Emissions Warning: This product is not designed for public highway or street use, and is only legal for formally sanctioned race use on a racing vehicle that may never be used on a public highway or street.

What is a Flex Fuel Kit in simple terms? It is basically a special sensor installed along one of your fuel lines that reads the amount of ethanol in your fuel, produces a signal, and sends a processed version of that signal to your ECU for use by your tuning device. Combined with a tuning device, it converts your Acura RSX to run on higher concentrations of ethanol (like E85) than is in standard pump gas.

TIP: Your gas tank is not required to just have all E85 fuel in it after installing this kit (hence the name Flex Fuel). It can have any combination of E85 and non-E85 gasoline in it. Your tuning device will automatically adjust on the fly for your current fuel mixture.

IMPORTANT NOTE: These kits are only compatible with the Hondata S300 v3 and K-Pro v4 systems, and the purchase of this product does not include a Hondata S300 or K-Pro. Also, Hondata's base settings are usually good enough to run the engine temporarily, but custom tuning is highly recommended.

• Allows you to run E85 fuel and mix it with regular pump gas.
• Huge increases in horsepower and torque.
• Helps to spool a turbo earlier and faster.
• Allows the engine (and turbo) to operate considerably cooler.
• Enables the ECU to dynamically adjust your tune, for a given amount of ethanol percentage.

• Best bang for the buck power adder (especially for boosted/forced-induction vehicles).
• Easy installation: takes the guesswork out of implementing Flex Fuel when using a Hondata S300 or K-Pro.
• Thoroughly tested and designed with very reliable components.
• Features optional fuel lines/fittings to plumb the Ethanol Sensor.
• Comes with comprehensive installation instructions.
• Covered by SiriMoto's 1 Year Limited Warranty.

• Includes everything you need for a complete installation.
• Plug and Play (PnP) solution, does not require any cutting/splicing of wires.
• Premium Harnesses constructed with:
• Mil-Spec Tefzel Wiring.
• Deutsch DTM Connectors.
• Potted Resistor (S300 Kit only).
• Flame-Retardant Nylon Sleeve.
• Sturdy Ethanol Content Sensor Bracket for lifetime reliability.
• Fuel Hose Kits for OEM and -6AN Fuel Lines (Optional).
• Custom SiriMoto Flex Fuel Badge included with every kit!

Note: This kit is ONLY compatible with 'v3' Hondata S300 systems. Older versions of the S300 are currently not compatible with this kit.

• Plug and Play Harnesses:
• S300 Board ECU Harness with built-in 2.4k Ohm Resistor.
• Ethanol Sensor Harness.
• 12v Power Harness (for Mini or ATC / ATO Fuse Type).
• Ethanol Content Sensor (Genuine GM Original Equipment).
• 2x Ethanol Sensor Mounting Brackets (Raised and Flat variants).
• M6 Mounting Hardware (Nut and Bolt with Washers).
• Cable Zip Ties.
• Optional Hose / Plumbing Kit (see Hose / Plumbing Kits bellow).
• Detailed Install Guide.

Note: This kit is ONLY compatible with 'v4' Hondata K-Pro systems. Older versions of the K-Pro are not compatible with this kit.

• Plug and Play Harnesses:
• K-Pro Board ECU Harness.
• Ethanol Sensor Harness.
• 12v Power Harness (for Mini or ATC / ATO Fuse Type).
• Ethanol Content Sensor (Genuine GM Original Equipment).
• 2x Ethanol Sensor Mounting Brackets (Raised and Flat variants).
• M6 Mounting Hardware (Nut and Bolt with Washers).
• Cable Zip Ties.
• Optional Hose / Plumbing Kit (see Hose / Plumbing Kits bellow).
• Detailed Install Guide.

• 6 mm Return Hose Kit:
Suitable for Honda / Acura vehicles with a OEM return style system (i.e. EF / EG / EK / DC2 / BB6 / S2000).
• 2x 90 deg. 3/8" Pipe to 1/4" Barb Quick Connect Fittings.
• 4x Hose Clamps for 1/4" Hose.
• 60" Length of 1/4" Gates Barricade EFI Hose.
• Quick Connect Hose Kit:
Suitable for Honda / Acura vehicles with a returnless system (i.e. RSX / EP3 / EM2 / TSX).
• 2x 90 deg. 3/8" Pipe to 5/16" Barb Quick Connect Fittings.
• 1x 90 deg. 1/4" Pipe to 5/16" Barb Quick Connect Fitting.
• 1x 1/4" Pipe to 5/16" Barb Quick Connect Fitting.
• 1x 90 deg. 5/16" Pipe to 5/16" Barb Quick Connect Fitting.
• 4x Hose Clamps for 5/16" Hose.
• Tube of PTFE Synthetic Grease (1 ml).
• 60" Length of 5/16" Gates Barricade EFI Hose.
• -6AN Male Adapter Kit:
Suitable for vehicles using -6AN Fuel Lines (Feed or Return).
Note: Additional Female Hose Ends might be required and is dependent on your setup.
• 2x 3/8" Pipe to -6AN Male Quick Connect Fittings.

Q: What is E85 and why does it easily give so much more power?
A: E85 is a biofuel composed of up to 85% ethanol. The remaining 15% of the fuel is traditional gasoline. Keep in mind the ethanol percentage can be lower during the winter months in some areas. The ethanol often is made from corn and is the same type of alcohol you would find in hard liquor, with the exception that fuel ethanol is denatured with additives to make it undesirable and harmful to drink.

The main reason E85 allows for some much more power than traditional gasoline is that it has a very high octane rating, usually from around 100 to 105 octane, compared to 91 to 93 octane from normal gasoline. This high octane rating allows E85 to resist engine knock. Engine knock occurs when areas of the air fuel mixture ignite before the should due to excessive heat for the fuel type used. This is bad because it can cause extra stress on the engine, and doesn't make optimal power either. From the factory, a new engine is almost always "knock limited", which means it cannot achieve its maximum design power on normal gasoline due to engine knock occurring. E85 basically eliminates this constraint, allowing the engine to achieve the maximum power possible. This especially applies to engines that are turbocharged from the factory.

One nice side effect of that is that extra E85 fuel will help cool your combustion chamber and turbo, and thus help maintain maximum power and reliability. E85 fuel is also generally a lot less expensive than normal pump gas too!

Vehicles sold in the U.S. are designed to operate correctly on the factory tune when using fuel that contains between 10% (E10) and 15% (E15) ethanol. E10 is normally found at almost every standard gas pump in the U.S., so you most likely fill up with it all the time. The reason for this is that ethanol has been found to reduce overall emissions while keeping engine performance strong (see https://afdc.energy.gov/fuels/ethanol_benefits.html for more information).

Q: Why a Flex Fuel kit?
A: The "Flex Fuel" part of this kit refers to the ability to run a varying amount of ethanol without having to re-tune or worry about exactly how much E85 you filled up with. In general, the more you fill up with, the more power you get, up to a certain extent. 30-50% ethanol is a typical range for maximum performance and efficiency.

Q: Ok, so what do I need to buy?
A: All you need is this SiriMoto Flex Fuel Kit and a Hondata S300 v3 or K-Pro v4, along with some E85. The Plug and Play Flex Fuel Kit constantly monitors how much ethanol is in your fuel, then passes this information along to your S300 or K-Pro. With the ethanol content information, the Hondata system dynamically recalibrates your ECU to give the optimal power gains on any percentage of ethanol you happen to have in your tank.

Q: Is a custom tune necessary?
A: Yes, for optimal performance and reliability, a custom tune is highly recommended. However, the Hondata basemaps are conservative and should allow your engine to run/drive normally. That said, full throttle pulls or high-RPM driving should be avoided until fueling and ignition-timing can be carefully monitored with a datalog and adjusted if needed.

Installation Info: The SiriMoto PnP Flex Fuel Kit requires a Hondata S300 v3 or K-Pro v4. It will not work with older versions of these systems currently. Also, to experience the power gains of this product, you will need access to E85 fuel.

Ethanol Sensor Info: Direction of flow and orientation of the sensor is not critical. Also, the sensor can be installed on the fuel feed (pressure) side but is not recommended it be subjected to over 100 PSI of pressure. Plumbing the sensor to the return line is possible as well, but not always necessary as the sensor can flow enough fuel for 500+ hp.