Mazda’s Dynamic Pressure Turbo – A Closer Look

There has been a lot of buzz about the new(ish) turbocharged SkyActiv-G 2.5L first found in the Mazda CX-9 and now in the Mazda 6.  Along with all this buzz, there are a lot of unknowns as well. Here at CorkSport, we’ve taken the step to try and address some of these unknowns.  What is Mazda’s “Dynamic Pressure Turbo” and how does it work? There have been diagrams bouncing around on the internet, but no close-up view of the turbocharger itself.  That’s about to change.

If you haven’t already read Daniel’s first installment, “Mazda Dynamic PressureTurbo an Introduction.” You wouldn’t want to miss out on the extra information before reading on.

The turbocharger found in the 2.5T equipped CX-9 and 6 is quite complex in design.  There are many aspects to the OE turbocharger we could discuss, but today we are going to focus solely on the dynamic pressure system and turbine housing.  

If you are reading this, then you’ve probably already seen various diagrams depicting how the dynamic pressure system works and showing Mazda’s clever 3-2-1 exhaust port design.  If you haven’t, check it out below.  Image credit to Car And Driver Magazine for the fantastic diagram.  

Mazda’s 3-2-1 exhaust port design takes full advantage of the engine cylinder firing order.  The advantage is improved exhaust gas scavenging for the adjacent cylinder (more or less the cylinder that just fired helps pull the exhaust gases out of the next cylinder that is about to fire).  Ok moving on; this is great, but how does the dynamic pressure system come into the mix?

Shown here are the turbocharger assembly and the dynamic pressure valve assembled as one unit (the first two images also showed the fully assembled setup).  The three ports are clearly visible along with the “vane” that passes through the three ports. This vane rotates depending on engine RPM to control the exhaust gas velocity entering the turbine housing.  The vane itself is controlled by the larger blue colored actuator.

Now let’s take an even closer look.  The vane does not open until approximately 1600rpm, but the engine could not run of no exhaust gas can flow out of the engine.  To resolve this Mazda has designed the dynamic pressure system with two exhaust gas paths.  Looking at the above image you can see a small opening just above the vane. This is the sub-1600rpm exhaust gas path.  

By reducing the cross-sectional area of the exhaust gas path, the exhaust is forced to accelerate through the dynamic pressure system and into the turbine wheel.  This effectively reduces turbo lag, improving the vehicle’s response at low engine RPM. Once the engine revs past 1600rpm the vane opens, allowing the larger path to be used.   

Here we show the turbocharger assembly (right) and the dynamic pressure valve assembly (left) separated.  Looking at the dynamic pressure valve assembly, you can now more clearly see the three small paths above the larger path with the vane inside.  Then look at the turbocharger assembly and you will see the small upper path and the larger lower path.

The fact that these two assemblies are separate systems is great news for the enthusiast.  The development of a performance turbocharger will be much more feasible and the dynamic pressure valve can be retained with the performance turbocharger.  One more detail to point out.

Mazda put a lot of thought into the design of the wastegate port; let me show you why.  First, looking at the inlet of the turbine housing you can see a small vertical wall in the large path.  This wall creates a completely separate path to the wastegate port which is very unusual on an OE turbocharger. Combine this design with a very large wastegate port and you get a design that can “waste” or divert an excessive amount of exhaust gas.

This tells us the SkyActiv-G 2.5L engine is creating a lot of (currently) unused exhaust gas energy.  Again this supports the feasibility of a performance turbocharger suiting Mazda’s new turbo engine quite well.  

Great things are on the horizon for the 6, now if only Mazda would put this engine in the 3 paired with a 6-speed manual transmission.  Oh, one can dream.

-Barett @ CS

CorkSport and Mazda Events

I absolutely love it when the fantastic humans at Corksport approach me to blog it up for them.  So let’s dive right in, no time to waste.

August is kind of a sad month if you look at a calendar.  No real holidays to speak of, it’s hot and miserable across the entire United States, and with the exception of Vigil of Assumption Day(whatever that is), August is kind of boring.  But, look no further than the CorkSport’s Dyno Day, Show & Shine and Drag Racing on August 25th!!! It’s almost like Christmas in August. Free stuff, raffles, food and drink but most importantly, great people.  Be sure to let them know if you are coming on their EVENT PAGE!

Oh, you forgot who I am.  Well, I put on one of the craziest meets for us Mazda junkies.  Mazda Takeover, yeah, I’m that guy that annoys you on the Facebook groups reminding you to come and have a weekend of a lifetime.  You might be wondering what that has to do with a Corksport Dyno day? I will gladly tell you.

Corksport has gotten behind Mazdaspeed Idaho’s little shindig in a big way.   You see, the good folks over at CS year after year make the trek, a pilgrimage if you will to Idaho for Takeover weekend.  It’s only right that we return the favor! As soon as CorkSport announced their dyno day event, posts from Mazdaspeed Idaho members flooded our local page with questions, ideas, plans and straight up commitment to making the trip to CS in August.

I might be a little biased about the Mazdaspeed Idaho group being the best group of people ever, and they are. The cars in Mazdaspeed Idaho may not be showpiece material, nor are they the fastest on the planet, but us members love our Mazda’s as if they were show cars or all out HP cars.  

Hell, one member sold his Gen 1 speed and within a year picked up a Gen 2 just because he loved the community more than the other community options given his other cars, so that’s saying something about not only the Mazda brand, his local Mazda community, but it says a lot about Corksport as well.  Having owned his new Mazdaspeed 3 less than a week, he was the first to commit to wanting to go with the group that forms to the  CorkSport dyno day! He is beyond excited to meet the people and see the building where his car part dreams come to fruition.

As of right now, I’m guessing Idaho will roll into Vancouver with 10-20 Mazda’s, which is a huge improvement over the 4 we took last year.  I’m really looking forward to this event, mostly because it gives the Western Washington Mazdaspeed and Nator OR communities another group to bond with.  Which is what Mazda should be about, forming and building a strong, unbreakable community that forges lifelong friendships through one shared passion.  I really hope some California members make the trip as well. It’s always refreshing to see other Mazda’s, other ideas, and other builds.

I didn’t ask my boss, I told him I won’t be available because I have race car stuff to do with my race car family.  And you all should tell your boss the exact same thing, and show up for one hell of a weekend out at Corksport.

See you @ CorkSport August 25th!

 

Keith Eggert

 

3 Turbos and a Supercharger for Mazda

A year ago we were all complaining at Mazda saying “where is the forced induction?” and it looks like Mazda was listening.

First up is the Mazda 6 turbo which Mazda has priced to sell as you can get into a GT Mazda 6 turbo for $29200.  Granted there is no manual gearbox but I can say first hand they are fun to drive and the torque from the boost is really addictive.  I find it hard to not want to screw with people in the 6 since it has no visible exterior queues that it has a turbo. I will say we have already been tweaking on the car and found that it does respond well to modifications.

Second up is the SkyactivX which Mazda says will be available later this year.  This engine is supercharged to allow it to be an HCCI engine, aka compression gas motor.  The forced induction setup is pretty tricky and the initial look I have done with it I get we can crank it up a bit more to improve the efficiency of the intercooler to give it more heat capacity to allow you to use the boost longer in the car for high performance driving.  Until it shows up we won’t know for sure but we are looking forward to trying it out.

Third is the Mazda 6 diesel which uses 2 turbos.  Mazda tried to release the 6 in the past but when they couldn’t match what VW was doing they declined to just “Send It” as the car didn’t perform as they needed it to and still hit the emissions targets without urea injection.  Later we all found out VW was a cheating bastard which kept us from having the Skyactiv diesel engine here to crank up the boost on. About every publication in the planet has posted up about the 2018 Mazda 6 diesel being seen in the EPA parking lot for testing along with a pile of other diesel models.  This is a good sign if Mazda says it will pass the US emissions and handed one over to the EPA we can expect it and soon.

I am going out on a limb here and saying that besides the announced Mazda 3 Skyactiv we are going to get something fun in the new Mazda 3 ~ a year after the initial release.  If you are reading this Mazda, please give us a Mazda 3 GT with a turbo motor.

 

-Derrick

The Top Five Things YOU NEED to Know Before You Buy a Mazdaspeed

The Mazdaspeed 3 and Mazdaspeed 6 are some of the most unique, exhilarating, and frustrating sport-compacts out on the market today. If you’re reading this, then it’s because you are in the market for a Mazdaspeed or you have one already and are looking for a good laugh. For you are newbies to the Mazdaspeed game…listen up; we’ve got some words of advice and things to check as you are shopping around.  

First, let’s start with the top two must do inspections when shopping around.  

One: Has the car been modified?  If so then what parts are on the car and has it been properly tuned for the parts.  This also means the car should have some type of tuning tool such as the Cobb Accessport or Versatune Tuning Solution.  

Two: You MUST check the engine compression!  This is the easiest way to get the overall health of the engine and know if you are getting a solid Mazdaspeed to start your journey with or a Speed on it’s last leg.  Most auto parts stores can loan an engine compression tool for a small deposit then only basic hand tools are need to do the test.

Now let’s get the top five things you should know before buying a Mazdaspeed.  

Maintenance is KEY, but that’s really not special to just the Mazdaspeed, all performance engines/vehicles, especially turbocharged and direct injected ones, will require a higher level of care and cost when it comes to routine maintenance.  This means better quality oils, oil filters, premium grade fuel, and an acute awareness of the vehicle itself; if you’re ready for that than let’s move on.

Next up are the three “not if it happens, but when it happens” about the Mazdaspeed engine.  

The variable valve timing (aka VVT) system is prone to failure from the factory so this should be on your radar for an upcoming replacement.  You may get lucky and find a car that has had the VVT system replaced, but I wouldn’t plan out. It’s a medium difficulty project that can be done over a weekend and cost around $400 in parts. If you are not mechanically inclined, it is going to be expensive to have a shop perform the work.

The poor little OEM K04 turbocharger just never had a chance on the 2.3L DISI MZR engine!  Sadly, the OEM turbocharger is an honest to gosh ticking time bomb. The OE turbo will fail at some point and need to be replaced.  Fortunately there are a lot of exciting options on the market to take you and your Speed to the next level. For example check out the CorkSport Drop-In Turbocharger.  It bolt’s in like OE, but packs a punch in the performance department, supporting up to 450 horsepower. Note: Updating your turbo requires tuning.

Lastly for the Mazdaspeed quirks; the high pressure fuel pump internals (HPFP).  Like the name states, these parts provide an upgrade for the camshaft driven high pressure fuel pump so your engine does not experience fuel starvation during wide open throttle (WOT). These are absolutely required if you plan to make in modifications to the engine that would increase power and for any performance tuning.  Honestly, we recommend the HPFP internals for 100% stock Mazdaspeed as well because the drop in fuel pressure is even an issue for stock cars.

So you read all that and you’re probably thinking “damn I’m not buying a Speed, sounds like a total PITA”.  Well hold on, I didn’t mean to shine a poor light on the Mazdaspeed platform, but it does have its quirks to overcome.  However, after those few concerns are taken care of the platform is A LOT of fun and probably one of the best bang-for-the-buck sport compacts available.  Just a few thousand dollars can net you a Mazdaspeed around 350whp and more smiles than you’ll know what to do with.

The last thing you need to know before you buy a Mazdaspeed…jump straight in and don’t look back because you won’t regret it.  From the late nights in the garage installing the latest performance parts, to the early mornings at the car show, and then the midnight highway pulls making V8s owners second guess their purchase. The community, the journey of building YOUR car, and of course the car itself is so awesome.  

-Barett

Mazda Hybrid?

Mazda 3 Hybrid??

I was looking at the Mazda Japan website the other day and noticed that there is now an option for a Mazda 3 gasoline hybrid listed.  Years ago Mazda announced that they were working with Toyota hybrid tech and this looks to be the result.

There isn’t a lot of detail listed with the description of the model so I decided to do a comparison of the Mazda 3 against the current model year of Prius as the 2 vehicles are most likely running the same hybrid drive setup.

Price:  With the current exchange rate the Mazda 3 hybrid is ~$23500 which is almost the same as the current Prius price shown of $23475.  You get more car with the Mazda 3 for the price and a car which handles like a car should. Win here for the Mazda.

Styling:  Right away I can tell you I prefer the styling of the Mazda 3 over the Batmobile inspired Prius which looks like someone used a late 50s Chevy and applied the styling.  

Fuel Economy: This one is the funniest thing and really shows where Mazda’s engine tech is beating all of the other manufacturers.  Toyota Prius 1.8 hybrid gets 56mpg in combined city/highway. Mazda 3 2.0 hybrid gets 63mpg. Caveat on this data, I took the economy listed on the Japanese page and converted it to MPG so they are not based on the same drive cycles.

If your Japanese skills are on point check out the landing page for the 2018 Mazda 3 Hybrid yourself here.  Just a note google translate won’t let you convert the page due to SSL from Mazda’s page.

So you are asking why do I care about a hybrid and in all honesty I probably won’t own one myself but if it does happen I prefer to at least own one that handles worth a crap and has decent driving dynamics.  I can’t say I have ever heard anyone raving about how good the chassis is in a Prius.

 

-Derrick