The cryogenic treatment of turbochargers can extend the life and improve the performance of turbo parts made of aluminum, titanium, magnesium, or stainless steel alloys. During this computer-controlled process, the temperature of the turbocharger is gradually reduced to -300° F and then kept at this cryogenic temperature for 24 hours. By promoting the transformation of retained austenite (RA) into martensite, cryogenic metal treatment reduces the risk of fatigue failure and improves heat dissipation.
When turbocharger metal is heat treated, some – but not all – of the austenite is transformed into martensite. If the retained austenite percentage (RA%) is high, microscopic voids in the metal can promote fracturing and premature failure. During cryogenic metal treatment, carbon particles precipitate and fill these voids for a more consistent microstructure. In addition to relieving stresses, cryo treatment improves heat dissipation so that the turbo releases more heat into the engine bay.
Why Turbochargers Fail
Turbochargers can fail for a variety of reasons, but high heat is often to blame. Heat soak, a temperature rise that occurs after engine shut-off, can eventually starve turbochargers of engine oil because of a problem known as “coking”. Coke, the solid residue that’s created when oil undergoes severe thermal and oxidative breakdown, can block turbocharger passageways. At extremely high temperatures, these deposits become harder, blacker, and more brittle.
Turbochargers can also fail if the compressor wheel spins without lubrication, such as when a driver takes off without idling or abruptly turn-off the car after a hard run. High heat and lack of lubrication cause excessive wear on the turbo’s bearings. Over time, this can cause the compressor and shaft to run out of alignment. The resulting damage can affect not only the compressor wheel but also the turbo housing itself. Since turbochargers are expensive to repair, some mechanics advise just replacing them.
Ignoring turbo problems isn’t an option – at least for long. If you keep driving a car with a damaged turbocharger, the engine may eventually “suck in” some of the turbo’s small metal parts. The resulting engine damage can be both significant and expensive. The grinding sound that a damaged turbo makes is a warning, but it’s not the only sign of a problem. A large cloud of blue smoke at start-up and take-off can also signify a turbocharger issues. Sometimes, leaky oil seals are to blame.
Improving Turbocharger Life and Performance
Synthetic oil is recommended for most turbocharged engines but can cause rubber seals and gaskets to “weep” over time. Non-synthetic motor oil can reduce the risk of weeping but is prone to coking, which can eventually result in catastrophic failure. The cryogenic treatment of turbochargers isn’t suitable for rubber parts, so it can’t eliminate seal failure. However, cryogenic metal treatment can extend the life of metal motorsports components and promote overall performance.
For example, the cryogenic treatment of the compressor housing removes residual stresses that can result in housing misalignments and fatigue failure. Cryo treatment of the bearings, compressor wheel, and shaft can also improve service life. Bearings that run smoothly and stay within their critical tolerances won’t cause the shaft and compressor wheel to contact the wall of the turbo housing, a problem that can cause turbo failure. By improving the turbo’s heat dissipation properties, cryogenic metal treatment also helps to protect against heat soak and oil coking.
Are you in the market for a new turbocharger? It’s a major purchase, so make sure to protect your investment with cryogenic treatment from Nitrofreeze®. If you’re going to rebuild a turbocharger instead, don’t just buy a rebuild kit. Ask us to cryo treat the bearings. To get started, contact Nitrofreeze® at the phone number and email listed below.
(508) 459-7447 x109 | email@example.com