At Ivor Searle, the demand for remanufactured turbos is on the rise, not least because the cost of buying new OEM units is often prohibitive within the automotive aftermarket, where competition for repair business is fierce. Whilst it’s cheaper to source a remanufactured turbo, the process of bringing it back to its original specification, or better, involves a great deal of skilled technical expertise, advanced testing and recalibration.
Within five years, more than half the world’s new cars will be turbocharged. That’s according to engineers at Honeywell, one of the biggest global turbo manufacturers. Remanufacturing these precision parts requires a highly specialised process.
Vehicle turbochargers operate in a hostile environment. Whilst rotating electrics such as starter motors and alternators turn at a few thousand rpm, turbos spin considerably faster, at up to 360,000 rpm (6,000 revs per second) and need to cope with searing heat of up to 1,000 degrees centigrade.
As vehicle manufacturers explore ways of improving power output from smaller and lighter engines, turbocharging technology is advancing rapidly. Over the past decade, improvements in the durability of component materials and manufacturing design have helped make turbos more reliable. Due to the increasing number now in operation, however, often the reason for turbocharger breakdown does not come from the device itself but rather any one or combination of external factors. For example, oil contamination, insufficient or lack of lubrication, contaminants in the exhaust and intake system and prolonged operation under extreme load can all play a role in damaging parts or causing total unit failure.
As with engines and gearboxes, the first stage in the turbo remanufacturing process at Ivor Searle’s facility in Cambridgeshire is the strip down of the turbo into its constituent parts. Ivor Searle insist that only the best ‘core’ units are retained for remanufacturing and at this point, certain components will need to be discarded into the recycling bin if there’s a risk that they could underperform in a remanufactured unit. Those that are suitable then undergo a thorough, multi-step cleaning process, involving both thermal and chemical cleaning to remove 100% of contaminants. A final blasting treatment on the housings ensures the component is returned to the same visual condition as new.
Once spotlessly clean, the inspection process can begin in order to measure each component for the correct tolerances. They need to be certified for re-use and at this stage, some parts may not make the grade, so they are also discarded.
The next part of the process is the remanufacture. All gaskets, bearings and seals are always brand new. The CHRA (Centre Housing Rotational Assembly), turbine shaft, turbine wheel and compressor wheel are checked according to OE specification, following which the unit undergoes a dynamic balancing test prior to final assembly. If this doesn’t meet our stringent criteria then a new CHRA will be fitted. This is a crucial phase as it ensures the turbocharger will perform at its optimum, with minimum vibration, minimum bearing wear and minimum operating noise.
If the unit meets Ivor Searle’s exacting standards, the final assembly of the compressor and turbine housings takes place, and additional pre-running checks are undertaken. This includes the setting and calibration of the actuators and flow test for optimal performance. Only after successful completion of each and every test is the remanufactured turbocharger ready to be signed off for packaging.
Commented David Eszenyi, Ivor Searle’s Commercial Director:
“For 70 years, we’ve built up a reputation for engines of excellence and this philosophy extends to the remanufacture of turbos, which is an increasing part of our business and one in which the company has invested heavily. Every turbocharger leaving our facility will perform as if it were brand new and customers also have the benefit of a 2-year Ivor Searle warranty.”