Get Spooled! W2-BB Turbo Now Available
What is the W2-BB and which W2 is right for me?
Years of research and testing have led us to this big day for 27WON. After a successful launch of our W2 journal bearing (W2-JB) turbocharger upgrade about a year ago, we are excited to release the more durable and robust twin of that W2 turbo. The all-new W2 ball bearing (W2-BB) unit has the same power-proven design as the W2-JB but with a key upgrade on the inside. Dive in below to learn the difference between a JB and BB turbo and let us help you decide which one is right for you.
If you are not familiar with the components of a turbocharger then check out our Turbos 101 blog so this blog will make more sense. We will be focusing on the CHRA section of the turbocharger for this article. Also, check out the design blogs below for the W2 turbocharger release because those are super helpful.
As shared in the Turbos 101 blog, the center housing and rotating assembly (CHRA) is comprised of two wheels, a metal rotating shaft, bearings, and the housing that encases all of these. It is what engine oil and coolant are pumped in and out of to make sure the unit is properly cooled and lubricated.
If you put the W2-JB and W2-BB CHRA next to each other you would probably think they are the same. Both units use the same compressor wheel and turbine wheel. However, it is what you can’t see that makes all the difference.
JB vs BB refers to the type of bearing system within the cast housing that supports the rotating shaft and wheels. A journal bearing system consists of a pair of journal bearings, one on each end of the shaft closest to each wheel, and a thrust bearing located near the compressor wheel. The two journal bearings support the shaft in the radial direction. Think of that as the shaft spinning on its axis. It keeps the shaft from wobbling like a spinning top. The thrust bearing helps support the unit in the axial direction. This is the in-and-out direction. Together these have the super important job of making sure everything stays where it should when your turbo is spinning north of 100,000 rpm.
Both the thrust and journal bearing are made of a babbitt material that relies on a thin film of oil to keep them from contacting the metal shaft directly. You will notice they have precisely drilled holes that control the flow and movement of oil around them. Journal bearing systems are much cheaper to produce and more widely available to source than their ball bearing counterparts. While great at stock to mid-power level upgrades, for the big boost they become less than an ideal choice.
A ball bearing CHRA ditches the two journal bearings and the thrust bearing for a cartridge that houses ball bearings. A ball bearing assembly looks like the image below; A metal sleeve with two inner and outer races at each end with small ceramic ball bearings in them. The round/ball nature of the bearings allows them to handle both axial and radial play mentioned above. Ball bearings are much more resilient to the sudden movement changes seen in a turbo application. Due to the precise machining of both the ceramic balls and the spacers/washers in the cartridge, a ball bearing unit is more expensive to produce than its journal bearing counterpart
Here are some of the differences in performance from a journal-bearing turbocharger when compared to a similar ball-bearing counterpart.
A BB unit requires less engine oil. Because less oil goes into the CHRA the chances of any type of oil leak coming from the CHRA is reduced.
A BB unit has less internal drag than a JB unit does. Bearings do spin inside the CHRA and the effort to spin requires some work. By eliminating that parasitic drag the system can spring more freely and easier which in the real world translates to a faster spool.
Reliability is the key difference between a BB and JB unit. Given the angular contact of the ceramic balls and the ability of the cartridge to dampen and control shaft motion, a BB unit is superior to a JB unit in performance applications. It can handle more extreme conditions and is less likely to fail under these adverse conditions.
Now that you are ready to order your W2, which one is right for you?
A more budget-critical streetcar, perhaps with a few race days here and there, might go the way of a JB. If cost is not a factor and outright durability and performance are key then a BB is worth a few hundred extra dollars. If you usually drive your car hard on the street or race it often then a BB turbo is the way to go. BB units also are great in very cold environments as they handle cold starts better than the JB.
Regardless of which version you choose, 27WON is here to help you enjoy the newfound power. If you have any other questions please feel free to drop a comment below and let us know.
-Vincent