A properly balanced turbocharger is critical to the overall performance of your diesel engine. Without proper balance, you run the risk of poor performance and failure.
While many turbos might claim to be balanced, not all processes are equal. You want a balancing process that helps reduce the risk of failures. That’s why we recommend a VSR balanced turbo. What exactly does VSR balancing mean and why do you want it in your diesel engine? We’ve got the details for you! All About VSR Turbo Balancing So just what is VSR balancing? What makes it different? In short, a VSR balanced turbo has had the shaft and wheel inside the bearing housing, the rotating assembly, put on a VSR balancing machine. There, it undergoes high-speed balancing. What Does the VSR Balancing Process Look Like? During the VSR balancing process, the turbo is spooled up to around 30,000 or 40,000 RPM. While this is happening, we look for harmonics in the shaft and wheel. These are ground to ensure they are level. It has to be balanced, or your turbo won’t function correctly. Generally, the smaller the turbo, the faster it spools. Your larger turbos just aren’t going to spool as fast. An average turbo, an ISX for example, will spin right around 70,000 to 80,000 RPM. What Makes VSR Balancing So Great? A lot of places just aren’t doing the VSR balancing. And, as we mentioned, not all balancing processes are going to give you the same level of precision. You’ll have places that have a standard balancer, and that’s okay, but you’ll likely not get all the harmonics out of the shaft and wheel. Wondering why the turbo needs to be balanced? Essentially, you want to keep it true and level, but you also need to get rid of issues that can appear when the RPM builds. That’s where you see the harmonics. Other Balancing Practices Sometimes a rebuilder who doesn’t use a VSR balancing machine will put a notch on the compressor wheel, the bolt, the nut that goes on it, and the shaft. That’s because on a low-speed balancing machine, you have to take apart the assembly to reinstall it in the turbo. This makes all those notches necessary. Then, the rebuilder reassembles, lining up the notches. It might seem like it should be balanced, but it is actually still out of balance. Because of the metal it’s made of, it will just inherently go out of balance when taken apart. That’s just its nature. How VSR Balancing Fixes the Problem VSR balancing actually eliminates the problem caused by taking the assembly apart. The components are inspected as the balance is measured the first time to ensure everything is still okay. The shaft, for example, might be out. When you balance something as a complete assembly, it’s possible to remove all the harmonics, and the final assembly can be verified in the cartridge. This, in turn, leads to fewer failures. Aspect Ratio’s Effect on Turbo Performance What is Aspect Ratio? Aspect Ratio is something commonly used to indicate the housing size of your turbo. It is the ratio of the area of the exhaust turbine inlet to the radius from the turbine impeller center. Aspect Ratio can affect the spool up time of the turbo (Turbo Lag), as well as the maximum airflow. Aspect Ratio and Spooling Time In general, larger numbers increase your airflow. This does, however, increase the spool-up time as well. If the Aspect Ratio is too large, you might experience sluggishness as it takes too long to spool up. On the other hand, a smaller number will decrease the airflow and increase the spool-up time. If the spool-up time is too quick, you might not get enough air, leading to high EGTs. Calculating Your Aspect Ratio To calculate your Aspect Ratio, take the cross-sectional area and divide the radius from the turbo center line to the center of the area. For example, if the turbine housing has an area of 125.4mm2 and a radius of 95mm you’d have 125.4/95. This leads to an Aspect Ratio of 1.32. Final Thoughts In the end, a properly balanced turbo with a proper Aspect Ratio is key to a great performing turbocharger. That’s why we recommend a VSR balanced turbo. If you have questions about turbos or VSR balancing, we have a team of experts who can help. Our ASE Certified Technicians are ready to answer your questions and help you diagnose your diesel engine problems. We want to make sure you’re getting the parts you actually need. From diagnosis through delivery, we’re Highway & Heavy Parts!Related Videos:
