How to Make My Freightliner Go Fasterby Richard Rowe
Named for a class of transoceanic cargo vessels, Freightliner went into business in 1942 with the express purpose of creating a go-anywhere, land-driven equivalent. Now owned by Daimler, Freightliner trucks remain just as versatile as ever but rely on a variety of different engines. Following Daimler's acquisition of Detroit Diesel in 2006, Freightliner switched almost exclusively to engines from that manufacturer. Increasing the top speed of a Freightliner is fairly simple since the powerful Detroit is more than capable of propelling the truck far past its computer-governed speed.
Acquire a power-tuner or take your truck to a dealership with the equipment necessary to re-tune the engine. Introduced in 1987, the 12.7-liter Detroit Series 60 and its 14-liter replacement remain a standard to this day. In stock form, these engines produce between 250 and 575 horsepower but can produce as much as 850 with a few minor computer tweaks.
Re-tune the computer to increase turbocharger boost and increase fuel injection timing. This is fairly simple on Series 60 engines that use computer-controlled common rail injection or Amplified Common Rail Injection but may require physically altering the injector pump or injector sizes on mechanically-controlled engines. However, all modern Detroits use computer controls, so re-tuning up to 800 horsepower is generally only a matter of selecting a power setting using the computer tuner.
Disable the electronic governor. Increasing engine power will only increase your pulling power; without removing the speed governor, you're not going top see any increase in speed. Trucks are drag-limited, meaning that aerodynamics play the largest role in top speed. The average truck only needs about 350 horsepower to go 90 mph. After removing the governor, a 500 horsepower truck will do about 100 mph; 650 hp gets you about 110 mph and 850 hp gives you around 120. Hypothetically, you'd need around 4,000 horsepower to hit 200 mph.
Install a massive nitrous fogger system. Installing a nitrous system on a Series 60 is just like doing it on any other engine. You'll need to drill and tap the intake runners to accept the spray nozzles, and then connect them to a nitrous bottle and a fuel source. For the diesel engine, you might consider using propane injection to supplement the nitrous instead of diesel since it will help control combustion chamber temperatures. A stock Series 60 block is capable of withstanding over 3,000 horsepower's worth of boost or nitrous, so inject as much as you need to meet your speed requirements.
- Nitrous-injecting your way to 3,000 horsepower isn't going to come cheap. Nitrous generally adds about one horsepower per 0.34 pounds of nitrous injected per hour. Subtracting 850 horsepower for the engine, you'll need about 2,150 horsepower worth of nitrous, or 731 pounds per hour of nitrous, to reach 3,000 horsepower. Nitrous can run between $2-$5 per pound, so you're looking at about $24-$60 for the minute's worth of nitrous that it will take to get up to 180 mph.
- "Detroit Series 60 Service Manual"; Detroit Diesel; 2007
- "High-Performance Diesel Builder's Guide"; Joe Petitt; 2007
- Solusinc: Simple and Low-Cost Aerodynamic Drag Reduction Devices for Tractor-Trailer Trucks
- RBR Racing: Aero-Horsepower & Drag Loss Calculator
- Barani Design: Calculate Corner Exit Speed Effect on Lap Times
- Thomas Northcut/Photodisc/Getty Images