Photo: Brian Williams for Brenda Priddy & Company
Even though GM’s revolutionary 4.5-liter V-8 Duramax light-duty diesel is indefinitely shelved, some of the same advanced ideas are expected to live on in Ford’s upcoming heavy-duty oil-burner, code-named “Scorpion.”
Our spies have once again caught Ford’s new in-house-designed 6.7-liter V-8 diesel cradled under the hood of a Super Duty engineering mule. An earlier picture showed mostly radiator, but the latest photos show the highly complex air intake, exhaust gas recirculation and tight packaging needed to support this technically sophisticated and highly powerful clean diesel.
Industry sources say the Scorpion has the same unconventional reverse flow intake and exhaust setup that was a hallmark of the GM 4.5-liter V-8. Airflow through the cylinder heads is reversed (relative to conventional diesel-engine design), with the exhaust exiting directly into dual sequential turbos sitting in the engine's valley. The Scorpion will also likely use lighter aluminum cylinder heads, abandoning the cast-iron heads found in today's 6.4-liter V-8 Power Stroke.
The latest power targets are said to be more than 390 horsepower and 720 pounds-feet of torque. Today's Power Stroke diesel is rated at 350 hp and 650 pounds-feet.
Scorpion fuel economy is expected to improve by up to 3 mpg compared to the current Power Stroke. Helping the Scorpion's mileage will be a new six-speed automatic transmission, like the 2009 Ford F-150 has.
The Scorpion is said to use urea (aka diesel exhaust fluid) selective catalytic reduction to meet the EPA’s tough new 2010 nitrogen oxide exhaust standards. NOx is a major air pollutant that contributes to smog, asthma, and respiratory and heart diseases. It's a byproduct of diesel’s high combustion temperatures. DEF requires periodic maintenance on the part of the driver.
Another notable change: unlike the 2008-09 Super Duty, the hood on this Scorpion-powered truck lifts separately from the grille instead of as a single unit.
Production is expected to start this fall at Ford’s engine manufacturing plant in Mexico.