SamirD wrote:Even if their weights are this different, that's a 10% difference. So a 10% difference in fuel economy would basically net them as being very similar. And that's my point--no real 20-30% gains in efficiency, so why bother with CVTs?
As far as the fuel economy is concerned, I'm driving an AWD Kizashi that is 15% heavier, has 20% more power, handles much better, and is as economical or slightly better than the Altima I came from. I'm happy with that, but that was basically what I was expecting when I bought the Kizashi.
I've been keeping track of my Kizashi on Fuelly, and once I get to 7500 miles the transfer case and rear diff are getting Redline 75w-85 (the lightest weight allowed in the owners manual) and I'm going to see how that impacts economy. I may try a high quality synthetic 0w-20 or 5w-20 oil, though I recognized the Kizashi manual recommends 5w-30. The J24B engine in other countries and vehicle applications lists 0w-20, and I'm familiar enough with oil specs to feel comfortable trying that. I would expect all of that may net me about 1 more MPG.
Losses due to pumping and to agitation of the CVT fluid are one of the biggest reasons that generation of Jatco CVT transmissions don't show fuel economy much better than a good 4 or 5 speed automatic with a reasonable overdrive. The newer Jatco CTV7 / CVT8 transmissions improve that significantly, and provide a wider ratio spread as well. Those improvements increase vehicle mileage about 10% from the CVT design used in the previous generation Jatco CVT found in the Kizashi.
http://www.jatco.co.jp/ENGLISH/products/cvt/cvt8.html