17 replies to this topic

[luvin_the_rings]

Hey All, 

 

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?

 

Thanks, 

 

-Z

[Jim Drago]

the auto is: B64J18881

the manual is  B61P18881

 

The automatic computer was  known cheat back in the day as it offered a flatter a:f curve than the manual.  If you tune the manual correctly I feel it is better than the auto computer. 

 

The auto cars have a TPS sensor that the manual cars do not. many use the auto THB for use with data and use that TPS sensor for data input

[luvin_the_rings]

Sorry,  

 

What do you mean by THB? 

 

Also, Drago, I'm very curious as to why you feel the Manual ECU is better?

 

-Z

[Jim Drago]

Sorry,  

 

What do you mean by THB? 

 

Also, Drago, I'm very curious as to why you feel the Manual ECU is better?

 

-Z

thb is throttle body...

 

No opinion as to why.. just results from testing..  the auto ECU gives you a really nice looking a:f curve, but the manual always seem to make the same or better power when I tested and it was compliant to the rule. 

[Johnny D]

I updated it.
http://mazdaracers.c...ek-bread/page-1

FYI, there's federal and CA (smog) versions too, and yes he's tested all of them.
J~

[luvin_the_rings]

Is there a certain part number for CA (smog) ECU's that I should avoid? 

[Jim Drago]

Is there a certain part number for CA (smog) ECU's that I should avoid?

You should run the one posted above..

avoid the 93 Ca emissions, it is 93 ca emissions only
B6AW18881

[luvin_the_rings]

Thanks Drago, 

 

Appreciate the dimes of wisdom and quick responses.  

 

-Z

[Dan Tiley]

We recently tested this one in a customer car.  Not sure of the part number, but it seemed to make for a nice gain in the 7200 - 8300 RPM range over the B61P ecu.

 

[David L]

Always glad to see you joking about cheating Dan!

[Jim Drago]

We recently tested this one in a customer car.  Not sure of the part number, but it seemed to make for a nice gain in the 7200 - 8300 RPM range over the B61P ecu.

 

dam, that has my car number on it, I thought I got rid of that thing   

[Dan Tiley]

Always glad to see you joking about cheating Dan!

 

C'mon... lighten up.  You don't find even a little bit of humor when a customer brings in a car that has an ECU labeled like that, which in a 1.6 car is right in plane sight on the floor?   Customer bought the car 2nd hand, and brought it to us because his said his "rev limiter was broken".  He left with a B61P, which actually made more power.  Well, up to 7200, it did

[davew]

At least he wrote on the bottom side of the ECU. Car probably had cams and compression too. Back in 2003, invasive tech was checking your socks !!!!!!!!!!!!!

[Steve Scheifler]

^ !!!

[David L]

I personally believe it is in poor taste coming from you.  But I understand why you would want to change the culture.

[Tom Sager]

We recently tested this one in a customer car.  Not sure of the part number, but it seemed to make for a nice gain in the 7200 - 8300 RPM range over the B61P ecu.

 

 

That's a Canadian unit.  With the exchange rate you get 8300+ RPM.  

[luvin_the_rings]

Its probably because a full rotation in Canada is actually 400 degrees rather than 360.  So with the conversion factor on the USDM tach's it just reads 8300, but its actually still 7,000.

 

[Tom Hampton]

I want a 7000*k* Rev limit!