For those who wish to add a turbo, or any power adder, to their new 5 liter 2011 V-8 Ford Mustang Coyote, forged pistons will be necessary to transmit the additional power.
For this purpose Diamond is announcing a new series of low-silicon 2618 forgings, comprising a variety of compression ratios from 8.5:1 to 11.5:1. They, in fact, are available in half-point compression ratios (9.0:1, 9.5:1, 10.0:1 and so on) as well as in four different bore sizes.
The piston illustrated (PN 30113) has a 6cc dish and when used in conjunction with the production 57cc Coyote cylinder head, contributes a compression ratio of 9.5:1, which is ideal for running pump fuel. It will also accommodate a small turbo producing 8-10 PSI of boost.
To protect the top ring from the increased heat generated by power upgrades it is positioned .300in down from the crown. In like manner Diamond also upgraded the piston pins, selecting 4130 chrome molybdenum material.
Double spiral locks have been selected to secure the pins, and access to them is via a small half-moon slot positioned in each pin bore.
A tang shape is featured at the bottom of each skirt. These reach the end of the cylinder when the piston travels to bottom dead center. Interestingly, one skirt of each piston also features a small notch. The notches are machined to provide clearance for factory oil sprayers—a technology reminiscent of earlier Winston Cup engines devised to provide additional lubrication to the piston pins.
Lastly, Diamond offers three optional barrier coatings for these pistons: Hard anodizing, a Teflon skirt coating, and a ceramic thermal barrier crown coating. The anodizing, a Type 3 Hardcoat, is particularly viable, protecting pistons against excessive combustion heat and detonation damage. It also increases corrosion- and wear-resistance, which is particularly useful on nitrous and blown applications. Moreover it creates a hard surface finish approaching 70 Rockwell and it contributes an excellent adhesive surface for the Teflon skirt coating—a moly-based dry-film lubricant that reduces friction and scuffing.
For more information contact Diamond Pistons at (877) 552-2112 or visit www.DiamondRacing.net.