Race-Gas fuel additive
04-20-2013, 11:17 AM
#1
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Race-Gas fuel additive
Is anyone using this? Aside from the convenience it seems more expensive. I believe I paid $10 per gallon for 100 octane at Lime Rock a few weeks ago.
To make race fuel with race-gas you need to add 8 oz. per gallon. If a 32 oz. can costs $30 that is an extra $7.50 per gallon. I pay about $4 per gallon in CT for a total cost of $11.50 per gallon.
www.race-gas.com
To make race fuel with race-gas you need to add 8 oz. per gallon. If a 32 oz. can costs $30 that is an extra $7.50 per gallon. I pay about $4 per gallon in CT for a total cost of $11.50 per gallon.
www.race-gas.com
RACE GASTM RACE FUEL CONCENTRATE FAQS
WHAT DOES A FUEL'S OCTANE RATING MEAN?
Octane rating is the standard of measure of the performance fuel in an engine. The octane number is an indicator of the fuel's tendency to burn in a controlled manner versus exploding in an uncontrolled manner. Fuels with a high octane rating and withstand higher compression before detonating or "knocking".
THERE ARE SEVERAL OCTANE NUMBERS FOR GASOLINE. WHAT DO THEY MEAN AND WHICH ONE SHOULD I CARE ABOUT?
There are 3 octane ratings commonly used in the US. Research Octane Number (RON), Motor Octane Number (MON) and Anti-Knock Index (AKI or (M+R)/2). Let's look at each of these individually.
Research Octane Number (RON): RON is the "laboratory" measurement of octane. The octane number is determined by running the fuel in a CRF Test Engine and varying the compression of the engine until the fuel "detonates" or Knocks. The engine is not under "load" and as a result RON numbers generally run higher than the other octane numbers.
Motor Octane Number (MON) is measured using the same CRF engine test however the engine is placed under a "Load" of 900 RPM. This test is a better indication of octane because it better simulates the octane in a real world setting, i.e. under load. MON numbers run lower than RON numbers.
AKI or (R+M)/2 is the Anti-Knock Index. This number is the average of the MON and RON numbers. This number is the most important because it averages the octane under load and at idle. This is the number that you should care most about. When a car company or an engine builder specifies a fuel's octane number for an engine, AKI is the number they are referring to.
WHEN SOMEONE REFERS TO A "POINT OF OCTANE" WHAT SPECIFICALLY DO THEY MEAN?
The scale of octane is a point of confusion for even seasoned motorsports enthusiasts and is a very important issue when evaluating octane boost products. A point of octane is 1/10 of an octane number. For example if you increase the octane of 87 pump gas by 8 "points" you are increasing the octane to 87.8. Many consumers see products on the shelf that promise to raise the octane by "10 points" and think that it will raise the octane by 10 octane numbers. That is not the case. Other suppliers rely on this confusion to sell their products. Don't be fooled!
HOW IS RACE GASTM DIFFERENT THAN OCTANE BOOST PRODUCTS?
First, octane boosters only add a few points of octane and cannot raise the octane of pump gas to that of racing fuel. What many people don't know is that a point of octane is 1/10 of an octane number. For example, if an octane booster says it raises octane by 9 points and it is blended with 87 octane fuel the final octane number will be 87.9 not 96.
Second, octane boosters will raise the octane they don't increase the chemical energy of pump gas. This is because they are not adding the high quality fuel aromatics that are used in Race Gas. As a result your engine will not "ping" but it will not generate as much power as it would using Race Gas.
I CAN'T GET HIGH OCTANE GAS FOR MY BOAT AT THE MARINA. CAN I USE RACE GASTM IN MY BOAT?
Yes! Race Gas will work in any engine that requires high quality, high octane fuel. Race GasTM can be used in:
Cars
Snowmobiles
Motorcycles
Boats
Personal Water Craft
WHY NOT JUST USE AVIATION GAS IN MY HIGH PERFORMANCE ENGINE?
There are two major factors that go into the formulation of aviation gasoline. First is altitude. Aviation gasoline is blended with specific hydrocarbons to target engine operation altitudes of 10,000 feet or more. Some of these hydrocarbons are detrimental to a high performance engine operating at much lower altitude and will degrade performance.
Secondly, aircraft engines don't run at high RPM loads under normal operation. An aircraft at cruise might be turning at 2,500 to 3,000 RPM, significantly lower than the 5,000 to 9,000 redline typically seen in an automobile engine. Aviation fuel is blended to balance performance and economy at these low engine loads and as a result will not be as effective at high engine load.
One other issue that should be considered with aviation fuel is the use of lead. Tetraethyl Lead is used in aviation gasoline to increase the octane, (even in so called "Low Lead" or LL fuels). Lead will damage O2 sensors and catalytic converters which can be expensive to replace.
WHY NOT USE JET FUEL IN MY CAR?
Jet fuel is more like diesel fuel than gasoline. It is designed to be burned in turbine engines at very high operating temperatures. Jet fuel would seriously damage your engine assuming that you could even get it to fire up in the first place!
I HAVE HEARD THAT "ETHANOL" BASED FUELS LIKE E85 AND E15 HAVE VERY HIGH OCTANE RATINGS. WHY NOT JUST USE THOSE FUELS?
"Ethanol" based fuels do have a high octane they also have lower chemical energy than regular pump gas. As a result your engine must be tuned to accommodate the decrease in chemical energy by increasing fuel flow, either though changes to fuel injection or carburetor jet size. On average you will need 30% to 40% more fuel to equal the chemical energy of non-ethanol fuels.
In addition, ethanol based fuels can have negative effect on your fuel system and engine. Ethanol will degrade components in the fuel system like fuel pumps and seals. Ethanol will also promote corrosion in the fuel system and exhaust system.
WILL RACE GASTM HARM MY O2 SENSORS OR CATALYTIC CONVERTER.
No. Race GasTM does not contain lead or other additives that can harm O2 sensors or catalytic converters.
IF A LITTLE RACE GAS IS GOOD, WOULDN'T A LOT BE EVEN BETTER?
No! It is possible to "over octane" an engine. While the effects on the engine are less than "under octane", the engine will not perform as well as it would with the right octane fuel. We encourage our customers to talk with their engine builder or people with similar engine configuration to determine the "right octane" for your car.
The chart below represents a good estimate of octane requirements by compression ratio. It is not specific to your engine so you may want to blend your fuel to an octane number or two higher than what is listed below.
Compression Ratio Octane Number Requirement
5:1 72
6:1 81
7:1 87
8:1 92
9:1 96
10:1 100
11:1 104
12:1 108
7:1 87
It is important to note that the octane numbers above are the "Anti Knock Index" number or (R+M)/2. The AKI number is important as it is an average of the RON, (Research Octane Number), and the MON,(Motor Octane Number). AKI reflects the "real world" octane and more accurately reflects the octane rating while driving versus a lab test.
WILL RACE GASTM BENEFIT A STOCK / STREET CAR?
It depends on the car. High performance cars like a Corvette, Viper, Porsche or BMW and turbo charged cars like a WRX will see improved throttle response and power. Cars with carburetors can be tuned to run Race Gas and will see more power, (changes will need to be made to the carburetor jets and the timing). Regular cars like a Chrysler 200, a Ford Focus or a Toyota 4Runner will not see a great deal of improvement.
It is important to remember to not "over octane" your engine as this will cause a decrease in performance
WHAT DOES A FUEL'S OCTANE RATING MEAN?
Octane rating is the standard of measure of the performance fuel in an engine. The octane number is an indicator of the fuel's tendency to burn in a controlled manner versus exploding in an uncontrolled manner. Fuels with a high octane rating and withstand higher compression before detonating or "knocking".
THERE ARE SEVERAL OCTANE NUMBERS FOR GASOLINE. WHAT DO THEY MEAN AND WHICH ONE SHOULD I CARE ABOUT?
There are 3 octane ratings commonly used in the US. Research Octane Number (RON), Motor Octane Number (MON) and Anti-Knock Index (AKI or (M+R)/2). Let's look at each of these individually.
Research Octane Number (RON): RON is the "laboratory" measurement of octane. The octane number is determined by running the fuel in a CRF Test Engine and varying the compression of the engine until the fuel "detonates" or Knocks. The engine is not under "load" and as a result RON numbers generally run higher than the other octane numbers.
Motor Octane Number (MON) is measured using the same CRF engine test however the engine is placed under a "Load" of 900 RPM. This test is a better indication of octane because it better simulates the octane in a real world setting, i.e. under load. MON numbers run lower than RON numbers.
AKI or (R+M)/2 is the Anti-Knock Index. This number is the average of the MON and RON numbers. This number is the most important because it averages the octane under load and at idle. This is the number that you should care most about. When a car company or an engine builder specifies a fuel's octane number for an engine, AKI is the number they are referring to.
WHEN SOMEONE REFERS TO A "POINT OF OCTANE" WHAT SPECIFICALLY DO THEY MEAN?
The scale of octane is a point of confusion for even seasoned motorsports enthusiasts and is a very important issue when evaluating octane boost products. A point of octane is 1/10 of an octane number. For example if you increase the octane of 87 pump gas by 8 "points" you are increasing the octane to 87.8. Many consumers see products on the shelf that promise to raise the octane by "10 points" and think that it will raise the octane by 10 octane numbers. That is not the case. Other suppliers rely on this confusion to sell their products. Don't be fooled!
HOW IS RACE GASTM DIFFERENT THAN OCTANE BOOST PRODUCTS?
First, octane boosters only add a few points of octane and cannot raise the octane of pump gas to that of racing fuel. What many people don't know is that a point of octane is 1/10 of an octane number. For example, if an octane booster says it raises octane by 9 points and it is blended with 87 octane fuel the final octane number will be 87.9 not 96.
Second, octane boosters will raise the octane they don't increase the chemical energy of pump gas. This is because they are not adding the high quality fuel aromatics that are used in Race Gas. As a result your engine will not "ping" but it will not generate as much power as it would using Race Gas.
I CAN'T GET HIGH OCTANE GAS FOR MY BOAT AT THE MARINA. CAN I USE RACE GASTM IN MY BOAT?
Yes! Race Gas will work in any engine that requires high quality, high octane fuel. Race GasTM can be used in:
Cars
Snowmobiles
Motorcycles
Boats
Personal Water Craft
WHY NOT JUST USE AVIATION GAS IN MY HIGH PERFORMANCE ENGINE?
There are two major factors that go into the formulation of aviation gasoline. First is altitude. Aviation gasoline is blended with specific hydrocarbons to target engine operation altitudes of 10,000 feet or more. Some of these hydrocarbons are detrimental to a high performance engine operating at much lower altitude and will degrade performance.
Secondly, aircraft engines don't run at high RPM loads under normal operation. An aircraft at cruise might be turning at 2,500 to 3,000 RPM, significantly lower than the 5,000 to 9,000 redline typically seen in an automobile engine. Aviation fuel is blended to balance performance and economy at these low engine loads and as a result will not be as effective at high engine load.
One other issue that should be considered with aviation fuel is the use of lead. Tetraethyl Lead is used in aviation gasoline to increase the octane, (even in so called "Low Lead" or LL fuels). Lead will damage O2 sensors and catalytic converters which can be expensive to replace.
WHY NOT USE JET FUEL IN MY CAR?
Jet fuel is more like diesel fuel than gasoline. It is designed to be burned in turbine engines at very high operating temperatures. Jet fuel would seriously damage your engine assuming that you could even get it to fire up in the first place!
I HAVE HEARD THAT "ETHANOL" BASED FUELS LIKE E85 AND E15 HAVE VERY HIGH OCTANE RATINGS. WHY NOT JUST USE THOSE FUELS?
"Ethanol" based fuels do have a high octane they also have lower chemical energy than regular pump gas. As a result your engine must be tuned to accommodate the decrease in chemical energy by increasing fuel flow, either though changes to fuel injection or carburetor jet size. On average you will need 30% to 40% more fuel to equal the chemical energy of non-ethanol fuels.
In addition, ethanol based fuels can have negative effect on your fuel system and engine. Ethanol will degrade components in the fuel system like fuel pumps and seals. Ethanol will also promote corrosion in the fuel system and exhaust system.
WILL RACE GASTM HARM MY O2 SENSORS OR CATALYTIC CONVERTER.
No. Race GasTM does not contain lead or other additives that can harm O2 sensors or catalytic converters.
IF A LITTLE RACE GAS IS GOOD, WOULDN'T A LOT BE EVEN BETTER?
No! It is possible to "over octane" an engine. While the effects on the engine are less than "under octane", the engine will not perform as well as it would with the right octane fuel. We encourage our customers to talk with their engine builder or people with similar engine configuration to determine the "right octane" for your car.
The chart below represents a good estimate of octane requirements by compression ratio. It is not specific to your engine so you may want to blend your fuel to an octane number or two higher than what is listed below.
Compression Ratio Octane Number Requirement
5:1 72
6:1 81
7:1 87
8:1 92
9:1 96
10:1 100
11:1 104
12:1 108
7:1 87
It is important to note that the octane numbers above are the "Anti Knock Index" number or (R+M)/2. The AKI number is important as it is an average of the RON, (Research Octane Number), and the MON,(Motor Octane Number). AKI reflects the "real world" octane and more accurately reflects the octane rating while driving versus a lab test.
WILL RACE GASTM BENEFIT A STOCK / STREET CAR?
It depends on the car. High performance cars like a Corvette, Viper, Porsche or BMW and turbo charged cars like a WRX will see improved throttle response and power. Cars with carburetors can be tuned to run Race Gas and will see more power, (changes will need to be made to the carburetor jets and the timing). Regular cars like a Chrysler 200, a Ford Focus or a Toyota 4Runner will not see a great deal of improvement.
It is important to remember to not "over octane" your engine as this will cause a decrease in performance
04-20-2013, 05:15 PM
#2
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I saw this in the latest Grassroots. Never tried it, but looks like it could be interesting if the price was better.
04-20-2013, 07:12 PM
#3
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Tried a similar product, starting with Sunoco 93, on my old Cup car.
Compared to straight VP race gas, it still had a propensity to pre-ignite.
It was easier jst to buy drums of straight race gas (I was already buying drums from the local VP distributor in Hampden MA), the added bonus was no ethanol.
Compared to straight VP race gas, it still had a propensity to pre-ignite.
It was easier jst to buy drums of straight race gas (I was already buying drums from the local VP distributor in Hampden MA), the added bonus was no ethanol.
04-21-2013, 10:10 AM
#4
Race Car
I have to take issue with several claims that are made.
I used to do engine development with Ford. I've never heard the term "AKI." It is (R+M)/2, period. It is also NOT USED in engine development. It likely would not be used in industry if not for the fact that the consumer knows the numbers. Furthermore, I don't believe much of the world outside of the US uses (R+M)/2 We use RON. MON is outdated.
Second, his little chart for what octane requirements are crap. There are so many variables for what drives octane requirement that putting together a chart like this is impossible. For example, the 951 is an 8.0:1 engine. The 968 is an 11.0:1 engine. They both require the same octane. What all goes into octane requirement?
Bore size
Spark plug location (i.e. 2V chamber, 4V chamber, dual plug 2V......)
CYlinder head material
Intake manifold design (tuning)
Cam timing
Fuel delivery (DI, PFI, carburetor)
Rod length
Vehicle weight
Gearing
Ambient conditions
Detonation is predominantly a low RPM, high load problem. In most cases, the knock sensor doesn't even work over about 4500 RPM or so (there's a huge range around that number, don't take it as absolute). By then, the pistons are moving so fast that detonation doesn't really have time to occur. In a race application, detonation is extremely rare.
Historically, all the manufacturers have had different philosophies for how to go about this. But generally, they had to design thier engines for worst case scenarios, which means a full cargo load going uphill while cruising, which puts a heavy load on the engine while keeping it at lower RPM. That means that for most scenarios, the engines not only would not benefit any from higher octane, they could actually run lower octane than they do.
As knock sensing and timing adjustment capabilities are changing, that philosophy is being tweaked. GM is notorious for designing their (primariliy truck) engines to run 93 octane, but only putting a little blurb in the owner's manual stating "for best performance use 91 or greater octane" to get by the CAFE police. They do this becasue they can design the engine with higher compression to give better fuel economy, knowing that the overwhelming majority of the time, the engine will not be running in a condition that would lead itself to detonation (i.e. the truck is fully loaded or towing a trailer).
In cars, and especially lightweight, powerful sports cars, they just don't run in conditions that are going to cause detonation. So for anyone running a stock class, or an SP_ whatever class, higher octane is more or less a waste of money. The only exception is when it is really, really hot outside, say the way VIR has seemed to be at the club races there, or the June or August DE's at Road Atlanta. And even then, turbos are probably the only ones that would be at further risk.
But again, in most cases, cars can actually run lower octane than they are rated to run - the exact OPPOSITE of what his chart claims.
Not, GT cars or Cup cars are a different matter, entirely. If you are running a 13.0:1 engine, unless it is DI with a 75mm bore and 100mm stroke, you probably need race gas. If you've taken your 951 and put 10.0:1 pistons in it and run 20PSI, you probably need race gas.
Now, none of this is absolute. But the claims this guy is making are I'll just say less than 100% honest.
Also, since it was mentioned, pre-ignition is completely unrelated to octane. Pre-ignition is compression ratio, cam timing, cooling, etc. It is exactly what it says it is - early ignition of the air/fuel mixture, usually caused by soot build up on valves or something similar that would create a hot spot. Detonation is a post-ignition explosion of the high pressure regions in the chamber, before the flame front reaches it. By itself, it isn't always a big deal, but can lead to PI from heating up spots of the chamber, and PI is what makes engines go boom.
I used to do engine development with Ford. I've never heard the term "AKI." It is (R+M)/2, period. It is also NOT USED in engine development. It likely would not be used in industry if not for the fact that the consumer knows the numbers. Furthermore, I don't believe much of the world outside of the US uses (R+M)/2 We use RON. MON is outdated.
Second, his little chart for what octane requirements are crap. There are so many variables for what drives octane requirement that putting together a chart like this is impossible. For example, the 951 is an 8.0:1 engine. The 968 is an 11.0:1 engine. They both require the same octane. What all goes into octane requirement?
Bore size
Spark plug location (i.e. 2V chamber, 4V chamber, dual plug 2V......)
CYlinder head material
Intake manifold design (tuning)
Cam timing
Fuel delivery (DI, PFI, carburetor)
Rod length
Vehicle weight
Gearing
Ambient conditions
Detonation is predominantly a low RPM, high load problem. In most cases, the knock sensor doesn't even work over about 4500 RPM or so (there's a huge range around that number, don't take it as absolute). By then, the pistons are moving so fast that detonation doesn't really have time to occur. In a race application, detonation is extremely rare.
Historically, all the manufacturers have had different philosophies for how to go about this. But generally, they had to design thier engines for worst case scenarios, which means a full cargo load going uphill while cruising, which puts a heavy load on the engine while keeping it at lower RPM. That means that for most scenarios, the engines not only would not benefit any from higher octane, they could actually run lower octane than they do.
As knock sensing and timing adjustment capabilities are changing, that philosophy is being tweaked. GM is notorious for designing their (primariliy truck) engines to run 93 octane, but only putting a little blurb in the owner's manual stating "for best performance use 91 or greater octane" to get by the CAFE police. They do this becasue they can design the engine with higher compression to give better fuel economy, knowing that the overwhelming majority of the time, the engine will not be running in a condition that would lead itself to detonation (i.e. the truck is fully loaded or towing a trailer).
In cars, and especially lightweight, powerful sports cars, they just don't run in conditions that are going to cause detonation. So for anyone running a stock class, or an SP_ whatever class, higher octane is more or less a waste of money. The only exception is when it is really, really hot outside, say the way VIR has seemed to be at the club races there, or the June or August DE's at Road Atlanta. And even then, turbos are probably the only ones that would be at further risk.
But again, in most cases, cars can actually run lower octane than they are rated to run - the exact OPPOSITE of what his chart claims.
Not, GT cars or Cup cars are a different matter, entirely. If you are running a 13.0:1 engine, unless it is DI with a 75mm bore and 100mm stroke, you probably need race gas. If you've taken your 951 and put 10.0:1 pistons in it and run 20PSI, you probably need race gas.
Now, none of this is absolute. But the claims this guy is making are I'll just say less than 100% honest.
Also, since it was mentioned, pre-ignition is completely unrelated to octane. Pre-ignition is compression ratio, cam timing, cooling, etc. It is exactly what it says it is - early ignition of the air/fuel mixture, usually caused by soot build up on valves or something similar that would create a hot spot. Detonation is a post-ignition explosion of the high pressure regions in the chamber, before the flame front reaches it. By itself, it isn't always a big deal, but can lead to PI from heating up spots of the chamber, and PI is what makes engines go boom.
04-21-2013, 10:16 AM
#5
Rennlist Member
I have to take issue with several claims that are made.
I used to do engine development with Ford. I've never heard the term "AKI." It is (R+M)/2, period. It is also NOT USED in engine development. It likely would not be used in industry if not for the fact that the consumer knows the numbers. Furthermore, I don't believe much of the world outside of the US uses (R+M)/2 We use RON. MON is outdated.
Second, his little chart for what octane requirements are crap. There are so many variables for what drives octane requirement that putting together a chart like this is impossible. For example, the 951 is an 8.0:1 engine. The 968 is an 11.0:1 engine. They both require the same octane. What all goes into octane requirement?
Bore size
Spark plug location (i.e. 2V chamber, 4V chamber, dual plug 2V......)
CYlinder head material
Intake manifold design (tuning)
Cam timing
Fuel delivery (DI, PFI, carburetor)
Rod length
Vehicle weight
Gearing
Ambient conditions
Detonation is predominantly a low RPM, high load problem. In most cases, the knock sensor doesn't even work over about 4500 RPM or so (there's a huge range around that number, don't take it as absolute). By then, the pistons are moving so fast that detonation doesn't really have time to occur. In a race application, detonation is extremely rare.
Historically, all the manufacturers have had different philosophies for how to go about this. But generally, they had to design thier engines for worst case scenarios, which means a full cargo load going uphill while cruising, which puts a heavy load on the engine while keeping it at lower RPM. That means that for most scenarios, the engines not only would not benefit any from higher octane, they could actually run lower octane than they do.
As knock sensing and timing adjustment capabilities are changing, that philosophy is being tweaked. GM is notorious for designing their (primariliy truck) engines to run 93 octane, but only putting a little blurb in the owner's manual stating "for best performance use 91 or greater octane" to get by the CAFE police. They do this becasue they can design the engine with higher compression to give better fuel economy, knowing that the overwhelming majority of the time, the engine will not be running in a condition that would lead itself to detonation (i.e. the truck is fully loaded or towing a trailer).
In cars, and especially lightweight, powerful sports cars, they just don't run in conditions that are going to cause detonation. So for anyone running a stock class, or an SP_ whatever class, higher octane is more or less a waste of money. The only exception is when it is really, really hot outside, say the way VIR has seemed to be at the club races there, or the June or August DE's at Road Atlanta. And even then, turbos are probably the only ones that would be at further risk.
But again, in most cases, cars can actually run lower octane than they are rated to run - the exact OPPOSITE of what his chart claims.
Not, GT cars or Cup cars are a different matter, entirely. If you are running a 13.0:1 engine, unless it is DI with a 75mm bore and 100mm stroke, you probably need race gas. If you've taken your 951 and put 10.0:1 pistons in it and run 20PSI, you probably need race gas.
Now, none of this is absolute. But the claims this guy is making are I'll just say less than 100% honest.
Also, since it was mentioned, pre-ignition is completely unrelated to octane. Pre-ignition is compression ratio, cam timing, cooling, etc. It is exactly what it says it is - early ignition of the air/fuel mixture, usually caused by soot build up on valves or something similar that would create a hot spot. Detonation is a post-ignition explosion of the high pressure regions in the chamber, before the flame front reaches it. By itself, it isn't always a big deal, but can lead to PI from heating up spots of the chamber, and PI is what makes engines go boom.
I used to do engine development with Ford. I've never heard the term "AKI." It is (R+M)/2, period. It is also NOT USED in engine development. It likely would not be used in industry if not for the fact that the consumer knows the numbers. Furthermore, I don't believe much of the world outside of the US uses (R+M)/2 We use RON. MON is outdated.
Second, his little chart for what octane requirements are crap. There are so many variables for what drives octane requirement that putting together a chart like this is impossible. For example, the 951 is an 8.0:1 engine. The 968 is an 11.0:1 engine. They both require the same octane. What all goes into octane requirement?
Bore size
Spark plug location (i.e. 2V chamber, 4V chamber, dual plug 2V......)
CYlinder head material
Intake manifold design (tuning)
Cam timing
Fuel delivery (DI, PFI, carburetor)
Rod length
Vehicle weight
Gearing
Ambient conditions
Detonation is predominantly a low RPM, high load problem. In most cases, the knock sensor doesn't even work over about 4500 RPM or so (there's a huge range around that number, don't take it as absolute). By then, the pistons are moving so fast that detonation doesn't really have time to occur. In a race application, detonation is extremely rare.
Historically, all the manufacturers have had different philosophies for how to go about this. But generally, they had to design thier engines for worst case scenarios, which means a full cargo load going uphill while cruising, which puts a heavy load on the engine while keeping it at lower RPM. That means that for most scenarios, the engines not only would not benefit any from higher octane, they could actually run lower octane than they do.
As knock sensing and timing adjustment capabilities are changing, that philosophy is being tweaked. GM is notorious for designing their (primariliy truck) engines to run 93 octane, but only putting a little blurb in the owner's manual stating "for best performance use 91 or greater octane" to get by the CAFE police. They do this becasue they can design the engine with higher compression to give better fuel economy, knowing that the overwhelming majority of the time, the engine will not be running in a condition that would lead itself to detonation (i.e. the truck is fully loaded or towing a trailer).
In cars, and especially lightweight, powerful sports cars, they just don't run in conditions that are going to cause detonation. So for anyone running a stock class, or an SP_ whatever class, higher octane is more or less a waste of money. The only exception is when it is really, really hot outside, say the way VIR has seemed to be at the club races there, or the June or August DE's at Road Atlanta. And even then, turbos are probably the only ones that would be at further risk.
But again, in most cases, cars can actually run lower octane than they are rated to run - the exact OPPOSITE of what his chart claims.
Not, GT cars or Cup cars are a different matter, entirely. If you are running a 13.0:1 engine, unless it is DI with a 75mm bore and 100mm stroke, you probably need race gas. If you've taken your 951 and put 10.0:1 pistons in it and run 20PSI, you probably need race gas.
Now, none of this is absolute. But the claims this guy is making are I'll just say less than 100% honest.
Also, since it was mentioned, pre-ignition is completely unrelated to octane. Pre-ignition is compression ratio, cam timing, cooling, etc. It is exactly what it says it is - early ignition of the air/fuel mixture, usually caused by soot build up on valves or something similar that would create a hot spot. Detonation is a post-ignition explosion of the high pressure regions in the chamber, before the flame front reaches it. By itself, it isn't always a big deal, but can lead to PI from heating up spots of the chamber, and PI is what makes engines go boom.
What about a Stock class race car that has been flashed to use 100 octane ?
04-21-2013, 10:22 AM
#6
Rennlist Member
"Due to several changes in federal and Minnesota state law it is nearly impossible to legally transport large quantities of fuel by highway"
Last edited by Oddjob; 04-21-2013 at 11:09 AM.
04-21-2013, 10:48 AM
#7
WRONGLY ACCUSED!
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I have to take issue with several claims that are made.
I used to do engine development with Ford. I've never heard the term "AKI." It is (R+M)/2, period. It is also NOT USED in engine development. It likely would not be used in industry if not for the fact that the consumer knows the numbers. Furthermore, I don't believe much of the world outside of the US uses (R+M)/2 We use RON. MON is outdated.
Second, his little chart for what octane requirements are crap. There are so many variables for what drives octane requirement that putting together a chart like this is impossible. For example, the 951 is an 8.0:1 engine. The 968 is an 11.0:1 engine. They both require the same octane. What all goes into octane requirement?
Bore size
Spark plug location (i.e. 2V chamber, 4V chamber, dual plug 2V......)
CYlinder head material
Intake manifold design (tuning)
Cam timing
Fuel delivery (DI, PFI, carburetor)
Rod length
Vehicle weight
Gearing
Ambient conditions
Detonation is predominantly a low RPM, high load problem. In most cases, the knock sensor doesn't even work over about 4500 RPM or so (there's a huge range around that number, don't take it as absolute). By then, the pistons are moving so fast that detonation doesn't really have time to occur. In a race application, detonation is extremely rare.
Historically, all the manufacturers have had different philosophies for how to go about this. But generally, they had to design thier engines for worst case scenarios, which means a full cargo load going uphill while cruising, which puts a heavy load on the engine while keeping it at lower RPM. That means that for most scenarios, the engines not only would not benefit any from higher octane, they could actually run lower octane than they do.
As knock sensing and timing adjustment capabilities are changing, that philosophy is being tweaked. GM is notorious for designing their (primariliy truck) engines to run 93 octane, but only putting a little blurb in the owner's manual stating "for best performance use 91 or greater octane" to get by the CAFE police. They do this becasue they can design the engine with higher compression to give better fuel economy, knowing that the overwhelming majority of the time, the engine will not be running in a condition that would lead itself to detonation (i.e. the truck is fully loaded or towing a trailer).
In cars, and especially lightweight, powerful sports cars, they just don't run in conditions that are going to cause detonation. So for anyone running a stock class, or an SP_ whatever class, higher octane is more or less a waste of money. The only exception is when it is really, really hot outside, say the way VIR has seemed to be at the club races there, or the June or August DE's at Road Atlanta. And even then, turbos are probably the only ones that would be at further risk.
But again, in most cases, cars can actually run lower octane than they are rated to run - the exact OPPOSITE of what his chart claims.
Not, GT cars or Cup cars are a different matter, entirely. If you are running a 13.0:1 engine, unless it is DI with a 75mm bore and 100mm stroke, you probably need race gas. If you've taken your 951 and put 10.0:1 pistons in it and run 20PSI, you probably need race gas.
Now, none of this is absolute. But the claims this guy is making are I'll just say less than 100% honest.
Also, since it was mentioned, pre-ignition is completely unrelated to octane. Pre-ignition is compression ratio, cam timing, cooling, etc. It is exactly what it says it is - early ignition of the air/fuel mixture, usually caused by soot build up on valves or something similar that would create a hot spot. Detonation is a post-ignition explosion of the high pressure regions in the chamber, before the flame front reaches it. By itself, it isn't always a big deal, but can lead to PI from heating up spots of the chamber, and PI is what makes engines go boom.
I used to do engine development with Ford. I've never heard the term "AKI." It is (R+M)/2, period. It is also NOT USED in engine development. It likely would not be used in industry if not for the fact that the consumer knows the numbers. Furthermore, I don't believe much of the world outside of the US uses (R+M)/2 We use RON. MON is outdated.
Second, his little chart for what octane requirements are crap. There are so many variables for what drives octane requirement that putting together a chart like this is impossible. For example, the 951 is an 8.0:1 engine. The 968 is an 11.0:1 engine. They both require the same octane. What all goes into octane requirement?
Bore size
Spark plug location (i.e. 2V chamber, 4V chamber, dual plug 2V......)
CYlinder head material
Intake manifold design (tuning)
Cam timing
Fuel delivery (DI, PFI, carburetor)
Rod length
Vehicle weight
Gearing
Ambient conditions
Detonation is predominantly a low RPM, high load problem. In most cases, the knock sensor doesn't even work over about 4500 RPM or so (there's a huge range around that number, don't take it as absolute). By then, the pistons are moving so fast that detonation doesn't really have time to occur. In a race application, detonation is extremely rare.
Historically, all the manufacturers have had different philosophies for how to go about this. But generally, they had to design thier engines for worst case scenarios, which means a full cargo load going uphill while cruising, which puts a heavy load on the engine while keeping it at lower RPM. That means that for most scenarios, the engines not only would not benefit any from higher octane, they could actually run lower octane than they do.
As knock sensing and timing adjustment capabilities are changing, that philosophy is being tweaked. GM is notorious for designing their (primariliy truck) engines to run 93 octane, but only putting a little blurb in the owner's manual stating "for best performance use 91 or greater octane" to get by the CAFE police. They do this becasue they can design the engine with higher compression to give better fuel economy, knowing that the overwhelming majority of the time, the engine will not be running in a condition that would lead itself to detonation (i.e. the truck is fully loaded or towing a trailer).
In cars, and especially lightweight, powerful sports cars, they just don't run in conditions that are going to cause detonation. So for anyone running a stock class, or an SP_ whatever class, higher octane is more or less a waste of money. The only exception is when it is really, really hot outside, say the way VIR has seemed to be at the club races there, or the June or August DE's at Road Atlanta. And even then, turbos are probably the only ones that would be at further risk.
But again, in most cases, cars can actually run lower octane than they are rated to run - the exact OPPOSITE of what his chart claims.
Not, GT cars or Cup cars are a different matter, entirely. If you are running a 13.0:1 engine, unless it is DI with a 75mm bore and 100mm stroke, you probably need race gas. If you've taken your 951 and put 10.0:1 pistons in it and run 20PSI, you probably need race gas.
Now, none of this is absolute. But the claims this guy is making are I'll just say less than 100% honest.
Also, since it was mentioned, pre-ignition is completely unrelated to octane. Pre-ignition is compression ratio, cam timing, cooling, etc. It is exactly what it says it is - early ignition of the air/fuel mixture, usually caused by soot build up on valves or something similar that would create a hot spot. Detonation is a post-ignition explosion of the high pressure regions in the chamber, before the flame front reaches it. By itself, it isn't always a big deal, but can lead to PI from heating up spots of the chamber, and PI is what makes engines go boom.
Question, don't all these same claims made by the race-gas people, and your responses, stay the same for using "real" race fuel?
In other words, your car either benefits from it or it does not?
That being said, if this additive made a "type of race fuel" for $6 a gallon including the cost of the pump gas I might be inclined to say "what the hell" so long as it didn't do anything negative to my engine.
However, the purchase price makes it MORE EXPENSIVE than buying real race gas so it just doesn't make sense on any level to me.
I also saw this in the most recent issue of GRM as someone else pointed out.
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04-21-2013, 01:03 PM
#8
Race Car
Again, GT cars or others that have had some hardware changes, primarily compression ratio, are a different story. Those are the kinds of cars that the stuff is there for. Stock cars, not so much.
I should have listed ignition timing and boost level as two other things that drive octane requirements.
Ignition maps are turned to run MST or MBT, which is minimum timing for specified/best torque. Specified under part throttle, best under WOT. Just like LBT (leanest mixture for best torque), you can overdo it. You can add more timing, and lose power.
That said, there are some companies that use a strategy of late timing for NVH. It lowers cylinder pressure, making the engine quieter. It also makes less power and uses more fuel. Toyota used to do that, not sure who else. That is a case where you may actually be able to change your ignition maps to a point where more octane is required.
As for the others, if it is a normally aspirated engine, I'm skeptical that there is anything there by flashing to 100 octane. I could manipuate a car to see a benefit if I were tuning on a dyno, basically by heat soaking the chamber, but in the real world, I'm skeptical. When you are accelerating, you don't really heat soak a chamber. if it is a turbocharged application, then yes, a flash would increaes boost, and the engine would then need higher octane fuel to maintain the same ignition maps.
04-21-2013, 04:29 PM
#9
"Large quantities" needs to be defined. Anyone know anything about this from a federal level? I am looking for something specific to MN, but cant find anything that restricts personal/private transportation, only commerial - and there is a "material of trade (MOT)" exemption for commerial use up to 200kg.
I haul a full tank in the 996 plus 40 ga. That gets me through the typical weekend. Last year I was paying $6.95 for 102 non oxy. The additive would make that over $11 a ga. when starting with 92 non oxy. Not for me. On the website they allude to having a engine problem with race gas from a suspect provider thus the need to mix your own. I guess you need to trust where you purchase it. See you at BIR for FF?
