31 spline 8.8 axle option
 

Not really sure that this is a new discovery or anything, but I thought I would toss it up there since I've not seen it mentioned anywhere else.

In case you haven't seen my build thread, I purchased a 17k mile rear end from an 03 cobra to use in my build, in excellent condition. As most people know, the cobra rear end is aluminum so it has a fair weight savings from the thunderbird ones, plus it has 3.55 gears and a factory trac-lok. Sounds great right? All those options in an already good to go package? Problem is that they had 31 side spider gears and the axle shafts that go along with those require cv boots that are too big to clear the shocks.

After a fair amount of reading I had figured out that the 28 spline side gears would go right in to the rear in place of the 31's so that was my plan all along. With those I would then be able to just put in a set of martins axles and off I went. Luckily since I am still saving to completely finish my car, I had time to research more before I actually bought axles. Keep in mind this worked out good for me but maybe not for everyone.

I called thmotorsports and he quoted me prices on 400hp and 600hp axles from the DS shop, that would drop right in with a 28 spline 8.8 rear in a miata. The key there is that the 600hp axles come with bolt in inner stubs, and DS shop sells 31 spline inner stubs seperately, so after some talking over a period of 4 separate conversations I have a set of axles coming that will be more than strong enough with custom hubs and wheel studs, that will slip right into my cobra rear end, and clear the shocks, for $1010 to my door. As I said, this option is not for everyone, but here is how it broke down for me:


Martins:

450 for axles, boots, cv's, etc
150 for his hub work, with a suitable core
160 for a set of axles to send as cores since I didn't have any from my car
200 for the side gears to replace my cobra's
86 for a set of hubs to use as cores because my parts cars hubs were rough

Total $1046 for axle setup to get into my car not including shipping to and from martin, which would probably be another 100 or so.


As you can see, this option didn't save me a crazy amount of money or anything, it did however give me and perhaps others an option for putting a 31 spline cobra rear into a miata.

Once the axles come in and I get it all assembled I will report back, but theres no reason it shouldn't work. I have seen others have success with the DS shop axles, so my different inner stub shouldn't cause any trouble at all.

NICE! Wayyy better than changing to 28 spline side gears IMO. That is going to be a really sweet set up.

One thing I learned when I toasted one of my shafts is Martin will sell just his shafts. That might be an option for folks if the inner 31 spline CV will go on the Tbird sized Martin shaft.

Thanks for posting this is good stuff.

When you order axles from V8R, you have the option of 28 or 31 spline stubs. If you later decide on a different size, it's a pretty simple matter of removing the stubs and replacing them, without changing anything else.

Can the 28 outer be ran with the 31 inner though?

Yeah, the axle components are really mix and match. Just contact the Drive Shaft Shop or V8R and let them know what you need, and they'll hook you up.

Who makes the v8r axles? Are they sourced from DSS

That's where mine came from.