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Old 04-19-2013, 04:00 AM   #1
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Boxster Gear Ratios

i have seen a lot of questions / comments lately about gear ratios. for reference, here they are. lots of people mention the difference in gears 3-5 on the 2.5L vs. the 2.7L.

the reality is that because the final drives are different, the effective ratio for EVERY gear is different. in fact, the differences are more prominant in the LOWER gears. 1st, 2nd and 3rd are 8.5% shorter on the 2.5L while 4th and 5th are only 3% shorter.


2.5L / 2.7L




3.2L (6 speed)

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Old 04-19-2013, 05:41 AM   #2
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Thanks for the info. I always wondered what the difference in ratios was between the 6 speed I bought and a 5 speed. I like the fact that the 6 speed ratios are lower (higher numerically).
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Old 04-19-2013, 05:54 AM   #3
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Quote:
Originally Posted by Joe B View Post
Thanks for the info. I always wondered what the difference in ratios was between the 6 speed I bought and a 5 speed. I like the fact that the 6 speed ratios are lower (higher numerically).
actually, they're not. you have to consider the final drive. the 6-speed FD is 3.44. the 2.5L is 3.889 and the 2.7L is 3.555. you need to multiply each geary by this number to get an EFFECTIVE gear ratio.

the truth is, the 2.5L has is geared lower than either of the others by a pretty substantial amount. the 2.7L, IMO, is the LEAST desirable. next is the 6-speed. the 2.5L 5-speed has the most useful ratios from a performance perspective.

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Old 04-19-2013, 05:57 AM   #4
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Oh, right . Well at least 4th and 5th are lower, gears that I use a lot.
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Old 04-19-2013, 09:07 AM   #5
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Any idea how difficult it is to swap out only the final drive on a G86.01?

I'm already swapping in the early diff cover to install a Guard LSD, so if it's not much additional work, I might as well add in the extra 8.5% advantage (although I do already have trouble keeping the power to the ground in auto-x).
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Old 04-19-2013, 09:42 AM   #6
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you have to change the ring gear & pinion. not that easy. you can pick up a G86.00 for $600. i would do that & sell your G86.01. should be close to a zero sum. then put the guard in the 00 box.
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