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Old 01-11-2013, 09:53 PM   #1
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Default RX-7 trans for better cruising?

Found this on another site, and it got me thinking about an RX tranny swap. Seems that 1-3 are nearly the same but 4 and 5 are much taller. Have a peek.

I wish I knew- the parts interchangeability page went away a few years ago.

According to the spread sheet I made for this work- my '99 has a 4.30 rear, 3.136 1st, 1.888 second, 1.33 third, 1 4th, and 0.814 5th.

and I chose gears that are supposed to go into that box and FD that went into the rear- but I'm not sure.

But in choosing a 86-91 RX-7 5 speed (3.415, 2.002, 1.366, 1 and 0.691) and a 3.91 rear end (can't recall where that came out of) I got a comparison, gear, Stock, modified- in rear wheel ratio:

1st- 13.48, 13.59

2nd- 8.12, 7.83

3rd- 5.72, 5.34

4th- 4.3, 3.91

5th- 3.5, 2.7

So 1-3 are pretty close, and 5th would lower a 4000rpm cruise to 3087 rpm. Gotta think that would do wonders for fuel economy.

I had been thinking of a turbo 1.6l. But could not figure on how to make the calibration production quality and reliability vs. my '99. so...

Is this really possible? If so I'm going to find an RX as soon as Pick-and-Pull opens.
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Old 01-11-2013, 11:14 PM   #2
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Tl dr.

Different car for better cruising.

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Old 01-15-2013, 03:09 PM   #3
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Pretty sure the input shaft is different. If you think a 5th gear swap is easier than just wearing earplugs, go for it.
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Old 01-15-2013, 03:19 PM   #4
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After reading all the crap about tII trans and the adapter plates etc... I've realized the same thing i'm sure sav and others have realized... We may all want a better trans option but when it comes down to it the 6 speed is where it's at. Not worth going through all the trouble to be different. Not enough pros and too many cons.

Just like reading the f20c thread makes me want an f20c swap... if you think about it you should just buy an s2k and not swap cause the cars are pretty similar and it already comes with the motor (they are to be had for around 10k now days for an older one)... ***** and giggles are fun but when it comes down to it. we being practical or we playing for ***** and giggles?
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Old 01-15-2013, 03:22 PM   #5
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Read here. Then just buy a 3.63 R&P because that's way easier than opening up your gear box.
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