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Discussion Starter #1
I have heard this time and time again from many people in the MIATA community (especially my fellow autocrossers) "There is no difference between a USDM and JDM motor for the Miata"

I recently read an post today on M.net saying that the BP-ZE motor (01+, aka my motor) in Japan had a 10.5:1 compression ratio giving it 160ish at the crank stock.

Also last night I was watching a BMI video the with the New NC Roadster vs the NB Roadster, and I could have sworn that NB roadster rev'ed to 8K??

Am I going crazy? and how do I make mine do that!!!
 

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From what I have heard, they are the same motor, but are tuned differently for different regions/countries to meet regulations and other factors.

One can change the rev-limit by changing the crystal in the ECU that controls the "clock".

Let me dig up the link on Miata.net, but a friend here in Tampa has done it successfully.
 

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Discussion Starter #3
How "dangerous" is it to bring the rev limit up to 8K from 7.4K? I know a friend who autocross' with me has a BP motor (2000) which he's running on a Link ECU and he's running it to 8K. Do you think there would be much benift?
 

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Well, my friend did some dyno runs with and without the rev limit raised, as well as the Bipes unit on and off, including a combination of both.

The resulting differences were minimal. Maybe a few HP; that's it.

There's a thread about it on m.net
 

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Keep in mind they also run a higher pump gas in Japan. Also, my buddy was station in Japan and he says that his 91 (B6-ZE) would not allow him to go over 100mph. Some kinda speed controlled fuel limiter? But yeah, i would have to say the motors are all the same, just differet computer controlled thingamabobs on the ECU.


PhatMiata
 

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Discussion Starter #8
I had a friend with a NA8C which wouldn't go over 100mph either... but for a completely different reason :)

(bad rings which lead to hitting a deer, blowing the motor and nearly burning the car to the ground, which he then fixed and sold two weeks later for an S2k... traitor!) NO I'M NOT BITTER!
 

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Also last night I was watching a BMI video the with the New NC Roadster vs the NB Roadster, and I could have sworn that NB roadster rev'ed to 8K??

Am I going crazy? and how do I make mine do that!!!
I just rewatched the clip, that NB was actually redlining @ 7500.

But agree w/ others JDM NB's are most likely tuned differently for the better gas and such.
 

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Discussion Starter #10
I guess they must have a different gauge face then on the late model NB, because though mine will tack up to 7200 or so... my red bar starts at 7. Hmmm... it would even be nice to raise my rev limit 500rpm's. With as much autocross as I do that would help...
 

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I guess they must have a different gauge face then on the late model NB, because though mine will tack up to 7200 or so... my red bar starts at 7. Hmmm... it would even be nice to raise my rev limit 500rpm's. With as much autocross as I do that would help...
On NA's, it's an easy fix on the ECU, but I don't know about NB's.
 
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