calculating octane - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

sil80phobia · 08-06-2003, 10:59 AM

Anyone know how octane calculations work?

In california, we get this 91 octane crap. Instead of dumping $10 octane booster in every fillup (which I doubt works), i'm considering buying a 5 gallon drum of 114 octane racing unleaded, and adding a gallon or two to each fillup.

Do I just average it out? Let's say

13 gallons of 91 + 1 gallon of 114 = ~92/93 octane equivalent

or
12 gallons of 91 + 2 gallons of 114 = ~94/95 octane equivalent?

or I can just dump in a tank of 100 octane all the time, which turns out to over 70 bucks a tank. Ouch.

I'm looking either into that or a suitable water injection setup.

AKADriver · 08-06-2003, 01:28 PM

Yep, that's pretty much how it works.

How much is that 5 gallon drum of race gas? Try finding some toluene (which also has octane of about 114 and no lead) at a paint supply store and using that for your mix instead.

R.W.240 · 08-06-2003, 07:07 PM

Ive heard Mothballs dissolved in the fuel work too from someone that worked at Exxon... im not sold on it though.

08-06-2003, 10:59 AM	#1
sil80phobia Join Date: Jul 2003 Location: Los Angeles Posts: 31 Trader Rating: (0) Feedback Score: 0 reviews	calculating octane Anyone know how octane calculations work? In california, we get this 91 octane crap. Instead of dumping $10 octane booster in every fillup (which I doubt works), i'm considering buying a 5 gallon drum of 114 octane racing unleaded, and adding a gallon or two to each fillup. Do I just average it out? Let's say 13 gallons of 91 + 1 gallon of 114 = ~92/93 octane equivalent or 12 gallons of 91 + 2 gallons of 114 = ~94/95 octane equivalent? or I can just dump in a tank of 100 octane all the time, which turns out to over 70 bucks a tank. Ouch. I'm looking either into that or a suitable water injection setup. __________________ ======== Dave

08-06-2003, 07:07 PM	#3
R.W.240 Join Date: Aug 2003 Location: Austin Posts: 3 Trader Rating: (0) Feedback Score: 0 reviews	Ive heard Mothballs dissolved in the fuel work too from someone that worked at Exxon... im not sold on it though. __________________ the world is your oyster, cause thats all the world is -Adam Corrola

08-06-2003, 01:28 PM	#2
AKADriver Post Whore! Join Date: May 2002 Location: Springfield, VA Age: 43 Posts: 3,518 Trader Rating: (1) Feedback Score: 1 reviews	Yep, that's pretty much how it works. How much is that 5 gallon drum of race gas? Try finding some toluene (which also has octane of about 114 and no lead) at a paint supply store and using that for your mix instead.