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Guest Message by DevFuse

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R200 rear diff

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5 replies to this topic

#1 Subi_Sam



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Posted 17 August 2014 - 07:02 PM

So I recently just purchased my RX. Now I want to do a full EJ swap including drivetrain engine etc. I know if I went with a typical R180 the driveshaft would need to be shortened 55mm. My question thou is if I went with a R200 with a STi 6 spd what length am I going to need for the driveshaft and what will my overall end drive be? I'm shooting for 3.54

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#2 Numbchux


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Posted 18 August 2014 - 05:11 PM

Rear diff doesn't effect driveshaft length (at least, not between r160 and r180, I think the same holds true for the r200, but the only times I've seen that done was with a RWD swap, and there are other factors there). It is the 6-speed that requires the shorter driveshaft. Also, I think the 55mm is assuming an EJ chassis, which you do not have, so you'll have to start over on that measurement. IMO....just get your engine, transmission, and diff mounted how you want it, and start taking measurements.


I'm betting you'll be best off starting with the stock RX driveshaft and having the front half shortened to match the transmission. You may have to have the rear half shortened as well to compensate for the rear diff (I don't think so, though), and you may also have to do some creative swapping/modifying for the flange between the diff and driveshaft (for example, I know the r180 bolt pattern is larger than the r160, but the flanges can be swapped between them.....some of that might hold true for the r200)



That said, the r200 is available in many different vehicles, with many factory ratios available, and even more aftermarket. 3.54 is probably possible....

#3 wagonist


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Posted 18 August 2014 - 06:14 PM

for the rear diff, I've never been able to figure this out, but maybe the diff housing is slightly narrower, so the shafts tend to pull out of the diff.

The easiest way around this is to get rear shafts from an 85-87 which can have floating CVs on both ends of the shaft (like the inner fronts). This gives a bit of extra leeway.


If there is a problem with the front shaft length, conversions using an EJ engine into an ea81 engined car usually have problems finding shafts short enough. Impreza shafts normally work well with EJ conversions into EA82 engined cars, so maybe find out what the EA81 engined guys used, as it may be a little shorter.


Apart from this, get very friendly with your local driveshaft shop. Sometimes its possible to mix 'n match CVs & shafts from different cars/manufacturers to achieve what you want.

ie I've got a mix of Mitsibishi & Hyundai CVs with some unknown length shaft in my Elantra powered Accent (which had a 20mm wider trans)

#4 Subi_Sam



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Posted 20 August 2014 - 05:14 PM

Interesting. And the 55mm is what people have recommended to me to shorten my driveshaft for a EA chassis. I'll probably end up using a R180 I was just curious if a R200 could work without major modifications and such. But thanks for both of your inputs!

#5 czny


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Posted 20 August 2014 - 06:05 PM

Here's a link to year models & ratios for donors:




Look  for 81-83 turbo 280zx for the 3.545 R200. Companion flange would be smaller I believe.


Some of the earlier Z car diffs were bolt-in stubs with 4 bolt flanges. Later diffs were mostly snap-in but as the years progressed the spline count/diameter increased.




Happy hunting.

#6 Caboobaroo


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Posted 21 August 2014 - 10:33 PM

For doing the complete EJ engine/manual transmission conversion into an EA82 chassis, the stock drive line needs to have the front section shortened by 55mm. This is only for the 5-speeds though. Since the STi 6mt is longer then the 5mt, the driveline will need to be shortened more or a sweet aluminum 1 piece custom driveline made.

Edited by Caboobaroo, 21 August 2014 - 10:33 PM.

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