-i just got a type-r with the following mods. i had to switch out my JDM ecu for the my USDM for inspection my question is should i stay with the USDM ecu or switch back to JDM. right now it runs perfectly fine with Both. i just hear that the JDM's run rich sometimes so idk i havent gotten strait answers most ppl are either for or against it.
- also my temp guage plays games and never actally heats up to normal temp is that from the mugen thermo?

Mods:
-JDM ITR header
-Carsound 2.5" cat converter
-T1R 2.5" stainless b-pipe
-Comptech OEM replacement filter
-JDM P73 ECU
-Skunk2 short shift
-Clutch masters FX100 clutch
-Finanza lightweight flywheel
-Mugen thermostat

 

the JDM ecu also has a higher idle around 1100rpm if you haven't noticed - bad for emissions and yes, getting a bit **** here, fuel consumption as well.

If your motor is USDM, then stick with it, and even if it wasn't, the USDM ecu has more conservative timing maps.

Get rid of the mugen thermostat. That's unless you run a mugen ecu or some ecu that ignores that particular sensor. Running too cool will affect your fuel consumption as the car thinks it's too cold outside and will stay in the warm-up map.

 

o damn does the motor really think that its cooler because wouldnt the idle be higher, i dont think it makes it think its cooler, cause the idle is at the normal amount

 

it's when the temperature drops below a certain threshold where it will cause the ecu to trigger the warm up maps.

Just because the car has a normal idle doesn't mean it has reached operating temperatures. The ecu adjusts and compensates as required till all preset parameters are met.

I know this from having my car cool down for 30mins after a lapping session and despite the stock gauge reading normal operating temps (not accurate obviously) the car will continue to backfire due to running rich for a few more laps till it completely warms up. My car is also equipped with a mugen thermostat but also a fluidyne rad.

With that said, I don't really see the point in having a low temp thermostat if one also runs a larger radiator. I can understand that it's obviously easier to cool something that is not as hot - in this case a thermostat with an opening point lower than stock, but once on track your temps will rise and be dictated/normalize by the amount of airflow and capacity your radiator has.

It wouldn't matter in the end if you had a low temp thermostat but a super thin half core radiator from a DX and were running in 100F temps for 30mins on end. You'll likely overheat irregardless.

 

JDM ecu for some reason doesn't pull as good as USDM ecu. I experienced both on my B18C-R motor.

And the JDM ecu has limiter at 130MPH.