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Mixing race gas with 93 octane

Guys,

If goal is to raise octane of the 93 I use during fill ups to about 95-96 octane or so, what ratio of 112 octane would I need to mix? One gallon of 112 in five gallons of 93, something like this?

Thanks,

Jimmy
Old 05-28-2011, 04:07 AM
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Should have mentioned:

I am not looking for HP gains at all. Motor is a built 2.5SS with 10:5:1 compression /twin plugged and is tuned for the 93 octane we have here. Problem is I live in South Florida and it gets very hot here in the summer months. Fuel quality concerns at the pumps and the heat concern me and I want to raise the octane a few points every fill up as an insurance measure only. I keep VP fuel at the house and just want to know what I need as a mix to raise the octane numbers a few points and make my barrel of 112 stretch as far as possible.

Thanks,
Jimmy
Old 05-28-2011, 06:32 AM
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Hi Jimmy,

I inserted a table here: Welcome to Rennsport Systems, Porsche Performance Products for the 21st Century that you may find useful. Scroll down aways to find that.

Its a matrix for 91 octane and 100 race gas but you can do the math to get very close to your objective. Good for you for recognizing the need for more octane in hot weather!!!

Hope this helps,
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Old 05-28-2011, 06:55 AM
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Big Help...

Thank You Sir,

Jimmy
Old 05-28-2011, 07:17 AM
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Max Sluiter
 
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(# gallons 93)*93/(total # gallons) + [(total # gallons)-(# gallons 93)]*112/(total # gallons) = equivalent octane rating

Ax/C + [(C-x)B]/C = D

x = # gallons 93
C = total # gallons
A = octane rating of first fuel (93)
B = octane rating of second fuel (112)
D = equivalent octane

solve for x
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Old 05-28-2011, 10:27 AM
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Flieger

Thanks, I think.

I am trying out your formula now, I am in the army and do not exercise my math skills all that often. I have a 16.5 gal tank in my 71, I was figuring a 20% ratio would bring up the octane 2 points on 93 using 112.


Thanks Again,

Jimmy
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Max Sluiter
 
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Quote:
Originally Posted by Jimmy18E View Post
Flieger

Thanks, I think.
That's what you get when you ask an engineer.

No worries;

14.76 gallons of 93, rest 112 to make 16.5 gallons of 95.

To be safe, go shoot for 14.5 gallons of 93 in case you do not fill the tank all the way (hard to ensure no air space in there).
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1971 chassis, 2.7RS spec MFI engine, suspension mods, lightened

Suspension by Rebel Racing, Serviced by TLG Auto, Brakes by PMB Performance
http://www.flickr.com/photos/max_911_fahrer/

Last edited by Flieger; 05-28-2011 at 03:02 PM..
Old 05-28-2011, 02:59 PM
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Old 05-28-2011, 02:59 PM
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