What is a CHRA cartridge?
The CHRA (Center Housing Rotating Assembly) is the turbo’s centre housing together with the shaft, turbine and compressor wheels, bearings and seals. On variable geometry turbos it often includes the vane mechanism too. This is the part that wears – the compressor and turbine housings usually stay serviceable.
Advantages over a new turbo
- Lower cost than a new turbo, as the housings are reused
- Shorter turnaround when the cartridge is in stock
- The cartridge arrives balanced and ready to fit
- Original housings, mounting points and actuator are retained
Why set-up after replacement is essential
On variable geometry turbos every cartridge has a slightly different mechanism position. Without correctly setting the minimum flow and actuator travel, the turbo may over-boost or under-boost and the car may go into limp mode. That’s why a cartridge swap always ends with set-up – never just “unbolt and bolt in”.
Frequently asked questions
When is a cartridge better than a rebuild?
When the shaft, wheels and centre housing are badly worn or damaged – a new cartridge then works out cheaper than replacing every part individually.
Does the actuator need replacing too?
Not necessarily. If the actuator works, it is reused but set up again to suit the new cartridge.