Fuel & Octane level
Discussion
I keep getting a optimax pop-up when i log-in,so whats the big deal,is this any better for our cars??and is there a limit to octane levels that we can put in our vettes as ZR1s run around 12.1 compression,not sure what compression other vettes run.
Ive always used unleaded or super unleaded.
Ive always used unleaded or super unleaded.
American Gas (Fuel) has a lower octane rating than European fuel. It is recommended that Corvettes (C5) run on Premium which is 91 or 93 Octane in the U.S. However, as with all things American I am not sure of the way they measure Octane rating is the same as the way us European measure Octane rating. We use R.O.N. (no idea what R.O.N. stands for but I would bet the O. is Octane!!)
Putting my 
hat on again...
Octane number relates only to the anti-knock (a.k.a. detonation or pinking) properties of fuel. The higher the number of the fuel the higher compression ratio you can use in the engine without running into detonation issues. Using higher octane fuel in an engine that is not designed to take advantage of it will NOT produce any more power.
In the UK we use Research Octane Number (RON) which is based on a single cylinder engine with ability to vary compression ratio running at 600 rpm and being fed with inlet air at a temperature of 65.6 degrees centigrade. Fuel samples are given their RON number based on the performance of the fuel under test compared to a standardised control fuel blend. This method was established at around the time of WWI.
There is another, supposedly more severe and realistic system called Motor Octane Number (MON). This uses an engine running at 900 rpm and inlet air at 148.9 centigrade. It usually returns octane numbers 6 to 12 less than the RON method. It is a more accurate representation of how fuels behave in modern engines - particularly super or turbocharged ones.
The Americans rate their fuels using the Pump Octane Number (PON) which is the average of the two methods, i.e. (RON+MON)/2.
Fuel companies can vary the blend of constituents such that it gives high readings under one method and low under another - hence all the fuss about whether Formula 1 engines use "pump" fuel or not. The blend also changes between summer and winter to ensure the fuel vapourises correctly.
N.B. Fuel for piston engined aircraft, Avgas, has a rating of 100/130 but is rated using a different test method. There are two varieties, green and blue, which contain high and low proportions of lead respectively. Yes, green Avgas is high lead !! Both will kill your catalytic convertors though.
hat on again... Octane number relates only to the anti-knock (a.k.a. detonation or pinking) properties of fuel. The higher the number of the fuel the higher compression ratio you can use in the engine without running into detonation issues. Using higher octane fuel in an engine that is not designed to take advantage of it will NOT produce any more power.
In the UK we use Research Octane Number (RON) which is based on a single cylinder engine with ability to vary compression ratio running at 600 rpm and being fed with inlet air at a temperature of 65.6 degrees centigrade. Fuel samples are given their RON number based on the performance of the fuel under test compared to a standardised control fuel blend. This method was established at around the time of WWI.
There is another, supposedly more severe and realistic system called Motor Octane Number (MON). This uses an engine running at 900 rpm and inlet air at 148.9 centigrade. It usually returns octane numbers 6 to 12 less than the RON method. It is a more accurate representation of how fuels behave in modern engines - particularly super or turbocharged ones.
The Americans rate their fuels using the Pump Octane Number (PON) which is the average of the two methods, i.e. (RON+MON)/2.
Fuel companies can vary the blend of constituents such that it gives high readings under one method and low under another - hence all the fuss about whether Formula 1 engines use "pump" fuel or not. The blend also changes between summer and winter to ensure the fuel vapourises correctly.
N.B. Fuel for piston engined aircraft, Avgas, has a rating of 100/130 but is rated using a different test method. There are two varieties, green and blue, which contain high and low proportions of lead respectively. Yes, green Avgas is high lead !! Both will kill your catalytic convertors though.
There will be no stopping me now I,ve registered!
Keith and I both use Optimax on all cars. It does seem to make a difference on both the LT1 engines and we find it really good on the C5 although it works even better with an Octane Boost we've tried several brands and have found a really good one, not sure if it can be named here due to the advestising thing.
Keith and I both use Optimax on all cars. It does seem to make a difference on both the LT1 engines and we find it really good on the C5 although it works even better with an Octane Boost we've tried several brands and have found a really good one, not sure if it can be named here due to the advestising thing.
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