dasaboi

i want to do the swap but i'm concerned about 2 things

1. Its a D16Y7 and the Y8 Head, would the automatic still be able to function correctly? will it adapt its shift points or what? what about when Vtec Engages?

2. How much would this swap affect MPG?

j0keefe21

not 100% sure but ive done some reading up on this. your automatic will be fine you have to swap ecu's so it will shift when the y8 does. and i would assume your gas mileage would be what a y8's is.

98civdx

yep you we golden, you going to have to swap a y8 ecu in so that it run, doing that it will think its a y8 motor and tranny, and it will shift where the y8 motor is supposed to shift.
im planning the same thing,
it might be higher or lower I dont know, cause your using a dx or lx block and ex head, so you might get dx millage or ex, or somewhere in the middle. maybe higher.

dasaboi

ok, thank you!

JimDCXC

I just got done doing this and I have to say the above information is incorrect. The P2P ECU out of the Y8 will not work correctly with the Y7 tranny. You will need to run the P2E ECU with a VTEC Controller. I found out the hard way.

kp

Makes this swap literally useless.

94EG8

And how exactly do you figure that? Considering that so far as I can tell Y8 automatics use the same transmission as the Y7s (B4RA, or S4RA depending on the year) So long as you use an automatic P2P ECU you should be perfectly fine, and like the guy above me said the vtec controller is absolutely useless. You need a vtec ECU to actually change the fuel and timing maps for vtec to actually do anything other than sound like vtec.

JimDCXC

I apologize if I'm wrong and I'll be the first to admit if I am but when mine was done (in the last two weeks) the P2P absolutely did not work. The car would start but it wouldn't shift correctly or sometimes at all. I had a Y7 engine and automatic tranny and was putting on a Y8 head. I tried 2 different P2P ECU's thinking maybe one was damaged but they both did the same thing. When I plugged in the P2E it ran fine but had no VTEC. The solution that we came up with was to install the P2E with a VAFC-II to activate VTEC. I'm not really looking to use most of the functionality of the VAFC, just really using it to activate VTEC. I always thought that the gears were different from the Y7 to Y8 trannys on the automatics as well. I was told that was the cause of the problem with the P2P ECU's. I'd rather be running the P2P ECU but it didn't work. If anyone can chime in on this I know I would appreciate it. Maybe there is something wrong with my set-up but I don't know what it could be.

JimDCXC

how so?

94EG8

My guess is you used a 5 speed P2P ECU, if you can post the numbers on the side of the ECUs you tried this will tell me for sure one way or the other.

JimDCXC

They were both sold as 96-98 EX, Auto ECU's but maybe they aren't, one was from eBay, and one from a junkyard parts desk.

The numbers are,

37820-P2P-A71
272-102270

37820-P2P-A82
273-205890

Which number identifies if it is auto or manual? I know that 37820 is just Honda's ECU part number and the P2P is all 96-00 EX but beyond that I'm unsure.

94EG8

I've bolded the important numbers

The A in front of the bolded number designates the country code, in this case US, the next digit (the bolded one determines if the ECU is auto or manual, 5,7,9 is usually automatic, 0 and 1 are 5 speed. I've never seen or heard tell of 8 before though.

JimDCXC

I remember seeing that the A means USDM before. I haven't opened either ECU up yet but I believe it says AT or MT somewhere on the circuit board. I read that somewhere, I'll have to find it again.