Quote:
Originally Posted by torqdork
http://www.fueleconomy.gov/feg/Find....n=sbs&id=33907
Realistically, I get closer to the city rating during my DD's in the foothills here, about 21-22 mpg, spot on the EPA city rating. That also compares favorably with Corvette's city rating of 17 mpg and both require premium fuel. I wouldn't call that horrendous for the performance, I'll save that term for my 10-11 mpg 4,400lb. FJ Cruiser M/T over the same roads and for track days where those of us data logging in twins see 8-10 mpg.
But I question your 4hp/lb estimate in cars, maybe in model aircraft. Even the new BMW i3 is a fraction of that (2.5kW/kg) at a little over 1hp/lb. and the LEAF is about half that.
...the capacitive systems don't appear ready for mass market production yet. They've produced Atkinson cycle ICE's with variable lift and timing for years.
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The problem with the EPA cycle is it can be very different or very close to real world based on car and driving style. All I'm going to say here is, if your FRS can only get 22mpg on that road, a Corvette is not going to get 17 just based on the higher curb weight alone.
As for the electric motors thing, okay 2.5kW/kg is 1.2kW/lb or 2.5hp/lb, which isn't far off, but I guess 4hp/lb isn't as easy as I made it sound. The permanent magnet motors in the Leaf and Prius have very low maximum speed limits and if I understand correctly the maximum rotational speed is more or less what determines the power output as the torque limits are hit very easily. The Tesla Roadster's motor is hand wound but it has 288hp for a bit over 4hp/lb, but if you look at the published torque curves it seems like that number is power electronics limited because the hp is constant past a certain point (whereas if it were mechanical strength limited, you wouldn't have to reduce the torque that much).
The capacitative systems are close but probably not ready. Taiyo Yuden and such kept on announcing the production of hybrid capacitors a few years back, and nowadays you can buy them online, but they aren't much better than the traditional ultracapacitors.
Also Toyota definitely has not produced variable lift engines for years, the only ones have been the 2ZZ-GE, and recent 1ZR-FAE/2ZR-FAE/3ZR-FAE. Everything since 97 has had VVTi on at least the intake cam though, but so has every other manufacturer... That said their Atkinson cycle strategy could work well; The 2GR-FXE is rated 247hp (much healthier than the 1NZ-FXE in terms of hp/L), and can probably make more power if you spin it faster. It's a nice solution because it's very cheap compared to turbo + smaller engine, but if that smaller engine is say a BMW N20 or even a Honda R18 you're going to lag on efficiency.
Quote:
Originally Posted by torqdork
Honda's first VTEC application was the 1983 CBR400 motorcycle.
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Depends on your definition of VTEC. That "VTEC" was just shutting off one of the two intake tracts, which is inferior to even a cam phasing system. Toyota had it too on the 4A-GE.
That aside, F1 doesn't seem to be the best way to develop production car relevant things. Yes new rules force them to figure out how to build certain things certain ways but there isn't much room for getting creative when the entire powertrain is basically specified for you, minus some tweaking of materials here and there. I don't know if VTEC really came from F1 but I kind of doubt it seeing how fixed camshafts was part of the rules for so long.