Quote:
Originally Posted by jchammond
Speedometer drives off of the 2 output sensors; mounted on the diff cover.
They read the toner rings on the output stub shafts,,,so 3.36 to 4.36 gear ratios will not affect speedometer- pending that you’re running a 27” tire (+ or - a tick)
Your 15’ Nismo has 3.92 axle ratio,,,pre 15’s had 3.69.
They make 3.54 & 3.36 if you want taller gears.
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Thanks so much for the info! With the numbers you provided, I was able to do a better search, and came up with this thread:
3.54 Final Drive Swap Review
One thing that was brought up in the linked thread was that with a taller diff, there is an approximately 4% hp/tq loss. Some members in the thread mentioned that they would rather go the other way to 4.08, for quicker acceleration...but they don't seem to realize the problem with the time required to shift more often (at speeds less than, say, 80mph) adding to overall acceleration times. If you could knock out one shift in an average acceleration run, the benefits would be huge...for example. The way my car is geared now, there's no point in using 3rd at all except for downshifting into corners. Accelerating in 4th at most speeds above 40mph or so is most efficient.
The OP in the thread never came back to explain whether the loss of cruise control was due to the new diff, or the cable malfunction he suggested. Any input here?