Low Heat Rejection engines were all the rage back in the 80's and 90's. If you take a gallon of fuel 1/3 of the energy goes to the wheels, 1/3 goes to the coolant, and a 1/3 goes to the exhaust gas temperature. LHR engines try to cut the pie with a bigger piece going to powering the wheels.

 Here are a few things I'm researching for my 7.3L IDI engine.

1. Ceramic coatings and filled block- so less heat goes into the cooling system.
2. Alcohol injection

PERFORMANCE AND ENERGY BALANCE OF A LOW HEAT REJECTION DIESEL
ENGINE OPERATED WITH DIESEL FUEL AND ETHANOL BLEND
Murat Ciniviz
Technical Education Faculty, Mechanical Education Department, Selcuk University, 42003 Konya, Turkey
E-mail: mciniviz@selcuk.edu.tr
Received June 2009, Accepted December 2009
No. 09-CSME-33, E.I.C. Accession 3119

<cite>www.tcsme.org/Papers/Vol34/Vol34No1Paper6.pdf</cite>

http://www.adiabatics.com/Research___Development2.php



Check this out:

Cummins Modified with Ceramic Coatings