Myths About Diesel Engines FAQs

1 You can’t tune a diesel

WRONG. Diesels can be tuned.

In fact, diesels have always withstood tuning better than petrol engines. Diesels have adjustable components that need periodic setting for economy and longevity. However, optimum tuning of a petrol engine means extra components have to be added.

2 Diesel fuels aren’t as good as they used to be

RIGHT. Poor fuel has become a world-wide problem.

In the last 10-12 years diesel fuels have been degraded slowly by the removal of sulphur (the carrier of the lubricant in the fuel). This means a rapid decrease in power and economy in your diesel vehicle and an increase in component wear. The diesel injector pump and injectors are the heart of the diesel engine and without the lubricity in our fuels we need to substitute that lack of lubricant carrier by the use of additives.

To maintain the highest level of filtration, at TEC we offer a full range of products and components plus professional injector system services, repairs and monitoring of components' serviceability and performance.

Ray's handy diesel tips:

  • Use only high volume diesel fuel outlets and brand name fuels eg. BP, Shell, Mobil or Caltex
  • Change fuel filters at 20,000km intervals and use filter assemblies with a warning indicator (either electronic or visual glass bowl type (eg CAV)
  • Use lubricity additives and algaecides to control the quality of your diesel fuel once it enters your vehicle’s tank and fuel system

3 The manufacturer does not have a turbocharged model. How can you fit one in this case? The manufacturer's agent says not to do so

WRONG. Most diesel engines manufactured from 1984 onwards have been designed with turbocharging in mind.

Quite often they are available in other countries with a turbo fitted at factory. Oil cooled pistons, keystone reinforced top piston rings, steel piston rings, oil to water engine oil cooling, auxiliary oil coolers are all standard build and fitment in Nissan, Toyota, Mitsubishi, Mazda, Fold, Iszuzu and others. These inbuilt features are specifically for diesel turbocharged engines.

4 My mate had a Turbo fitted and his engine blew up because of it

WRONG. Turbochargers are the innocent link here.

They only supply additional air in this equation. Unlike petrol or gas engines, more air actually cools the diesel engine - it is the fuel that creates the heat. The culprit is either an incorrectly installed diesel injection system or a faulty cooling system. The additional horsepower from a turbocharger is anywhere between 25 - 50% and, used sensibly, only enhances your vehicle’s driveability, economy and longevity. Turbocharged engines usually operate for 400,000 to 600,000 km with complete reliability.

5 You should not fit a turbocharger to an old engine or a brand new engine

RIGHT and WRONG. Right, if the engine has pre-existing wear and faults due to high mileage and it requires reconditioning anyway. At TEC, we stipulate a dyno test and engine evaluation on all vehicles with 100,000 km or more. If the engine fails the test the customer is advised not to have a turbocharger fitted until the recommended repairs are performed. Wrong relating to new. This is not correct for a brand new engine, however.

A vehicle straight off the show room floor is, in fact, the best choice for the turbocharger upgrade. The new engine will complement the turbocharger characteristics - PERFECT!

6 Water cooling is unnecessary in a diesel

WRONG. Water cooling is necessary in any conversion to maintain engine oil temperatures to factory specifications.

The addition of the turbocharger means using the engine oil supply for lubrication. This creates heat transfer into the engine oil which requires additional cooling. Water cooling almost entirely eliminates the need for idle-down thus allowing instant engine cut-off without the usual resultant long-term damage to the turbocharger.

7 Don’t boost your factory non-Turbo engine more than 5 to 7 lbs per square inch

WRONG. Modern, high speed diesel engines are overbuilt with strong bottom ends, certainly incorporated for Turbocharging.

Low boost on a diesel engine means less air and more heat.

Boost pressures of 8 to 12 lbs mean more air, that is, less heat. At TEC all systems are set up to run air rich and override the fuel delivered. This creates a gradual reduction of piston crown temperatures with RAM increased. In other words, the harder you push it the cooler it gets.

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