[California98Civic]

I found this interesting, and I thought I'd share and see what others find believable.

From "Automotive Fuel Economy: How Far Can We Go?" (National Academies Press, 1992) by "Committee Staff on Fuel Economy of Automobiles," Appendix B, p.202:

1 - claims that 5-6% increase in compression (9.0:1 to 9.5:1) would yield 1.3 to 2.0% increase in FE.

2 - On p.205-6 under "variable valve timing" Honda's VTEC-e in the VX is specifically cited as producing 15% more torque at 2000 rpms than the DX. The report claims Honda asserts that VTEC-e along with lean burn produces 10-15% greater FE but even without lean burn the variable timing still produces 7-8% better FE.

3 - On p. 212 the authors of the report (not Honda) claim that aerodynamic differences between the VX and DX account for 0.7% of the FE improvements in the VX. [I wonder what the differences were?]

4 - On page 212 the report claims that a 10% decrease in drag will produce a 2.3 or 2.4% increase in MPG.

5 - On p. 212, a 10% weight reduction yields a 5% increase in FE.