In the automotive world, the debate between naturally aspirated and turbocharged engines is always hot. As the name suggests naturally aspirated engines do not require forced air induction into the engine for combustion.
In a turbocharged engine, the turbocharger compresses the air to a higher pressure before it enters the engine. This process boosts the engine’s horsepower.
The additional power output enabled by a turbocharger is typically in the range of 30-40%.
Combustion In Diesel Engines:
An internal combustion engine is a driving force behind automotive applications that use conventional fuels such as gasoline or diesel. See Internal combustion engine basics
Let’s look at how a diesel engine generates power.
Imagine a four-stroke engine powering a diesel mini truck. The diesel fuel from the tank is delivered to the engine by the fuel injection system. During the compression stroke, air is compressed and prepared for ignition within the engine cylinder.
At the end of this stroke, the fuel injector sprays diesel at very high pressure. This air and fuel mixture ignites, powering the mini truck.
While this process sounds simple, it involves several complex systems working together within the vehicle.
What is a Turbocharger?
A turbocharger is a device that enhances the power delivered by an engine. In a diesel engine, the turbocharger can enhance the horse powerhore leading to faster acceleration and improved traction when compared to a naturally aspirated engine.
Components of a Turbocharger:
- Housing
- Turbine
- Compressor
- Shaft
- Bearings
- Waste gate and blow-off valve
- Sensors and other accessories
The turbine and compressor are mounted on the same shaft supported by bearings. This compact assembly is placed in a housing.
How Does a Turbocharger Work?
The exhaust gases from the engine cylinder are fed to the turbine enabling its blades to rotate at a high speed. As the turbine is connected to the compressor through a shaft the compressor comes into play enabling compression of incoming air.
Air is boosted from atmospheric pressure to 6 – 10 Psig.
The high-pressure compressed air then passes to the engine through the air intake manifold.
The pressurized and dense air that is rich in oxygen accelerates the combustion process producing more horsepower with the help of diesel fuel whose supply is also proportionately increased by the engine’s Electronic Control Unit or ECU
How Much Horsepower Does a Turbocharger Add:
An accurate answer to this question may not be possible as it depends on several factors like the engine capacity, size, and design of the turbocharger, the ability of the other components in the engine to work in synergy with the turbocharger, and the quality of installation.
As a rule of thumb, a turbocharger could typically boost your horsepower by 30 to 40%.
Let’s delve into the factors that impact turbocharger performance.
Turbocharger Sizing:
Smaller turbos get into action very quickly at lower RPMs and provide an instant response to throttling.
The bigger the turbo greater its ability to generate more airflow enabling the engine to generate more power through the combustion process.
Turbocharger Design:
Compatibility and rating of components used in the turbocharger have a major effect. If the compressor is not properly sized for the turbine, it will result in a mismatch in performance.
The turbine’s ability to produce more power will go unutilized if the compressor is unable to deliver its performance due to sizing mismatch.
Engine Limitations:
Engine limitations can have an impact on how much power can be derived from a turbocharged engine. The engine and its components may not be capable of handling the increase in performance aided by the turbo.
The engine’s design may limit the capacity of the engine to use the added power.
Let’s look at some of the limitations.
Engine components: Piston, connecting rods, crankshafts, and cylinder heads should be capable of withstanding higher stresses because of higher power output.
ECU: The engine control unit monitors and controls several key functions including the air-fuel mixture ratio and the timing of fuel and air injection in the chambers. Suboptimal tuning can lead to the engine not keeping up with the enhanced performance.
In addition to the above, other factors like engine size (displacement), fuel quality, use of intercooler, and exhaust gas flow system will determine if the engine can handle the additional power provided by a turbocharger.
What is Turbo Lag?
The time delay that occurs before the turbocharger gets into action when the throttle is pressed is referred to as turbo lag.
Why Does it Happen?
The turbo kicks in when the exhaust gases have enough pressure to drive the turbine blades. At lower RPMs, the exhaust gases may not be able to drive the turbine to its rated speed. As a result, the engine may appear sluggish to throttle response.
How to Fix Turbo Lag?
Upgrade your Turbo: A smaller turbo can quickly get into action. Water-cooled chargers can also help in reducing the lag.
Twin Turbo: Go for a twin-turbo system that has two turbochargers to deliver a higher air output reducing the lag.
Upgrade Your Exhaust System: A less restrictive exhaust system will ensure that your turbo spools up quickly.
Engine Tuning: Tuning the engine to deliver an optimal air-fuel mixture can help in reducing the lag.
Conclusion:
Turbocharger is a game changer as it can improve the power output of your truck by 30-40%. The performance characteristics of the engine can be greatly altered by adding a turbo.
However, you need to be careful as improper selection of turbo may lead to overboosting or increase in boost pressure which can damage the engine if it is not addressed properly.
Diesel Fuel Components Inc. has been in the business since 1977 serving several territories in North America and countries around the world. Our forte is heavy-duty, on and off-highway vehicles.
We offer specialized services for Turbochargers and their Installation – Diesel Turbocharger Repair Services
Whether you need help selecting the right turbocharger specs for your needs or require repair and replacement of your existing turbos, our trained technicians are here to ensure the job is done to your satisfaction.
