Engineered for Racing (EFR)
Over the past two years, BorgWarner Turbo Systems has invested heavily in new material research and other pioneering technologies to take a clean sheet approach to what a high performance turbocharger is and should be. With no OEM restrictions, a development team came up with their list of “wouldn’t it be cool if” and started work. The results are the all new EFR Series (Engineered For Racing) of turbochargers and there is an impressive list of salient features which we would like to share with you.
Pulling from BorgWarner’s extensive OEM knowledge, all EFR compressor covers have integrated CRV (compressor recirculation valve) ports and mounting. The CRV will allow users who need a blow off valve to simply install a valve and a boost line. No longer does the installer need to buy an entire blow off valve assembly, cut and weld it into the system. That not only takes up precious room but adds a lot of expense.
Creating the boost is a forged aluminium, fully milled compressor wheel. The EFR line will be comprised of 6 billet compressor wheels ranging from 62mm to 91mm OD. All of the wheels will feature Extended Tip Technology to increase boost pressure and flow capabilities.
Getting the compressor wheel turning is the job of the turbine wheel. Probably the most exciting new technology developed is the titanium-aluminide (Gamma-Ti or Ti-Al) turbine wheels. Gamma-Ti is extremely difficult to cast and once cast, the material is rock hard. So, new casting and machining processes had to be developed to successfully bring this technology to market in a cost effective package. The Gamma-Ti turbine wheels are roughly half the weight of the typical inconel wheel. This reduction of weight results in improved response, higher boost levels at lower rpms and higher wheel speeds overall can be achieved.
Keeping up with the thrust load and new capabilities of the Gamma-Ti turbine wheel and forged milled compressor wheels, is ball bearing technology to keep everything spinning smoothly. A dual ceramic ball bearing system was designed for the EFR line. While the gains over traditional journal bearing technology are marginal at high shaft speeds, there is a noticeable (3 to 5%) improvement in efficiency at low shaft speeds. This is most noticeable for street machines where driving conditions regulate engine rpm and load.
In addition to the dual ceramic ball bearing system, a new water cooled bearing housing was created. While the addition of water is optional, it will help to combat heat soak. The housing has one inlet and outlet on each side making for easy installation.
The turbine housing connects to the bearing housing and directs the exhaust to the turbine wheel. There have been significant improvements made in the design as well. One major issue that the designers wanted to address is cracks. High exhaust gas temperatures regularly crack cast iron housings. So the EFR line uses cast stainless steel which is extremely crack-resistant. The new housings will range in size from a T25 .64 A/R to a T4 1.05 A/R.
Many of the turbine housings will, also, feature internal wastegate designed specifically for the higher flow of gasoline engines. There are two sizes offered for the internal wastegate. The 36mm and 42mm valve are swivel-valve gates instead of poppet valves. This means there is no stem diameter losses resulting in additional flow. The wastegate valve, shaft, bushing and lever are, also, investment cast. The valve heads have an anti-rotation tab to prevent vibration-inducing skidding wear and the lever arms were designed to maximize valve motion yielding 35 to 40 degrees of movement.
We are pleased to advise that this exciting new range of both EFR Series (gasoline performance) and Airwerks Series (diesel performance) productsturbochargers are now available to order.