Robbks
08-30-2010, 10:08 PM
After purchasing my 94 JDM BG5 GT Legacy a year ago, the time has come to finally upgrade the ECU.
The previous owner swapped the tired old EJ20H that as stock in the JDM GT with a low mileage (40,000km) EJ20R from a Manual JDM GT-B but still using the standard EJ20H ECU, injectors, AFM, etc .
the main differences between the two is
the EJ20R has much better flowing heads/ cams,
440cc (yellow) injectors,
higher factory power output,
lower compression ratio (allows more boost, safely)
bigger turbo combination
single wastegate (primary only)
larger throttle body
and also a few different engine sensors (AFM, MAP)
The issue with swapping the engines is that the EJ20R simply flows a lot more air than the EJ20H and as such, the engine runs very lean when on boost.
Along with the lower compression engine requiring much more ignition timing to get the same power from the engine. And as such the car was very lifeless to drive.
I have used a Haltech Interceptor (Piggyback ECU) to adjust the fuelling correctly and add some ignition timing to make the car nicer to drive.
however, when running only 11-12psi of boost pressure, the stock injectors were maxxed out at 5000rpm.
So I swapped in a set of 440cc units and now I have more than enough fuel. however, the Interceptor has to make a lot of adjustments at idle and low RPM to compensate for the larger fuel flow, which gives me issues with a higher than normal idle when warm, and poor driveability when very cold.
The solution.
Wire in the correct ECU for the EJ20R.
This also requires the MAP sensor and AFM to be changed for the matching items.
the major issue is the entire ECU loom needs to be re-pinned to suit the different ECU plugs, and actually finding the correct wiring diagrams in an English translation is a nightmare.
however, I finally have all the pieces together to start building an adaptor loom, that can be easily plugged in and out as required
along with swapping the AFM and MAP sensors.
I will get pictures and part numbers of all the parts required, along with posting all the pinouts once they are confirmed correct.
m,y only other hassles is the fact that the EJ20R was only put into Manual GTB's and my car is (and will stay) an auto. hence the ECU does not supply torque control signals to the TCU and transmission. however, this has been done many times before and does not cause major issues with the transmission until you're making very big power
The previous owner swapped the tired old EJ20H that as stock in the JDM GT with a low mileage (40,000km) EJ20R from a Manual JDM GT-B but still using the standard EJ20H ECU, injectors, AFM, etc .
the main differences between the two is
the EJ20R has much better flowing heads/ cams,
440cc (yellow) injectors,
higher factory power output,
lower compression ratio (allows more boost, safely)
bigger turbo combination
single wastegate (primary only)
larger throttle body
and also a few different engine sensors (AFM, MAP)
The issue with swapping the engines is that the EJ20R simply flows a lot more air than the EJ20H and as such, the engine runs very lean when on boost.
Along with the lower compression engine requiring much more ignition timing to get the same power from the engine. And as such the car was very lifeless to drive.
I have used a Haltech Interceptor (Piggyback ECU) to adjust the fuelling correctly and add some ignition timing to make the car nicer to drive.
however, when running only 11-12psi of boost pressure, the stock injectors were maxxed out at 5000rpm.
So I swapped in a set of 440cc units and now I have more than enough fuel. however, the Interceptor has to make a lot of adjustments at idle and low RPM to compensate for the larger fuel flow, which gives me issues with a higher than normal idle when warm, and poor driveability when very cold.
The solution.
Wire in the correct ECU for the EJ20R.
This also requires the MAP sensor and AFM to be changed for the matching items.
the major issue is the entire ECU loom needs to be re-pinned to suit the different ECU plugs, and actually finding the correct wiring diagrams in an English translation is a nightmare.
however, I finally have all the pieces together to start building an adaptor loom, that can be easily plugged in and out as required
along with swapping the AFM and MAP sensors.
I will get pictures and part numbers of all the parts required, along with posting all the pinouts once they are confirmed correct.
m,y only other hassles is the fact that the EJ20R was only put into Manual GTB's and my car is (and will stay) an auto. hence the ECU does not supply torque control signals to the TCU and transmission. however, this has been done many times before and does not cause major issues with the transmission until you're making very big power