Quote:
Originally Posted by PaleMelanesian
We have to compare gear ratios, not just number of gears. The 6-speed's 6th gear actually turns a few more rpm at speed than the 5-speed's top gear. I don't doubt the 6 is a better transmission, but it's not going to be any more fuel efficient.
C59 5-speed
5th: 0.815
Final: 3.941
Combined engine-wheel ratio: 3.212
C60 6-speed
6th: 0.725
Final: 4.529
Combined engine-wheel ratio: 3.284
source: 2004 Toyota Matrix Gear Ratios
Does that high compression require premium fuel? That's an added expense. I doubt the per-gallon savings outweigh the extra per-dollar cost. |
That is completely true about the combined final drive and overdrive ratios, however many 1ZZ engines such as the ones in the Celica GT 5-speed actually came with 4.312 final drive ratios, resulting in a 3.51 combined ratio. Thus a 1ZZ Celica in 5th is spinning faster than a 2ZZ Celica in 6th.
The best option for pure MPG is a rebuilt with a 3.941 final drive ratio and a 0.725 overdrive in either the 5 or 6 speed.