View Poll Results: What is your typical fuel octane rating?
87 octane
42
30.88%
89 octane
10
7.35%
91 octane
33
24.26%
93 octane
51
37.50%
Voters: 136. You may not vote on this poll
Octane poll for 16V cars
#62
There are a lot of specs for many different engines, but generally the 16 valve engines had lower compression ratios. That is why the 16 valve engines are considered non-interference and the 32 valve engines are interference.
Dennis
Dennis
#64
Rennlist Member
whatever is the highest at the station, thats what she gets. However I was told by a race engine guy that high octain doesnt make any power. Lower octain actually makes mroe power.??? I dunno.. I always took his word for it. after all he was the engine guy, I was just the parts salesman
#65
Race Car
Join Date: Sep 2007
Location: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
Posts: 3,663
Likes: 0
Received 0 Likes
on
0 Posts
whatever is the highest at the station, thats what she gets. However I was told by a race engine guy that high octain doesnt make any power. Lower octain actually makes mroe power.??? I dunno.. I always took his word for it. after all he was the engine guy, I was just the parts salesman
#66
Pro
Join Date: Jun 2008
Location: Québec, Québec, Canada
Posts: 695
Likes: 0
Received 2 Likes
on
2 Posts
Interresting reading :
Octane : http://en.wikipedia.org/wiki/Octane_rating
"Knocking" : http://en.wikipedia.org/wiki/Engine_knocking
Basicly, different octane doesn't mean faster ignition nor more energy. It means resistance to autoignition by pressure.
Not using the require octane in a car will result in badly timed explosion, most likely cause by early ignition, or pocket of non-ignited fuel exploding too late. This can lead to lost of power, but may also burn your engine down much faster by submiting it to higher pressure than designed for. Sure your car will run... But in long run, it won't help.
Please, less myth and more science.
Octane : http://en.wikipedia.org/wiki/Octane_rating
"It should be noted that octane rating does not relate to the energy content of the fuel (see heating value), nor the speed at which the flame initiated by the spark plug propagates across the cylinder. It is only a measure of the fuel's resistance to autoignition. It is for this reason that one highly branched form, or isomer, of octane (2,2,4-trimethylpentane) has (by definition) an octane rating of 100, whereas n-octane (see octane), which has a linear arrangement of the 8 carbon atoms, has an octane rating of -10, even though the two fuels have exactly the same chemical formula and virtually identical heating values and flame speeds."
"Under ideal conditions the common piston internal combustion engine burns its fuel/air mix in the cylinder in an orderly and controlled fashion. The combustion is started by the spark plug some 5 to 40 crankshaft degrees prior to top dead center (TDC), depending on engine speed and load. This ignition advance allows time for the combustion process to develop peak pressure at the ideal time for maximum recovery of work from the expanding gases.
The spark across the spark plug's electrodes forms a small kernel of flame approximately the size of the spark plug gap. As it grows in size its heat output increases allowing it to grow at an accelerating rate, expanding rapidly through the combustion chamber. This growth is due to the travel of the flame front through the combustible fuel air mix itself and due to turbulence rapidly stretching the burning zone into a complex of fingers of burning fuel air that have a much greater surface area than a simple spherical ball of flame would have. In normal combustion, this flame front moves throughout the fuel air mix at a rate characteristic for the fuel-air mixture. Pressure rises smoothly to a peak, as nearly all the available fuel is consumed, then pressure falls as the piston descends. Maximum cylinder pressure is achieved a few crankshaft degrees after the piston passes TDC, so that the increasing pressure can give the piston a hard push when its speed and mechanical advantage on the crank shaft gives the best recovery of force from the expanding gases."
The spark across the spark plug's electrodes forms a small kernel of flame approximately the size of the spark plug gap. As it grows in size its heat output increases allowing it to grow at an accelerating rate, expanding rapidly through the combustion chamber. This growth is due to the travel of the flame front through the combustible fuel air mix itself and due to turbulence rapidly stretching the burning zone into a complex of fingers of burning fuel air that have a much greater surface area than a simple spherical ball of flame would have. In normal combustion, this flame front moves throughout the fuel air mix at a rate characteristic for the fuel-air mixture. Pressure rises smoothly to a peak, as nearly all the available fuel is consumed, then pressure falls as the piston descends. Maximum cylinder pressure is achieved a few crankshaft degrees after the piston passes TDC, so that the increasing pressure can give the piston a hard push when its speed and mechanical advantage on the crank shaft gives the best recovery of force from the expanding gases."
Not using the require octane in a car will result in badly timed explosion, most likely cause by early ignition, or pocket of non-ignited fuel exploding too late. This can lead to lost of power, but may also burn your engine down much faster by submiting it to higher pressure than designed for. Sure your car will run... But in long run, it won't help.
Please, less myth and more science.
#67
Race Car
Join Date: Sep 2007
Location: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
Posts: 3,663
Likes: 0
Received 0 Likes
on
0 Posts
Interresting reading :
Octane : http://en.wikipedia.org/wiki/Octane_rating
"Knocking" : http://en.wikipedia.org/wiki/Engine_knocking
Basicly, different octane doesn't mean faster ignition nor more energy. It means resistance to autoignition by pressure.
Not using the require octane in a car will result in badly timed explosion, most likely cause by early ignition, or pocket of non-ignited fuel exploding too late.
Please, less myth and more science.
Octane : http://en.wikipedia.org/wiki/Octane_rating
"Knocking" : http://en.wikipedia.org/wiki/Engine_knocking
Basicly, different octane doesn't mean faster ignition nor more energy. It means resistance to autoignition by pressure.
Not using the require octane in a car will result in badly timed explosion, most likely cause by early ignition, or pocket of non-ignited fuel exploding too late.
Please, less myth and more science.
#68
#69
Pro
Join Date: Jun 2008
Location: Québec, Québec, Canada
Posts: 695
Likes: 0
Received 2 Likes
on
2 Posts
From the (77-79) bracket, to the (80-82) and (83-85), which are all 16v, Prosche probably require different octane, or changed the explosion timing accordingly.
It's if you want the best timed explosion, you use the octane require by the builder.
#70
Rennlist Member
#71
Race Car
Join Date: Sep 2007
Location: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
Posts: 3,663
Likes: 0
Received 0 Likes
on
0 Posts
Quick note. Ran my first tank of premium today. Car seems to run well maybe even better than on 89 Octane. Test on going
#72
Dennis
#74
Rennlist Member
I'm really surprised the 89 Octane has received so few votes. It would seem to be a good compromise for those that get a little pinging with the lower octane.
#75
928 Collector
Rennlist Member
Rennlist Member
I accidentally put 87 into my Godzilla for the first time in almost 10 years' ownership. I swear I feel a performance boost. I have been very careful to keep revs down though.