What is High Flowing?
High Flowing, the most commonly asked question in the turbocharger industry! People often get the perception that "high flowing" is putting a turbocharger on a test bench, to make it flow better, this is not the case.
What is High Flowing? High flowing a turbocharger involves fitting a larger compressor, or turbine wheel to a turbocharger to improve its physical flow capabilities. Take a VL Commodore turbo for instance, this will be stripped, cleaned, reconditioned, and at the same time, fitted with a compressor wheel that has a larger inducer, and exducer measurement. The fitment of the larger compressor wheel also means that the compressor housing will require machining to fit the larger wheel. As this wheel is now larger than factory, this would be classified as a "high flow" turbocharger, as the compressor wheel is "higher flowing" than the standard item. All of this process is done in house at GCG Turbochargers. High Flowing usually adds 1-2 days turnaround on top of a standard repair.
What is a Ball Bearing Highflow? Ball Bearing high flows are usually the biggest combination possible in the factory housings. This process is when we take a factory turbocharger, fit a Garrett Ball Bearing core, and machine both the turbine, and compressor housing to suit. This means the Garrett core is bigger on the exhaust, and compressor side of the turbo, which will give a considerable increase in power over just a compressor wheel upgrade. We commonly fit ball bearing cores to the twin turbo Soarer, Supra and RX7, as some customer's want to keep the factory twin turbo system but have the added power and reliability of the Ball Bearing core. Ball Bearing highflows do require modification of the oil and water lines, as the Garrett cores are completely different threads most of the time.
Are off the shelf ball bearing turbochargers High Flowed? Simple answer, no. They are an off the shelf combination that Garrett manufacture to a particular specification. If you were to take a ball bearing turbocharger, and fit a larger compressor or turbine wheel, then it would be classified as high flowed. The prime example of this would be GCG's custom GT3566R, which is an off the shelf GT3582R, high flowed using the 66mm T04Z Compressor Wheel.
What are the advantages of High Flowing? High flowing allows the factory housings to be retained, so the vehicle looks factory, but the internals are much bigger, and produce a lot more airflow than the factory turbo. It is also a direct bolt back onto the vehicle, with no further modifications required, which is great and does not bring unwanted attention in the engine bay. A prime example is GCG's GTS-T Highflow, where the turbocharger looks factory, takes factory oil and water lines, factory dump pipe, factory intake and intercooler piping, but is capable of pumping an awesome 250rwkw on 18psi of boost.
Can anyone high flow my turbo? GCG have a vast knowledge of compressor to turbine wheel combinations, and this knowledge allows us to pick the perfect combination every time. If the wrong compressor wheel is chosen, the turbocharger can surge violently, which can cause premature failure of the turbo, not to mention make the vehicle near impossible to tune. If the wrong turbine wheel is chosen, the turbocharger can become laggy, and make power too high in the rev range. There are also certain precise measurements and clearance factors that need to be taken into account, and there can also be very precise machining involved, such as machining the back plate, and back of the compressor wheel to make it fit into a turbocharger where it didn't look possible to begin with. GCG have all the experience, equipment, parts and knowledge to pick the best possible combination for your vehicle.