HPD Innovations – HR28TT – P2 Engine


In 2010, the FIA/ACO announced a revised set of engine rules for the Le Mans Prototype (LMP2) class, requiring the use of a production-based car engine selling more than 1,000 units per year. Working in partnership with Honda R&D Americas in Ohio, HPD developed the HR28TT from the 3.5-liter, V-6 port injected engine found in the Accord, Odyssey and Pilot.

First raced in 2011, the engine won all five of the American Le Mans Series’ LMP2 races in which it was entered. In 2012, the engine earned the series Manufacturers’ Championship for the LMP2 class. In January of 2013, Honda engineers won Race Tech magazine’s Race Engine Designer award for the HR28TT.


Through its 2011 rules package, the FIA/ACO desired to implement a lower-cost price target for the LMP2 class power plant. The HR28TT allowed HPD to offer an engine product to LMP2 competitors which met the ACO’s requirement.


Wanting to offer our customers improved fuel efficiency and improved overall engine performance, HPD added direct injection to the HR28TT in time for the 2013 race season. Initial design work began in September 2012, with development testing starting the following December. The first race application took place at the 12 Hours of Sebring in March 2013, where HR28TT-powered cars finished first and second in class. The engine claimed its second American Le Mans Series’ LMP2 Engine Manufacturers’ Championship as the 2013 season closed.

Product Specs

Engine Type:
Aluminum V-6, twin turbocharged, direct fuel injection

2.8 liters

Single overhead camshaft, 4 valves per cylinder

Alloy steel

Forged aluminum, low-friction coatings

Connecting Rods:
Alloy steel

Engine Management:
McLaren Electronics Engine Control Unit (ECU), Honda fuel-injection driver-control unit

Injection System:
Electronic combined direct and indirect fuel injection

Dry sump

Mechanical water pump

ALMS – VP MS100 E10, 100-octane
WEC – Shell LM24 E10, 101-octane

30.0 mm x 2

Boost Pressure:
195 kPa absolute


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