Sunoco Racing Fuel
Le Mans Master
Joined: Jun 2019
Posts: 5,430
Likes: 2,154
From: Loveland
Did someone say "crazy horse power"? It is true, many conditions can cause detonation, and if you use a higher octane fuel the detonation will be reduced or stop all together. If you drive like grandpa you can get away with less octane, than if you drive like Parnelli jones.
If your car needs 85 octane,,, "EDIT: TO NOT DETONATE" and you put 100 octane in it,,,,,, the engine will deliver less power. This is true.
If your car needs 85 octane,,, "EDIT: TO NOT DETONATE" and you put 100 octane in it,,,,,, the engine will deliver less power. This is true.
Last edited by kodpkd; Mar 4, 2024 at 06:27 PM.
Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
You're dancing around trying to be "right" when you don't understand the physics. And stop using your straw argument "crazy horsepower." You will not receive debate points by arguing the exaggeration.
In point of fact it is possible for a high-performance automobile to see detonation at certain altitudes, temperatures/relative humidity levels that would not show detonation otherwise. The ECM will dial in knock retard, and that will equal a loss of power. Conversely, injecting your referenced 100 octane fuel will retard knock and in the absence of a knock imput, the engine controller can take advantage of the elevated knock threshold and increase the timing in a more aggressive manner to the limits of the internal timing tables. This almost always shows increased power output. Not a lot, but measurable, as seen in the that same August 2019 Car and Driver article I referenced.
In point of fact it is possible for a high-performance automobile to see detonation at certain altitudes, temperatures/relative humidity levels that would not show detonation otherwise. The ECM will dial in knock retard, and that will equal a loss of power. Conversely, injecting your referenced 100 octane fuel will retard knock and in the absence of a knock imput, the engine controller can take advantage of the elevated knock threshold and increase the timing in a more aggressive manner to the limits of the internal timing tables. This almost always shows increased power output. Not a lot, but measurable, as seen in the that same August 2019 Car and Driver article I referenced.
Burning Brakes
Joined: Jan 2019
Posts: 954
Likes: 376
From: Louisiana
Did someone say "crazy horse power"? It is true, many conditions can cause detonation, and if you use a higher octane fuel the detonation will be reduced or stop all together. If you drive like grandpa you can get away with less octane, than if you drive like Parnelli jones.
If your car needs 85 octane,,, "EDIT: TO NOT DETONATE" and you put 100 octane in it,,,,,, the engine will deliver less power. This is true.
If your car needs 85 octane,,, "EDIT: TO NOT DETONATE" and you put 100 octane in it,,,,,, the engine will deliver less power. This is true.
Burning Brakes
Joined: Jan 2019
Posts: 954
Likes: 376
From: Louisiana
This is all that opens and it doesn't address your claim that higher octane produces less power.
Burning Brakes
Joined: Jan 2019
Posts: 954
Likes: 376
From: Louisiana
The comments section is a good read, as others are understanding the flaws with his conflation.
The sources here will mention how stored energy or flame speed is related to elements like gasoline and ethanol mixture. Not octane.
https://www.corvetteforum.com/forums...post1607546555
Last edited by CPB; Mar 4, 2024 at 10:05 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
Le Mans Master
Joined: Jun 2019
Posts: 5,430
Likes: 2,154
From: Loveland
https://www.progressive.com/answers/premium-vs-regular-gas/
What happens if you use premium gas instead of regular?
The only thing that will happen if you use premium gas "in an engine designed for regular" fuel is that you'll spend more money, according to Cars.com. An engine that runs on regular gas will not perform better because you put premium gas in the tank. If you fill up on premium because the engine knocks when you use regular, your car might need a mechanic.!
DOH! "In an engine designed for regular fuel"
https://www.cars.com/articles/if-my-...1420684149356/
!
But if the vehicle manufacturer says your engine needs only 87-octane regular, that is what you should use. The higher octane of premium gas won’t make your car faster; in fact, the opposite is possible because higher-octane fuel technically has less energy than lower-octane fuel. It’s the fuel’s ability to be compressed more without pre-igniting that results in more power when used in the appropriate engine. Premium gas is not “stronger” gas.
Last edited by kodpkd; Mar 5, 2024 at 09:47 AM.
Burning Brakes
Joined: Jan 2019
Posts: 954
Likes: 376
From: Louisiana
https://www.progressive.com/answers/premium-vs-regular-gas/
What happens if you use premium gas instead of regular?
The only thing that will happen if you use premium gas "in an engine designed for regular" fuel is that you'll spend more money, according to Cars.com. An engine that runs on regular gas will not perform better because you put premium gas in the tank. If you fill up on premium because the engine knocks when you use regular, your car might need a mechanic.!
DOH! "In an engine designed for regular fuel"
Le Mans Master
Joined: Jun 2019
Posts: 5,430
Likes: 2,154
From: Loveland
https://www.cars.com/articles/if-my-...1420684149356/
But if the vehicle manufacturer says your engine needs only 87-octane regular, that is what you should use. The higher octane of premium gas won’t make your car faster; in fact, the opposite is possible because higher-octane fuel technically
""""has less energy"""" than lower-octane fuel. It’s the fuel’s ability to be compressed more without pre-igniting that results in more power when used in the appropriate engine. Premium gas is not “stronger” gas.
HAS LESS ENERGY!
But if the vehicle manufacturer says your engine needs only 87-octane regular, that is what you should use. The higher octane of premium gas won’t make your car faster; in fact, the opposite is possible because higher-octane fuel technically
""""has less energy"""" than lower-octane fuel. It’s the fuel’s ability to be compressed more without pre-igniting that results in more power when used in the appropriate engine. Premium gas is not “stronger” gas.
HAS LESS ENERGY!
Burning Brakes
Joined: Jan 2019
Posts: 954
Likes: 376
From: Louisiana
https://www.cars.com/articles/if-my-...1420684149356/
But if the vehicle manufacturer says your engine needs only 87-octane regular, that is what you should use. The higher octane of premium gas won’t make your car faster; in fact, the opposite is possible because higher-octane fuel technically
""""has less energy"""" than lower-octane fuel. It’s the fuel’s ability to be compressed more without pre-igniting that results in more power when used in the appropriate engine. Premium gas is not “stronger” gas.
HAS LESS ENERGY!
But if the vehicle manufacturer says your engine needs only 87-octane regular, that is what you should use. The higher octane of premium gas won’t make your car faster; in fact, the opposite is possible because higher-octane fuel technically
""""has less energy"""" than lower-octane fuel. It’s the fuel’s ability to be compressed more without pre-igniting that results in more power when used in the appropriate engine. Premium gas is not “stronger” gas.
HAS LESS ENERGY!
Octane math: https://www.wikidoc.org/index.php/Octane_rating
Heat Value math: https://www.engineeringtoolbox.com/f...ues-d_169.html
Burning Brakes
Joined: Aug 2004
Posts: 1,207
Likes: 147
From: St. Louis MO
I'm not sure you are aware of how puerile that statement is. You have consistently argued points that are in direct contravention of known chemical processes and physical laws, and your stubbornness in a face of a losing argument is not an endearing quality.
Race Director
Joined: Jul 2018
Posts: 10,538
Likes: 8,286
From: San Antonio, TX/Mahopac, NY
2024 Corvette of the Year Finalist - Modified
2024 Corvette of the Year Finalist - Unmodified
2023 C7 of the Year Winner - Modified
I bowed out of this foolishness earlier due to challengers who added no empirical data to support their claim and when presented with valid, contradictory evidence continued to nitpick, twist words, and argue unrelated points as if they were relevant.
It is a fact that using high octane fuel in an engine designed for 85 or 87 will result in less efficient combustion or lower performance. People can argue about knock sensors, electronic engine management and all sorts of other gizmos but that does not change the science. And just because some hack wrote an article does not mean it is true. If you believe that is true, then you must believe everything you read on the internet is true. Not.
It is a fact that using high octane fuel in an engine designed for 85 or 87 will result in less efficient combustion or lower performance. People can argue about knock sensors, electronic engine management and all sorts of other gizmos but that does not change the science. And just because some hack wrote an article does not mean it is true. If you believe that is true, then you must believe everything you read on the internet is true. Not.
Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
Is there a laboratory test on a modern engine that shows that? Perhaps that's the way to end the speculation. Modern car designed for 85 on a dyno using 85 and then run with 108. See what happens.
Team Owner
Joined: Jul 2004
Posts: 40,353
Likes: 787
From: Redondo Beach, California
I buy racing fuel.
1) I use it in my C3 1968. I don't drive it much and, as a California resident, I use it because it is alcohol free. Don't have to worry about water corrosion in the fuel system.
2) Modern corvette engines have relatively high compression ratios, and they can get away with that because they have ping sensors that detect engine knock and automatically retard the timing. I think elevating your octane rating slightly will increase horsepower since the ping sensors will less frequently reduce timing. I agree that a large increase in fuel octane rating is not going to do anything.
Energy content per pound. Higher octane fuel have a higher content of aromatic low carbon chain molecules. Their energy content per pound is less than low octane fuel. Diesel fuel has the highest energy content per pound. Alcohol, which has an equivalent very high octane rating, has a vey low energy content per pound....that's why alcohol fuels get poor "gas" mileage.
Military AvGas in WWII was 130 octane! It was highly leaded in addition to a large aromatic content. Last time I looked, you could buy 130 octane leaded automobile fuel as a racing fuel.
1) I use it in my C3 1968. I don't drive it much and, as a California resident, I use it because it is alcohol free. Don't have to worry about water corrosion in the fuel system.
2) Modern corvette engines have relatively high compression ratios, and they can get away with that because they have ping sensors that detect engine knock and automatically retard the timing. I think elevating your octane rating slightly will increase horsepower since the ping sensors will less frequently reduce timing. I agree that a large increase in fuel octane rating is not going to do anything.
Energy content per pound. Higher octane fuel have a higher content of aromatic low carbon chain molecules. Their energy content per pound is less than low octane fuel. Diesel fuel has the highest energy content per pound. Alcohol, which has an equivalent very high octane rating, has a vey low energy content per pound....that's why alcohol fuels get poor "gas" mileage.
Military AvGas in WWII was 130 octane! It was highly leaded in addition to a large aromatic content. Last time I looked, you could buy 130 octane leaded automobile fuel as a racing fuel.
Drifting
Joined: Dec 2013
Posts: 1,519
Likes: 212
From: FL
Short answer. There is no benefit to running fuel with an octane rating higher than what the owners manual calls for.
Longer answer. The octane rating in fuel is just telling you how stable the fuel is. By this I mean how resistant it is to premature ignition. When you increase cylinder pressure through higher boost, more compression, or more timing advance the fuel needs to be stable enough to not self ignite. When this happens we call this knock.
Luckily our cars are smart enough to hear this through knock sensors and can pull power to safely run lower octane fuel. Though I obviously don't suggest running regular in your corvette especially not a boosted one. Unfortunately this only goes one way with the factory ecu and tune.
So unless you're suffering from knock running race fuel will not benefit you in anyway over a quality premium fuel from the pump.
Now you can have your car tuned for race fuel and it will make more power. Especially if it's modified.
This is also why people have their cars tuned for Ethanol fuel like E85. As the Ethanol is effectively an octane booster and also burns cooler compared to normal gas.
Longer answer. The octane rating in fuel is just telling you how stable the fuel is. By this I mean how resistant it is to premature ignition. When you increase cylinder pressure through higher boost, more compression, or more timing advance the fuel needs to be stable enough to not self ignite. When this happens we call this knock.
Luckily our cars are smart enough to hear this through knock sensors and can pull power to safely run lower octane fuel. Though I obviously don't suggest running regular in your corvette especially not a boosted one. Unfortunately this only goes one way with the factory ecu and tune.
So unless you're suffering from knock running race fuel will not benefit you in anyway over a quality premium fuel from the pump.
Now you can have your car tuned for race fuel and it will make more power. Especially if it's modified.
This is also why people have their cars tuned for Ethanol fuel like E85. As the Ethanol is effectively an octane booster and also burns cooler compared to normal gas.
good information here. Engine Masters on Motor Trend TV did an interesting Dyno test with different octanes and showed no real increase in power until they used E85 which has more O2.
Burning Brakes
Joined: Jan 2019
Posts: 954
Likes: 376
From: Louisiana
Lab testing for BTU is how you'd determine which fuel has more stored energy.