www.RX7fb.com

G'day to all.
Around the place we have a couple of RX7 S2's and a heap of spares from another.
One complete car will soon be a road going navigation trials car, mostly stock with selected improvements while being rebuilt. JDM 12A 6PI 6 port engine, manual trans, usual urethane suspension upgrade, Koni shocks & strut inserts, QFM competition brake pads all round, mildly lowered with stiffer springs, gutted interior with SAAS seats, half cage, no rear seat, no carpets etc. Even ditched the door inner cards as too heavy, aluminium sheet panels instead.
The other is a complete rust free spares / storage car with a mildly bent right rear subframe rail. J port engine, manual trans, pretty much standard otherwise.
Why use an RX7? Our Datsun 240Z is too valuable these days to risk bending!
Price difference aside, the little Mazda isn't far behind the Zed.

Now going to be searching for a means of putting a decent LSD in a 24 spline rear end.

Hi, many welcomes!

some good lsd info here....

http://www.rx7fb.com/viewtopic.php?f=64&t=1757

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Welcome. We like pics here.

Thanks guys.
Apologies for delayed reply, nearby lightning strike and resulting flashover last Wednesday took out wireless broadband radio, router, VOIP gateway and a colour laser printer. Few days to get radio replaced (up above roof), all sorted now.

Had a good read of the rear end topic before joining, got some better ideas now on what to do.
Seems the 2 bent axle shafts I have (both left side between flange & bearing) are not exactly rare so I'll probably go with 26 spline LSD after all.
Shafts are easy enough, make new ones out of either Ford F100 or Mercedes light truck shafts. Much better steel and I can leave large radius from the bearing to the flange outer edge.
Having my own small machine shop (lathe, mill, TIG, press etc) helps a lot.
Still not sure about Torsen vs clutch LSD but either should do the job.

Pics will have to wait a while but I'll try to get some 'in progress' pics as things come together - that's after building a 6m x 9m granny flat!

Torsens are plentiful and don't require periodic maintenance. Straight swap of the centre. I put one in Kiwidave's car.

I like the clutch type units as you can set the breakaway and they are still supported by Mazda. You may need to strip and rebuild every 60k kms but that would take me 20 years so no big deal.

They make a huge difference to the handling of the car.

Thinking seriously of pulling down a BT50 centre, looks almost possible to be the same size guts as the RX7.
Lot's of those around in Oz.
60k ! I'd be in heaven if a clutch diff lasted that long in nav trials use.
I know what you mean about handling difference, not had an open diff for decades. Even my Mitsubishi Triton tradie tray top 4WD runs a rear LSD.
Gotta have one in the RX.

Most ute stuff will be too big. You need 7 inch diffs. Unless you try and swap the whole thing in.

Check out Spac's thread on ausrotary:

http://www.ausrotary.com/viewtopic.php?f=16&t=2695

Duane has loads of loads of knowledge and he's happy to share it.

Diff centre I'm looking at is early Mazda BT50 (badge engineered to Ford Courier) and at tape measure accuracy the crown wheel is very close to RX7 S2 centre.
I'll strip it and see - no cost so why not

Give it a shot, iirc there's a 7.5 inch out there before you get into the 8 inch FC and FD stuff.

That could be the BT50.

The early BT50 is a bust, LSD case out of 7.5" is adaptable but 28 spline axles.
I didn't know Mazda even made 28 spline LSD's but apparently so, maybe only for the Oz market. Side gears are not interchangeable with 26 spline either.
I have discovered alternatives so I'll start a project thread soon.