Time to return to the Dawes Devices MKII Hybrid Boost Controller and see how it did with our test vehicle, a 2012 Subaru WRX STI
As I mentioned in the past, we have used Dawes Devices products many times over the years, for everything from a Shelby Dodge, to an SRT-4 Neon, to a Subaru WRX. Each time, the experience has been positive, with more area under the boost curve and quicker throttle response. It is clear from our experience with the electronic factory boost control solenoids, that they need to open the wastegate early, in order to prevent overshooting the target boost level. That makes them slower to achieve peak boost, the net result being a lazy boost curve and lost mid-range torque. To give you some real-world numbers, we were going to review the Dawes Devices MK Hybrid on a Mitsubishi EVO. However, it was taking too long to hook up with that guy and he was in the middle of re-calibrating his ECU to make use of the fatter boost curve. So, we found another guy with a stock 2012 WRX STI, to use as a guinea pig (thanks Jerry, and you ARE a pig!).
Darren Dawes supplied us with a length of hose for the install, shown in the picture below. If you need silicone hose, I’d suggest getting some from www.dawes-devices.com. This stuff has a 4mm id, but stretches to much larger and the wall thickness will hold over 60 psi. That should be good enough for most of you……
We were going to show an actual install video, but decided to focus on the results and the boost controller itself. Reason being, there are about 3000 install videos for a manual boost controller in a WRX out there and this is a “BOOST CONTROLLER REVIEW” site, so we don’t want to go off on a tangent. But, about those results:
In the graph at the top of the page, you can see the results of adding JUST the boost controller, to a WRX. Note that we recorded boost for various RPMs, using the digital output of the boost gauge. We then plotted this to make the curve, since we didn’t have access to the software needed to record to a graph (like on a dyno). You can see that the boost comes in earlier AND hits a higher level at that same RPM. We also bumped the maximum boost on the WRX STI up a couple psi, which is well within the capabilities of the factory ECU to fuel. As you know, boost without fuel equals heat….and detonation. However, the stock ECU programming on the WRX and WRX STI is mapped to provide a 20% + margin of safety. Why would that be? Well, with the crappy factory solenoid boost control, you often get boost spikes. They have to put in enough fuel to protect against detonation when those spikes occur. By improving the boost control and eliminating the spikes with the Dawes, we can safely exploit the margins for added power.
And the power is there…..everywhere. I would compare it to driving your turbo car on an 80 degree day (stock) to driving it on a sub-zero day (Dawes Device Installed). The mid range pull is AMAZING and the added boost at the upper end is definitely adding horsepower. We would guess a conservative 15-20hp, but it doesn’t really matter what the peak power is, as this is about mid-range pull. From a rolling start, the boost appears instantly. It’s like a switch (actually, a LOT like hitting the nitrous at low RPM….incidentally, not something we’d recommend). I’d say this is the best performance modification for the money (Net cost $50 on Amazon) and the best thing is that you can do it on a stock vehicle, or one that is heavily modded. It’s amazing how many cone filters and K&Ns we see out there that really add nothing to a turbocharged engine. Cold air induction can add something, but it costs more than double this mod and you are never really sure it is helping, unless you dyno it. With the Dawes manual boost controller, it’s night and day. There will be no doubt that it is working, dyno or no dyno!
OK, so back to the “boost controller review”. We thought it would be interesting to disassemble this Manual Boost Controller, to look at what’s inside and what separates it from the DIY boost controllers out there.
The Dawes Hybrid is made up of a ball (ceramic), spring (rate is a secret), adjustable knob/tip, lock nut, and body. The body is one piece of solid brass, to eliminate the possibility of leaking boost on the input end. Darren suggests opening the controller and flushing it out with brake cleaner, about every 50,000 miles.
Here you can see it assembled, with the locking nut loosened for adjustment. Once you get the peak boost you want, you lock it down to prevent any changing of the peak boost level.
The MKII Hybrid Manual Boost Controller has a polished seat, for better sealing. Darren says that elimination of burrs is key to reliable operation. Brass is chosen because it is soft enough for the ball to peen into a perfect seal, yet tough enough to handle turbo heat. Brass also has a natural lubricity that prevents the components from seizing and you can’t scratch the finish off of it (like anodized aluminum)
Darren tested various industrial ceramics to find what held up the best. He states that he has sourced the ball from a Canadian company with the best mix of mass, hardness, and longevity. He also states that some of the bigger companies that copied the ceramic ball are using an inferior Chinese sourced compound that tends to flake off. That means the ball will no longer seal and the boost controller loses performance.
A breather hole allows boost trapped between the ball and the wastegate to vent out, slowly, when the ball goes back on the seat. Without the right sized hole, you will shoot up to the boost level you want and then the boost will slowly roll off. This is because pressure gets trapped in the line and the wastgate stays open. Darren says it will “work” without the hole, IF you have a leaky homade boost controller. But, performance is inconsistent. This feature is one of the things that is missing from cheap Ebay controllers.
Note that you can buy the Dawes Devices MKII Hybrid from our Amazon link:
Dawes Devices MKII Hybrid Boost Controller
It does not cost you any more to buy it there, but we receive a small part of the sale, to help keep our site running. Or, you can buy it straight from Darren at www.dawes-devices.com
So if you are looking for a manual boost controller for your WRX, SRT-4, EVO, or even a turbodiesel, you can do worse (a LOT worse) than the Dawes Devices manual boost controller, the MKII Hybrid. If you don’t like it, Darren will take it back and refund your money. How can you go wrong?!
Thanks for reading!
Special Thanks to Jerry, for letting us pound on his car and then refusing to post his crappy iPhone pictures 😉