Hi Everyone - I just can't seem to find enough information searching to satisfy myself before purchasing this diff...

I found a 1990 Ford T-bird Super Coupe, with 5 speed transmission at a local scrap yard... it has no wheels, and it’s in 3 feet of snow and frozen to the ground so i was unable to get a look at the differential itself.

The sticker on the door has an M code for Axle, which from all I’ve read online means: M = 2.73:1 w/ locking (Traction-Lok) differential.
it seems the 5spd super coupes came with 2.73 instead of 3.27...

My question is, is anyone using 2.73 with a 5.0L EFI and T5 transmission in a 1st gen Miata? These differentials are very hard to find out here, and it's the only one I’ve found, plus with the T-Lok is a real bonus for me…

And if no one has any experience, would anyone care to give me opinions?

 

OH! i forgot: thank you very much for any info!

 

It depends on the first gear in the T5 you are running but the Miata is so light it really doesn't matter much. If the price is right grab it. You can always upgrade ring and pinion later.

 

Thanks! that's what i was thinking...

I spoke to Martin at Monster Miata (He just sold me my monster v8 kit) and he told me the 2.73 gear ratio should be perfect with the stock fox body T5... so i think I'm going to go for it!

still - would love to hear more opinions if anyone else has any

 

That exact set-up came in my 1988 Mustang GT, & I hated it. The car had absolutely NO POWER & it got crappy fuel mileage due to the fact that the engine had to be turned at a higher RPM to produce power & overdrive was only used during highway driving. The only highlight of that set-up was the insane top end speed. I swapped it out for a 3.55 gear & performance & economy improved. Your results in a Miata with its lighter weight & smaller diameter tires may vary.

 

When I first put mine together, all I had was the 3.08 that came with the Tbird. I was happy with it, later came across a 3.27 out of a Mustang Cobra, so now have that. But the 3.08 was really not a problem.

I would say go for it, it will get you on the road, and just keep looking for another, under no pressure.

Mike

 

Thanks guys, I think i'll pull the trigger on this one - i see the ring and pinion 3.27 for about 240$ brand new online... so worse case, i'll put new one in... or even i could probably steel one from a non-IRS car and would work... if it ever comes down to that.

 

I have repaired thousands of Ford rear ends. If it was me, I would find a differential with the 3.27 ring & pinion. If it has Traction-Lok, great. If not, install a Traction-Lok carrier. A NEW CARRIER can be had for about the same money as a set of the desired 3.27 gears. The used differential will most likely need a new set of clutches installed to operate properly.

 

+1 ^^ for sure. Start with the right gear ratio and put posi in it is much better than swapping gears. Cheaper too.

That being said you did not mention the price on this 2.73. If you were going to swap gears to anything but a 3.27 and it was very cheap then I would go for it. But there is no reason to swap a 2.73 to a 3.27 when there is a zillion 3.27s in yards out there ready to roll.

I got my 8.8 with 3.27 locker for 110 bucks shipped from a guy on tccoa. TCCoA | TCCoA With 80 bucks in new Ford racing clutches it would have been fine to run as it was but I put 3.55s in it.

 

ahh! too late - i already bought it...

I didn't mention the price, because i know everyone would say it was very steep, however for me it is cheap, it was 200$. But what people don't realize is that everything is much more expensive in Canada, new cars are much more expensive, used cars are more, oem parts are more, and thus parts at wreckers are also more expensive... usually anywhere from 1.5 to 2.5 times the price.. furthermore, there are much less parts to be found here... buying across the border with hefty shipping costs, duty, and brokerage fees ends up costing the same as paying the higher Canadian price...


ANYWAY!! I'm very happy to have heard all the input here, and at the least, this will get me through the project, until i can find a 3.27, and i'll be able to write back on this post my input on the experience i get with the 2.73, a small contribution to the v8miata community

 

I don't have the 8.8, but have the 7.5 with and locker and the 2.73's. For a power plant, I'm running a 408 SBF and to be honest, the 2.73's are perfect.

1st gear is actually mildly usable. 2nd gear hooks a little. 3 gears hooks pretty good.

And on the highway in 5th gear I can get 25mpg at 70-75mph while running below 2000 rpms.

 

oh great! i was really hopping to hear from someone that tried the 2.73... now i'm planing on having a 5.0L with trickflow hci kit... probably way less power and torque than you... curious what size wheels you have, and what transmission? are you using stock T5?

 

Transmission is a T5Z from Summit Racing. Wheels are 225/45/16 in the rear (I believe). I'll double check that tonight...I'm running 205/45/16's up front...

 

Oh Cool - sounds like a sweet setup, the T5z i beleive has a slightly higher 1st gear ratio then a standard T5 am I right?

I have the 8.8-2.73 sitting in my garage now, so it's going in, i'll definately let everyone know how it feels with 5.0 with stock T5