Turbosmart Blow Off Valve For 2015 Mustang EcoBoost Adds Big Power

As enthusiasts we’re all looking for that one Holy Grail modification. The single mod that changes the game for our car and sets the stage for how we measure all future modifications. This is especially true when we’re dealing with a car that’s been significantly changed or with a new engine platform. Whether it’s a new engine, new chassis, or both, when there’s a big change to the Mustang, the book of what works gets rewritten for the new model.

Project 5-Liter-Eater, our 2015 Mustang EcoBoost, is a prime example of the above. We know there’s plenty of potential lurking within the 2.3-liter 4-banger, we just have to find ways to unlock it. One of the areas we’ve heard rumblings about since these cars hit the streets is the electronic blow off valve. Ford not only constructed this valve from plastic, but also went with an electronic computer control for its operation, rather than the traditional mechanical vacuum line. There are several issues with the OEM BOV, fortunately the team over at Turbosmart has recently released a solution for EcoBoost Mustang owners to remedy their blow off valve blues.

BOV Blues

Side by side you can see the stock plastic BOV internals (left) and the Turbosmart Kompact BOV billet construction and higher quality internals. The stock BOV is so light we can easily push the piston in with a finger.

The OEM computer is adaptive, even when tuned, it may still want to go back to the original parameters. Controlling boost pressure through the factory BOV is one way to do that. -Marty Staggs, Turbosmart

We know the stock blow off valve bleeds boost, restricting performance. Ford has a number of reasons for using this BOV as there are emissions considerations, fuel economy, and possibly engine longevity to consider. This electronic control is part of what caused some peaks and valleys in our early dyno results. While our SCT tune has helped out tremendously with smoothing this out and making more power, the interference from the BOV is causing some other issues as well. As Turbosmart’s Marty Staggs points out, “The OEM computer is adaptive so everything you throw at this engine, even when tuned, may still want to go back to the original parameters. Controlling boost pressure through the factory BOV is one way to counter that.”

We also have concerns about the plastic construction of the OEM BOV. We wonder just how much boost this component can withstand before we literally blow it apart. The valve was likely made from plastic to save money and weight on the car. This valve is so weak, we can actuate it with the press of a pinky finger when removed from the charge pipe, leaving us to wonder just how much boost is being left on the table. That being said, with us already seeing 25 psi on the factory boost gauge we’re pretty sure the OEM design isn’t robust enough for our intentions.

Turbosmart includes everything needed to perform the BOV install pictured left. Center: This billet aluminum block is the key to making the mechanical BOV work. Since the system needs a vacuum signal to operate, this billet block provides a way to obtain that by installing in the MAP sensor port. Right:There's no computer update necessary thanks to a resistor that connects to the OEM harness in place of the connection to the stock blow off valve.


Turbosmart has been making blow off valve upgrades for direct OEM replacement, performance oriented models for aftermarket turbo systems, and more aggressive upgrades for several years.

For our EcoBoost, the Kompact blow off valve, part number TS-0203-1081 , is a direct replacement for the OEM valve although some minor modification is required (more on that in a minute). The Kompact BOV is constructed from billet aluminum, making it more robust than the OEM BOV. It is mechanically actuated via a vacuum line, like the traditional BOVs.

The Kompact BOV is also what’s known as a 50-percent or dual port valve. The stock BOV vents all of the boost back to the air inlet, whereas the Kompact vents 50-percent of that boost back into atmosphere giving the satisfying swoosh sound commonly associated with high output turbo engines. “Not only does this valve give enthusiasts the sound they’re looking for, it also will grow with the application allowing owners to make use of this valve in applications making up to 500 hp,” says Staggs.

Left: The MAP sensor is located on the intake manifold and secured with a single screw. Right: After removing the MAP sensor, the billet block is inserted. We threaded in the supplied nipple for our blow off valve vacuum line, and then installed the MAP sensor in the sensor port on the block.


The BOV is located on the hot side of the charge pipe, and is secured with three Allen-head bolts. These bolts will be reused to install the new Turbosmart Kompact BOV.

Because the Kompact BOV is a direct fit in terms of OEM replacement, the install will take most enthusiasts 30 minutes or less to complete. Turbosmart provides a resistor that connects to the factory BOV harness. This resistor sends the proper signal back to the ECM, leaving it none the wiser that the electronic BOV has been replaced. “We designed this part so that most typical enthusiasts can replace it in their garage in under an hour, and there’s no special tuning or adjustments required -just bolt it on and go” says Staggs.

Also included with the Kompact BOV is a vacuum line and a billet aluminum adapter. This adapter goes into the intake manifold at the MAP sensor port, allowing the MAP sensor to plug into the new port. The adapter has two threaded NPT ports, and a nipple is included for the supplied vacuum hose, as well as a plug for the second port which could be fitted to a boost gauge, data logger, or other device that needs a vacuum source.

Left: The plastic BOV next to the turbosmart BOV. Center: The new BOV is put into position and secured using the stock screws. Right: We connected the supplied vacuum line to the BOV and the block on the intake manifold, routing the vacuum line to follow the air intake.

The final step was to install the Turbosmart resistor onto the stock harness. This prevents a check engine light from being tripped, and also means we don’t have to reprogram the computer. Staggs says the first batch of BOVs received a line-tap style connector, but they are working on a direct connector.

Dyno Testing

We bolted on the Turbosmart Kompact valve in about 15 minutes with the car strapped to the Dyno at London Chassis Dyno (LCD). We previously baselined the car at 291.8 hp and 339.9 lb-ft of torque with our only modification currently on the car being a SCT 93 octane tune that was included with our X4.

Spinning the rollers at LCD, we did a double take as LCD owner Chad Epperson shouted the numbers to us as the dyno coasted down. Our car’s boost gauge was reading 26-27 psi, and given what Epperson was yelling, we decided an immediate second pull was in order.

Nearly 300 hp at the tires, and 384.2 lb-ft of torque after installing the Turbosmart Kompact BOV.

With the car pulling strong on the dyno again, our second test was completed, and the results were confirmed. We had only gained 7.3 hp at the wheels, however the real results were showing up in the torque, 44.3 lb-ft more to the rear tires, giving us a total of 384.2 lb-ft of torque at the rear tires, and 299.1 hp. Both dyno pulls had been within 0.1 hp and 0.1 lb-ft of each other, and the dyno was recently calibrated. Furthermore, the temperature was in the high 50s outside, our IAT was 63-degrees at the air intake, and the dyno weather correction factor was 1.006, making our conditions ideal for testing.

Peak power seldom tells the whole story, and we’re finding that’s very true with our Mustang EcoBoost. Comparing our two dyno graphs, we can see that the blow off valve made more horsepower and torque throughout the RPM band of our test window, which began at 2,500 rpm and ended at 5,800 rpm. Using the dyno software we can see that the engine made an average of 293.1 lb-ft for the entire pull with a tune alone, while it made an average of 318.2 lb-ft after swapping the BOV. Horsepower averages were also improved as our Mustang produced an average of 257.1 hp on tune alone, and produced a 270.2 hp average after swapping the BOV; for an average gain under the curve of 13.1 hp and 25.1 lb-ft.

Our previous run with the SCT tune (included tune not custom) compared to this run with only the addition of the Turbosmart Kompact BOV.

Since the Kompact BOV is mechanically controlled, instead of electronically, it allows the turbo to build boost more rapidly, getting the turbo to high boost pressure fast and allowing it to stay there.

Going even deeper and looking at the graphs, you can see at some points we’re making just under 30 more horsepower in the lower RPM range over the stock BOV. That is power where it counts, and where most of us will spend time driving.

We now have torque that is beating what we’ve tested a stock Mustang GT at (369.7 lb-ft). With only two modifications to our EcoBoost, it also exceeds what many modified Mustang GTs are seeing with a tune and some similarly priced bolt-on parts.

Staggs explains the gains like this. “Since the Kompact BOV is mechanically controlled, instead of electronically, it allows the turbo to build boost more rapidly, getting the turbo to high boost pressure fast and allowing it to stay there.” According to Staggs this lets the engine make more horsepower and much higher torque since there’s more boost coming in sooner and staying there until you lift or reach the engine’s peak power -we’re seeing more of the engine’s true potential.

With V8 level torque numbers now coming out of our project car, we’re one step closer to it fully earning the name 5-Liter-Eater. Our Turbosmart Kompact BOV will undoubtedly help us as we continue to modify the car, and make more changes.

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About the author

Don Creason

Don Creason is an automotive journalist with passions that lie from everything classic, all the way to modern muscle. Experienced tech writer, and all around car aficionado, Don's love for both cars and writing makes him the perfect addition to the Power Automedia team of experts.
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