Donor car we've been working on came with a wiring harness and ECU from a 91 automatic, we jumped the auto trans connector to the neutral switch so the car would start.
I am under the impression that the automatic ECU's are detuned a bit. Is this correct? Am I loosing ~10hp just from the ECU? I need to straighten this out before I take it back to the dyno.
Also, I have found an ECU on Ebay that was out of a Mazda Eunos Roadster MX-5?? I imagine this is the JDM version of the Miata?
I am aware that in SM we are only allowed to use parts that came on the Miata that was sold in USDM; however just out of professional curiosity, will that ECU have different tuning parameters that could possibly make more power due to minimal smog regulations in Japan?
Finally, I see on Ebay that the USDM Manual Transmission ECU's mostly have this part number: B61P18881B
Are there different part numbers for the 90-93 ECU's that came with a 5 spd, or am I good with any ECU with this matching Part Number?