BP5A ECU
 

Out of curiosity, does anyone know if our US cars could swap the BP4W to the BP5A ECU?

I ask because I'm in an OBDII emissions county and know that the BP5A did not have an EGR, so the possibility of finding an ECU that would allow me to delete the EGR and stay legal would be quite convenient.

Thanks!

Do they require that the vin stored in the computer matches the chassis?

They might, but I'm sure it could be argued that a bad ECU had been swapped out. Not 100% sure on this though.

Does the Miata NB ECU even have an internal VIN tag?

I see where you are going with the BP5A ECU. It might be nice to have a factory ECU that's better matched to the hardware... I've got a squaretop and a 5A cam, I wonder if the 4W brain leaves anything on the table compared to the 5A. If you have a source, I might be interested.

Off the top of my head, pinouts may also be different so may not be 100% PnP. Revenant would probably be a good person to ask about this.

Any update/follow-up on this?

Also curious to know the answer.

I know I've read about the Spec Miata guys swapping around stock ECUs to get an extra 3-4hp here and there on the dyno. I don't know if that's within the deviation on the dyno or some sort of deviation in the ECU itself, or maybe mental damage withing the SM community? Either way, there is somewhat of a precedent for it.

I think the NB has a vin tag that the machine see's. I cant remember 100%, but I think it pop'd up on the smog machine and there's a good possibility that the tech checked my vin on the dash.

Seems like if this is true, only CARB-legal way to replace a dead ECU is to get a new one with VIN burned in. curious to know if this is the case. I know there's some smog techs and experts over at m.net - might be worth asking this question over there.

IIRC, I believe the VIN data comes from the state. The first step for the tech is scanning the code (or entering the man readable code for older machines) on the form the DMV sent you. The machine then calls home to Sac and pulls down relevant info, including the VIN. I believe tech then confirms via visual.

But you are right, this is an m.net question fer sure.

Well they are certainly not going to swap right over. The location, wiring, and harness are not the same.

But perhaps you could completely custom re-wire it to work. I can't confirm or deny if that's possible. Doubt it.

The BP4W/Y and BP5A have the same connector. I am betting that it will swap right in. According to some threads at mx5nutz, BP5A is the only [non-US market] NB1 ECU that does not require an immobilizer. It should also have a 7500RPM redline, not use the EGR system, and have slightly better tuning for higher-flow intake/exhaust.

BP5A:

https://www.miataturbo.net/attachmen...ine=1372091069

BP4Y:

https://www.miataturbo.net/attachmen...ine=1372091069

Really? Wow my mistake then. I vaguely remember comparing the harnesses a long time ago and not arriving at the same conclusion.

*EDIT: did I go full retard and confuse bp5a with bp05? I think so. Nevermind

Did any of you buy this one that was up on ebay earlier this month?

Mazda Miata ECU BP5A for 1999 2000 Engine Control Unit | eBay

Out of curiosity/stupidity I ordered a BP5A ECU today, I'll let you guys know if it works when it arrives next week.

Ordered from where? YAJ?
I should be getting mine on Monday, but probably wont be able to try it for a while.

I look forward to your findings!

Mine arrived today. I also have a BP4W(49-state) and BP4Y (CA) to compare. WBO2 is installed, but I dont know if I'll have time to test it out any time soon.

https://www.miataturbo.net/attachmen...ine=1373925566

Some other fun parts arrived as well ;)

https://www.miataturbo.net/attachmen...ine=1373925566

Those appear to actually have EGR nipples on them :squint: Now I really want one.

Yeah, theyre actually UK-spec manifolds with EGR fittings. It took a long time but managed to build 2 complete sets of manifold, downpipe, and heatshield with each type of 4->2 header.

If youre actually interested, PM me and I can tell you how I managed to get all the parts.