Put simply, Mazda's all-new Sky-G and Sky-D engine families, along with similarly new transmissions, form the building blocks of the company's future. And we've driven them. Well, early prototypes of them, anyway.
Here's some background. Sky-G (the G is for gasoline) and Sky-D (diesel) are a new series of all-aluminum direct-injected four-cylinder engines wholly conceived and developed by Mazda. These engines will, over time and in different guises, supplant the company's current entire powertrain lineup save for the rotary.
The first Sky-G we'll see in the US will be a 2.0-liter version, debuting in the facelifted 2012 Mazda 3. For the Mazda 6 and CX-7, Sky-G will be expanded to 2.5-liters. Another version of Sky-G with a lower deck height will displace 1.3- and later 1.5-liters for the Mazda 2. And in the coming years, a boosted Sky-G of some flavor will replace the V6 currently used in the CX-9. All of these engines will share a common bore to stroke ratio along with other key relationships in order to retain a fundamentally scalable combustion system. Only fine-tuning will be needed this way, shortening development cycles dramatically, say Mazda engineers.
In a novel twist of powertrain forethought, the Sky-D and Sky-G fundamentally share the same architecture and they are built on the same manufacturing line. This commonality will permit cross-pollination in upcoming variants. More on that later. Also, Sky-D will be covered in a follow-up post.
For now, hit the jump for a closer look at Sky-G including driving impressions.
Sky-G: 2.0-liters in 2012
In normally aspirated 2.0-liter form, Sky-G produces 158 horsepower at 6000 rpm and 151 lb-ft at 4000 rpm.
This is intended to a bread-and-butter engine, and although fuel economy is the engine's raison d'etre, the spread of torque available is said to be at the top of the 2.0-liter class. Its combination of efficiency and power is owed primarily to a stratospherically high 13:1 compression ratio.
Note that the figures above are for the US version, which will run without complaint on 87 octane -- other parts of the world get 14:1 compression which requires higher octane and produces 163 hp and 155 lb-ft while returning a tick better fuel economy.
Mazda is bullish on the high-compression normally aspirated approach in lieu of downsizing plus boosting as, the company says, it's equally fuel-efficient and more cost effective. Such a strategy means that knock abatement was a priority during development. As such, direct knock sensing has been integrated into the ignition coils, while a horny-looking tri-Y exhaust manifold -- together with VVT on both cams -- was said to be instrumental in preventing the crosstalk of hot exhaust gases between cylinders. A cooler cylinder is a more knock-resistant cylinder.
Friction reduction, too, was an area of intense focus. This resulted in roller finger followers in the valvetrain, a two-stage oil pump and myriad other details we weren't allowed to photograph. The high-pressure die-cast block is open-deck, and the rods and crankshaft are forged, saving some 13 pounds in the bottom end alone.
All-new transmissions include a 6-speed auto and a 6-speed manual, also lighter than the current gearboxes. Both transmissions will be produced in two flavors -- a 200 lb-ft (max) version and a high-torque variant that can handle up to 339 lb-ft. Key point: all gearboxes are interchangeable from Sky-D to Sky-G and vice versa. If you're thinking dirty thoughts, you're not alone.
Driving Sky-G
At a briefing in Berlin, Germany, we drove various development mules (TPVs or Technology Proveout Vehicles in Mazda-speak) of the next-generation Mazda 6 equipped with the 2.0-liter Sky-G coupled to the new gearboxes. These were the higher-compression ratio versions, not the US-spec ones.
Right away, the thing you notice is that this is not an engine that needs revs to deliver the goods. Torque is ample even at the low end of the tach, and it is delivered brightly all the way through the midrange and near the upper reaches.
In its current guise this is not intended to be a performance-car engine, but for everyday use it provides the right kind of motivation -- solid and linear thrust from low revs. The combination of direct injection and high compression provides sharp throttle response, too. It's the kind of engine that will serve Mazda's workaday applications quite well.
It could use a bit more personality like a more mellifluous intake note as today it sounds fairly prosaic. Final calibration and NVH work is still underway, though, so maybe there's a chance Mazda can fruitify the engine note. Yes, fruitify.
40 MPG On The Highway
Perhaps the best part about the engine is its frugality -- Mazda tells us that with the 14:1-compression 2.0 Sky-G, the next-gen Mazda 6 returns 40 mpg on the US highway cycle according to their simulations.
They also tell us that their simulations tend to err on the slightly conservative side.
--Jason Kavanagh, Engineering Editor
blueguydotcom says:
07:04 AM, 08/30/10
That'd be a miracle. The current mazda engines are horrendous - rough, poor mileage, no power, no torque. Just garbage engines matched to garbage gearing. Love their handling but man Mazda can't build an engine... maybe these will be the turning point.
ed124c says:
07:38 AM, 08/30/10
I am a bit confused: Will the Mazda6 come with both the 2.0 and 2.5?
Is the Mazda6 you drove a new, smaller model or just the already smaller Japanese version? After all, 163hp and 151lbft torque would be lower hp and torque than our current US 6, so I would not have expected such praise about its performance.
arumage says:
10:01 AM, 08/30/10
@ed124c:
It's a Japanese/Euro version of the Mazda6 which weighs a few hundred pounds less in it's current form. Add to that the lighter Sky-G engine and the new, lighter 6-speed transmissions (vs. 5-speed in the current US Mazda6), and you probably have plenty of get up and go. I would be the DI Sky-G engines have a beefier torque curve. They might lack in quantity and make up in availability.
Jason Kavanagh replied to comment from ed124c
10:16 AM, 08/30/10
It is indeed confusing.
We drove development mules of the next-gen Mazda 6. These mules started life as Euro/Japan-spec current-gen Mazda 6, which is smaller than the current US-spec 6. The mules were basically donor vehicles which were hacked up so that Mazda can perform testing of the new, next-gen chassis and powertrain bits.
The decision on whether the US will again get a larger version of this next-gen 6 is yet to be decided. Also, Mazda is mum on whether the 2.0 or 2.5-liter Sky G will be powering the next US-spec 6, but it's a likely bet that it'll be the 2.5.
santiagofdz says:
10:17 AM, 08/30/10
14:1 Compression in a gas engine....nice s#it!
All of this sounds very promising, altough I'll be waiting to see how de Sky-D fairs.
barich1 says:
01:01 PM, 08/30/10
blueguydotcom, I don't think that's overly fair. They're getting dated, given that they're largely the same as they were in 2002, but they were competitive at that time when they launched the first gen 6 and 3 a year later. They were certainly vast improvements over the 2.0 in the Protege and 626.
When I bought my 3, none of the other cars that I test drove had engines as smooth or as powerful. Obviously, they don't compare well to current direct-injected engines in terms of performance or economy, which is why Sky-G and Sky-D are coming.
3pedals_only says:
06:58 PM, 08/30/10
OH MY GOD!!! A MAZDA engine that has TORQUE!!! AT THE LOW END TOO!!!
redgeminipa says:
05:42 AM, 08/31/10
"the 14:1-compression 2.0 Sky-G, the next-gen Mazda 6 returns 40 mpg on the US highway cycle according to their simulations. "
It's kinda odd they would even test that engine for the US cycle, considering we're supposed to get the version that's 13:1...
ms3hothatch says:
05:49 AM, 08/31/10
Mazda has had DI engines since 2005 (or possibly earlier)! That's more than 5 years ago, but then they procrastinated and even Hyundai went passed it with DI engines. Even before Hyundai Ford's EcoBoost and GMs ISDI (versus Mazda's DISI). What happened? They should have been able to launch the Mazda 2 with 40+mpgs this year with a DI engine and better transmission choices. It will not be until late 2011 or even 2012, which will make it more than 6 or 7 years since Mazda has been working with DI. Was it lack of cash for R&D? Will they come up with a Rotary DI and turbo? That should be interesting. I average 27 mpg in the city on my '07 Speed3 with a DISI Turbo and I have 310 lbs. of torque.... with some mods... of course it's premium gas, but a lot of fun with a nice mpg/power balance.
weege says:
08:09 AM, 08/31/10
So will the new 2.0 replace the current 2.0 and 2.5 in the 2012 Mazda 3? Not sure about trading 167 ft. lbs. from the current 2.5 for 151 with the 2.0 Sky-G. But would you really want to take the old-tech 2.5 over a new-tech 2.0 if it's available? This would make for an odd choice, unless the Sky-G 2.5 comes online and into the Mazda3 soon after.
iskch says:
09:16 AM, 08/31/10
Is worth the wait. For everyday day commuting more torque & MPG is ideal.
arumage says:
10:27 AM, 08/31/10
@weege:
It's not always the sheer amount of torque that matters. It's the way it is delivered. Lots of low end torque makes a vehicle feel better in everyday driving.
weege says:
01:52 PM, 08/31/10
Good point arumage, but unfortunately another site's report of this first drive (hint, initials are C and D) claims the 2.0 still felt slower than the existing 2.5 in the Mazda6. Tech is good but I don't know if it can completely outweigh 25% more displacement.
So maybe it's a decision to choose a little bit less power for a whole lot better mileage?
aviboy97 says:
08:11 AM, 09/ 1/10
Good point arumage, but unfortunately another site's report of this first drive (hint, initials are C and D) claims the 2.0 still felt slower than the existing 2.5 in the Mazda6. Tech is good but I don't know if it can completely outweigh 25% more displacement.
____
There will be a 2.5L SKY-G engine, as the article stated. The NA Mazda6 will most likley have the 2.5L. Remember, the 2.0L was in a test mule. Also of note, it looks like the Mazda6 we will get here in NA will be just like the rest of the world. That's good news.
I have already seen the 2012 Mazda3 refresh, they showed it at the Mazda dealer metting in Cowboy's Stadium a few months ago. Mazda did not touch on the details of the SKY-G though.
scottiedoo760 says:
07:22 PM, 02/25/11
First of all anyone who says mazda engines are junk is a fucking FOOOOOL! go drive a civic then drive a mazda 3, you tell me which engine is better? i hate it when people go off reputation and not experience.......