U.S.A Freedom Diesels
Missoula, Montana | (866) 225-9153

Office Hours

Nationwide Service Is Available

Monday – Saturday, 8 a.m. – 11 p.m.

Truck Defender

Fuel Preporator®
The Original Air/Fuel Separation & Delivery System

Increases Fuel EconomyReduces EmissionsIncreases Power Output

5% Minimum Fuel Savings Confirmed By Controlled Fleet Testing.

NEW for 2007
Fuel Preporator® Model 200-C
Die Cast with Injection Molded Cover

Air Separation Tested and Confirmed by University of Illinois College of Engineering.

Fuel Preporator® Reduces Emissions
Hydro Carbons Reduced by 29 to 87.9%
Nox Reduced by 31 to 46%
Total DPM Reduced by 8.57%
CO Reduced 82.7%

Increased Torque: U of W.Va. Testing Confirms:
Torque Rise Off Idle Increased by 106%,
Peak Torque Increased By 6% and
Holding at The Higher Operating RPM’s.

Performance Verified by CARB & EPA Certified Olsen Ecological Labs under ISO 8178 8 Mode Test Criterion.

Military Testing at Missouri University/Rolla Confirms Improved HumVee Performance with Fuel Preporator.

Call to See What Fuel Preporator® Can Do For You



Injector Spray Pattern
Air in Fuel

The Fuel Preporator® overcomes filter plugging and the inadequacies of the conventional vacuum feed system. Removing the entrained air and preventing vapor from cavitation restores injection timing and engine performance to ensure maximum power output and peak efficiency at all times!


Injector Spray Pattern
with Fuel Preporator ®
No Air in Fuel


The Physics Behind the Fuel Preporator® Technology

Fuel Preporator® is about diesel engine performance, efficiency and reduced exhaust emissions. Filtration and diesel fuel go hand in hand. In the past, filtration has been at the expense of engine performance. Fuel Preporator recognizes and addresses fuel filtration and delivery needs for the diesel engine.

Here’s What Happens

Sloshing in the fuel tank causes diesel fuel to entrain tiny air bubbles. Also, the fuel transfer pump operating under a vacuum cavitates, producing vapor.  Air/vapor from cavitation increases at higher rpms and as the fuel filter gets dirty with use.

The air/vapor, a result of the “vacuum feed” system, is compressible and is carried with the fuel into the fuel injector. The injector plunger now must travel farther to compress the air/vapor and inject the fuel. This delays injection.

Retarded Injection Timing of the engine, which varies with each injection, is the source of rough idling, lost power, increased fuel consumption, increased tail pipe emissions and the reason identical diesel engines do not run the same. All of these are the result of the inadequate “vacuum feed” fuel supply system, the system that is on your engine.


The patented Fuel Preporator® removes air/vapor from the fuel restoring injection timing and performance to factory specs.

Never heard of “entrained air?” These people have:

Caterpillar Special Bulletin 651-1250:
“Normally, #2 Diesel Fuel contains about 10% air in solution, although the air is not visible.”

Cummins Service Topic 5-135:
“The source of the vapor is the fuel itself.”

The Fluid Power Institute at the Milwaukee School of Engineering
confirms that entrained air and vapor is present in all liquids, especially petroleum-based liquids.