2vang

just wondering whats the difference between a jdm engine and the us version.
is the wiring harness and ecu different. i know people say jdm engines are harder to pass emissions.... why is that.

VacavilleFC

don't buy a jdm motor, half the time they have bad compression and need a rebuild as soon as you receieve it which will cost another 1000 ontop of the 1500-1800 you spend on it. just rebuild the motor that you have , or pick up a blown usdm t2 motor and rebuild it, it'll save you money and headaches

NZConvertible

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/us-vs-japan-fc3s-490591/
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/how-do-you-know-if-you-have-j-spec-13b-505382/
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/jspec-usdm-t2-motors-same-479910/
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/difference-usdm-s4-tii-motor-vs-jdm-385109/
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/usdm-vs-jdm-13bt-374578/
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/jspec-motor-hp-272752/

That ought to cover it...

Yes and yes. The harness is completely different because it's for a RHD car. The ECU is physically identical but has some minor differences (fewer emission controls, speed limiter), plus I found on mine the manifold and atmospheric pressure sensors were in opposite locations than the US wiring diagram showed. You'll make your life easier simply using a US harness and ECU. There's no need or advantage to using JDM ones.

Fewer emission controls.

SureShot

I ran a used JDM block for nearly a year until I rebuilt my origonal motor.
I reputable vendor will certify good initial compression.
Six months later I sold it locally & it's still going.

VacavilleFC

you got lucky, i'm not saying everyone is bad but it's a 50/50 chance, and i don't like those odds when we're talking about 1500 bux

2vang

thanks guys