Dawes Devices Manual Boost Controller Review Part 1

A Review of what our team sees at the Best Manual Boost Controller, the Dawes Devices MK II Hybrid.

Dawes Hybrid

Dawes Devices Mark II Hybrid Boost Controller

OK, we’ve done something a bit unusual with our reviews.  We are reviewing our favorite electronic boost controller (below) and the best manual boost controller, first.  That kinda takes some of the surprise out of it, but here’s why we are doing it that way:  We don’t want you to spend your hard-earned money on something, only to find out later that there is something better.  So, we are putting the biggest bang-for-the-buck items first.  Keep reading our reviews though!  You may find something that fits YOU better, in an upcoming review.  Alrighty, here we go:

In the interest of full disclosure, we are acquainted with Darren Dawes over at Dawes-Devices.com and www.3 Bar Racing.com.  We first read about his products in Sport Compact Car (this is linked to the article) and then one of our local club members bought his air/fuel meter and the old “MK I” boost controller.  Darren is one of those guys that has been doing this for 15+ years and stands behind his products.  The design has evolved over time, but still uses the same internal components, for consistent performance.  Since we’ve talked to Darren on a number of ocassions, we got him on Skype, to tell us his story.  To hear Darren tell it, the original g-valve boost controller was the invention of Gus Mahon, who at one time had the fastest mini-van in the country.  We asked Darren to tell the rest of the story, for this review:

“At the time, I was driving an 88 Dodge Daytona T1.  I used a “g-valve boost controller” which was a design that Gus Mahon came up with, using off the shelf parts.  Gus was a great source of information to the Turbo Dodge crowd and a very generous guy.  Unfortunately, he was killed a few years later, in a motorcyle accident.  Anyway, his initial design used a plastic barb pushed into the end of the g-valve and that was how I built mine.  Then, I suggested that we could improve it by threading the barb into the valve, in addition to the epoxy that we were already using.  Gus didn’t think it was necessary and looking at it 15 years later, I’d have to agree.  I’ll get back to this in a bit.”

“At the time, everyone was tuning Air/Fuel ratios using  Cyberdyne or Autometer gauges.  Really, you weren’t tuning, just making sure you had enough fuel to support the boost.  So you were running rich.  Anyway, I had trouble reading the meter on the fly and so, I had my 6 year old counting LED segments while I hit 15 psi in third gear.  Not the best approach (by the way, he survived and is currently in college.)  So, I made my own A/F meter, using the same chip, but different electronic components and display.  You can still see them if you go to the internet archive wayback machine and look up www.dawesdevices.com.  Unfortunately, a Japanese company caught me sleeping and stole the domain.  So now I am at www.dawes-devices.com and www.3barracing.com.  My meters were made with discrete LEDs that would let you tune by color, without looking directly at the display.  In fact, they caused retina burns if you did (laughing).  Those were some f’ing bright LEDs and I ended up adding a dimmer circuit.  The meters could also be tuned internally, to match specific applications.  Sold a lot to the DSM crowd.  So, I put one in the Daytona and showed some of the guys in the local Shelby Dodge Club.  More than a few people asked if I could build one for them.  I then thought, “hey, I can make a business out of this, to support my car habit”.  I figured that if I could get one of my A/F meters talked up on the Shelby Dodge Mailing List, then I could sell more, so I approached Gus.  I offered to make him one in his custom tune (he was running BIG boost), to try out.  He liked it and posted it on the mailing list, which launched the business.  Around this time, people started referring to them as Dawes Devices.  Oh yeah, you were wondering about boost controllers……”

“So, I went back to Gus and said, hey, do you mind if I sell your G-valves along side the A/F meters, since a lot of people don’t want to build their own.  He said, “go for it”.  Well, I couldn’t in good conscience sell something with a plastic barb that could melt, so I started fitting a brass barb and soldering it in place.  That made it kind of a bitch to drill the breather hole that is really the key to these g-valves working correctly.  Gus came back with an elbow that could be pressed into the end, eliminating the soldering, and showing his superior genius.  We stuck with that design for awhile and later added a special ceramic ball, replacing the stainless steel one.  I called this the Hybrid and developed it because my 1.8T Jetta’s boost would oscillate with the steel ball controller.  That seems to happen if you run a very big or in this case, undersized, turbo.  The Hybrid reacted faster and stabilized the boost.  By the way, we were first with the ceramic ball innovation.  I made the mistake of talking about it at SEMA and then everyone copied it (laughing).  That story would take up another 10 min, so let’s skip it.  OK.  After that, we started polishing the internal ball seat and have now developed our own boost controller from scratch.  I’m making air quotes over “scratch” because the internal dimensions are exactly the same as the g-valve.  But, we machined the input barb into the valve itself, reducing the weight and size and reducing the “fill” dimensions.  This is called, “the Mark II Hybrid Boost Controller”.  It is the fastest responding controller, due to a number of internal specs, that I don’t want to give away.  So, although its heritage can be traced to the original G-valve design, it is really a different beast and trumps the ol’ g-valve performance, in every way. ”

OK Darren, thanks for that rambling story 😉  We are kidding, Darren!

Now that you have the history, we’ll close out by talking about ball/spring boost controllers in general.  The next post will address the Dawes Devices, specifically.

When you look at the different types of boost controllers available, the manual style fall into two general categories.  Bleed, or ball and spring, aka “check valve”.  A bleed is what the DIY boost controller builder usually starts with.  They are cheap and easy (see earlier posts) and do raise the boost.  Unfortunately, they are not very quick to respond.  That is because at the wastegate opening event, they are letting boost pressure out at the same time they are trying to open the wastegate.  This causes overboost, or a situation where the boost spikes above a set point, then settles back down.  Also, they allow pressure to cause wastegate creep BEFORE you actually want the wastegate to open.  In other words, it starts opening the wastegate early, which slows the boost rise time.  All of this is similar to the factory electronics, except that you can get a higher boost setting, overall.  Performance is, meh……

With a ball and spring boost controller, the pressure builds behind the valve until the threshold is reached and then it opens all at once.  This allows for a VERY fast boost rise time, as the wastegate does not even begin to move until the boost peak is reached.  In fact, half of what you think of as turbo lag is the result of the crappy factory ECU control.  After all, if horsepower sells cars, they only need to worry about peak numbers, not the boost/torque curve).  Of course, YOU know that it is torque that wins races!  The quick boost rise of the ball/spring manual boost controller gives you more area under the curve, even if the boost peak is the same.  In fact, you can use it WITH the factory controls, to improve response at lower boost levels, then let the factory ECU control the peak.  Drop Darren a note (d@3barracing.com) and he’ll talk you to death about it (kidding again!).

The Dawes Devices MK II Hybrid Boost Controller

The Dawes Devices MK II Hybrid Boost Controller

At the opposite end of the boost curve, the ball/spring controller snaps the wastegate open at the last moment, dumping boost immediately to reduce spiking.   Some designs work better than others and they definitely are not all the same.  The reason for this is that you have to keep the fill volume (amount of space between the boost controller input and the wastegate actuator) small, to reduce spiking.  You also need a breather hole, or once the space is filled, the boost becomes trapped and the boost drops way below the threshold.  The result is boost oscillation.  It is the ratio of this breather hole to the fill volume that Darren says is critical.  Considering that some of those Ebay/Amazon pipe-fitting boost controllers (link here) don’t even have a breather hole, there is a good point for buying a Dawes Devices (also, by the way, available on Amazon, here).  Darren also had something to say about the DIY models people are selling on Ebay and Amazon:  “Look, if you want, I’ll show people how to properly build a DIY g-valve boost controller for less than they can get those pieces of crap.  It costs less than those POS pipe fittings they sell on Ebay.  The problem with those is that there is no proper seating of the spring, or seat for the ball.  Also, there is a lot of space around the spring, which can let it move out of position.  Everyone thinks they are great, because when they work the performance is better than their bleed valve.  It is, provided the spring doesn’t jam and overboost you.  Then you are f’d.  I guess they are at least pretty f’ing heavy and some people associate that with quality.  But, the g-valve works better and of course, our Hybrid is the best.  Sorry if that sounds conceited. ”

Well, when you have the best, you need to talk about it.  So no, it doesn’t sound conceited to us!  Watch for Part 2 of this series, where we really dig into the Dawes Device.




3 thoughts on “Dawes Devices Manual Boost Controller Review Part 1

  • Really Really Looking forward to the 2nd Part of this Review. My only concern with in-line “check valve” type boost controllers is in the event that they fail (not saying this one is prone to failure) you have potential overboost on your hands. Still really really interested.

    • Thanks for reading! Yeah, the ball “sticking” on the seat used to be an issue on the 80s cars, if the crankcase got gummy. Some of the cheaper boost controllers use regular steel balls, instead of stainless or ceramic, so watch for that. I usually clean mine out once a year, with brake cleaner. Never heard of anyone having an issue, but I can understand your concern. I DID have a solenoid stick open once, on an electronic BC. That was fun, for a couple secs….


  • Well, I’m just waiting anxiously for Part II of the review. A good PM program will eliminate any potential malfunction, I definitely agree.


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