Hey H-T, I am wondering if a P28 can fit into a P72 case? I'd like to get a P28 w/ OBD2 connections from Hondata but I would like to have it fit into an OBD2 P72 case.

TIA

 

I'm pretty sure that a USDM OBD1 P28 board (rectangle) will not fit in a USDM OBD2 P72 case (square).

 

From what I gather from consulting the google, the square cases are OBD2b, not OBD2a.

 

Do you have a square case or rectangle case P72? Why do you want to switch cases? Is it to have the P72 bar code on the side? If that is the case the bar code stickers peal off very easily and you could just as easily move the P72 sticker to the P28 case. Ebay scammers do it all the time. it's not hard to tell once you open the case that it's not a P72. The processor is what makes it a P72 not the case........too each his own I guess.

 

sorry for the hotlinked images...

OBD1 P28:


OBD1 P72:


OBD2 P72:

 

My swap is currently sitting in storage and I don't remember. The reason is that I'd like to run S300 and I will be assessed more points in my class if I add an ECU that doesn't come OEM with the swap (i.e. a P28). It is a little more obvious if I were to use an adapter harness (which explains the need for a P28 with OBD2 connections). I talked w/ Hondata and they said that the P28 is the only ECU that can be repinned to OBD2 and that it might fit in a P72 case. If I run S300 with my OEM ECU, I don't get assessed any additional points.

 

I guess I could try and fit the P28 into an OBD1 P72 ECU case if the OBD2a case wouldn't work... To me, I see P72 and think GSR and not OBD1/2.

Or I could do like you said and swap stickers...

 

I can see right off the bat that the OBD1 IC12 switch that is braced to the case wall of the ECU is in a different location between the two. The OBD2 P72 doesn't look like it has room for it at all. It seems to have two switches braced against it's case.

Your image of an OBD2 P72


My image of an OBD1 P75, same case configuration as the P28.


I'm guessing that it's not going to work just from comparing the two pics. There are a few key components that would be in the way. What are the dimensions of your P72 case anyway? The OBD1 P28 case is 9 1/2" x 6 3/8"

That could work as long as Hondata doesn't modify the P28 case to fit the OBD2 connectors that they use. If they do you could try and modify the OBD1 P72 case in the same fashion. Probably easier to swap stickers if that's all the techs at the track are looking for... :shakeshead:

 

The holes look like they may be in the right spots, however, the mount for the regulator is not, which means it will have no proper heatsink. This may cause problems down the road. All and all, I don't see why you didn't just try it already.

On another note, all of this to try and cheat the *fair* rules of your class. Just remember if you win, you didn't really win. Good luck to you.

 

lol a racer with a conscience about playing fair...... Hell they don't have any when there are thousands/millions at stake. You figure a few back yard racers vying for a $250-$500 purse are going to be any better

 

lol, purse? there aren't any purses... just small trophies... maybe some contingencies.

and about the "cheating", I don't necessarily think it's cheating, more of taking advantage of grey area... if my GSR was OBD1, I wouldn't be in this position. Besides tuning, what other advantages does the 94-97 GSR have against the 98-99? Nothing that I'm aware of.

That being said, it seems that I'll probably just take the points, I have room for them anyways.

Thanks for all the replies

 

I was going to be involved with a spec class racing series where all vehicles run the same setup and chassis within spec so it's solely based on driver skill. I'm sure you'll understand where I'm coming from, people trying to work their way around the rules. Good luck in your series!

 

unless there is a 3rd party group that keeps the cars in their possession (and builds and maintains them as well), it's not truly a spec class... Look at Spec Miata, the differences between the top runners and bottom dwellers is unreal. I hear what you're saying though

 

Ya, definitely.