Diesel Engine Tuning Theory

Fueling

• While most diesel enthusiasts simply dump more fuel into the engine, this often results in excessively high exhaust gas temperatures and black smoke. You can compensate for a little extra fuel by installing a bigger turbo down-pipe.
  
  

Gas-Like Performance

• Diesel engines traditionally produce twice as much torque as horsepower. Modern diesel tuners are experimenting with limiting torque at lower rpm, revving the engine higher for a more gas-like power.
  
  

Boost Limiting

• The best solution to boost-lag issues is to use a set of medium-sized twin turbos. They will spool up to their maximum speed at low RPM, and then remain at that speed with an electronic boost controller.
  
  

Head Porting

• When porting a diesel head, remember that absolute flow is secondary to air turbulence and mixture swirl. A head that flows like the Lincoln Tunnel but doesn't promote swirl and good fuel mixture will result in black smoke and a loss of power.
  
  

Weight

• A high-revving diesel's Achilles heel is the weight of its rotating assembly. Consider having the crankshaft lightened, knife-edged and contoured. Have it shot-peened and cryo-treated for strength.