One could argue that every diesel engine should have a turbocharger. They increase engine performance, boost fuel efficiency, and deliver more horsepower and towing capacity. In addition, turbochargers give your vehicle the functional power and capacity of a much larger engine without the actual size, allowing for reduced emissions.
Size Doesn’t Matter
An engine’s power, or the strength of its combustion, depends on how much fuel and oxygen it can burn. When you have a smaller engine, the amount of air you can bring in is naturally limited by space. Conventional wisdom would say that if you want your vehicle to generate more powerful combustion, you’ll need additional motor size to accommodate more air and fuel.
A turbocharger changes that dynamic by routing high-pressure engine exhaust gasses back into the turbocharger through a turbine wheel. Those gasses power the turbo’s compressor fan blades at extremely high speeds. This process draws more compressed air into the engine, and your fuel injection automatically increases to match the level of additional oxygen, creating bigger and stronger combustion.
Thus, armed with a turbocharger, your little sedan’s engine can deliver a power boost to match that of a plus-sized diesel. No structural expansion required.
Turbos Require Precision Care
A turbocharger needs more vigilance and care than your average diesel engine to function at optimal levels. That’s because of the way it works. When you have a machine rotating at such a high rate of speed, having even the smallest part out of sync can do tremendous damage.
As a longtime diesel parts supplier, we have seen our fair share of brand-new and rebuilt turbochargers. And the high-quality ones always have one thing in common - they have gone through a thorough balancing (or rebalancing) process before going under the hood.
Think of your turbo like the tires on your car. When you get new tires, you need them balanced. If they’re not balanced, they will wobble, and you’ll have a lot of noise and vibration. The tires will also wear incorrectly, possibly causing them to fail prematurely or even damage your vehicle.
The same goes for your turbocharger, which rotates at significantly higher speeds than your car’s wheels - we’re talking up to 300,000 RPMs (rotations per minute) fast. An unbalanced turbo can burn through bearings and seals in minutes at that level, causing it to malfunction or fail altogether. It could also spin off debris into the engine generating catastrophic damage.
Even if you had your turbo balanced initially, you must keep an eye out for signs that it may have become unbalanced in the course of its operation. Any whistling or ‘screaming’ from the turbocharger when it hits higher speeds indicates that an unbalance is breaking down the oil film protecting the bearings.
An out-of-balance turbo can also cause fan blade damage, oil leaks, and power loss. In many cases, the imbalance will cause the turbocharger to fail within hours or days of use.
How to Balance (and Protect) Your Turbocharger
When you purchase a new or rebuilt turbocharger, it’s important to note that it may or may not arrive pre-balanced. If it turns out to be pre-balanced, does this mean you don’t have to worry about additional balancing? Simply put, No. You should still check the balance levels on the individual components and the complete assembly.
A turbocharger consists of three main parts: the Center Housing Rotating Assembly (CHRA), the turbine wheel and housing, and the compressor wheel and housing. It’s essential to balance the turbine and compressor wheels individually before balancing the assembled turbocharger.
Note there is no such thing as achieving a ‘perfect’ balance for anything that rotates around a central axis. A certain amount of imbalance will always be left in the process, usually referred to as a tolerance level. Individual balancing helps keep tolerance levels in line with tight industry standards by preventing them from ‘stacking up’ when you put all the components together.
A typical balancing proceeds as follows:
- Balance turbine and compressor wheels on separate planes on a low-speed, conventional machine.
- Assemble the rotor stack with turbine and compressor wheels and balance.
- Put the assembled rotor back into CHRA and balance the cartridge on a VSR machine (designed to run the complete assembly at high speeds, reflecting regular use).
Since you likely don’t have complex balancing machines ready to go in your garage, it’s a good idea to have your turbo balanced by professionals at a reputable shop. The cost usually hovers somewhere between $50 and $120, and when you consider the alternative of replacing your entire turbo (in the thousands), it’s a solid deal.
For more tips on keeping your new or rebuilt CHRA cartridge and other turbo components in excellent working condition, call us at (301) 770-4514.
