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Does anyone know if the ECU from a JDM Roadster is the same as one from a US spec car? Assuming they are from the same model year of course. I'm looking for a spare to mod when I install either a MS or emanage.

Thanks,

Bob
 

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No, they are not the same. Physically they use the same hardware and enclosure but the software code is different. For instance, the JDM ECU for NA6 has been cracked and tuners modify it in Japan. The same cannot be said for the US version of the same ECU.
 

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Actually even the hardware is different amazingly. It looks like the JDM one doesn't have a barometer in the ECU.
 

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Interesting...I did not know that. The engines are still the same, however, right?
 

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AFAIK the long block is same. On M.net one guy says all the ancillaries are the same.... but according to the Hyper-Rev book, the JDM NA6 has 52mm throttle body and 220cc injectors.

So I don't know....
 

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What makes the USDM ecus so uncrackable ?? There's money to made there.

I guess the question is can a JDM ecu be used on USDM engines like most Honda ecus can?
The Roadster ECU, like most modern ECUs, is encrypted. So even if you could access the data you'd have to decrypt it to make any sense of it. No one has bothered to crack the encryption on the USDM ECU. Plus you'd have to figure out how to write new values to the ECU. Unfortunately, the Roadster ECU isn't MAP based like many Honda ECUs.

For more information, check out Grid ECU Tuning.
 

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Actually I had my 1994 roadster ECU "tuned" by Dinan back in 1995. I have attached a piece of lit that came with it. It did/does feel quicker for a NA, but I had also added a free flow exhaust, header, and HKS intake all at the same time.
As far as octane goes, I generally use middle grade w/o problems (it knocks with regular), but in a pinch, I can get away with a mix of regular and middle grade.

They no longer produce roadster ECU's, I think Dinan mainly does BMW's now.
 

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Cool post. I imagine you had to send them your ECU and they returned it to you after performing their magic? I wonder if they swapped the JDM ECU into your case or whether they really did crack the USDM code.
 

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Just to clarify, the comment about the barometer refers only to the 90-93 ECU. The 90-93 ECU (both JDM & USDM) require a latch IC board to reprogram. The 94-95 ECU already has a EEPROM, so you can directly reprogram it without a lacth IC board.

As to the potentials for reprogramming the ECU... well the 90-93 ECU suffer from 2 problems:
1. flapdoor AFM- this is a real restriction to any kind of serious horsepower.
2. 8 bit processing- this is seriously deficient, especially when it comes to forced induction.

I don't remember if the 94-95 ECU is 8 bit or 16 bit now. The 96-97 ECU is a completely different animal, and I don't think it's ever been cracked even in Japan.
 

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Cool post. I imagine you had to send them your ECU and they returned it to you after performing their magic? I wonder if they swapped the JDM ECU into your case or whether they really did crack the USDM code.
I had some down time with my car, so I sent them the ECU. Turn around time was nominal. I got back what I had sent them. They replaced a chip (gots a Dinan sticker on it) and did what ever voodoo they do. So I guess they did 'crack' the USDM ECU.
 

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Or I wonder if they simply removed your B61 program chip and soldered in a chip running a tuned version of the B63 program?

Edit: Nevermind. I forgot you said you have a BP** ECU in your car.
 
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