I had roughly 5 gallons of vp c16 in my gas tank when i went for a fill up recently. I took my car out for a tune on my new turbo and i am getting the results i dreamed about...lol. With that mixture, what kind of an octane rating do you think i am getting. I would like to believe that i am getting these results on pump gas but realize that is highly unlikely. I am going to the track on Saturday and basically i am trying to figure out what kind of gas should i pick up to keep this tune good.

this method doesn't 100% work out but its close. To do it perfectly, you'd need both ratings that achieved the pump ranting (RON and the other one), and you'd have to figure out if the amount of lead in C16 will react with the pump, blah blah blah---whatever its not important. I think gsx's have a 15.9 gal capacity?

so you do



(octane race)(volume race) + (octane pump)(volume pump)
-------------------------------------------------------
fuel tank capacity

or <(117)(5) + (93)(15.9-5)> / 15.9

so if you used 93 octane gas and have a tank capacity of 15.9 gallons, then your octane rating was about 95.5.

note that this method is flawed becuase of the chemical contents of C16; but its close enough....

BOO YAH math can be fun---when it involves cars..

vandy

It doesn't exactly work out like that because the chemicals in those 2 gasses won't exactly "mix" the way you'd think they would. The weights in some of the chemicals are different so some will sink, some will rise.
Just run the highest octane pump gas you can find for the street and drain the tank at the track and use the race fuel.
Todd (VX100)who is a chemist did a nice writeup about this somewhere but I can't remember which board it was on.

Originally posted by eclipzGST
It doesn't exactly work out like that because the chemicals in those 2 gasses won't exactly "mix" the way you'd think they would. The weights in some of the chemicals are different so some will sink, some will rise. Just run the highest octane pump gas you can find for the street and drain the tank at the track and use the race fuel. Todd (VX100)who is a chemist did a nice writeup about this somewhere but I can't remember which board it was on.

Originally posted by Vandy420a
this method doesn't 100% work out but its close. To do it perfectly, you'd need both ratings that achieved the pump ranting (RON and the other one), and you'd have to figure out if the amount of lead in C16 will react with the pump, blah blah blah---whatever its not important.

yeah but he's not looking for an exactly qualitative measure here...he'd have to have exactly 5 gallons of C16 and know the exact octane of the gas he used, plus where the pump shut off, plus the additives in the pump gas, etc. The actual octane is probably a bit lower, but whatever, its close.

wow...lol. It was 93 Octane form Sunoco mixed with Roughly 5 Gallons of VP C16. I came up with about 100 octane but i figured someone had a formula to verify this. I will prolly run 116 this weekend to be safe with the numbers i am getting. I only wish i could get this on pump gas on a 95 degree day....lol.

IDC ques was split off to here: http://forums.2gnt.com/dcboard.php?az=show_topic&forum=17&topic_id=10591&mesg_id=10591&page=
-Tony