Over Speeding Turbos
So Why does over speeding damage turbos?
Over speeding Turbochargers can operate at speeds in excess of 6,000 revs per second (360,000 rpm), with exhaust gases exceeding 800°C. To say that a turbo operates in an extreme environment is an understatement.
Each turbo is designed and manufactured to rotate at the correct speed for its application. Over speeding occurs when the turbo rotates at a greater speed than its operational limits.
Over speeding can push a turbo beyond its safe operating parameters, causing it to fail by damaging the turbine or compressor wheels and bearings. Turbos fitted to most vehicles usually have some tuning potential allowing them to spin faster but its limited and only a highly experienced tuner should be allowed to raise your boost limits.
If the turbo continues to over speed, it can over boost the engine, resulting in serious damage to the internal components and potentially complete engine failure !
Now days most vehicles engine management system detect an over boost moment however when the limits have been raised when they have been remapped etc and the limits have been extended to far the over boosting “cutout” or “limp mode” does not occur and the turbo over speeds…the results of which are expensive !
What causes over speeding ?
• A restriction in the air intake filter or pipe work, or a split or detached boost hose, allowing
incorrect amounts of air into the turbo.
• A badly ‘chipped/remapped’ or ‘over fuelled’ engine that isn’t to standard specification with over extended boost limits…very common so beware !.
• Tampering with the turbos wastegate causing to to stayed closed at higher boost settings.
• Worn injectors.
• Intermittent actuator fault that controls the opening and closing of the wastegate or VNT control causing excessive boost spikes and over speeding..again very common.
• Fitting the incorrect turbo.
• Split intercoolers producing a boost leak and over speeding as the engine management compensates.
Preventing turbo failure
• Check there are no restrictions or leaks in the air intake pipe work.
• Ensure the wastegate or VNT linkage is operating freely.
• Check the electronic sensors and ECU are operating correctly.
• Avoid cheap poor quality remaps.
We are always here to answer any questions regarding over speeding….