Multifuel capability allows cars such as Rich Maxon's '87 Grand National to automatically run on any kind of fuel.
By now you have probably seen at least one of the many stories about how ethanol and gasoline-blended fuel, such as E85, is excellent for performance applications. HOT ROD likes to show the outer limits of performance applications, so we tracked down flex fuel pioneer White Racing & Marine in Warren, Michigan, to find out more about the system it has developed that allows hot rodders to fuel their vehicles on gasoline, ethanol, race gas, or a combination of all the above, on electronic fuel-injected (EFI) cars. We learned that White Racing's multifuel kit is a simple way to make sick levels of horsepower in fully streetable cars-and who wouldn't want to make more power and be able to enjoy it on demand?
The Multifuel Kit
White Racing started developing its multifuel upfit kit back in 2004 and quickly found great results. Says Dan White, "The best discovery was that we could run the vehicle on just about any readily available fuel: gasoline, E85, E98, or race gas. Our big-boost, big-horsepower customers have found the ethanol-based fuels are very addictive because their engines make great power, the fuel is readily available, and it is way less expensive than C16 race gas.
There aren't a lot of pieces to the White Racing kit: a fuel sensor, some custom fittings to plumb it into the fuel system, and a wiring harness. But don't be fooled by the simplicity of it-this system works.
"Ethanol is incredible at withstanding massive amounts of boost. We believe it does so well with boost due to a combination of ethanol's high octane rating and the increased latent heat of vaporization-which is the amount of energy it takes to vaporize the ethanol. These make it perfect for EFI, boosted applications. The octane resists detonation and preignition, and the cooling effect of the fuel vaporizing cools the intake charge and the engine. Our customers seem to like it, too, as we are upgrading a lot of big-power, street turbo cars with our multifuel kit."
A Few Parts
The White Racing kit is impressive in how few components it has: a fuel sensor, custom fittings to allow AN fuel lines to be attached to the sensor, and some custom wiring. The fuel sensor is the most important (and expensive) part in the kit. It is plumbed into the return line of the fuel system and can read the percentage of ethanol. It sends that information to the EFI controller so the air/fuel ratio can be altered accordingly. To alter the air/fuel ratio on the fly, White Racing has developed special software and calibrations for many of the aftermarket EFI controllers (BigStuff3, FAST, and so on) and some of the original equipment (OE) controllers that come in production cars. In this way, the hard parts of the kit are just the tools that allow the system to work.
The custom wiring harness comes with the correct connector already installed on one end for White's sensor, and on the other end, depending on the kit, is the appropriate connector to tap into the factory harness. The kit shown in the photos is for a Buick Grand National. The plug on this jumper harness plugs into one of the unused sensor connectors located in the engine bay.
The multifuel kit is easy to install. The sensor is usually mounted somewhere out of the way under the hood, and custom fuel fittings make it easy to plumb the sensor into the return side of the fuel system. The wiring connects the sensor to the main engine controller wiring harness. From there, the software in the engine controller is adjusted to make it all work.
How It Works
You need the multifuel kit to run gasoline and ethanol in various percentages mostly because ethanol has approximately 30 percent less Btu (British thermal units-a measurement of potential energy in a compound) than gasoline. This lower Btu amount is partly offset by the fact that ethanol has a higher specific gravity (weight/gallon of the liquid) than gasoline (it weighs about 6.6 lb/gal versus gasoline's 5.5 lb/gal). But even with the offset, the engine needs to be fed up to about 50 percent more fuel (compared with gasoline) when it is running on ethanol to maintain the appropriate air/fuel ratio for combustion.
To do this, the fuel pump, lines, fuel filter(s), fuel injectors, and regulator/return system need to be upgraded to be able to handle the additional fuel flow. The key to increasing the fuel system capability is to not go so big with the components that the vehicle can't run on gasoline anymore. Unfortunately, there really is no way to provide more detail than that, as vehicle fuel systems vary dramatically-so each application is dealt with on a custom basis.
The White Racing kit allows you to run alcohol-based fuels to make more power but also have the option to run gasoline when it is the only choice. You can dump whatever fuel is available to you at that moment in the car and it will adjust on the fly-though most enthusiasts who have made this upgrade become addicted to the benefits of E85 and will do their best to keep the tank full of ethanol. Beyond the power potential, the great thing about this kit is it allows cars that would usually have been on a very short fuel load leash to be driven around like regular cars-and that just means more time and miles behind the wheel of that monster power ride.
When E85 Isn't E85
An interesting tidbit is that for a better part of the year, E85 from your local gas station is not actually E85-it's probably closer to E70. The fuel blend is altered, as ethanol can be difficult to combust in colder temperatures. This is important to understand because let's say you converted your vehicle to run specifically on an E85 blend (85 percent ethanol, 15 percent gasoline) without something like the sensing capability of White Racing's kit. With an E70 blend in the tank, the engine would likely run dead rich. For this reason, to run on multiple fuels, a vehicle will need the ability to alter the air/fuel ratio based on the fuel going into the engine-not on what the pump says is going in the tank.
Using an aftermarket engine controller, like the FAST system shown here or a BigStuff3, makes this upgrade much easier. White Racing has spent a lot of time developing software and calibrations to utilize the capability of the sensor and instantly alter the air/fuel ratio for optimal performance and durability.
