Finding 93 Octane
Team Owner
Joined: Feb 2000
Posts: 53,478
Likes: 77
From: Arizona
Originally Posted by rwebcon
How would one go about finding stations that have 93 octane fule? I live in the phoenix area and have not seen one!
By the way can you see any difference between 91 and 93?
By the way can you see any difference between 91 and 93?
There was an old comparison on the forum last year, if memory serves me right, 10-15 peak HP loss using 89 vs 93 octane. And I think this was Z06. But that's peak. Day to day driving the HP loss is less.
Le Mans Master
Joined: Feb 2006
Posts: 5,762
Likes: 4
From: Chandler Arizona
Originally Posted by rwebcon
How would one go about finding stations that have 93 octane fule? I live in the phoenix area and have not seen one!
By the way can you see any difference between 91 and 93?
By the way can you see any difference between 91 and 93?
You can mix 2.5 gallons of 101 to every 10 gallons of 91 to get 93 octane. However, if you look at the cost, you will pay $2.20 for 91 right now, add the 101 at $6 per gallon, that works out to an average of $2.96 per gallon. That's a rip.
Pro
Joined: Sep 2006
Posts: 567
Likes: 53
From: Sumter SC
Cruise-In VIII Veteran
Originally Posted by Nifty C6
Octane demand decreases as altitude increases. One reason you can't find 93 octane is probably because at your higher altitude you don't need it.
Burning Brakes
Joined: Mar 2003
Posts: 1,030
Likes: 0
From: Pittsburgh PA
Originally Posted by Nifty C6
Octane demand decreases as altitude increases. One reason you can't find 93 octane is probably because at your higher altitude you don't need it.
I used to be a Sunoco only guy but now since they mix 10% meth. into the blend I won't use it.
Instructor
Joined: Aug 2005
Posts: 192
Likes: 0
From: Portland Oregon
St. Jude Donor '10
Limit to Octane Performance Gains
A local tuner in my area sells racing fuel. One of the fuels available is the Sunoco GT Plus. According to the Sunoco Inc website, the Sunoco GT Plus has a octane rating as follows:
RON, Research Octane 109 or M+R/2= 104. I believe the stations locally have the formula M+R/2 on the pumps so I suppose it is an apple to apple comparison 92 vs 104 octane. The fuel sells for $6.00/gallon. Would it be worth the extra cost to buy? To either burn straight or mix?
The tuners website has the following disclaimer/description:
This is one of the highest octane unleaded racing gasolines available! Sunoco GT Plus is specifically formulated for the professional racer and should not be used on the street. It is highly oxygenated to help produce maximum performance in classes which allow high dielectric fuels and is an excellent choice for modern computer-controlled applications which cannot otherwise tolerate tetraethyl lead (TEL).
Anyone have thoughts? I was thinking about purchasing some to see if I noticed any difference.
RON, Research Octane 109 or M+R/2= 104. I believe the stations locally have the formula M+R/2 on the pumps so I suppose it is an apple to apple comparison 92 vs 104 octane. The fuel sells for $6.00/gallon. Would it be worth the extra cost to buy? To either burn straight or mix?
The tuners website has the following disclaimer/description:
This is one of the highest octane unleaded racing gasolines available! Sunoco GT Plus is specifically formulated for the professional racer and should not be used on the street. It is highly oxygenated to help produce maximum performance in classes which allow high dielectric fuels and is an excellent choice for modern computer-controlled applications which cannot otherwise tolerate tetraethyl lead (TEL).
Anyone have thoughts? I was thinking about purchasing some to see if I noticed any difference.
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Drifting
Joined: Jan 2005
Posts: 1,940
Likes: 1,325
From: Houston Tx
There is no advantage to using gasoline higher than 91 octane unless you have modified your engine. I have some old posts on that topic that you should be able to find using search, either on my name or the topic octane. The reason most premium in the west is 91, while it is 93 elsewhere is mostly the California gasoline rules. Their formulation requirements make it more difficult to generate high octane components, which in turn drags down octane in all the areas supplied by refineries that supply California.
Instructor
Joined: Oct 2006
Posts: 200
Likes: 0
From: Berkeley Lake GA
Originally Posted by rwebcon
The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.
The compression ratio of your engine determines the octane rating of the gas you must use in the car. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more.
The compression ratio of your engine determines the octane rating of the gas you must use in the car. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more.
Ok that's my "learned something new" for the day... I'm turning my brain off until tomorrow. Very interesting. Thanks for the info.
Team Owner
Joined: Feb 2000
Posts: 53,478
Likes: 77
From: Arizona
Originally Posted by LDB
There is no advantage to using gasoline higher than 91 octane unless you have modified your engine.
http://www.chevrolet.com/corvette/specifications/
Le Mans Master
Joined: May 2005
Posts: 5,865
Likes: 2
From: Hope, Arkansas - '07 LMB Coupe
Cruise-In VIII Veteran
According to the '07 user manual:
The 91 octane will be fine.
If your vehicle has the 6.0L V8 engine (VIN
Code U), use premium unleaded gasoline with a
posted octane rating of 91 or higher. You may also
use regular unleaded gasoline rated at 87 octane
or higher, but your vehicle’s acceleration may
be slightly reduced, and you may notice a slight
audible knocking noise, commonly referred to
as spark knock. If the octane is less than 87, you
may notice a heavy knocking noise when you
drive. If this occurs, use a gasoline rated at
87 octane or higher as soon as possible.
Otherwise, you might damage your engine. If you
are using gasoline rated at 87 octane or higher
and you hear heavy knocking, your engine needs
service.
Code U), use premium unleaded gasoline with a
posted octane rating of 91 or higher. You may also
use regular unleaded gasoline rated at 87 octane
or higher, but your vehicle’s acceleration may
be slightly reduced, and you may notice a slight
audible knocking noise, commonly referred to
as spark knock. If the octane is less than 87, you
may notice a heavy knocking noise when you
drive. If this occurs, use a gasoline rated at
87 octane or higher as soon as possible.
Otherwise, you might damage your engine. If you
are using gasoline rated at 87 octane or higher
and you hear heavy knocking, your engine needs
service.
