Just out of curiosity, has anyone ever used 87 and has their Z lived to tell the tale
09-13-2006, 05:55 PM
#41
Registered User
[QUOTE=abyss]
High octane does NOT contain more energy, more heat, does not burn hotter, does not burn faster, slower, etc. Octane rating a measure of resistance to ignition, or a measure of its anti-knock characteristic. Nothing else.
"Another factor that octane doesn't predict is combustion temperature which may or may not relate to the power produced. It's possible to blend two mixtures of branched-chain paraffins along with aromatics to create two concoctions both of which have higher octane than pump gas, and one of them will have higher combustion temps than pump-gas, and yet the other will have lower combustion temps.
A lot of people also confuse octane with flame-front propagation speed which is yet another independent factor. Take the old-days measurement of octane-ratings with iso-octane (2,2,4-trimethylpentane) with a octane-100 rating and n-heptane with a 0-octane rating. They both have the exact same flame-front speed, yet one of them has a fairly high anti-knock index. The other, n-heptane, has such low knock-resistance that you can just tap the beaker and the stuff would explode!
Octane Does Predict...
In the end, all that octane predicts is AKI-Anti Knock Index as measured on a knock engine. These are variable-compression single-cylinder engines that can vary their compression between about 7.0:1 to 15.0:1. There's a highly-sensitive and accurate knock-sensor and computer hooked up to this engine that gives a readout of knock. The engine is run with the mystery fuel and starts at a low-compression. Then the compression is increased gradually while knock is monitored. Various levels of compression-ratios are used and the corresponding knock measured. This is looked-up on standardized tables and the MON-octane rating of the fuel is then determined. In the end, that's ALL that the octane predicts, is how much resistance the fuel has to knock."
http://www.offroaders.com/tech/octane.htm
bill
Originally Posted by i8acobra
Octane has nothing to do with how "hot" the gas burns.QUOTE]
Sorry to bust your bubble but the higher the octane the hotter it burns, thats why the same warning goes out for people running higher octane than they should be risking burning a hole in their motor.
Sorry to bust your bubble but the higher the octane the hotter it burns, thats why the same warning goes out for people running higher octane than they should be risking burning a hole in their motor.
"Another factor that octane doesn't predict is combustion temperature which may or may not relate to the power produced. It's possible to blend two mixtures of branched-chain paraffins along with aromatics to create two concoctions both of which have higher octane than pump gas, and one of them will have higher combustion temps than pump-gas, and yet the other will have lower combustion temps.
A lot of people also confuse octane with flame-front propagation speed which is yet another independent factor. Take the old-days measurement of octane-ratings with iso-octane (2,2,4-trimethylpentane) with a octane-100 rating and n-heptane with a 0-octane rating. They both have the exact same flame-front speed, yet one of them has a fairly high anti-knock index. The other, n-heptane, has such low knock-resistance that you can just tap the beaker and the stuff would explode!
Octane Does Predict...
In the end, all that octane predicts is AKI-Anti Knock Index as measured on a knock engine. These are variable-compression single-cylinder engines that can vary their compression between about 7.0:1 to 15.0:1. There's a highly-sensitive and accurate knock-sensor and computer hooked up to this engine that gives a readout of knock. The engine is run with the mystery fuel and starts at a low-compression. Then the compression is increased gradually while knock is monitored. Various levels of compression-ratios are used and the corresponding knock measured. This is looked-up on standardized tables and the MON-octane rating of the fuel is then determined. In the end, that's ALL that the octane predicts, is how much resistance the fuel has to knock."
http://www.offroaders.com/tech/octane.htm
bill
09-13-2006, 07:55 PM
#42
New Member
iTrader: (6)
Originally Posted by bailey bill
High octane does NOT contain more energy, more heat, does not burn hotter, does not burn faster, slower, etc. Octane rating a measure of resistance to ignition, or a measure of its anti-knock characteristic. Nothing else.
[I]"Another factor that octane doesn't predict is combustion temperature which may or may not relate to the power produced. It's possible to blend two mixtures of branched-chain paraffins along with aromatics to create two concoctions both of which have higher octane than pump gas, and one of them will have higher combustion temps than pump-gas, and yet the other will have lower combustion temps.
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