You want an NA Miata? Flyin' Miata's Keith Tanner offers advice.

J.A.
By J.A. Ackley
Jun 19, 2024 | Mazda, Miata, NA Miata | Posted in Buyer's Guides | Never miss an article

Photograph Courtesy Mazda

Why an NA Miata? Well, for more than 30 years, it’s remained a viable answer to nearly every question. Autocross. Hillclimbs. Time trials. Rallycross. Road racing. Modern-day or vintage classes. It works for all of the above.

Sure, the newer Miatas feature many improvements over the original. However, there’s just something about the NA Miata.

Maybe it’s the pop-up headlights, the …

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Comments
AnthonyGS (Forum Supporter)
AnthonyGS (Forum Supporter) PowerDork
10/4/23 5:00 p.m.

You definitely interviewed the right person for this article.  I look forward to reading it all later.

Colin Wood
Colin Wood Associate Editor
10/5/23 10:04 a.m.

In reply to AnthonyGS (Forum Supporter) :

It's also really cool that Keith is a regular here on the forum. He always has some really good advice to offer.

AnthonyGS (Forum Supporter)
AnthonyGS (Forum Supporter) PowerDork
10/5/23 2:10 p.m.

In reply to Colin Wood :

It was a good read.  Of all the cars I have ever owned, my 94 Miata R is one of the ones I wish I still had.  

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
10/5/23 5:53 p.m.

Being a suspension geometry nerd, I am curious about what the specific differences are between NA and NB.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
10/5/23 6:58 p.m.

In reply to Pete. (l33t FS) :

Every year, Mazda publishes the "service highlights" that goes over the changes for the new year. The 1999 one is a gold mine.

Upper mounts: single piece to replace the old multi-piece one. Urethane bumpstops for better cornering. 
Front subframe: lower control arms moved forward by 2.1mm and upper arm moved backwards 3mm for more caster trail. Lower arm also moved down by 5.7mm for lower roll center. Steering gear mount is more rigid. 
Rear subframe is the same geometry as before but has more bracing.
Front knuckle: Steering arm moved up by 7.1mm for bump steer control. Different taper on the upper ball joint but that's not mentioned.
Rear shocks have 10mm more stroke. Rear knuckle moves the mounting flange out by 5mm each side to widen the track.

The NB Yamaguchi book goes into the reasons for a lot of these decisions.

AnthonyGS (Forum Supporter)
AnthonyGS (Forum Supporter) PowerDork
10/6/23 10:29 a.m.

The Yamaguchi book is really good.  Did he write the FD RX-7 one too?  It's also amazing.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
10/6/23 1:09 p.m.

For anyone who wants to retrofit NB geometry up front, you need to swap the rack/subframe/upper control arms/knuckles at a minimum.  Lower control arms are the same geometry. The widened track in the rear can mean tire interference on the narrower NA body - my Targa Miata is built this way, with the complete NB front end and the NA rear uprights attached to an NB rear subframe due to improved bracing options.

fidelity101
fidelity101 UberDork
10/6/23 1:44 p.m.

In reply to AnthonyGS (Forum Supporter) :

I have his FC book and the miata book - they are great

grubinski
grubinski New Reader
10/8/23 9:54 a.m.

Keith ... do you know if the V8R front subframes use NA or NB geometry?  Reading between the lines "my Targa car has "the complete NB front end" makes me think that V8R used NB geometry, since your Targa car has the V8 swap.

Given that the front knuckle changed on the NB, should I be running an NB knuckle with the V8R subframe for optimum bump steer?

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
10/8/23 10:44 a.m.

Yes, my V8R subframe has NB geometry. I don't recall if they all do or not, but it's certainly a question for them. I would recommend beefing up the steering rack mounting tabs with gussets as well. 

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