Diesel engines and performance tuning

The only difference between petrol and diesel engines is the fuel/ignition systems.  The rest, including the intake, exhaust, and intake and exhaust valves is basically the same.

So all the different methods of getting more power still apply!  More airflow equates to more horsepower, so adding a Turbocharger, or a supercharger, or Nitrous Injection all work just fine!  Generally chip tuning works too on modern turbo diesels.  The same result is produced by manually increasing the boost level, and subsequent fuelling.  The only problem is the way the fuel is burned is slow so 5000 rpm is about it for a car diesel engine!  All the tuning does is increase torque lower down the rev range.  Consequently conventional tuning brings little gain on a diesel.

Never try adding extra diesel fuel via the air intake though! It will pre ignite during the compression cycle... You may run over your own crankshaft!  If you need extra fuel because you have fitted a turbo, turned up the boost level, or fitted Nitrous Injection you must either fool the normal injection system into giving more fuel, or add Propane (because it will not ignite due to compression alone) in the intake system. 

This works because Propane (or LPG, Methanol, or high octane petrol) have a high Octane Rating.  Octane is a measure of the fuels ability to not ignite under compression alone!  So the ignition point in a diesel still depends on the normal Diesel injection pump's timing. The extra Propane fuel is ignited by the diesel burning as it Self ignites upon injection via the injector.  Diesel is very low Octane, so the heat of compression alone is enough for reliable ignition as it is injected.

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