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how strong is the auto box

2K views 24 replies 19 participants last post by  fun02SE 
#1 ·
hi all , just a quick question,
how strong is the auto box for above standard power?

not planning on doing anything too adventurous to mine just yet but it would be nice to know if it is possible in the future.



And please don't recommmend i get a manual. This is the first auto i've owned and there is a reason i've gone for a auto box.
 
#12 ·
Good ol' Euro NB's with a 1.6 what a ripoff that would be!

Honestly selecting a auto miata is probably one of the worst things, I think Jermey Clarkson of Top Gear commented on it once to the tune of "Its ****" or something along the lines of that. The miata engine is too weak to be coupled to a auto parasitic loss of power on a auto is typically 15-20% which is a lot when you engine puts out 120HP at best.
 
#14 ·
WTF guys? Give the guy a break sheez. I drive an NA auto and my guess is that all you **** slinging auto haters never have. I drive one as my legs no longer work due to an old spinal injury, and the op may have a similar situation - so dump the manuals only bullshit and answer his question.

There are a couple of guys on m.net running JR45 superchargers on stock auto boxes with no problems whatsoever. They're probably netting @ 150 rwhp. I autocross mine frequently and also frequently beat manual trannied miatas.

Now, I did a couple of minor valve body mods to mine to crisp up the shifts - to the op, if you're interested send me an email or pm and I'll explain it all.

To you haters - eat **** and grow up....my 2 cents :)

mark aka http://www.miata.net/motm/2007/thomson.html
 
#15 ·
It is understandable that most Miata enthusiasts are purist who can't understand why one would want to dilute the driving experience with an auto. But when faced with someone who has consciously made the choice to go auto there is no need for all the sarcastic remarks from the peanut gallery. Be a pal and help the guy out like Mark did. Thanks, Mark.

As to the OP's question, there is a guy in Japan with one arm who races his auto trans Miata. He even put a turbo on it. That being said, both the manual and automatic transmission in the Miata are rather small and cannot take big power. I don't know for sure where the limit is but you should be relatively safe with a JR45 supercharger or Greddy turbo kit. Just change the fluid regularly and maybe install a trans fluid temp gauge just to be on the safe side.
 
#17 ·
The auto tranny from the late 90s 1.8 NA was sourced from a Mazda diesel produced for Europe. So it was actually made to withstand a bit more torque than the standard auto box. If you've ever driven one you know what I'm talking about. The shift pattern is like a diesel truck. I think they're cool for supercharging. Would make a nice smooth powered car.
 
#21 ·
From Flyin' Miata:
Q: I have a 96 Miata (1.8L Automatic). Can this engine and trans configuration handle a turbo? If so, at what boost and what HP at the rear wheels without destroying the trans or engine?
There are a few automatic Miatas with turbos running around and they are not having any transmission problems. You may also need to modify the downpipe slightly to clear the larger bellhousing of the automatic. For your 1994-05 automatic car you will need to buy a Voodoo. Our FM II will not work on the 1994-05 automatic cars because the FM II replaces the factory ECU. The factory ECU operates the automatic transmission on the 1.8 and our ECU does not. 1990-93 cars can use the Link or Hydra ECUs if desired.
 
#24 ·
If the FM downpipe follows the path of the original downpipe modification will likely need to be done - bent slightly. I had to bend the 4-2-1 header I bought to clear the auto bellhousing as it was designed for manual trans Miatae.
 
#25 ·
Check out the Fast Forward supercharger forum. There is a guy with an NB auto with a 190 WHP S.C. on his. runs great no problems. Ask on the forum or ask Tom (of FFS) as he helped with the install and drove the finished car.
FWIW FSS now has a kit for the 1.6 that would really make your auto trans car move out!!!
 
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