Upgrading the factory-fitted turbocharger on your diesel engine is no small feat. The key to choosing the right performance turbo for your diesel is to know your horsepower target – and whether or not you will have to pair your upgraded turbo with other performance parts and upgrades.
Although upgrading a standard turbo to a performance turbo seems like a simple method to increase your power outputs, there are a number of important factors to consider before choosing your new turbo. Choose one that is too big for your engine, and you will likely experience turbo lag; choose one that is too small, and you may never see the horsepower you were aiming for in the first place!
Are you looking for a turbo upgrade for your diesel engine? Keep reading to find out how to choose the right performance replacement…
What is a Turbocharger?
A turbocharger is an engine component that all modern diesel vehicles (and a considerable amount of modern petrol cars!) have fitted to the engine. Akin to an air pump, a turbocharger feeds additional, compressed air into the combustion chamber of the engine. It is driven by the exhaust leaving the engine – as the engine pumps air out, it turns the turbo, which pumps air back to the engine.
The compressed air pushed to the engine by the turbo has a higher atmospheric pressure than the air circulating in non-turbocharged engines. Higher atmospheric pressure means that more fuel is fed to the engine, which in turn causes a spike in horsepower. This is how turbos provide an additional ‘boost’ to power and improve engine efficiency.
Why Do Diesel Engines Need Turbos?
Naturally aspirated diesel vehicles, or non-turbocharged diesel vehicles, are sluggish in power at low RPMs. Despite their impressive torque abilities, diesel engines are not very efficient – until a turbo is fitted to them, which is why naturally aspirated diesel vehicles are not available anymore.
Modern diesel engines have turbochargers to enable all-terrain driving. Without the turbo, driving a diesel in areas of high traffic, suburbs or cities would actually be dangerous. Without the added horsepower provided by the turbo, a diesel engine would not be fit for urban driving.
Replacing The Standard Turbo
Despite modern diesel engines requiring turbos to work efficiently, factory-fitted turbochargers can often be a little underwhelming. Vehicle manufacturers may make use of high-quality materials, but stock-standard diesels are usually considerably under-tuned, meaning that there is a lot more power available in the engine than what is being outlaid. Replacing the standard turbo with a performance turbo is a popular way of getting more power and efficiency from your engine.
However, simply replacing the standard turbo with a performance turbo may not give you the results you want. When choosing a new turbo for your diesel, it’s important to keep in mind the horsepower target you are after, whether your engine is capable of utilising the new turbo as intended, and whether you will need additional upgrades to factor in the part change.
Reasons to Fit a Performance Turbocharger
The main reason to upgrade your standard turbo is for the huge power increase potential. Turbochargers produce more power with every stroke of your engine’s pistons, and an upgraded turbo will produce more power within the same engine, making it an effective performance upgrade. Turbochargers also increase torque, particularly at low revs, as well as reduce emissions.
Diesel engines are already considerably efficient – more so than petrol engines – and a turbocharger amplifies this. Matching the right turbocharger upgrade with your engine can help you cut back on fuel costs and see your engine use fuel more efficiently.
Improved Towing Capabilities
Towing a trailer or caravan adds weight to your vehicle, which can put your diesel engine under strain. Upgrading your turbo will provide your engine with additional power and torque, making those heavy loads a breeze to tow.
Reducing Turbo Lag
If you drive a factory-standard turbocharged diesel vehicle, you may have experienced turbo lag before – especially while driving in urban areas. Turbo lag is a delayed throttle response experienced before the turbo starts to work. It is caused by the time it takes the exhaust system to spin the turbine within the turbo, and for it to force more air and fuel to the engine. Upgrading the standard turbo can greatly reduce how often, if at all thereafter, turbo lag is experienced.
Avoid Turbo Lag Altogether!
A sure-fire way of almost eliminating turbo lag entirely is through a variable geometry turbocharger (VGT). Also known as variable-nozzle turbines (VNT), these performance parts are designed to improve the aspect ratio of the turbocharger within your engine.
Low engine speeds are when you are most likely to experience turbo lag. However, with a variable geometry turbocharger fitted, the aspect ratio of your turbocharger is able to alternate depending on driving conditions.
If the aspect ratio is too big, the turbo will be unable to produce boost at low speeds, resulting in turbo lag. If the aspect ratio is too small, the turbo will choke the engine at high speeds, leading to high exhaust manifold pressures and lower power output. VGTs eliminate this problem by altering the geometry of the turbine housing as the engine accelerates, allowing the aspect ratio to maintain an optimal level regardless of how or where you are driving!
Where Can You Upgrade Your Turbo?
The best place to have your turbo upgraded is at Just Autos’ workshop. The many risks associated with upgrading your turbo means you should always consult an experienced professional before making any function or part changes to your engine. Our team can provide sound advice on possible horsepower targets, engine compatibility, and whether your desired performance results will require additional part upgrades.
Diesel engines are our speciality, and we have provided Queensland’s diesel enthusiasts with upgrades for every occasion: off-road driving, towing, and touring, improved performance, you name it!
For reliable turbo upgrades and professional advice, contact Just Autos today.