7tooZ

280ZX vs 280ZX 2+2 transmissions

38 posts in this topic

On 4/7/2017 at 2:04 PM, Terrapin Z said:

I think there are 3 different ones, with the later two being very similar other than the slight difference in the 5th ratio.

280 ZX (8/78-7/79) FS5W71B 
5 spd "B" type
3.321 2.077/37% 1.308/37% 1/24% 0.864/14% also 810 Maxima
280 ZX (8/79-6/80) FS5W71B 
5 spd "B" type
3.062 1.858/39% 1.308/30% 1/24% 0.773/23%  

280 ZX (7/80-6/83)

FS5W71B 
5 spd "B" type
3.062 1.858/39% 1.308/30% 1/24% 0.745/26%
 

 

I believe you use one clutch or the other. The throwout collar is different as well. 

You will need to address the shifter clearance at the tunnel opening. 

I am putting the same set up together myself. I just found a shifter that should work without having to trim anything out of the tunnel. I haven't tested it yet though. 

Have you finished. I am curious about the driveline. Did the stock driveline work or did you have a new one made?

I am currently waiting for delivery of the transmission and the diff, so I haven't started yet.

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I haven't started yet. I picked up the trans locally about 8 months ago, and had been gathering parts for it. I then found the R180 3:70 K style and had that shipped in. I swapped out the stubs in it so it installed like the stock 240's 3:36 instead of the clip in stubs. I found the flywheel and a clutch kit next. Then ordered all new seals, gaskets, the speedo drive, the rubber bits, bushings and new oil. The only thing I was missing was a shifter as I spoke of earlier. Having located two now I plan on doing the swap in the near future. 

As for the driveline I understand the difference from an "A" trans to a "B" trans is only a 1/6 of an inch in length. Therefor I expect the stock driveline will work just fine. I had new U joints put in when I got the car and was changing out the bushings in the rear. I also put in a 3:54 rear end at that time, as the PO had installed a 4:11 set. Too tall for me.

Looks like it might be you telling me of the idiosyncrasies of the job. Do post about it!!

 

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It is the Exedy clutch and a SPEC flywheel.

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My understanding is that the percent variance between 79-80 and the 7/80- 6/83 is only 3%. Doesn't seem like, it would make a big enough difference in front of a 3.70 diff, to the extra cost to find one.

If you take and multiply the transmission gear ratio by the diff gear ratio you'll see the difference.
I run a 4.44 rear diff in one of my 240's using the '83 five speed. With the .745 5th gear this gives me an overall ratio of 3.308. If I used the '79 five speed with the .864 5th gear I'd have an overall ratio of 3.836, not good for street use.
In my other 240 I run the '79 5 speed with a 3.90 rear diff. With the .864 5th gear it gives me an overall ratio of 3.369, which is basically what a stock '71 240 with the 4 speed and 3.36 diff has in 4th gear.
Attached are some examples of the calculations

Sent from my K88 using Classic Zcar Club mobile

1492703225254.jpeg

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You're using "overall" in place of highway gearing, I think.  There are usually two reasons people start thinking about transmission or diff changes - the car is sluggish from a stop or takes a lot of clutch to get going or 1st gear is so "short" that they  have to shift to 2nd right away, or 5th gear cruising RPM is too low or too high.

You have to consider both ends, I think.  Depends on which streets you're planning for, city or highway.

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I'm using an 11.5 lb 225mm aluminum flywheel. Exedy p/n 6009 I think, clutch kit on a '79 ZX wide 5 out of a 4 seater.  75 mph in 5th is right at 2,250 rpm on the highway. 180 differential. It's perfect for me, quick to rev around town but nice and quite on the interstates.

Everything bolted up just as the www.com said. It popped out of reverse and 5th until I ground a little on the front and backside of my shifter. Everything is "a okay" now.

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22 minutes ago, 7tooZ said:

Found this speed calculator on line
 

Don, This is the one I used, currently for me it indicates I am missing a plug in, and no longer works for me. Perhaps you have said plug in and can utilize it.  

http://www.webring.org/l/rd?ring=zcars;id=157;url=http%3A%2F%2Fwebspace.webring.com%2Fpeople%2Fcz%2Fz_design_studio%2F

It almost looks like the site might be completely NLA to me, but try at least. I looked for other trans calc. sites and really never found any as good as this one. At leased for me. 

 This thread is enticing the voices to just dive into my swap now. I have a blown water hose and need to drain the coolant to fix it anyway, why not pull the motor and trans now for clean up and T swap. 

I was thinking the same for mine, ZX outer, inner and a new fork boot.

IMG_1426.JPG

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