V.P. C-11 vs. C-12

Mike Croley · 09-11-2015, 04:00 PM

There are other important aspects of racing fuel of course. Specific Gravity, and RVP ( Reid Vapor Pressure ) are two that matter.
All brands and all blends of racing fuel have different specs. 4 different brands of 116 will all have different Specific Gravity and RVP numbers. If there was only one RVP, or one Specific Gravity that was the best, all manufacturers would just plug those numbers into every blend and be done with it. Each manufacturer works very closely with racers and engine builders to come up with blends that make power, make torque, and most important, control detonation and pre-ignition.

James L Miller · 09-11-2015, 07:32 PM

https://en.wikipedia.org/wiki/Octane_rating

Usually the short chain alkanes like methane and ethane have the higher octane ratings. And they usually are the ones that boil off first, so the old stale/flat gas has probably lost the good stuff and eventually you end up with paint thinner or varnish.

That chart I think is wrong on benzene. I've always heard it's off the chart and they couldn't get an engine to knock on it, so MON of 130 or so. I think that is the top number in the rating system.

All these ratings are performed on a single cylinder engine made by Waukesa. It probably doesn't look like anyone's racing engine. Perhaps closer to a farm tractor engine.

http://www.waukeshacfr.com/f1-f2/

09-11-2015, 04:00 PM	#1
Mike Croley Member Join Date: Apr 2010 Posts: 182 Likes: 0 Liked 0 Times in 0 Posts	Re: V.P. C-11 vs. C-12 There are other important aspects of racing fuel of course. Specific Gravity, and RVP ( Reid Vapor Pressure ) are two that matter. All brands and all blends of racing fuel have different specs. 4 different brands of 116 will all have different Specific Gravity and RVP numbers. If there was only one RVP, or one Specific Gravity that was the best, all manufacturers would just plug those numbers into every blend and be done with it. Each manufacturer works very closely with racers and engine builders to come up with blends that make power, make torque, and most important, control detonation and pre-ignition.

09-11-2015, 07:32 PM	#2
James L Miller Member Join Date: Apr 2005 Posts: 494 Likes: 6 Liked 25 Times in 16 Posts	Re: V.P. C-11 vs. C-12 https://en.wikipedia.org/wiki/Octane_rating Usually the short chain alkanes like methane and ethane have the higher octane ratings. And they usually are the ones that boil off first, so the old stale/flat gas has probably lost the good stuff and eventually you end up with paint thinner or varnish. That chart I think is wrong on benzene. I've always heard it's off the chart and they couldn't get an engine to knock on it, so MON of 130 or so. I think that is the top number in the rating system. All these ratings are performed on a single cylinder engine made by Waukesa. It probably doesn't look like anyone's racing engine. Perhaps closer to a farm tractor engine. http://www.waukeshacfr.com/f1-f2/ __________________ Mopar 2 Ya!