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Old 06-04-2013, 12:22 AM   #408 (permalink)
California98Civic
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Join Date: Mar 2011
Location: Coastal Southern California
Posts: 6,299

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
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Quote:
Originally Posted by Shortie771 View Post
This did not make since to me... Could you reword or explain further?
Somehow I missed this question. But I can answer it. The Vehicle Speed Sensor gears (VSS) on these Civic manual transmissions were designed to allow the speedometer gauge on the dash to report 60mph when the VSS turns at 1025 rpms. That feature of the design did not change when the fifth generation was replaced by the sixth generation. Further, the speedometer gear on the differential gear inside both generations' transmissions is the same size (about 90.7mm, IIRC). But there is one thing Honda changed fro the fifth gen when they launched the sixth gen: the stock wheel changed from 13" to 14" and the stock tire from 175/70-13 to 185/65-14. The tire change was probably meant to compensate for the effect the larger tires would have on the speed and distance calculations the car would report. The wheels/tires are like an "extra" gear. And not all tires within a specific size seem to have the same revs per mile, at least not according to the information available from the manufactures and posted on tirerack.com

I think Honda's stock design in 1992, when they first launched this transmission, was that the speedometer would run fast (to avoid lawsuits over speeding tickets) and the odometer to run slow (to avoid lawsuits over warranty limits).

Just in case this message makes me look like I know a lot--accidentally--lemme just say that I am a novice. I just researched this question fairly carefully, on the forums, in the relevant factory issued service manuals, and under my car. Getting my facts learned, as Springsteen once sang it.

I hope I've explained it clearly enough.

james
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See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.



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