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Old 10-04-2012, 09:50 AM   #2770
DannyZRC
Studly Adventurer
 
Joined: Oct 2004
Location: Merced, CA
Oddometer: 808
Quote:
Originally Posted by Midnullarbor View Post
Beemerlover (#2750) makes a very good point.

The gearbox/transmission is remarkably over-complex. Power from the crankshaft must go through four pairs of gears before reaching the shaft in the swingarm. (Versus only two pairs, in the current & past boxers ~ certainly one of the reasons contributing to the current fuel efficiency superiority over the transverse-crankshaft "big shafties" like the S10 and the Explorer.)

The extra friction must worsen fuel consumption a bit ~ probably more noticeable at lower throttle openings.
Maybe the slightly higher compression ratio will counteract that, to some extent.

Still, you can see that the engineers were aiming at compactness of design, and were okay with some compromises in order to achieve it. (In the face of an un-compact cylinder layout which had to persist.)

Transmission efficiency aside . . . it all looks very impressive.
The S10 afaik has been reporting better economy than the boxers, despite having to turn the power twice AND using a hypoid rear end.

So while it may be true that there are more meshes in the new tranny than the old one, this factor doesn't necessarily guarantee increased fuel consumption. Factors that suggest better economy : no separate chain drive for balance shaft, gear driven rather than belt driven alternator, water cooling.
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