Turbocharger

Performance Turbo Guide

 

How a Turbocharger Works:

A turbocharger consists of a turbine wheel & compressor wheel, which are connected via a shared shaft. The turbine wheel is located in the turbine housing, and the compressor wheel in the compressor housing. Exhaust gases flow through the exhaust manifold & into the turbine housing, where the high pressure exhaust gas is used to spin the turbine wheel. Exhaust then exits the turbine housing and is forced through the downpipe & out of the exhaust system. Since the turbine & compressor wheels are connected via a shared shaft, any rotation of the turbine wheel equally rotates the compressor wheel. As the compressor wheel spins, it sucks air through the air intake system and compresses it in the compressor housing. This is how turbo boost is created. The compressed air is then forced out of the compressor housing, through the intercooler (if equipped), and into the intake manifold of the engine. By forcing air into the engine, each cylinder is packed with much more air, thus allowing more fuel to be injected than would be possible with a naturally aspirated diesel. In its simplest form, this is how a turbocharger works.

 

Journal Bearing vs. Ball Bearing:

OEM turbochargers utilize journal bearings because they are cost effective to produce and provide adequate performance. A journal bearing is a bushing that surrounds the shaft of the turbocharger. The bushing, or sleeve, has holes that allow for high pressure oil to enter. The turbocharger shaft is then suspended on the thin film of oil between the shaft and journal bearing sleeve. Theoretically, there is no metal-to-metal contact between the shaft and bearing, therefore providing restrictionless operation. While journal bearing turbochargers are more affordable, they tend to fall short in performance applications and turbo longevity becomes a concern as turbo speeds and boost pressures are increased (a hard working diesel turbo can spin to 100,000 RPM). Ball bearing turbochargers feature ball bearings that suspend the shaft within the turbo housing. While lubrication is still essential, they do not need high pressure oil flow to ensure proper operation. In a ball bearing application, the turbo shaft is supported by the bearing cartridge, not a thin layer of oil. Ball bearing turbochargers operate with less friction than journal bearing turbos, thus decreasing turbocharger lag, reducing longevity concerns, allowing for higher boost capabilities, and making them the turbocharger of choice for performance applications.

 

When do I need to Upgrade my Turbo?

- If your truck is suffering from high exhaust temperatures, which is caused by a rich air-fuel mixture.
- Excessive black smoke is being produced, a sign that your air-fuel mixture is rich.
- You are running large injectors and want more airflow to match the increased fueling characteristics.
- You want quicker turbo spooling (decreased turbo lag).
- Aggressive tuning resulting in too much black smoke, high EGT, or both.

 

What Kind of Performance Increases Can I Expect?

Performance increases for turbocharger upgrades and swaps are difficult to estimate because each application will vary considerably. If your engine is running out of air (excessive smoke on the top end), or you're tired of putting up with turbo lag, a new turbocharger can make a huge difference. Turbochargers are generally advertised by the maximum horsepower range they can support, not how much horsepower they will add. Given you choose the proper turbocharger for your application, you can expect reduced turbo lag, increased hp/torque, and lower exhaust gas temperatures.

Turbocharger Upgrades:

Many manufacturers offer upgrades for OEM turbochargers, an affordable way to boost turbo efficiency and engine performance. Compressor wheels, turbine wheels, compressor housings, turbine housings, and any combination of parts can be swapped to change the characteristics of the turbocharger's performance. This is a great solution for owners on a budget who need a little more airflow or reduced lag but don't necessarily need to drastically alter how the turbo behaves.

 

Compound Turbochargers:

A compound turbocharger setup utilizes 2 turbos with very different characteristics. A compound turbo setup consists of a low pressure and high pressure turbocharger. The low pressure turbo is larger in size than the high pressure. Exhaust gases flow through the low pressure turbo and then into the high pressure turbo. The low pressure turbocharger compresses air and sends it to the high pressure turbo, where the air is further compressed and sent to the engine. The goal of the low pressure turbo is to provide air to the high pressure turbocharger, therefore giving the entire compound system the characteristics of both a small and large turbocharger (reduced turbo lag while providing large volume of airflow). Compounding turbochargers creates very high performance potentials and is the setup of choice for drag racers and sled pullers.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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