Deprecated: Assigning the return value of new by reference is deprecated in /home/hefley/public_html/pear/DB-1.6.8/DB.php on line 310

Deprecated: Assigning the return value of new by reference is deprecated in /home/hefley/public_html/pear/DB-1.6.8/DB.php on line 384

Deprecated: Assigning the return value of new by reference is deprecated in /home/hefley/public_html/pear/DB-1.6.8/DB.php on line 890
Welcome to Hefley Engine
The Hefley Engine Gives You The Best of Both Worlds

Imagine an engine powerful enough to pull an 18-wheeler but efficient enough to give you 45 MPG out on the highway. It’s not science fiction. The Hefley Engine actually changes its working size from a small engine when low power is sufficient to a maximum sized engine when you want more power. It achieves this amazing performance profile by changing the displacement—the space where the fuel is burned—according to your driving need at the moment. If your transmission has more than one gear, then it makes sense for your engine to have more than one displacement size.

How An Engine Uses Fuel

The Hefley X1 Engine can change its displacement according to the amount of power that is immediately needed for your driving needs.

And now with the Hefley X2 Engine you can have both varabile displacement and varible compression ratio.. Both diesel and unleaded gasoline are combustible fuels but both will not work in the same conventional engine. That is because each kind of fuel gives you the most energy when it’s compressed to a certain pressure range before it is ignited. The pressure range is different with each type of fuel.  The Hefley Engine X2 is the only known engine that can quickly and easily change the compression ratio to adjust to all kinds of fuel!

How The Hefley Engine Is Different

The Hefley Engine gives you the best fuel economy in the world because it smoothly and automatically changes its working size as needed. So each combustion occurs under optimum conditions for power, economy, or in between. This results is a cleaner burning car with fewer emissions. That’s good for the environment. This new engine can use any and all available fuels, from gasoline to diesel to bio-diesel and all current alternative


Your car engine is powered by a carefully timed series of fuel explosions in a process called combustion. Inside your engine a piston compresses air as it moves up inside its cylinder. A small amount of fuel is sprayed in and the mixture is exploded with a spark. This sends the cylinder back down again, moving the crankshaft and sending power to the drive train. The working space for this combustion process is called the displacement.
This Hefley X2 has all the features as the X1 but it also will adjust to a wide variety of fuels. It has adjustable compression ratio built in.

It can run on regular or high test gas, E85 ethanol, diesel, bio-diesel and other fuels still under development.

All was top secret

For years we have been determined to make a completely new and  highly efficient engine. We new made designs, analyzed, made models, prototypes. There has been no news from us because we were never completely satisfied.

...»