15 Jan
2003
15 Jan
'03
4:35 a.m.
Damn,
You can't hardly find higher than 93.5 or so here in Colorado... < jealous
of those who can get 100 octane at the pump. Sure, my car needs only 87, but
if I could get higher octane gas I could drive a car with higher compression
;p
Will J
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15 Jan
15 Jan
6:28 a.m.
Damn,
You can't hardly find higher than 93.5 or so here in Colorado... < jealous
of those who can get 100 octane at the pump. Sure, my car needs only 87, but
if I could get higher octane gas I could drive a car with higher compression
;p
Well, before compareing Octane numbers we have to define what
measurement we use. At German stations usualy the ROZ is given.
ROZ stands for Research Oktane Zahl. The English/German mixup
is a historical thing. As far as I know, the whole octane
calculation was made up by some German scientists who did
develop the measurements. The result was a calculation where
the given fuel is compared to a mixture of n-Heptan or
Trimethylpentan (OZ=0) and Isooktan (OZ=100). Since fuel
mixtures can be better than Isooktan, numbers higher than
100 are possible. The measurement is done with a defined
standard engine runing at a specific speed, a fixed advance
angle and an air intake at 50 C.
Anothor number is the so called MOZ (Motor Oktan Zahl),
where the test series runns at a higher speed and an
intake temperature of I think 150 C, which is closer
to a real situation. For modern fuels this number is
usualy 8-10 lower then the ROZ. For example:
MOZ ROZ
Regular 83 91
Super 85 95
Super Plus 88 98
US station _in_most_states_ give the POZ (Pump Oktan
Zahl) which is the average between MOZ and ROZ, so if
we take the above examples, A German 91 ROZ (lowest
quality available) would be sold as 87 in the US. These
numbers are just as rough rule of thumb usable.
Beside ROZ, MOZ and POZ there's also:
SOZ, Strassen (Street) Oktan Zahl, where the tests are
done with more real profile. One interesting fact is
thet the SOZ calculations give backing to both, MOZ
and ROZ. It looks like the ROZ value gives a good number
for performance during acceleration (for acceleration
profiles SOZ and ROZ are similar), while MOZ seams to
sow the high load reaction of a given fuel.
Last there is also the FOZ, Fron Oktan Zahl, where the
fuel will be distilled, and only the parts with a
boiling point above 100 C are used for the OZ calculation.
The idea is to look closer at the volatile parts within
the mix.
Now, all these numbers are taken from my memory. There
may be some twists by now.
Gruss
H.
--
VCF Europa 4.0 am 03./04. Mai 2003 in Muenchen
http://www.vcfe.org/
3:57 p.m.
On the other hand this is a dying technology and new
fuel sources are popping up every day. Good riddance I
say. There is a plant that is producing ethanol not far from
where I live that uses straw for its fuel source and getting
funding from a normally conservative provincial
government.
Of course the political front-men for the car
manufacturers, and "Big Oil", will try and quash any
attempts to develop alternative non-poluting energy
sources but their demise is as sure as Jaquard
looms or Stanley Steamers.
Lawrence
On 15 Jan 2003, , Hans Franke wrote:
lgwalker@ mts.net
Damn,
You can't hardly find higher than 93.5 or so here in
Colorado... < jealous of those who can get 100 octane at
the pump. Sure, my car needs only 87, but if I could get
higher octane gas I could drive a car with higher
compression ;p
Well, before compareing Octane numbers we have to define
what measurement we use. At German stations usualy the ROZ
is given.
ROZ stands for Research Oktane Zahl. The English/German
mixup is a historical thing. As far as I know, the whole
octane calculation was made up by some German scientists who
did develop the measurements. The result was a calculation
where the given fuel is compared to a mixture of n-Heptan or
Trimethylpentan (OZ=0) and Isooktan (OZ=100). Since fuel
mixtures can be better than Isooktan, numbers higher than
100 are possible. The measurement is done with a defined
standard engine runing at a specific speed, a fixed advance
angle and an air intake at 50 C.
Anothor number is the so called MOZ (Motor Oktan Zahl),
where the test series runns at a higher speed and an intake
temperature of I think 150 C, which is closer to a real
situation. For modern fuels this number is usualy 8-10 lower
then the ROZ. For example:
MOZ ROZ
Regular 83 91
Super 85 95
Super Plus 88 98
US station _in_most_states_ give the POZ (Pump Oktan
Zahl) which is the average between MOZ and ROZ, so if
we take the above examples, A German 91 ROZ (lowest
quality available) would be sold as 87 in the US. These
numbers are just as rough rule of thumb usable.
Beside ROZ, MOZ and POZ there's also:
SOZ, Strassen (Street) Oktan Zahl, where the tests are
done with more real profile. One interesting fact is
thet the SOZ calculations give backing to both, MOZ
and ROZ. It looks like the ROZ value gives a good number for
performance during acceleration (for acceleration profiles
SOZ and ROZ are similar), while MOZ seams to sow the high
load reaction of a given fuel.
Last there is also the FOZ, Fron Oktan Zahl, where the
fuel will be distilled, and only the parts with a
boiling point above 100 C are used for the OZ calculation.
The idea is to look closer at the volatile parts within the
mix.
Now, all these numbers are taken from my memory. There
may be some twists by now.
Gruss
H.
--
VCF Europa 4.0 am 03./04. Mai 2003 in Muenchen
http://www.vcfe.org/
7861
days inactive
7861
days old
2 comments
3 participants
participants (3)
-
Hans.Franke＠mch20.sbs.de -
lgwalker＠mts.net -
xds_sigma7＠hotmail.com