Turbocharging is one of the less expensive ways of helping an engine generate more horsepower. A turbocharger should not be confused with a blower. Where blowers are usually belt driven and actually USE horsepower to generate boost pressure, a turbo does not take horsepower away from the engine to build boost pressure. Exhaust gas is forced through a turbine housing and drives a turbine wheel on it's way out the exhaust. The turbine wheel is attached to a shaft that rides on floating bearings and drives a compressor wheel. The compressor wheel pulls air through the air filtration system and channels it through a compressor housing, where it is compressed and directed into the engine intake manifold. The amount of "BOOST" generated by a turbo is determined by its design, which is usually determined by the engine requirements.

How does a turbo create more horsepower?

Horsepower is generated by the optimum burn of the fuel which is directly related to the fuel/air mixture. If extra air is added the fuel can be increased to bring the horsepower up. A factory turbocharged engine is designed to handle the extra fuel allowed with the added air. When installing a turbo to a non-turboed (naturally aspirated) engine, caution should be taken to assure that the system has been engineered so as not to cause engine damage.

What is a WASTEGATE and how does it work?

Since a turbo works off exhaust gas, a certain amount of exhaust pressure has to be available before boost pressure can be generated. During heavy acceleration this can cause a delay in acceleration called turbo lag. A wastegate is used to allow the turbo to develop boost pressure faster at lower RPM's. As pressure builds to the maximum pressure allowed by the engine the wastegate opens dumping exhaust gas before it reaches the turbine wheel. This keeps the turbo from overboosting at the top end.

Turbo Maintenance

A turbo can turn in excess of 100,000 RPM and since most turbos rely totally on engine oil for cooling it is necessary to keep the engine oil clean. Anytime the turbo oil lines have been drained of oil it is critical that there be oil to the turbo before starting the engine. This prevents turbo damage from lack of lubrication. Lack of lubrication damage can also occur if the oil supply to the turbo is shut off before the turbo has had time to slow down. It is normally recommended that an engine be allowed to for a few minutes before shutting off the engine. This lets the turbo slow down as well as cool before shutting off the oil supply.

Common complaints, causes and possible solutions

1. Low Power

CAUSE: Dirty air cleaner or restricted air inlet.
SOLUTION: Replace air cleaner element and clean air passage.

CAUSE: Viscosity of oil bath air cleaner too high.
SOLUTION: Service air cleaner in accordance with engine manufactures service manual.

CAUSE: Loose compressor-to-intake manifold duct connections.
SOLUTION: Tighten connections as required.

CAUSE: Leakage at engine intake manifold.
SOLUTION: Refer to engine engine manufacturers service manual.

CAUSE: Leakage at engine exhaust manifold.
SOLUTION: Refer to engine engine manufacturers service manual.

CAUSE: Leakage at Turbocharger mounting flange.
SOLUTION: Check condition of gasket at turbocharger mounting flange and tighten loose bolts (Note: gasket is not used in all applications).

CAUSE: Restricted duct between the air cleaner and turbocharger compressor.
SOLUTION: Remove restriction or replace damaged parts as necessary.

CAUSE: Restricted duct between compressor and engine intake manifold.
SOLUTION: Remove restriction or replace damaged parts as necessary.

CAUSE: Restricted Engine Exhaust system (After   Turbocharger)
SOLUTION: Remove restriction or replace damaged parts as necessary.

CAUSE: Restricted Engine Intake or Exhaust manifold.
SOLUTION: Refer to engine engine manufacturers service manual.

CAUSE: Engine Malfunction (Fuel System component, valves, valve timing, rings, pistons, etc.
SOLUTION: Refer to engine engine manufacturers service manual.

2. White or Blue Smoke

CAUSE: Dirty air cleaner or restricted air inlet
SOLUTION:  Replace air cleaner element and clean air passage.

CAUSE: Viscosity of oil bath air cleaner too high.
SOLUTION: Service air cleaner in accordance with engine manufactures service manual.

CAUSE: Plugged engine oil filter.
SOLUTION: Service oil filter in accordance with engine manufacturers service manual.

CAUSE: Restricted duct between the air cleaner and turbocharger compressor.
SOLUTION: Remove restriction or replace damaged parts as necessary.

CAUSE: Seal leakage at compressor end of turbocharger.
SOLUTION: See #6 problem below.

CAUSE: Engine Malfunction (rings, pistons, valves, etc.)
SOLUTION: Refer to the engine manufacturers service manual.

CAUSE: Seal leakage at turbine end of turbocharger.
SOLUTION: See #7 problem below.

3. Engine oil consumption excessive

CAUSE: Wrong type or viscosity of engine lubricating oil.
SOLUTION: Service engine lube system in accordance with engine manufacturers service manual.

CAUSE: Seal leakage at compressor end of turbocharger (indicated by oil in housing or on wheel).
SOLUTION: See #6 problem below.

CAUSE: Seal leakage at turbine end of turbocharger (indicated by oil in housing or on wheel).
SOLUTION: See #7 problem below.

CAUSE: Oil in engine exhaust manifold (indicating malfunction of rings, pistons, valves, etc.)
SOLUTION: Refer to engine manufacturers service manual.

4. Noisy Turbocharger

CAUSE: Dirty air cleaner or restricted air inlet.
SOLUTION: Replace air cleaner or remove or replace restriction.

CAUSE: Foreign object or material in compressor inlet ducting or compressor housing.
SOLUTION: Remove foreign object. Repair air intake system and replace turbocharger if necessary.

CAUSE: Foreign object or material in compressor-to-intake manifold ducting.
SOLUTION: Remove foreign object. Repair air intake system and replace turbocharger if necessary.

CAUSE: Foreign object in engine exhaust system.
SOLUTION: Remove foreign object. Repair exhaust system and replace turbocharger if necessary.

CAUSE: Carbon build up in turbine housing.
SOLUTION: Clean housing or replace turbocharger - check engine operating procedures.

CAUSE: Turbocharger rotating assembly binding or dragging.
SOLUTION: See #5 below.

CAUSE: Loose intake or exhaust ducting systems
SOLUTION: Eliminate all leaks.

5. Turbocharger rotating assembly binding or dragging

CAUSE: Damaged compressor wheel due to foreign object impact.
SOLUTION: Clean and repair air intake system as necessary. Replace Turbocharger.

CAUSE: Damaged turbine wheel due to foreign object impact.
SOLUTION: Clean and repair engine exhaust system as necessary. Replace Turbocharger.

CAUSE: Compressor wheel or turbine wheel rubbing on housing.
SOLUTION: Worn bearings, shaft journals or bearing bores. Replace Turbocharger.

CAUSE: Excessive dirt build-up in compressor (on housing or wheel)
SOLUTION: Clean and repair air intake system as necessary. Clean compressor or replace Turbocharger.

CAUSE: Excessive carbon build-up behind turbine wheel.
SOLUTION: Coked Oil or Combustion Deposits. Replace Turbocharger.

CAUSE: Sludged or coked center housing.
SOLUTION: Service engine lubrication system. Replace Turbocharger.

6. Oil seal leakage at compressor end of turbocharger

CAUSE: Dirty air cleaner or restricted air inlet.
SOLUTION: Change air filter or remove or replace restriction.

CAUSE: Viscosity of oil in oil bath air cleaner too high.
SOLUTION: Service air cleaner in accordance with engine manufacturers service manual.

CAUSE: Restricted turbocharger oil drain line.
SOLUTION: Clean and remove restriction or replace oil drain line as required.

CAUSE: Plugged engine crankcase breather.
SOLUTION: Refer to engine manufacturers service manual.

CAUSE: Worn or damaged compressor wheel.
SOLUTION: Clean and repair air intake system as necessary. Replace Turbocharger.

CAUSE: Turbocharger bearings, bearing bores or shaft journal worn.
SOLUTION: Replace Turbocharger.

CAUSE: Engine malfunction (excessive piston blowby or high internal crankcase pressure).
SOLUTION: Refer to engine manufacturers service manual.

CAUSE: Over-full crankcase.
SOLUTION: Adjust oil level in crankcase to proper level.

7. Oil seal leakage at turbine end of the turbocharger

CAUSE: Excessive pre-oiling.
SOLUTION: Oil will burn away no action required.

CAUSE: Plugged engine crankcase breather.
SOLUTION: Refer to engine manufacturers service manual.

CAUSE: Restricted turbocharger oil drain lines.
SOLUTION: Clean and remove restriction or replace oil drain line as required.

CAUSE: Sludged or coked center housing.
SOLUTION: Service engine lubrication system. Replace Turbocharger.

CAUSE: Turbocharger bearings, bearing bores or shaft journals worn.
SOLUTION: Replace Turbocharger.

CAUSE: Engine malfunction (excessive piston blow-by or high internal crankcase pressure).
SOLUTION: Refer to engine manufacturers service manual.

CAUSE: Over-full crankcase.
SOLUTION: Adjust oil level in crankcase to proper level.

 

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