The stock HMMWV ECV vehicle engine with mechanical fan drive has shown it can be upgraded in the HMMWV to 250 or 300 horsepower. A 250 horsepower upgrade kit (250 HUK) was proven in the ECV2 and also selected and thoroughly tested in BAE MECV prototype vehicles. A HMMWV up-weighted to 18,000 pounds has also run the 250 horsepower kit in desert conditions demonstrating significant performance improvement in acceleration, torque and speed. Production versions of this same engine at 300 horsepower have been sold for years.

250 Horsepower Upgrade Kit

250kit replacement image for engine products page

  • Upgrade to existing engine retains 90% commonality.
  • Installs in hours, 30% increase in torque and HP.

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These UORVA horsepower improvement kits fit to the stock 6.5L turbo-diesel engine and combines higher available fuel flow with cooler turbocharger air for higher power. The right and left intercooler manifolds are low profile to fit under the hood and the charge air cooler sits above the existing radiator with a high efficiency fin and core design. No new wires, no electronics. This is a simple, affordable proven mechanical solution. (insert clip 250HP)

300 Horsepower Upgrade Kit

300 HUK replacement picture for engine products page

  • Upgrade to existing engine retains 85% commonality.
  • Installs in hours, 53% increase in torque and HP.

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To jump up to 300 horsepower a new turbocharger is installed. This turbo mounts the same and fits in the same space claim. A new turbo output casting is installed that provides higher flow along with a new high flow exhaust kit. The exhaust system was further designed so that it can stay mounted during service and removal of the transmission and transfer case.

High-Flow Exhaust Kit for Your Turbocharged HUMMER

Off-road pipe taking the place of the catalytic converter for your off highway excursions. Free flowing muffler proved at 300 HP.

High Flow Exhaust Kit


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  • Pipe and Muffler are mirror finish polished stainless steel
  • 4” tailpipe mirror finish polished stainless steel with all clamps
  • All brackets needed for installation
  • This kit include the mirror finish polished stainless steel muffler that is required on all highways and state and federal recreation areas.

Off-Road Pipe

Part #: 91-22001

Mirror finish, polished stainless steel with parts.