The Accufab is similar dimensionally...
The Accufab is similar dimensionally to the stock version, but it has more airflow potential thanks to its design.
With the truck still on the dyno, we removed the stock elbow and installed the Accufab unit. First, we removed the inlet tube and four retaining bolts. Once the stock elbow was removed, we could look inside and see the restriction right in the center of the short-turn radius. In this case, the restriction is a sharp edge in the casting, which causes the air to make an abrupt turn. In contrast, the Accufab elbow features a smoother turn that allows for improved airflow and less restriction. Ultimately, it took longer to photograph the parts than it did to complete the swap.
 It's necessary to swap over...  It's necessary to swap over the rubber gasket before installing the new elbow. |  Once the gasket was in place,...  Once the gasket was in place, we carefully lowered the elbow onto the engine and attached the retaining bolts. |  |
With the Power Elbow installed, we fired up the 6.0L, checked the engine and oil temp, and made a few pulls to see if anything changed. Lo and behold, we unlocked 9.33 hp and a generous 17.63 lb-ft of torque at the peak. On average, the Power Stroke picked up 5-10 hp and 5-15 lb-ft of torque from just off idle to 4,000 rpm.
 Next, we slid the hose over...  Next, we slid the hose over the elbow and tightened the clamp. |  Then it was ready to run....  Then it was ready to run. |  |
 On the dyno, the dualie picked...  On the dyno, the dualie picked up horsepower and torque at the peak and across the entire rpm range. | | |
Yet another gain may come in fuel economy. A 1-2 mpg increase has been reported, according to Klass. This is good news for 6.0L owners, who can add power for less than $200. Having more towing muscle on tap is nice, and, of course, you'll be doing better burnouts too.