Is there a way to tell the difference between a "old" and "new" Torsen? I would be curious to know which one I have.

 

03-up isn't a torsen. That's the easy way to tell. They stopped making them and went to a limited slip by Fuji

 

Except for the MSM as far as I am aware.

 

Correct, the MSM is a unique Torsen unit that isn't shared with any other Miata.

 

 

And the msm hsd bigger axles completely incompatible with everything else which you obviously don't have.

 

Hmm okay thanks for the clarification.

I started a build thread for my car now as I today started working with the rust problem of the car.
https://www.miataturbo.net/build-thr...8/#post1475323

 

NA is lighter than the later NB chassis with lower compression motors but also

• Less rigid body
• Smaller engine bay
• Worse flowing head and intake unless you swap
• No six speed
• Inferior suspension mounting points unless you swap in NB ones
• Less room under fenders for big rubber, more effort required to fit any given tire/wheel package
• Way older in general, so everything will be that much closer to wearing out- this is actually a fairly serious problem unless you're religious about replacing stuff that is normally reliable

I'm sure I've forgotten something, but NB is better than NA in a lot of small ways that honestly won't matter for most people.

If you're going for a low dollar build, NA will be slightly more boost friendly and generally cheaper to start with.

If you're going for a high dollar build, you can swap in all the stuff from the NB that matters. The hardest parts are the tranny and the head but every high dollar build involves removing them anyway.

 

What makes an NA more boost friendly?

 

Is the chassis actually lighter? Or is the increased weight from additional stuff the NB had? (I.e bracing, 6spd, body kit, air bags, abs, bigger brakes, bigger wheels, more interior and electrical doodads / modern car accoutrements)

If you stripped them back to the chassis / bare tubs only state, would there be much difference?

 

Lower compression? I think the pre 96 motors were 8.8:1 and the 96-97 were 9:1. The nb2's go up to 10.5:1, which gives you way less margin for error.

 

Blows up at same power level, so.... meh? If you have an IQ above 40, it's the same.

 

pre nb are 9:1 and I think the auto is ever so slightly lower or something. insignificant, like .02
the nb1 is 9.5 and the nb2 is 10. all handle approx the same torque and power, except the nb's make more of each everywhere, and feel better in every way possible.