OsosikMedia
Senior Member
- First Name
- Nick
- Joined
- Jun 15, 2017
- Threads
- 17
- Messages
- 91
- Reaction score
- 151
- Location
- California
- Vehicle(s)
- 2022 Civic Si, 2017 Civic SI x2
- Thread starter
- #1
...FUEL!!!
It’s no secret that fuel can play a big role in performance for your 11th Gen Civic (especially Si & Type R) but with so many options and opinions (especially if you’re a new enthusiast), all the info can have you yelling….What the Fuel?!?
I’m writing this for a few reasons. I get questions often regarding fuel, fuel system etc and realize most people don’t know or “misunderstand” what they’re told about parts/services they buy.
First you have to understand the basics.
2023 Civic Type R OEM Fuel Specs:
Recommends 91 Octane Minimum (Unleaded)
12.4 Gallon Fuel Tank
2022+ Civic Si OEM Fuel Specs:
Recommends 91 Octane Minimum (Unleaded
12.4 Gallon Fuel Tank
Octane:
An octane rating (Ex: 91 or 93), is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without detonating. The higher the octane number, the more compression the fuel can withstand before detonating.
In short: General rule of thumb, the higher the octane you pump in your Civic the better performance (especially if the tune has been optimized)
Air Fuel Ratio (AFR):
Is a ratio of the mass of air to the mass of fuel being supplied to the engine of a fuel-injected car. It is a critical parameter that determines the combustion efficiency and performance of the engine. The number before the colon
) represents the amount of air, while the number after the colon represents the amount of fuel. For example, an AFR of 14.7:1 means that for every 14.7 units of air, 1 unit of fuel is supplied to the engine.
In short: Your Civic AFR number represents how much air is mixed with the fuel in the engine. This number fluctuates in what’s often called Lean or Rich directions.
***AFR NUMBERS In-Depth:
The AFR reading is picked up by the o2 sensor and communicated to the ECU. An AFR number is an indicated value that’s targeted by the tune. If you review datalogs, you’ll see parameters like: AFR Command/target (what the tune wants) & AFR Actual (what the car gives), these should typically mimic each other. There is no specific “Set” value, there are general rule of thumbs of where your AFR target should be during certain moments based on mods/fuel etc.
Lean/Rich is NOT a specific AFR number, they simply represent a values direction based on the starting number (in basic math the starting number is Zero).
Lean:
Running lean is when the AFR actual value goes in the direction of a higher number from the targeting (set/starting) value. For example: if your targeting (set/starting) value is 14.7 then anything higher (ex: 15.7) than that number is “Lean”.
Rich:
Running rich is when the AFR actual value goes in the direction of a lower number from the targeting (set/starting) value. For EX: If your targeting (set/starting) value is 14.7 then anything lower (ex: 12.2) than that number is “Rich”.
----FLEX FUEL for Civic----
Flex Fuel Kits:
Great plug & play Civic flex fuel kits like @PRL Motorsports, is hardware that is installed on your vehicle.
Flex Fuel Software Support:
Engine managements like @Hondata FlashPro Manager is software that supports the use of a Flex Fuel Kit (hardware).
The sensor on the Flex Fuel kit measures the amount of ethanol content that's in your Civics fuel, and the ECU/Software (tune) adjusts the parameters accordingly. Allowing you to safely run any amount of ethanol (E10-E85) without having to change your tune.
Aside from having both hardware & software, you also have to make sure you have a tune that has been created to allow you to run this safely. In Hondata’s case they usually provide several preset calibrations, including flex fuel tunes. However, if you want the most out of your set up I’d recommend getting a custom tune or stage tune from someone like Powermetric.net
Now that you understand the basics (I hope). The purpose of getting a tune for your flex fuel set up is to allow you to run ANY amount of ethanol. A tuner who understands the platform and your fuel system limitations can provide you a tune to safely do this.
This is nothing new. Car manufactures sell new vehicles capable of running full ethanol (flex fuel e10-e85) on stock fuel systems.
https://www.fueleconomy.gov/feg/flextech.shtml
For Ex: All Flex Fuel tunes from Powermetric allow you to run from E10 (91 octane) - E85 (full ethanol) mixtures on the stock Civic Type R fuel system. Now, some set ups are more optimal (make more power) on certain blends because of fuel system limits but just ask your tuner which ethanol content % makes the most power for their tune on your set up.
Now if you get told you can not run outside of a certain blend, then what was the point of getting a flex fuel kit and flex fuel tune? Hate to say it but you could’ve spent your money more wisely (or saved). If you’re going to get a tune for a specific fuel (race gas or blend), then you don’t need a Flex Fuel Kit (hardware).
For Ex: I’m currently running a E50 Blend tune on my 2023 Civic Type R (stock fuel system and no flex fuel kit), I also ran full ethanol on my 2022 Civic Si with a stock fuel system. This is because the tune was created for this specific fuel mixture. So, just because the Hondata Flashpro software doesn’t support flex fuel for the Type R (Yet), and I’m not using a PRL flex fuel kit (yet) doesn’t mean you can’t tune for a certain fuel. Before the luxury of flex fuel kits/software support, we used to have different tune files for different fuels...we just had to make sure we didn’t upload or put the wrong fuel/tune.
If you’re not sure, just ask your tuner if your flex fuel tune parameters were adjusted for all ranges of ethanol. You should be able to run any amount of blend safely, but of course always go based off what your tuner tells you.
Another advantage of having a flex fuel set up that’s not often talked about is convenience. The ability to go to an ethanol pump and not have to worry about blending. Also depending on where you live (for me So Cal) ethanols way cheaper per gallon and the pumps are not connected, so in order to blend I'd have to pump at one and then drive up and redo the entire process.
The goal with this post was to be simple to understand, hope this helps…if you have any questions/comments feel free to ask.
Next topic Fuel System Upgrades...?
Bonus:
Below is a graph that shows the AFR & TRQ curve on a 100% stock 2023 Civic Type R (the o2 reading was placed in the rear tailpipe). We also tested this on two different types of dynos and locations.
Follow the socials:
@Ososik / @OsosikMedia
It’s no secret that fuel can play a big role in performance for your 11th Gen Civic (especially Si & Type R) but with so many options and opinions (especially if you’re a new enthusiast), all the info can have you yelling….What the Fuel?!?
I’m writing this for a few reasons. I get questions often regarding fuel, fuel system etc and realize most people don’t know or “misunderstand” what they’re told about parts/services they buy.
First you have to understand the basics.
2023 Civic Type R OEM Fuel Specs:
Recommends 91 Octane Minimum (Unleaded)
12.4 Gallon Fuel Tank
2022+ Civic Si OEM Fuel Specs:
Recommends 91 Octane Minimum (Unleaded
12.4 Gallon Fuel Tank
Octane:
An octane rating (Ex: 91 or 93), is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without detonating. The higher the octane number, the more compression the fuel can withstand before detonating.
In short: General rule of thumb, the higher the octane you pump in your Civic the better performance (especially if the tune has been optimized)
Air Fuel Ratio (AFR):
Is a ratio of the mass of air to the mass of fuel being supplied to the engine of a fuel-injected car. It is a critical parameter that determines the combustion efficiency and performance of the engine. The number before the colon
) represents the amount of air, while the number after the colon represents the amount of fuel. For example, an AFR of 14.7:1 means that for every 14.7 units of air, 1 unit of fuel is supplied to the engine.In short: Your Civic AFR number represents how much air is mixed with the fuel in the engine. This number fluctuates in what’s often called Lean or Rich directions.
***AFR NUMBERS In-Depth:
The AFR reading is picked up by the o2 sensor and communicated to the ECU. An AFR number is an indicated value that’s targeted by the tune. If you review datalogs, you’ll see parameters like: AFR Command/target (what the tune wants) & AFR Actual (what the car gives), these should typically mimic each other. There is no specific “Set” value, there are general rule of thumbs of where your AFR target should be during certain moments based on mods/fuel etc.
Lean/Rich is NOT a specific AFR number, they simply represent a values direction based on the starting number (in basic math the starting number is Zero).
Lean:
Running lean is when the AFR actual value goes in the direction of a higher number from the targeting (set/starting) value. For example: if your targeting (set/starting) value is 14.7 then anything higher (ex: 15.7) than that number is “Lean”.
Rich:
Running rich is when the AFR actual value goes in the direction of a lower number from the targeting (set/starting) value. For EX: If your targeting (set/starting) value is 14.7 then anything lower (ex: 12.2) than that number is “Rich”.
----FLEX FUEL for Civic----
Flex Fuel Kits:
Great plug & play Civic flex fuel kits like @PRL Motorsports, is hardware that is installed on your vehicle.
Flex Fuel Software Support:
Engine managements like @Hondata FlashPro Manager is software that supports the use of a Flex Fuel Kit (hardware).
The sensor on the Flex Fuel kit measures the amount of ethanol content that's in your Civics fuel, and the ECU/Software (tune) adjusts the parameters accordingly. Allowing you to safely run any amount of ethanol (E10-E85) without having to change your tune.
Aside from having both hardware & software, you also have to make sure you have a tune that has been created to allow you to run this safely. In Hondata’s case they usually provide several preset calibrations, including flex fuel tunes. However, if you want the most out of your set up I’d recommend getting a custom tune or stage tune from someone like Powermetric.net
Now that you understand the basics (I hope). The purpose of getting a tune for your flex fuel set up is to allow you to run ANY amount of ethanol. A tuner who understands the platform and your fuel system limitations can provide you a tune to safely do this.
This is nothing new. Car manufactures sell new vehicles capable of running full ethanol (flex fuel e10-e85) on stock fuel systems.
https://www.fueleconomy.gov/feg/flextech.shtml
For Ex: All Flex Fuel tunes from Powermetric allow you to run from E10 (91 octane) - E85 (full ethanol) mixtures on the stock Civic Type R fuel system. Now, some set ups are more optimal (make more power) on certain blends because of fuel system limits but just ask your tuner which ethanol content % makes the most power for their tune on your set up.
Now if you get told you can not run outside of a certain blend, then what was the point of getting a flex fuel kit and flex fuel tune? Hate to say it but you could’ve spent your money more wisely (or saved). If you’re going to get a tune for a specific fuel (race gas or blend), then you don’t need a Flex Fuel Kit (hardware).
For Ex: I’m currently running a E50 Blend tune on my 2023 Civic Type R (stock fuel system and no flex fuel kit), I also ran full ethanol on my 2022 Civic Si with a stock fuel system. This is because the tune was created for this specific fuel mixture. So, just because the Hondata Flashpro software doesn’t support flex fuel for the Type R (Yet), and I’m not using a PRL flex fuel kit (yet) doesn’t mean you can’t tune for a certain fuel. Before the luxury of flex fuel kits/software support, we used to have different tune files for different fuels...we just had to make sure we didn’t upload or put the wrong fuel/tune.
If you’re not sure, just ask your tuner if your flex fuel tune parameters were adjusted for all ranges of ethanol. You should be able to run any amount of blend safely, but of course always go based off what your tuner tells you.
Another advantage of having a flex fuel set up that’s not often talked about is convenience. The ability to go to an ethanol pump and not have to worry about blending. Also depending on where you live (for me So Cal) ethanols way cheaper per gallon and the pumps are not connected, so in order to blend I'd have to pump at one and then drive up and redo the entire process.
The goal with this post was to be simple to understand, hope this helps…if you have any questions/comments feel free to ask.
Next topic Fuel System Upgrades...?
Bonus:
Below is a graph that shows the AFR & TRQ curve on a 100% stock 2023 Civic Type R (the o2 reading was placed in the rear tailpipe). We also tested this on two different types of dynos and locations.
Follow the socials:
@Ososik / @OsosikMedia
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