just bought a 1997 JDM ITR motor and have the 1997 USDM p73-a02 ecu wired up. i've been debating on a pherable jdm basemap and obd1 conversion since it would allow AC to work but i was honestly wondering if the map is much different or if any time would be picked up in the quarter. it;s such a basic question i figured a few of you guys would know off the top of your head. i know the redline moves from 8400 to 8700? anything else like timing and fuel changed? think it's worth doing?

 

say hello to 180km/h speed governor.

 

From my experience (JDM ECU and USDM ITR ECU), the JDM ECU will not yield any advantage over it's USDM counterpart. In fact, i almost feel like there is better performance with the USDM ECU. Of course, this is all based on my butt dyno without any real figures to back it up. But the advantage to running a JDM ECU is that you can get away with running a test pipe as it only looks for one O2 sensor.

 

fuel, ignition maps tuned for different engine compressions and octane ratings.

 

that's the general impression that i also have. since the engines are identical other than the half a point of compression it seems like the usdm ecu would be safer since it was tuned for our fuel. from what i gather the JDM ecu has more aggressive timing which might add power or it might cause detonation on 100degree days. the governor is easy to get around since i would basically be burning a jdm basemap on a p72 obd1 ecu. of course if i keep the usdm ecu i keep the ability to use a scan tool and $250. has anyone in here ran a jdm map in the hot weather? any knocking problems on 91 octane? by the way, what is the compression of the 97 JDM ITR? the net says everything from 11:1 to 11:3

 

96-2001 JDM ITR compression is 11.1:1 I wouldn't run a JDM ECU without access to at least 96 octane fuel, (which is the minimum standard octane rating for premium gas here)

 

correction:

Running a JDM ECU with octane lower than 96 octane should be okay as long as you are maintaining stock USDM compression, but you won't gain anything from using a JDM ECU on a USDM engine

 

What about running a JDM ITR engine with USDM ITR ecu? This is my current setup also and I am wondering if there is any harm done with only 91 octane available. I also have the JDM ecu, but the plugs don't match my wiring harness. I think the JDM engine/ecu is a '98 and my Integra is a 2000. What is the difference between the '98 and a '00 wiring harness?

Thanks.

 

I've never seen or heard of anyone running USDM ECU with a JDM B18c. I would assume that it wouldn't run too well since the timing and fuel are different. My guess is that it would run too lean.

Not too sure of the USDM ECU connectors (someone else might need to shed some light on this) but I believe that all JDM cars are ODBI connectors.

If you're not too sure of what ECU is best for your setup, you might consider a stand alone, or even a piggy back and readjust the timing and fuel to what's best for your setup.

 

I have been using the USDM ecu for California smog testing. I don't think its running very lean, because it barely passed. It put out the maximum alowed hydrocarbons.
I think once I get my header and some cams Im going to just get hondata for my original GSR ecu and have a dyno tune.