octane gas available in other countries may result in more power
from the same engine (different tuning, though).
Bernardus
I
>So, does using higher octane fuel allow a higher compression ratio? And
>does using a higher compression ratio maybe provide potential for a few more hp?
The availability of a higher octane gas can allow a higher compression ratio,
I think up to around 10.5:1 for 93 octane, before you get easy detonation.
Going to a higher compression makes more power in an ever decreasing amount
until around 12.x:1 or so. After that you get very little improvment in street
cars. With higher octane you can also advance the timing to a point (depends
on each car, and if there is a knock sensor) and get a little more power. Most
after market ECU’s try and advance the timing while requiring 92+ octane.
lim…@hamlet.uncg.edu (Funj) writes:
: Also cars outside the US seem more peppy. Perhaps less
: emmissions restrictions = more powerful cars .. or maybe
: the type of fuel. I know that in parts of Asia, cars run
: on 98octane leaded/unleaded w/o catalytic converters, the
: cars get an additional 10-15hp compared to cars in the US.
Let’s make sure we’re comparing apples to apples here. Many
countries use a different octane measurement system than the
US does. There are two basic octane parameters: the "Research
Octane Number" (RON) and the "Motor [?? *] Octane Number"
(MON). The RON usually exceeds the MON by 8-10 points. The
octane ratings that appear on US gasoline pumps are listed as
using the "(R+M)/2 method" — i.e., the average of the RON and
the MON. In other countries, octane ratings are often based
solely on the RON, which makes them appear to be much higher
than US octane ratings. But in reality, fuel that is sold as
98 octane in a RON-only country will only come out around 93
octane if measured in the US using the (R+M)/2 method.
[*] Or is is "Measured"? I can never remember.
———————————————————————-
Bob Goudreau Data General Corporation
goudr…@dg-rtp.dg.com 62 Alexander Drive
+1 919 248 6231 Research Triangle Park, NC 27709, USA
In article <1994Aug9.174433.6…@dg-rtp.dg.com>, goudr…@dg-rtp.dg.com (Bob Goudreau) says:
>lim…@hamlet.uncg.edu (Funj) writes:
>: Also cars outside the US seem more peppy. Perhaps less
>: emmissions restrictions = more powerful cars .. or maybe
>: the type of fuel. I know that in parts of Asia, cars run
>: on 98octane leaded/unleaded w/o catalytic converters, the
>: cars get an additional 10-15hp compared to cars in the US.
>Let’s make sure we’re comparing apples to apples here. Many
>countries use a different octane measurement system than the
[snip]
>———————————————————————-
>Bob Goudreau Data General Corporation
>goudr…@dg-rtp.dg.com 62 Alexander Drive
>+1 919 248 6231 Research Triangle Park, NC 27709, USA
The car magazines often quote horsepower figures for European vs.
American versions of the same car. The European versions usually
are more powerful by 10-30 hp due to less stringent pollution laws.
The fuel is almost immaterial.
David Seghers (segh…@hpcc01.HP.COM) 415-691-3730
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Charter member of the "I HATE vi!" Club.
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The statements and opinions above are my own, entirely my own, and no one
else’s.