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Comment Re:Ever hear of Mazda? (Score 1) 269

and Corolla GT does 36mpg, in a 950kg, 124hp package from mid 80s and BMW M3 first model does 29-30mpg with ~200hp.

200SX does ~30mpg aswell.

BMW 750 does around 20-22mpg aswell.

A 80s RWD corolla 1.6l does around 30mpg aswell.

A Skyline GT-R i'd assume does around 20-22mpg aswell.

As you can see, mpg has very little to do with engine size, power, vehicle weight etc. when all the other variables keeps changing.

What if the Corvette utilizes direct port injection, direct ignition etc, while RX8 utilizes normal fuel injection and say wasted spark ignition? These are variables which has to be accounted for when doing a serious comparison of the engine type.

Comment Re:What took it all so long?? (Score 1) 269

Wankel can be efficient, it's been demonstrated many times in the past.

The problem with wankel is the low torque, high rev nature. Emissions limit it to extremely small engine sizes.

I wonder what would happen if wankel's idle rpm is allowed to be say 1500rpm, and the whole band at the same ratio higher.

You do realize 2-stroke is usually considered to be especially high emission engine? Yet, Lotus managed to build this very low emission engine ...

Comment Re:What took it all so long?? (Score 1) 269

I would assume they are so restricted engines due to emissions, and/or fuel consumption is not really on their "TODO" list when they design the cars.

Many sports cars consume A LOT, despite being highly efficient engines, so i would assume they don't really even try to cut the consumption at all for travel.

Big cars are always designed consumption in mind because they would have so so high consumption otherwise. ie. small trucks tend to consume a minimum of over 20l/100km when empty, and highway, that's around 12mpg. (Small truck just over 6000 pounds)

Comment Re:What took it all so long?? (Score 1) 269

Same goes for Wankel engines.
It's ridiculous that they are measured with the same standards than a completely differently working engine.

By design, Wankel is way more efficient (all rotating parts, no complete turns in direction). Downside with Wankel is inexistant low rpm torque, which comes from a multitude of factors (ie. lower rotating mass for one)

In wankel, on 1-cycle you have 3 ignitions, while on 4-stroke you have 1 ignition, and 4-stroke cycle is longer than wankel's ....

Comment Re:What took it all so long?? (Score 1) 269

Actually, higher fuel efficiency does likely translate to more power. But when it translates to more power, it's swapped to smaller engine, underpowered one, and then the fuel consumption is again higher because it's currently going on high loads.

For example, an old RWD corolla.

Stock 1.6liter, carburated engine. Producing around 70JIS HP. Sounds like doesn't consume much, yes?
minimum 8liters per 100km (@80km/h highway), practically mixed city + highway (@100km/h) translates to 12liters per 100km, sometimes you can get as low as 10l/100km.
RPM limit: 6,000RPM

Newer, high power, high rev 1.6liter, fuel injected, twin cam engine, from early 90s.
Same engine has been used as a very tuned up version in Formula Atlantic, and continues to be used in Rally and Drifting.
Produces 124 to 165JIS HP, depending upon engine variation. No low rpm torque to speak of, especially with the very first versions.
RPM limit 6,800 to 8,500RPM depending upon version.

Comparison engine: Latest 16v (circa 91-93), steel exhaust manifold, freeflow air filter, 8k rpm rev limit, produces ~135HP
Fuel consumption highway 100-120km/h: 6.5-7l/100km
Mixed fuel consumption average 8l/100km

As for the oil companies stopping highly efficiently engines: I agree with you 100%. There's so many cool, very high fuel efficiency motors invented, but none makes in the market?

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