Savington

iTrader: (31)

One small problem: S90 does not make a Miata throttle body. The Skunk2 has issues, yes, but they are all easily rectified with a little knowledge and 5 minutes of preparation before installation. I broke a throttle return spring on an early production part, but I've had absolutely no issues with the replacement Skunk2 TB on Rover over the last ~5 years.

Alternative

I love how this is some kind of closely guarded secret...

theshdwconspracy

iTrader: (1)

I know S90 doesn't make one for miata's but I have to change my flange regardless because it's a 1.6L car, so nothing is going to just bolt on for me. So if it's a DSM throttle or a 70mm from BEGI or a S2 I don't think it will fit on the current 1.6 flange.

Also, Did you guys test between a 52-65-70 mm TB as far as power gains? I was thinking maybe with my manifold and turbo setup I might see some benefits some where as far as power goes.

18psi

iTrader: (76)

no matter how you re-phrase the same silly question, the answer remains

you know what you should test with?

a higher flowing engine.

theshdwconspracy

iTrader: (1)

I was just curious what all people tried out there and if there were any results. If not, I'll just throw the stock one back on for the moment before going through all the trouble of re engineering my whole manifold/throttle body/swirl pot/car, just to fit a stronger throttle shaft.

18psi

iTrader: (76)

but you see, that's a concern for your car: the shaft on the stocker will likely break at some point, especially the way you use the car. if you cracked your manifold several times, the tb shaft will likely not last too much longer and can take out your engine as it goes.

this is not as much of an issue for a street car.

you just need to understand that its a reliability mod, not a power mod. not for your engine

Madjak

Issues are:
Sticky throttle is common... I think due to the next point
Movement in the throttle plate when partially open (ie sideways movement in the bearings)
Throttle return spring is too weak (ie return force) and the locating tag can break off
Idle adjustment screw doesn't offer enough idle adjustment so you have to use the throttle stop. (which also changes TPS)
Throttle stop bolt can come loose unless you loctite it or put on a better locking nut, or do it up very tight.

On the non Miata throttle bodies:
TPS locating tab is held on by the tiniest of screws. High reving motors can vibrate it loose.

Not all the above issues effect every throttle body. Some are fine and have no issues out of the box, but all the above are fairly common if you search. There is a good reason the Skunk2 products are referred too as Junk2 on the Honda forums. The Miata specific Skunk2 throttle body is actually one of their better throttle bodies...

KMiata

I wouldn't worry about throttle modulation with a 70mm. That's all we run on the K series cars, or 74mm, and they all feel fine. Domestic guys have been running 90mm+ forever.

Edit: I can also vouch for Skunk2 throttle bodies. That's all we use, and I assume their Miata piece is similar quality.