Question about fuel octane.
02-06-2009, 06:52 PM
#1
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Question about fuel octane. I need some help guys. I'm going to run VP fuel in my car to be safe. I've got a 383 with le2 heads and a le 3.2 cam with a compression ratio of 12.38 to 1. I went to the VP website and got alittle confused by the motor octane and the r+m/2 rating. What octane/fuel would you guys recommend? The car was fine on the dyno but he made sure to point out that it might knock under load. He recommended up'ing the octane by mixing some phillips 105 octane to be safe. Problem is I can't find it where I'm at only VP.
02-06-2009, 08:32 PM
#3
I've heard it's 100+, but don't you have to used different fuel system components, such as lines and filter that is compatable with E85? Who built your engine? Fuel octane requirements should have been discussed during the build. I would call up both Lloyd and VP and talk to them personally. They should be able to steer you in the right direction.
02-06-2009, 09:19 PM
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The r+m/2 equation is how they determine the octane of that particular fuel. E-85 is 100-110 depending on how well the company blended it and their particular additives. Another popular way to up the octane of a fuel is to mix toluene or xylene (YES THATS PAINT THINNERS that you can buy at your local stores!) to the mixture.
02-06-2009, 09:25 PM
#5
r+m/2 is the octane rating you would see at the pump ie 93. its the research and motor octance avg. vp uses the motor octane more since it is a more realistic number when trying to figure the octane level needed. your dcr is more important when figuring fuel octane required.
