Miata vs. AWD rear end, how close are they?

[teqnyck]

I'm friends with a guy who owns a driveshaft shop, he's making me a lighter weight one-piece driveline and possibly building me rebuildable rear axles. Yes, I'll take lots of pictures and post measurements. I don't think the driveshaft will cost me more than 250 or so, so if you want one I'll give you their contact info. But here's the thing, if I'm having him build me axles, what if I went ahead and upgraded to a NB Miata 7 inch rear end. The half shafts are different on the end that bolts to the diff, but for the most part all you need to do to swap diffs in a Miata is get the diff and the half shafts from an NB. I have no doubt that the Miata housings mount differently than the Protege's diff housing, but has anybody actually gotten a look at how close they may be? There aren't any Miatas in my local junkyards, other wise I would just buy one and mock it up. But I don't suppose anybody has tried this yet have they? Anybody?

[therieldeal]

they are 100% totally completely different. you would need a custom rear subframe to run a miata rear diff housing.

[jay]

I also don't know that it's any kind of upgrade, seeings how the guts of those 2 diffs are interchangeable.

[therieldeal]

he's talking about upgrading the 1.8 miata diff, which is in fact larger.

[teqnyck]

You know, I was hoping that Mazda had used more of a grab bag than they really did, it kinda blows goats that each car is completely different than the other. *Sigh* Guess I won't be buying that Torsen housing.

[therieldeal]

well the 1.6 miata diffs will fit in your awd housing. get a clutch or vlsd?

[teqnyck]

Yeah, I got a line on a Kaaz 1.5 way NA8 diff, I just figured I would upgrade if I could. I'm just worrying about my end HP goal and what will happen to the stock bits.

[therieldeal]

whats the power goal?

you could always go toyota...

[teqnyck]

Well, my Festiva had 380whp, now that I know it's doable I'll probably aim high. Ok, part of me is joking and part of me is serious. I'll definitely max out the stock internals and roll that way for a while, we'll just have to see what happens.

One of my worries is the stub axles needed to go from an open diff to a viscous diff. I am seeing diffs that are specifically for open equipped Miatas versus VLSD equipped Miatas. I'm guessing that I need to get a diff meant for an open diff Miata. Is that a reason for me to not get a Mazda VLSD, because I would need to change the stub axles? I've been looking at ones like this: http://cgi.ebay.com/ebaymotors/Mazda...Q5fAccessories
and I'm wondering if it would even fit.

[therieldeal]

usually its not hard to get the VLSD axle stubs with the diff... they are required in order to use it. someone selling one without them will be hard pressed to sell it lol.

[teqnyck]

Right, but what you're saying is that the Miata's stub axles will fit into the Protege diff housing and the axles will bolt right up, is that right?

[therieldeal]

yessir thats correct

trailrider098 just installed a miata VLSD and stubs in his awd pro, that i had bought for mine but never installed

[teqnyck]

I've been wondering about that, thanks for clearing that up for me! But the fact still is that only the diff from the 90-93 Miata will work in our cars, thank God for Spec Miata, means we have options!


Jay, Jason, you might as well chime in, you've both been eyeballing this thread since I started it.

[trailrider098]

ill chime im, heres the pic that i seem to be posting alot of recently. Protege/GTX rear diff housing and ring gear with a 1.6L miata LSD

[teqnyck]

Nice one! Thanks for posting that! Sounds like the more viable option for me.