High Test bad for 82s
Thread Starter
Race Director
Joined: Feb 2002
Posts: 11,622
Likes: 1,056
From: Compound in the Grove, Ga.
2026 Corvette of the Year Finalist - Unmodified
2025 C4 of the Year Winner - Unmodified
2024 C4 of the Year Finalist - Unmodified
2020 C3 of the Year Finalist - Unmodified
2019 C4 of Year Finalist (performance mods)
2018 C4 of Year Finalist
2015 C4 of the Year Finalist
St. Jude Donor '16
Thanks for the replys...
I guess I'll have 5 Vettes with burnt pistons one day 
I'll sell them cheep when I do..
Untel then its only High test for my Vettes...
Steve
I guess I'll have 5 Vettes with burnt pistons one day I'll sell them cheep when I do.. Untel then its only High test for my Vettes... Steve
Safety Car
Joined: Dec 2004
Posts: 4,071
Likes: 0
From: San Diego CA
Originally Posted by Twin_Turbo
Well, a more volatile flame front (eddy or fractal model) will propagate faster. It's not necessarily true that a fuel with a higher octane number will always burn slower, there are fuels out there (race fuels) that have high octane number and will burn quicker than lower octane numbered fuels, in reality the burn rate is not directly dependant on the octane number but they are closely related. For fuels you can get at your local gas station it pretty much holds true that a higher Anit Knock Index (PON) means it's a slower burning fuel. The octane number is the resistance to ignition.
The octane number is just chosen because of the " reference" fuel. N-heptane has a number 0 on the octane scale and iso-octane has a # of 100. That's why n-heptane is used to dillute the vol% to get a good reference without affecting the octane #. For instance a 91 PON (AKI) fuel is nothing more than a blend that tested to have similar ignition resistance as the 87vol% iso-octane reference fuel under the chosen circumstances (which differ for MON and RON, although pretty similar testing procedures)
The octane number is just chosen because of the " reference" fuel. N-heptane has a number 0 on the octane scale and iso-octane has a # of 100. That's why n-heptane is used to dillute the vol% to get a good reference without affecting the octane #. For instance a 91 PON (AKI) fuel is nothing more than a blend that tested to have similar ignition resistance as the 87vol% iso-octane reference fuel under the chosen circumstances (which differ for MON and RON, although pretty similar testing procedures)
It would be interesting if someone researched the differences between Euro and American gasoline.
Melting Slicks
Joined: Oct 2005
Posts: 2,057
Likes: 0
The octane rating of pump gasoline is a determinant of its resistance to pre-ignition via compression rather than spark. The higher the octane content/rating, the higher the resistance. It is not a value that determines the rate of fuel burn or how hot it burns, etc. High octane pump gas will not harm a low compression engine but will not help it either. It does not have any higher/different detergent qualities. Again, we are talking about pump gas and not "race fuels" or jet fuel or AvGas. Pump gas burns essentially the same across the octane ranges with regard to spark, but not compression. Compression ratio is the key detreminant as to which gas is appropriate to use.
