The Honda HR28TT engine is a twin-turbocharged, four-stroke, 2.8-liter, V6 racing engine, designed and produced by Honda Performance Development (HPD) for use in multiple Le Mans Prototype race cars, from 2011 to 2014.
The HR28TT was introduced in 2011, following the new cost-capped regulations for the LMP2 class. It is derived from the production J35 family of engines found numerous Honda/Acura production vehicles, using 400 production engine parts, including the engine block and heads, crankshaft, direct-injection fuel system, valve train components, drive-by-wire hardware. The engine also has turbo fresh air valve system, which eliminates turbo lag and provides improved reliability and performance.