Quote:
Originally posted by VTEC_boi
too short
Fritz, do you have AOL Instant Messenger?
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No. I live behind a thick firewall.
A "too tall" final gear is a very common problem in production built cars. Mainly because of one big factor I left out of the above - Mileage.
short gearing = higher rpm at lower speed = worse MPG
tall gearing = lower rpm at higher speed = better MPG
Auto mfgs must always take this into consideration when determining the final drive.
You'll notice two major trends in USDM drivetrains.
#1 - 60MPH (or 62MPH) always happens at redline in 2nd gear. This is to satisfy the all-important magazine reported 0-60MPH (or 0-100KPH) number. Completely regardless if a different ratio would make the car more competetive on the track or the street or just feel better driving around - You always will hit 60 at redline in 2nd!
#2 - 65MPH in the top gear is very close to the most fuel-efficient (BSFC) RPM that the engine can run at. This is to get those HWY MPG numbers as high as possible.
So you notice that 1st gear, 2nd gear, top gear, and the final drive end up all being strictly dictated by these two mfg. concerns. This leaves the poor engineers only 2 or 3 gears (in a 5 or 6 spd respectively) to actually optimize for your driving pleasure. 3spd automatic gearings are
totally dictated by these requirements, and 4spd autos only get one gear (3rd) well designed.
Kinda sucks, doesn't it! And I bet you had no idea...
