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We recently got to sample a prototype version of a Skyactiv G engine over a wide variety of driving conditions from city traffic to highway cruising. The Prototype engine was installed in a current Mazda 6 chassis, although it will be first available on our shores in the 2012 Mazda 3.
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| We got to sample the Skyactiv G engine in these prototype Mazda 6 chassis with both automatic and manual transmissions. The Mazda 6 is a mid size car, pretty big and heavy for a little naturally aspirated 4 cylinder. Nevertheless, the Skyactiv engine exhibited fairly brisk performance. Although the rev limit was a pretty low 6500 rpm, probably due to the long stroke, the engine was responsive and felt eager to rev through its power range. The engine felt like it had a wide and flat torque curve as well. The engine was also exceptionally smooth. In the compact lighter Mazda 3 the engine should have sparkling performance. VW TDI-like fuel economy on much cheaper 87 octane unleaded will be welcome as well! Mazda, we want one of these for a project car to give our Project Hyper-Miler and TDI a run for the money! |
Even in the heavier Mazda 6 chassis, the engine surprised us with reasonably peppy performance and a wide, tractable powerband. Although the engine had a somewhat low 6500 rpm redline, it was eager feeling, probably due to the wide powerband and a smooth willingness to rev freely to redline. The wide powerband made the redline feel higher than it really was.
In the lightweight Mazda 3 this engine should be more than adequate, and longer legged than a TDI diesel, for instance. All was not perfect. In transitional throttle applications like tipping in quickly from steady state to brisk acceleration, like when passing a car or when making a quick turn from a standstill, we could hear the sharp crack of detonation. This only lasted an instant to two but it was unnerving. We pointed this out to the Mazda engineers who were always nearby. We assume that this is either harmless by design or will be engineered out by further engine calibration before production.
We really like Mazda’s upcoming Skyactiv technology. It just plain makes sense to us. We like the idea of hot hatch performance with compact diesel-like fuel economy with low emissions and low operating costs. We also think that this engine will be about impossible to modify for the average enthusiast. It will probably make a fun and frugal daily driver so you can keep that fuel guzzling EVO or GTR in the garage to save for weekends!
6 comments
These type of engines are only restricted by the fact most owners want to use 87 octane. Imagine if you could tune these engines for a 91 or higher octane. I imagine in hot weather these high compression engines detune themselves a lot with 87 octane. It is unfortunate that even recommending a higher octane is taboo in America. At least some manufactures are now recommending higher octane fuels and mapping engine management to take advantage of that fuel. Especially with turbo engines that add to the heat issues that many times require a engine to aggressively detune itself to prevent pre combustion.
High octane fuel is taboo in America? Every car in my garage uses high octane fuel. One V8 and a couple I4 turbos.
we are limited to 91-93 octane by the R+M/2 method
I have a newer version of this engine in a 2015 Mazda 6. I will reach 400,000 miles by the end of the year. Still runs and shifts great and getting 32-35 MPG hwy. The only thing I’ve ever done to this car was replace a lower control arm at 300k miles and the belt tensioner at 150k miles.
Yeah, but the direct injection itself has reliability issues…the cylinder heada will need to be removed between 100000-150000 miles due to the valves gumming up. I believe Toyota solved this problem by placing an injector BEFORE the valves to keep them clean. Does THIS motor have this feature?
I have a hundred and seventy five thousand miles on my indie, miata, in five and a half years running, mostly low octane fuel, I have done a few cleanings in an oxygen sensor other than that, she’s running beautifully.I do a lot of highway driving sometimes two hundred miles a day