Does 100+octane race fuel really work for you?
Thread Starter
Le Mans Master
Joined: Nov 2000
Posts: 7,294
Likes: 1
From: Coral Springs Florida
Does 100+octane race fuel really work for you?
I don't know ..I've tried it a few times . At $5.00 a gallon I add maybe 2 gallons to a 1/8-1/4 tank of 93 octane just before the runs and I've run well but ..Who knows? 
Le Mans Master
Joined: Jul 2002
Posts: 7,370
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From: Slave to the evil empire
Cruise-In V Veteran
St. Jude Donor '04
I mix 93 with 104 octane when I go to the track, simply because I run 25* of timing which is great for normal driving on the street but if I push it I can hear the famous marbles in the can sound
Instructor
Joined: Aug 2001
Posts: 192
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From: Virginia Chesapeak
I made the mistake of adding 5+ gallons of 100 octane and my car actually ran slower. I didn't realize that higher octane gas actually burns slower, and can slow your car down if your engine doesn't really require 100 octane gas. However adding a gallon or 2 might help under certain conditions.
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Melting Slicks
Joined: Jun 2004
Posts: 3,439
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From: Newark, DE
St. Jude Donor '06
Adding 3-4 gallons to the CA 91 octane gas eliminates hot weather KR, but there is something about it that my car doesn't like. It always turns on the SES light (and yes, it's unleaded).
Le Mans Master
Joined: Apr 1999
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From: Burlington ON
Cruise-In I, II, III, IV & V Veteran
CI-I & II Auto-X Champ
Race fuel is actually not a performance enhancer at all for an engine that does not require it. If your car's compression ratio is right on the line of detonating with street gas, it will definitely help because it wills top the detonation and knock retard. It doesnt hurt to add enough to bring your octane up to 95-97 in my opinion. Running 100 octane straight isn't such a good idea unless you are over 12:1 CR.
I run 114 octane race fuel straight up in the Nova but the 565ci engine in it is 14:1 CR and would detonate itself to death real quick with anything lower than 108.
I run 114 octane race fuel straight up in the Nova but the 565ci engine in it is 14:1 CR and would detonate itself to death real quick with anything lower than 108.
Thread Starter
Le Mans Master
Joined: Nov 2000
Posts: 7,294
Likes: 1
From: Coral Springs Florida
Originally Posted by Face
.. Now with the 5.3 heads, it does help a little.
Well that's the point! I'm running ARE 5.3 Stage 3 heads with 67 cc chambers and 11.25 CR...so a couple of gallons should help..Just my opinion
Thanks all...
Drifting
Joined: Nov 2003
Posts: 1,288
Likes: 2
From: tucson az
only need enough to take care of any detonation that might occur...i had 55 gal drum of sunoco gt 100 that i made my mix with...had 5.3 heads with .027 head gaskets...91 pump gas didn't cut it...went back to stock cr....to much of a pita....like much better now!!!
Race Director
Joined: Mar 2001
Posts: 19,965
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From: Bonneville Salt Flats
For a typical street machine, you shouldn't need it. If you are getting detonation, find out why. If serious mods (high compression, big boost, etc.), sure.
Otherwise, don't waste the money.
And, $5.00/gal is cheap. Stuff we use at B'ville is $10.
All the best.
Otherwise, don't waste the money.
And, $5.00/gal is cheap. Stuff we use at B'ville is $10.
All the best.
. 
Racer
Joined: Nov 2002
Posts: 289
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From: supergirl avatar deemed inappropriate
Back in the early '70's my buddies and I used to get our High Octane fuel at the local (small airplanes) airport. At the time you could buy 102-103 octane at Sunoco, but the stuff at the airport was 110. They weren't permitted by law to pump it directly into the car so we took a 5 gallon gas can with us and just transferred it our self. The beauty of it was the price was only 25 or 30 cents a gallon more than pump gas. Keep in mind a gallon of premium gas was about 50 cents a gallon, then.
Last edited by Six Pak; Jan 4, 2005 at 05:41 PM.
Safety Car
Joined: Jul 2001
Posts: 4,661
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From: Ocean Springs MS
Originally Posted by Six Pak
Back in the early '70's my buddies and I used to get our High Octane fuel at the local (small airplanes) airport. At the time you could buy 102-103 octane at Sunoco, but the stuff at the airport was 110. They weren't permitted by law to pump it directly into the car so we took a 5 gallon gas can with us and just transferred it our self. The beauty of it was the price was only 25 or 30 cents a gallon more than pump gas. Keep in mind a gallon of premium gas was about 50 cents a gallon, then.
on todays cars.
Le Mans Master
Joined: Apr 1999
Posts: 7,820
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From: Burlington ON
Cruise-In I, II, III, IV & V Veteran
CI-I & II Auto-X Champ
Just use ratios. Ie. 5gallons of 100 octane and 5gallons of 95 work out to be 10gallons of 97.5 octane.
Originally Posted by Vince99FRC
Does anyone have a calculator to figure out what it would take of 100 octane to give you say 95 to 98 octane rating starting from 93 or 94?
Melting Slicks
Joined: Jun 2004
Posts: 3,439
Likes: 6
From: Newark, DE
St. Jude Donor '06
Originally Posted by Vince99FRC
Does anyone have a calculator to figure out what it would take of 100 octane to give you say 95 to 98 octane rating starting from 93 or 94?
http://www.76.com/products/76racing.asp
Melting Slicks
Joined: Sep 2007
Posts: 2,138
Likes: 139
From: Port St Lucie Florida
I know this is an old post but I would just like to add my thoughts.
I just added 3 gal of 100 octane from sunoco and wow, what a difference.
The car seems to not lag as much but is instant with throttle response and just instant power all over the place. My car is procharged and highly modified. I mixed 3 gal with about 12 gal of 93 octane. I live in Fla and right now the outside temp is 94-95 degrees. Sunoco says that this fuel is oxygenated. Just wanted to share my thoughts.
I just added 3 gal of 100 octane from sunoco and wow, what a difference.
The car seems to not lag as much but is instant with throttle response and just instant power all over the place. My car is procharged and highly modified. I mixed 3 gal with about 12 gal of 93 octane. I live in Fla and right now the outside temp is 94-95 degrees. Sunoco says that this fuel is oxygenated. Just wanted to share my thoughts.
