Quote:
Originally Posted by Allch Chcar
We get the same RON regular octane as Japan, it's the premium US 93 octane that we only have in certain states that differs since most cars are built to the lowest common denominator, US 91 Octane. I believe the lower compression has more to do with our stricter laws regarding NoX emissions. Ever notice that Honda stopped advertising lean burn?
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Lean burns are fine for emissions. The reason why automakers stick with stoich is that it's the most well-balanced. If you run say a 15.5:1, you get better hwy but worse city, and losing some smoothness. The 2012 Mazda3 run 12:1 compression with 14.7:1 air-fuel ratio because stoich ran the best according to them. On a side note, the Mazda3 runs only 12:1 on the Skyactiv G because it's retrofitting a new engine into an older model, and couldn't run a 4:2:1 header that's ideally suited for the engine.
200hp is impressive to me, when you consider that it does that at a lower RPM than a Honda K20 that gets wringed out to 8k.