ELITE DIESEL’S COST-EFFECTIVE PATH TO 900 RWHP
Big, streetable horsepower. We all crave it. Deep down, we all want a truck that can run low 11s yet still get us to and from work on a daily basis. The easiest way to make this possible (and not have a laggy truck or a transmission that hates you) is to run a compound turbo arrangement. Thanks to companies like Elite Diesel Engineering, 6.4L Power Stroke owners have the luxury of retaining the factory-based sequential turbo design when the need for added power arises. In short, both turbos can be upsized considerably, with virtually no tradeoff in drivability.
For years, Elite has been building compound arrangements based around the 6.4L Power Stroke’s compact factory system for any power level from stock to more than 1,000 hp. To appeal to 6.4L owners on tighter budgets, Elite recently brought its Raw-Power compounds to market. Making use of an 88mm low-pressure turbo for awesome top-end flow and a 63mm VGT high-pressure turbo for ultra-quick bottom end response, this system offers ’08-10 Ford owners the most affordable path to making 900 rwhp in Elite’s catalog.
“MAKING USE OF AN 88MM LOW-PRESSURE TURBO FOR AWESOME TOP-END FLOW AND A 63MM VGT HIGH-PRESSURE TURBO FOR ULTRA-QUICK BOTTOM END RESPONSE”
Tuning a wastegate is not a set-it-and-go type of proposition—it takes time to find an ideal boost-to-drive pressure ratio. A whole host of actuator springs (shown) can be tried and combined to achieve the perfect wastegate actuation threshold. Our goal with the Raw-Power turbos is to produce as much boost as possible while keeping drive pressure reasonable. With our primary objective being to avoid over-speeding the high-pressure turbo, we’ll start off with a lot of spring tension in the low-pressure turbo’s wastegate (the Precision unit) to make sure it’s not opening. On the other side of the coin, we’ll initially run a low spring tension in the high-pressure turbo’s wastegate (the Tial MV-R) as a starting point. We’ll progressively ramp up the spring tension, thereby allowing the turbo to see more and more pressure before the gate opens, until we see a boost-to-drive ratio we can live with. Then we can start dialing in the low-pressure turbo’s wastegate.
With a built 6.4L Power Stroke sitting in our stable, we plan to see how fast Elite’s Raw-Power system can push a standard cab, four-wheel-drive ’08 F-250 through the traps. The engine was put together with R&R connecting rods, River City Diesel fly-cut and coated International pistons, Elite’s Stage 1X cam, Stage 2 valve springs, Stage 2 chromoly pushrods, H11 head studs, 150% over nozzles, and Twin K16s, so it’s ready for a steady diet of fuel and boost. We’ll tackle the install this month, followed by a trip to the chassis dyno and a fair amount of fine-tuning the wastegates and PCM after that. Stay tuned…DW