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 Octane revisited
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cellguru
Master Technician

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216 Posts

Posted - Jul 04 2002 :  12:33:16  Show Profile  Visit cellguru's Homepage  Reply with Quote
Not too long ago we were discussing toluene as an octane booster.

The chart I saved shows 10% Toluene increases octane by about 2.2 points, and the cheapest I have found toluene for about $10 gal at Ace Hardware. If I am doing the math right that works out to about 37 cents per octane point per gallon.

One of the local gas distributors is now advertising 115 octane for $4.19 per gallon. Can I average the octane together to come up with an octane mix? If so then using 10% 115 octane with the 91 octane available here would result in an octane of 93.4. Again if my math is correct this calculates to a cost of less than 11 cents per gallon per octane point.

Hmmmmm . . . .

So what benefits does one reap from the increase, and how much increase is necessary for my cars running stock boost (for now)?

Would I notice a difference in acceleration, smoothness, and how about my ///M6 with a Dinan chip?

As always thanx for comments.





So many 745's so little time

dnliii
Over 745 Posts!

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1405 Posts

Posted - Jul 04 2002 :  17:40:27  Show Profile  Reply with Quote
here is my formula:
10 gallons of 91 octane = 910 octane
2 gallons of 110 octane = 220 octane
-----------------------------
12 gallons = 94.17 octane


Just buy a 5 gallon can and try it...remenber, the car needs minmum 93 octane for best performance - 91 octane isn't even close.
let us know what you think!

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cellguru
Master Technician

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216 Posts

Posted - Jul 04 2002 :  19:32:36  Show Profile  Visit cellguru's Homepage  Reply with Quote
So you can't just pull up to the pump and put a couple of gallons of 115 in?

Damn, gotta mess with gas cans.



So many 745's so little time
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dnliii
Over 745 Posts!

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1405 Posts

Posted - Jul 05 2002 :  00:10:41  Show Profile  Reply with Quote
I have yet to see a station that will let you pump 110 or 115 fuel directly into your car...illegal here in California. These fuels are not approved for highway use. Easiest way is the tall white plastic race fuel container. Easy to see how much is left and pours really quick. Has a long clear spout. Cheap too. Put 2.5 gallons of race fuel in and 12.5 gallons of 91 octane. Big question- is this race fuel leaded or unleaded?? Leaded WILL screw up you catalytic converter and O2 sensor.

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cliffo
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768 Posts

Posted - Jul 05 2002 :  02:04:30  Show Profile  Reply with Quote
do you guys have VP Racing Fuel distributors in the states? i can buy street legal 105 motorsport unleaded (octane rating 105) from a distributor here in melbourne. they also have stuff called C16 and C21, which have octane ratings in the high 110's to 120's. these are only available here if a statuatory declaration is produced to say that the fuel is only being used on a race track/drag strip. toluene can be bought thru a shell oil distibutor, and thats what i have been doing for use on bmw track days. elf racing fuels are another source for high octane fuels, but at about $4.00AUD per liter, i have yet to find a use for it.

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cliffo
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768 Posts

Posted - Jul 05 2002 :  04:55:59  Show Profile  Reply with Quote
another question, guys. why is the octane rating of american fuels as low as it is. our regular unleaded is 96RON, and premium unleaded is 98RON. so with the addition of toluene, i get 106RON. and yes kevin, it is a pain in the 'arts' to muck around with tins and funnels and spills and fumes. don's idea with the race fuel container is a great idea. you can mix the stuff away from the car, and no spills when putting it into the tank.

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dnliii
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Posted - Jul 05 2002 :  08:14:24  Show Profile  Reply with Quote
"There are two types of octane numbers for gasoline, the Motor Octane Number (MON) and the Research Octane Number (RON). The ASTM methods for MON and RON use the same test engine, but operate under different
conditions. MON is a measure of performance of the fuel at high speeds or under heavy loads, while RON repersents the performance during low speed conditions. The octane number displayed at the pump is the average of these two values ([R+M]/2)."

Cliffo- Two different rating systems
F-1 Octane [Research Method]
F-2 Octane [Motor Method]
In the States we use [F-1+F-2]/2
The fuel I use is F-1 115.5 + F-2 105.2 /2 = 110 Octane
Hope this helps.

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dnliii
Over 745 Posts!

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Posted - Jul 05 2002 :  08:17:37  Show Profile  Reply with Quote
One other thing- My way of mixing is to pour 2.5 gallons of race fuel in and drive to the gas station and pump in the other 12.5 gallons. Very little effort!!!

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Keith 85 H7s
Garage Guru

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180 Posts

Posted - Jul 05 2002 :  09:10:42  Show Profile  Reply with Quote
To find race fuels, search the web. Recent issue of the SCCA mag has an ad from Sunoco (maybe hard to find in UT) but they indicate they have 5 race fuels, 3 leaded and two unleaded, GT and GT Plus. They are not the only company in this business. Their site for this is www.racegas.com or call them at 800-RACE-GAS.

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cellguru
Master Technician

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216 Posts

Posted - Jul 05 2002 :  09:13:11  Show Profile  Visit cellguru's Homepage  Reply with Quote
Ok Don, where do I buy the "tall white plastic race fuel container" ?


So many 745's so little time
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dnliii
Over 745 Posts!

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1405 Posts

Posted - Jul 05 2002 :  09:56:44  Show Profile  Reply with Quote
At the place you buy the fuel.
At an off-road motorcycle shop.
At a local speed shop.


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