nicefighter80

i have a 97 dx hatch and im swapping in a 97 gsr, my plan was to use a obd2a to 0bd1 jumper harness and run a chipped p28 is that all ill need or will i need a obd1 dizzy too?

nicefighter80

anything?

96_civic_gsr

you can use a p72 obd2a ecu since thats an obd2a motor, no you dont need a 0bd1 dizzy.

D16SiHatch

i would recommend converting to obd1 if you have any intention of possibly needing tuning capabilities in the future. you do not need an obd1 dizzy, they are identical internally. you can convert the obd2a dizzy to obd1 plugs, or convert the obd2a engine harness to obd1 style. either way works

nicefighter80

yea my plan was to just convert the ecu harness via a obd2a->obd1 convershion harness and just run my chipped P28, that would work without modiflying anyparts right?

D16SiHatch

pretty much yea. if you are using a stock gsr manifold then you'll have to run a wire into the bay for the secondary butterflies (iab's). if you are using an aftermarket manifold then you can bypass that part obviously.

Vindicator9000

I've heard a ton of people say that chipped P28s still don't recognize IABs, and that you HAVE to run a P72 if you want to use them. I'm not sure if that's true, but it's certainly plausible. If the P28 just doesn't have circuitry to the right pin, then it doesn't matter how it's programmed.

If that's the case, you'll need either a OBD2a P72, OBD1 P72, or an aftermarket, IAB-less intake manifold for optimal performance.

You can run the GSR manifold without IABs hooked up, and it'll run 100% fine, but you'll lose a bit of torque below 5000 rpm. What they do is close the secondary set of intake runners at low rpm, allowing it to only use a set of runners that's tuned for low rpm torque. Above 5000-ish, the ECU cuts the signal to the solenoid that's holding them closed, thus allowing them to open up.

Without being wired, they'll run fully open all the time, thus robbing some low torque. A little strange, I know, but it's part of the magic that is the GSR.