The drivetrain shops in my home town are starting to get out of some of the specialty work. They used to shorten axle and make combinations of various things.

The drive shaft is no problem. But the Irs axles are another story.

So far I've eliminated several shops.

And think I have finally found one. We supposed to go over some details today.

If you know any shops that will do reasonable axles, to go from IRS 8.8 to the miata hubs. Let me know.

 

i will be talking to several shops shortly and will keep this thread alive with info. so far, axles are biggest pain in the butt toget deals on when it comes to the swap.

 

Ford Ranger Axles? I believe its what, 2 left sides that are required.
What about IRS from a mustang?

 

I talked to the guy and he told me to bring the 8.8 Irs cv axles and the miata axles. He said he may be able to miss match and interchange, or sleave and weld the two together, to make the stock hubs work with the 8.8 Irs. And If he doesn't think they will be stronge enough, he has another guy that can make them from scratch.

I'm trying to find the other guy. lol

Flying miata has a option to retain the torsen. So the stock axles may be fine. I talked to him about a adapter plate to weld on the shortened miata axles to make it work with the 8.8 IRS. He said he would look at the flanges and see what he could do. He said shortening the rod is no problem, but there could be a possibility of weakening the rod.

I'm off Saturday, if it isn't raining I'm going to try to hit the salvage yards and compare the rearend measurements. And mabe try to score a cheap IRS rearend and axles.

Or compare just throwing in a straight axle 8.8. Yea I know, flame me. LOL

 

FWIW The 2002+ Ford Explorer has a 8.8 (31 spline) all-aluminum housing IRS. That is where the diff in my LS1 Miata came from. So the Explorer could be another source for the inner part of the half-shafts.

 

Nice. I may just buy a wrecked explorer.

 

You could prolly get a complete running explorer with everything you need, even decent low mileage motor.

A 2nd gen '95-'05 should carry a 5L equiped with GT-40P heads. Damn, you could even be semi unique by going 4.6 L 16-valve Modular V8

 

do NOT use stock miata hubs. they are weak! i can get custom hubs made for $360 shipped. we just need to figure out what car to use outer CV form... today i was thinking 350z because those never break and are relatively cheap.

 

dont they have different diff case then other IRS diffs?

 

Yes I meant to mention that. The Explorer case mounts are different than the Cobra mounts from what I have seen.

 

Are you saying the boss frog diff mount won't work? You will have to fab your own.

If that be the case I'll probably find one the diff mount kit will work on.
I'd like to have 327 gears or lower.
What gears does the truck have?

 

ford gears are available left and right. plenty different ratios to choose from. im personally going for 3.55:1

 

Yea..LOL. The 400hp your going to to the ground. you would loss time if any lower. And you will still get great gas mileage. Especially with the T56.

 

Do Not let a shop weld the Ford and Mazda axles together between the joints. The original Monster Miatas were built by Monster Motorsports that way back in the early 1990's using a RX-7 rear and it was disastrous. Many of those original Monsters have since been upgraded to Martin's newer Ford 7.5 hanger and axles.
Good luck with your build,
-Jason

 

I've used gatorracingaxles.com to rebuild my axles before and so has another ls1 miata owner. They are out of jacksonville, fl. I've had zero issues with my axles since then. Stock miata rear hubs too... with over 10k miles now.

 

Bill at Miataroadster has new hubs designed for the RX7 TII axles which never break in the V8 Rx7's

 

What did these run you to get made?

 

They were already made, part of the racing concepts kit. Ford 8.8 inner, miata outer cv. They polished the ford cup, replaced and polished the miata cup, put new grease and boots on and painted the shaft. I think it cost me around $150 with shipping.

 

Wish I'd known they were that cheap! It would of been worth it to try

 

http://forum.miata.net/vb/showthread...es#post3588195

 

So were these the factory Miata axles or a factory 8.8 axle that was modified?

Michael

 

Sorry, we don't have that option. I suppose it could be done if you build a mount for the front of the diff and you're using one of the 5.3 engines, but it's not an option we recommend nor do we provide parts. Our base rear end setup does retain the stock Miata hubs, but new halfshafts are required to mate to the Getrag.

 

If you want to use a stock torsen, you can find the flange from an older Dodge car. Any good driveshaft shop should have the flange on hand.

My next build will be using a 3.6 Torsen. With only a 225 tire on it, it shouldn't have any issues. The 3.6 will make the rear end even stronger due to the torque multiplication reduction compared to the 4.1/4.3. Had someone bought my 8 inch rear end setup, I would of used it with the current build just to see if it'd work or not.

 

But can the stock 8'' take that much torque? I want to be able to do decent launches without worrying about the thing breaking. I will be using 225 tires as well (225/45/15 RS3) and I know those won't be hooking off the line, but still.

 

The stock miata torsen is a 7 inch ring gear.

The RX7 TII and FD are an 8 inch ring gear, and FC guys are not easy on the stock diffs with few if any failures. FD owners swap FC diffs into their pumpkins after they chunk the FD torsen using slicks on a prepped drag strip.