Integrated Features Why buy an external BOV? Why buy a boost control solenoid? In addition to buying these items separately and spending more money in the process, the user has needed to mount these parts which gives hassle and headache. The BorgWarner EFR turbos have these parts as integrated features. The CRV (compressor recirculation valve) vents boost quickly and efficiently when the throttle closes, and it is internally-recirculated to keep turbo speed high during the shift and to keep engine control systems (especially those with a MAF sensor) satisfied. The boost control solenoid valve (BCSV) is a convenience feature. Integrating the mounting of these valves onto the compressor cover is a trend we observed from the OE passcar side of the business. As such, you can trust that these are proven solutions that have worked for millions of customers for many years. For those that prefer an external blow-off valve, that’s fine too. We will sell a block-off plate that disables the internal CRV.

CRV We have had great success with integrating the compressor recirculation valve (CRV) into the compressor cover for quite a few years on OE gasoline engine applications. The major benefits are of course the underhood packaging space that is freed up by not having an external device and the cost savings from integrating it into the turbo assembly. Recirculating the flow back into the compressor inlet helps keep MAF engine management systems “happy” and also helps keep turbo speeds high during the shift. The only downside of this feature is the fact that it makes the compressor housing about 1” longer in axial length. For the users that opt not to use the internal valve, we offer a disabling cover plate. This cover plate installs in place of the plastic cover and uses the original diaphragm to seal the port. As a service replacement item, spare plastic cover plates (with hose nipple) are sold as part of a CRV service kit. An external valve (BOV) can be used in place of, or in addition to, the BorgWarner CRV if desired.



BCSV Integrating the boost control solenoid valve (BCSV) onto the compressor cover is another feature that has been widely used for a few years on OE applications. Any user of electronic boost control will need a solenoid valve. We use the highest quality part with OE-level robustness for this application. It is a value to the customer to buy it as part of the assembly so that they save money overall as well as have a tidy mounting solution. Loose BCSV’s will also be sold as a service item in case the original one is damaged. The solenoid valve uses an “injector type” connector, and the BSCV connector itself is marked with a polarity symbol. There are two connections, +12V and ground. The valve is pulsewidth controlled and the wave frequency should be less than or equal to 32 Hz. The resistance of the BCSV coil is 23 Ohms.

Speed Sensor Turbo speed sensors are of course not new technology, but the installation procedure has often (or perhaps always) been difficult for the end user. Competing products require the customer to remove their compressor cover and take it to a machinist. This machinist then has to set up the cover at a compound angle to precisely drill the speed sensor bore while carefully hitting the contour area of the wheel bore and at the right angle

The BorgWarner EFR solution provides this precision machining already done to the compressor cover. The hole stops short of protruding into the compressor wheel bore. If a user decides to buy a speed sensor as an upgrade accessory, they can remove the compressor cover and extend the hole the rest of the way through to the wheel bore using a hand drill. A 1/4” drill bit is used and the length required to be drilled is quite short. This hole allows the tip of the sensor to come flush with the contour surface. The hole does not have to be precise, as no sealing takes place in the small hole that the user just created. The hole should be de-burred where it pierces into the wheel bore. The goal is to make sure that there are no sharp edges remaining in the wheel bore that the compressor can become snagged on.