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Advances in turbocharging and the benefits of remanufactured turbos - 03.09.2018

With turbocharging one of the key areas of engine development, leading remanufactured turbo specialist, Ivor Searle, examines the direction that turbo technology is heading in.

As vehicle manufacturers explore ways of improving power from smaller and lighter engines whilst reducing fuel consumption and emissions, turbo technology is a central part of technical development. The use of electric turbochargers, for example, is set to grow exponentially within volume car manufacturing because of the advantages the technology brings.
Whilst an electric or e-turbo uses exhaust gas in the same way a mechanical turbo does, an electric version is coupled to an electric motor that assists in both spooling up the turbo to eliminate lag and generating electricity which goes back into the vehicle. This reduces stress on the alternator and the engine, which ultimately saves fuel.
E-turbos present a compelling proposition for carmakers because of their relative simplicity compared with conventional turbos. As well as constituting fewer parts, the lower RPM of around 100,000 means there is less heat build-up. 
However, even after the turbocharging process is finished, there is still some energy left in the exhaust gases. In answer to this, a system of harnessing this otherwise wasted energy has been developed, called Electric Turbo Compounding (ETC), which uses the waste gases from the turbo to drive a generator that converts it into electrical power.
The ETC process has a number of benefits, chief of which is making the vehicle more efficient. The extra energy can also provide additional power to the engine, making the vehicle faster or more responsive, as is demonstrated in the latest generation of Formula 1 cars, which utilise ETC as part of their Energy Recovery System (ERS).
Over the coming years, similar energy recovery systems look set to enter the passenger car and commercial vehicle market, all focused on improving fuel-efficiency and reducing emissions. For hybrid vehicles, ETC could provide a great way of charging batteries or directly powering electric motors, helping to keep wasted energy to an absolute minimum. Major manufacturers, including Audi, Mercedes and BMW, are already looking towards ETC as a way of eliminating turbo lag.
Whilst improvements in the durability of materials and manufacturing design have undoubtedly helped make turbos more reliable, other factors are generally responsible for their breakdown, such as oil contamination, insufficient lubrication, contaminants in the exhaust and intake system and prolonged extreme load.
At Ivor Searle, the demand for remanufactured turbos is on the rise, not least because it is far more cost effective to buy a reman turbo than sourcing a brand-new OE unit. The saving can be as much as 40%.
Ivor Searle ensures that only the best ‘core’ units are used in the turbo remanufacturing process. These undergo a thorough thermal and chemical cleaning to remove 100% of contaminants. A final blasting treatment on the housings ensures the unit is returned to the same condition as new.  
Once fully clean, each component is inspected and measured for the correct tolerances. They need to be certified for re-use and if any don’t make the grade, they are discarded. Gaskets, bearings and seals are always replaced with brand new. The CHRA (Centre Housing Rotational Assembly), turbine shaft, turbine wheel and compressor wheel are replaced with a new OE specification unit, following which the unit undergoes a dynamic balancing test prior to final assembly.
Only when the unit meets Ivor Searle’s exacting standards is the final assembly of the compressor and turbine housings carried out and additional pre-running checks undertaken. This includes the setting and calibration of the actuators and flow test for optimal performance. Following the successful completion of each test the remanufactured turbo is signed off for packaging, which comes with the added benefit of a 2-year, unlimited mileage warranty.

Filed under: reman, remanufactured turbos, turbo, turbochargers, turbos, uk