The EJ20G ECU Thread
Posted: Mon Jun 13, 2011 5:41 am
THIS IS A WORK IN PROGRESS - Please PM any suggestions/corrections.
This is a Sticky for the stock EJ20G ECUs and their use on the 1991-1994 US Domestic Market (USDM) Legacy SS and TW with the stock EJ22T engine. Thread also includes info on running the Rob Tune Chipped EJ20G ECU.
DISCLAIMER: Any changes made to your car are your responsibility and at your own risk. Please do your own research!
What's REALLY Required to Run an EJ20G ECU?
- Ignition adapter
- MAF
- Injectors
- Intercooler - highly recommended due to higher boost levels creating more heat
- Wiring
Edit - 3 additional things I recommend:
- Boost gauge (needed to see boost level and for MBC adjustment)
- MBC / Manual boost controller - Per Rob of 'Rob Tune' fame, "I always recommend a cheap manual boost controller, or any expensive EBC to manage boost." But not the stock Boost Control Solenoid (BCS). The stock Legacy SS/TW BCS DOES WORK w/the EJ20G ECU and the ECU's stock boost level will be used (see levels per ECU below) if preferred.
- REMEMBER > the EJ20G ECUs have fuel cut, too.
- ECU Case: The JECS-labeled case from a '92-'94 NA/non-turbo Legacy ECU works well w/the EJ20G's ECU board (not the '90-'91). The screws on the side match up and hold it in place like stock. Unscrew the 6 (PITA!) screws on the sides of the case, remove the 2 screws that attach the ECU board to the case's bottom piece, swap it to the bottom of the NA case, and reattach the cover. You'll likely need a set of vice-grips to remove 1 or more of the screws on the sides as they strip easily.
(See below for more details.)
LIST OF THREADS:
Rob's:
EJ20G "RobTune" Info- Info on getting a custom tune for the EJ20G ECUs. Please NOTE that only certain EJ20G ECUs can be tuned - reference the thread for specifics.
Rob's 4to2 Igntion Converter - This will simplify this task by installing a converter in the EJ22T's system that will work w/the EJ20G ECU.
Adapting an EJ20G ECU - Another thread by Rob to explain the techinal differences between the EJ22T and EJ20G ECUs. Includes How To reuse the stock ECU case for mounting in the stock location.
PhyrraM's:
How to: install a 4 channel ECU - Check this out if you want to save a few $$ and wire it yourself.
ECU INFO
Here's an incomplete list (scroll down for a list of injectors/turbos associated w/these ECUs):
U8, 2C - 1993/1994 WRX - 11.47psi
W6 - 1993 WRX RA - 11.47psi
W9 - 1994 WRX RA - 11.47psi
SA (STi chipped) - Ver1 STi (Sedan and Wagon) - 14.94psi
SB (STi chipped) - Ver1 STi-RA - 13.64psi
SC (STi chipped) - SAME AS Z4 - Ver2 STi Wagon - 12.78psi
Z4 - 1995/1996 WRX - 12.78psi
Z5 - 1995/1996 WRX-RA - 12.57psi
6K - Ver2 STi Sedan - 13.34psi
7K - Ver2 STi-RA - 13.19psi
Prodrive UK ECU (Prodrive Chipped) -- SAME AS 6K - 13.34psi
1C, 3B, V9, V5 - All WRX Wagons 10psi, dropping to 6.8psi
V7, 7D, 6D - 1993 to 1996 UK/Euro 11.47psi
Nearly all 4-plug EJ20G ECUs will work from Imprezas or Legacys that were available from 1989 (?) - 1996 (?).
Here's a list w/ECU, Injectors, and Turbos from HERE (remember, Rob's tune overrides the stock injector size so this is just for reference):
Impreza JDM / UK EJ20 ECU info:
Classic import (saloon) <sedan> '92- '94 (wagons are called 'estate')-
(note: 440cc = gray; 480cc =yellow as noted below.)
2C ECU code = 440cc injectors, 240ps TD05H turbo
W6 ECU code = 440cc injectors, 240ps TD05H turbo
U8 ECU code = 440cc injectors, 240ps TD05H turbo
SA ECU code = 440cc injectors 250ps TD05H turbo
SB ECU code = 440cc injectors 250ps TD05H turbo
Classic import- (saloon) 95-96
Z4 ECU code = 440cc injectors, 260ps TD05H turbo
Z5 ECU code = 440cc injectors, 260ps TD05H turbo
6K ECU code = 440cc injectors. 275ps TD05H turbo
7k ECU code = 440cc injectors, 275ps TD05H turbo
How To: 440cc Injectors in Legacy Turbo Rails
-Thread on installing the 440's.
Note on 440cc injectors. These are the JDM/UK Side-Feed, Gray top injectors. They are commonly referred to as '380cc' in the UK. I've emailed many sellers on ebay and they use '380' more often than not. If buying these injectors, make sure you understand what you're getting. My guess is the difference is due to the use of a different pressure standard in the UK vs. what the USDM market adheres to. I've also seen JDM/UK 480cc yellow tops, listed as 440cc on the ebay UK sites.
So, UK 380cc= 440cc, and UK 440cc= 480cc.
The 440's (UK 380's) actually flow closer to 450cc, when tested @ 43.5 psi/3BAR.
The JDM/UK 440's and 480's WILL FIT in the stock Turbo rails.
I don't know if the '02+ USDM WRX 440 top-feeds can be made to work w/the EJ22T intake.
And don't confuse the UK/JDM 480's w/the USDM STi 550's (closer to 525cc @ 3 BAR) used from '04-06, which are also side-feed yellow tops.
This is a Sticky for the stock EJ20G ECUs and their use on the 1991-1994 US Domestic Market (USDM) Legacy SS and TW with the stock EJ22T engine. Thread also includes info on running the Rob Tune Chipped EJ20G ECU.
DISCLAIMER: Any changes made to your car are your responsibility and at your own risk. Please do your own research!
What's REALLY Required to Run an EJ20G ECU?
- Ignition adapter
- MAF
- Injectors
- - 440/450cc gray colored side-feed from '92-'96 (?) JDM or UK WRX/Sti
- Intercooler - highly recommended due to higher boost levels creating more heat
- Wiring
Edit - 3 additional things I recommend:
- Boost gauge (needed to see boost level and for MBC adjustment)
- MBC / Manual boost controller - Per Rob of 'Rob Tune' fame, "I always recommend a cheap manual boost controller, or any expensive EBC to manage boost." But not the stock Boost Control Solenoid (BCS). The stock Legacy SS/TW BCS DOES WORK w/the EJ20G ECU and the ECU's stock boost level will be used (see levels per ECU below) if preferred.
- REMEMBER > the EJ20G ECUs have fuel cut, too.
- ECU Case: The JECS-labeled case from a '92-'94 NA/non-turbo Legacy ECU works well w/the EJ20G's ECU board (not the '90-'91). The screws on the side match up and hold it in place like stock. Unscrew the 6 (PITA!) screws on the sides of the case, remove the 2 screws that attach the ECU board to the case's bottom piece, swap it to the bottom of the NA case, and reattach the cover. You'll likely need a set of vice-grips to remove 1 or more of the screws on the sides as they strip easily.
(See below for more details.)
LIST OF THREADS:
Rob's:
EJ20G "RobTune" Info- Info on getting a custom tune for the EJ20G ECUs. Please NOTE that only certain EJ20G ECUs can be tuned - reference the thread for specifics.
Rob's 4to2 Igntion Converter - This will simplify this task by installing a converter in the EJ22T's system that will work w/the EJ20G ECU.
Adapting an EJ20G ECU - Another thread by Rob to explain the techinal differences between the EJ22T and EJ20G ECUs. Includes How To reuse the stock ECU case for mounting in the stock location.
PhyrraM's:
How to: install a 4 channel ECU - Check this out if you want to save a few $$ and wire it yourself.
ECU INFO
Here's an incomplete list (scroll down for a list of injectors/turbos associated w/these ECUs):
U8, 2C - 1993/1994 WRX - 11.47psi
W6 - 1993 WRX RA - 11.47psi
W9 - 1994 WRX RA - 11.47psi
SA (STi chipped) - Ver1 STi (Sedan and Wagon) - 14.94psi
SB (STi chipped) - Ver1 STi-RA - 13.64psi
SC (STi chipped) - SAME AS Z4 - Ver2 STi Wagon - 12.78psi
Z4 - 1995/1996 WRX - 12.78psi
Z5 - 1995/1996 WRX-RA - 12.57psi
6K - Ver2 STi Sedan - 13.34psi
7K - Ver2 STi-RA - 13.19psi
Prodrive UK ECU (Prodrive Chipped) -- SAME AS 6K - 13.34psi
1C, 3B, V9, V5 - All WRX Wagons 10psi, dropping to 6.8psi
V7, 7D, 6D - 1993 to 1996 UK/Euro 11.47psi
Nearly all 4-plug EJ20G ECUs will work from Imprezas or Legacys that were available from 1989 (?) - 1996 (?).
Here's a list w/ECU, Injectors, and Turbos from HERE (remember, Rob's tune overrides the stock injector size so this is just for reference):
Impreza JDM / UK EJ20 ECU info:
Classic import (saloon) <sedan> '92- '94 (wagons are called 'estate')-
(note: 440cc = gray; 480cc =yellow as noted below.)
2C ECU code = 440cc injectors, 240ps TD05H turbo
W6 ECU code = 440cc injectors, 240ps TD05H turbo
U8 ECU code = 440cc injectors, 240ps TD05H turbo
SA ECU code = 440cc injectors 250ps TD05H turbo
SB ECU code = 440cc injectors 250ps TD05H turbo
Classic import- (saloon) 95-96
Z4 ECU code = 440cc injectors, 260ps TD05H turbo
Z5 ECU code = 440cc injectors, 260ps TD05H turbo
6K ECU code = 440cc injectors. 275ps TD05H turbo
7k ECU code = 440cc injectors, 275ps TD05H turbo
How To: 440cc Injectors in Legacy Turbo Rails
-Thread on installing the 440's.
Note on 440cc injectors. These are the JDM/UK Side-Feed, Gray top injectors. They are commonly referred to as '380cc' in the UK. I've emailed many sellers on ebay and they use '380' more often than not. If buying these injectors, make sure you understand what you're getting. My guess is the difference is due to the use of a different pressure standard in the UK vs. what the USDM market adheres to. I've also seen JDM/UK 480cc yellow tops, listed as 440cc on the ebay UK sites.
So, UK 380cc= 440cc, and UK 440cc= 480cc.
The 440's (UK 380's) actually flow closer to 450cc, when tested @ 43.5 psi/3BAR.
The JDM/UK 440's and 480's WILL FIT in the stock Turbo rails.
I don't know if the '02+ USDM WRX 440 top-feeds can be made to work w/the EJ22T intake.
And don't confuse the UK/JDM 480's w/the USDM STi 550's (closer to 525cc @ 3 BAR) used from '04-06, which are also side-feed yellow tops.