Ok maybe you guys can help, I searched and really have not found any reasons why.

Let me give you guys a quick run down, a b18c5 is going into an 1994 ex auto, yes its being converted to manual. Anyways back to my question.

I am hearing a lot of people tell me, if I use the p73 make sure its the jdm p73, not the usdm one. Can some of you guys tell me the main differences, I don't understand how one could be used, and the other can not.

 

Have you tried here first https://honda-tech.com/zeroforum?id=18 ??
Since you have a hybrid it might be slightly better, Good luck.

After all most of us don't know **** about building cars we just bought our Rs to be cool

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bbasso &raquo;</TD></TR><TR><TD CLASS="quote">Have you tried here first https://honda-tech.com/zeroforum?id=18 ??
Since you have a hybrid it might be slightly better, Good luck.

After all most of us don't know **** about building cars we just bought our Rs to be cool </TD></TR></TABLE>

I will try there next , just figured some guys in here would know a little about the p73 ecu.

 

JDM P73 is tuned for JDM gas (94 RON) & 11.1 compression. I say keep the ECU matched to the motor (i.e. USDM P73 for your B18C5). Plus the JDM P73's have a speed cut at 118mph.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Stealth 95 GS-R &raquo;</TD></TR><TR><TD CLASS="quote">JDM P73 is tuned for JDM gas (94 RON) & 11.1 compression. I say keep the ECU matched to the motor (i.e. USDM P73 for your B18C5). Plus the JDM P73's have a speed cut at 118mph. </TD></TR></TABLE>

Well it seems like the other reason is because the jdm one does not look for a second 02 sensor.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 90blackcrx &raquo;</TD></TR><TR><TD CLASS="quote">

Well it seems like the other reason is because the jdm one does not look for a second 02 sensor. </TD></TR></TABLE>

Why would that be? I have always been under the impression, through all the various articles that I've read over the years, that the Japanese had more stringent smog laws than California.

Also, if what you say holds true, why would someone have to install a chipped P28 to make an OBDII car, OBDI (for the use with mods)?

Aloha,
Brandon

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Haleiwa-Brando &raquo;</TD></TR><TR><TD CLASS="quote">
Why would that be? I have always been under the impression, through all the various articles that I've read over the years, that the Japanese had more stringent smog laws than California.
</TD></TR></TABLE>

Well that seems like the only advantage to using a jdm ecu, is the wiring is a tad easier, if anyone else has any other reasons chim in.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Haleiwa-Brando &raquo;</TD></TR><TR><TD CLASS="quote">
Also, if what you say holds true, why would someone have to install a chipped P28 to make an OBDII car, OBDI (for the use with mods)?

Aloha,
Brandon</TD></TR></TABLE>

The reason the chip needs to be installed is so you can have a higher rev limiter, and maybe a different vtec engagement point. And there are other reasons but I would think those are the main ones.

 

Actually, the JDM P73 does not look for a number of sensors: second oxygen sensor, VTEC pressure switch, and purge valve. It also doesn't look for a crankshaft speed fluctuation sensor. But accoring to the local Acura dealership, neither does the early USDM SCU (not so sure he is correct on this one). The absence of these sensors may seem trivial. But there can be ALOT of trouble and expense associated with getting them wired up.

The oxygen sensor is perhaps the easiest to deal with. All you have to do is have a bung welded into the cat or exhaust system to mount the oxygen sensor. Then you need to install the wiring. Of course, the sensor can be pricey. But having to install this sensor is more of a nuisance than anything else.

Things get worse with the VTEC pressure switch. Not only do you need the sensor and the wiring. But you also need to buy the mount for the switch and spool valve, as the mount on the JDM motor has no provisions for the VTEC pressure switch. This probably won't come cheap.

With the purge valve, you will find yourself having to buy a USDM intake manifold (~$250), as the JDM manifold does not have provisions for it.

And if you DO need a crankshaft speed fluctuation sensor, you will need a new oil pump cover and lower timing belt cover in addition to the sensor itself.

So as you can see, you might just want to run the JDM P73 instead. That is what I am running in my CRX. And it works just fine. Even on 91 octane California gas.

 

The other thing to take into consideration...00-01 P73 ECU's, OBD2b, have the infamous IMMOBILIZER.

Edit: Just to clarify, I'm talking about the USDM ecu's.

 

p30 will be used, with a jdm b18c

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by -=Zeqs=- &raquo;</TD></TR><TR><TD CLASS="quote">The other thing to take into consideration...00-01 P73 ECU's, OBD2b, have the infamous IMMOBILIZER.

Edit: Just to clarify, I'm talking about the USDM ecu's.</TD></TR></TABLE>

no OBD2b in JDM land...