ej20 question

subarutech7 · Post by **subarutech7** » Wed Apr 28, 2004 5:48 am

hey new to the site and a few questions too. first i work at a subaru dealership and the owners have a ej20 motor with a wrx turbo and intercooler on it but the problem is that the engine is still running off the old ej18 motor ecu. So they had some guy fix, or tune the ecu to run the turbo motor. the tech who did the swap pulled all the ej18 sensors off the old motor and put them on the turbo model. so they want to sell me the motor for 1000. but i can get the same motor with the wiring harness and ecu from nippon motors for the same price. also i have a 91 n/a car and if i were to buy the motor from nippon motors what mods am i looking at besides a crossmember. what about wiring for the rest of the car "dashboard,a/c, radio,cruise,etc. so please fill me in on the details about this swap. or else i'm going to be putting a 2.5 n/a in it. what about a 2.5 block with 2.2 heads? would it work? what's the compression ratio on that?

thanks.

subarutech7

rsstiboy · Post by **rsstiboy** » Wed Apr 28, 2004 12:06 pm

i wouldn't touch it if its been running on a EA82 ECU, its probably stuffed by now..........

greg donovan · Post by **greg donovan** » Wed Apr 28, 2004 1:14 pm

i may try a phase II ej25 short block w/ej22 heads. we have no idea what the C/R will be but it will be a little high. will definately need the highest octane available. and may build a water injection setup.

Post by **Legacy777** » Wed Apr 28, 2004 2:31 pm

rsstiboy wrote:i wouldn't touch it if its been running on a EA82 ECU, its probably stuffed by now..........

he said ej18 ecu......which is pretty much the same as the ej22 series

vrg3 · Post by **vrg3** » Wed Apr 28, 2004 5:12 pm

I think you should find out more about what this guy did to make the ECU appropriate for the engine.

Depending on the year of the motor from Nippon Motors, it could be a fairly easy swap. Do a search for "ej20 swap" or something to see what others are doing. The wiring could be fairly similar to your car so you might be able to get away with modifying your car's existing harness rather than trying to incorporate the JDM harness.

Matt Monson · Post by **Matt Monson** » Thu Apr 29, 2004 10:23 pm

vrg3 wrote:I think you should find out more about what this guy did to make the ECU appropriate for the engine.

Depending on the year of the motor from Nippon Motors, it could be a fairly easy swap. Do a search for "ej20 swap" or something to see what others are doing. The wiring could be fairly similar to your car so you might be able to get away with modifying your car's existing harness rather than trying to incorporate the JDM harness.

Well,
My experience in this realm is showing this to be a bit more work than initially planned. The main reason is compatibility of connectors. I don't know if it is because my car was made in USA and runs a Hitachi ECU, or if it is a difference between '90 (the car) and '93 (the engine) harnesses in general. Jaxx is running an Ej20G just like the one you described at the dealership. He took the Ej18 engine harness off of his stock motor and rewired the EJ20G with it so he could plug it in. I was going to do the same thing with my Ej22 to EJ20G conversion until I scored a JDM bulkhead harness that will mate to my engine. Buying that engine prewired will be a lot easier to get in if it will mate to your car's harness. While Jaxx runs a TECII on his engine, others have done this swap using the EJ18 ECU and a boost controller and AFC for engine management.

If you get an EJ20G from Nippon, you will end up doing exactly what I am doing and repulling the harness through the car. I have decided this is easier than taking off the manifold and rewiring the engine itself. And you will also be running the correct ECU once you get it in there.

Whatever you decide, it isn't terrbily simple to do...

vrg3 · Post by **vrg3** » Thu Apr 29, 2004 11:21 pm

Matt, I'm curious what was so different... It seemed to me that you could just switch a couple of contacts in the ECU connectors and add several more.

Matt Monson · Post by **Matt Monson** » Fri Apr 30, 2004 3:08 am

vrg3,
I was under the initial impression that would be the case as well. What is so different is the connectors themselves. I don't know if it is because my '90 is US made and Hitachi brained. Or if they are connectors that are specific to the '89-91 Legacies, and if I got an older engine they would match up. But I know that I have 3 different engine harnesses in my garage and they have three different sets of connectors. Without counting how many pins per connector, they are as follows:
1. USDM American made Hitachi brained '90 BF EJ22 engine harness with three square connectors
2. USDM unknown country JECS brained '93 BF EJ22T engine harness with 2 square connectors and one round white one
3. JDM JECS brained '93 BF EJ20G engine harness with two square connectors that have more pins that the others.
I don't expect this to be my only swap, so I should be able to gather more about this over time, but I was left deciding between one of two things:
1. Pull the EJ22 NA harness of the engine coming out and rewire it to the EJ20G so it would plug into the car.
2.Get a JDM leftside chassis harness and replace the one in the car.
I chose #2 because I don't have to pull the main bulkhead harness. That harness stays and not only runs the ABS, MAF, etc, but powers the stereo,heater, A/C and all that jazz. I have one of these harnesses from the same '93 Legacy turbo and it is quite indimidating. And as you know, most, if not all of the pinouts where it plugs into the ECU are the same (assuming the connectors on a Hitachi ECU are no different than a JECS ECU, seeing as I haven't checked that out yet. If not, I have that other bulkhead harness) And then I just need to add a handful of wires for the wastegate control solenoid, the pressure sensor,etc. that are extra on the turbo and part of that bulkhead harness. I will absolutely post a blow by blow in the electrical forum once I start on this over the weekend...

vrg3 · Post by **vrg3** » Fri Apr 30, 2004 3:16 am

Ohh... you're talking about the connectors that go behind the battery... I thought you were talking about the connectors on the ECU end, which is why I was confused.

They used a bunch of different setups for those connectors between the car harness and the intake manifold harness, yes. They are different between turbos and non-turbos, and probably between Hitachi and JECS among non-turbos as well.

Why couldn't you just pull the harness off the intake manifold of the stock engine and put it on the intake manifold of the turbo engine (in other words, use the complete stock harness for your car)? The sensor/solenoid/etc connectors should all be the same except for the ignition coils, right? And then you add the couple of wires for the turbo-specific stuff... And swap the + signal wires for the cam and crank angle sensors.

When mTk swapped an EJ22T into his car that's how he ended up doing it (minus the modifications for the coils of course).

Matt Monson · Post by **Matt Monson** » Fri Apr 30, 2004 3:45 am

Re-read. That is option #1 above. It is more work than option #2. Either rewire 2 engines, including switching any connectors and accessories that are not compatible with the new engine. OR, pull the harness out of the car and pull a new harness through in it's place. It is costing a little more, but option #2 is far less time consuming...

vrg3 · Post by **vrg3** » Fri Apr 30, 2004 4:46 am

Yeah, it sounded like option #1... but you said option #1 was a lot of work and what I described didn't seem like that much work.

Why is it so much work? What connectors other than the ignition differ?

Matt Monson · Post by **Matt Monson** » Fri Apr 30, 2004 11:01 pm

Jaxx made a post somewhere about the connectors and accessories that wouldn't plug into the old car's harness. Beyond that, you've got to dismantle a ton of hoses and lines, coolant tank, replace the gaskets for the manfiold, etc. etc. There is also the issue of the ignition that you mentioned. It is not a simple as it sounds. Plus, why cut and extend wires when you can just get a factory harness and plug it in?

vrg3 · Post by **vrg3** » Sat May 01, 2004 2:42 am

If I remember right, mTk didn't have to remove the intake manifolds to swap the harnesses. All he had to do was add a few wires, which is significantly less work than changing a wiring harness. I've tried to pull a wiring harness from a Legacy and after a couple hours gave up and cut some wires to get them out of the car.

I'd be interested in reading Jaxx's post if you can find it... I didn't see it in a search; was it on another board?

Matt Monson · Post by **Matt Monson** » Sun May 02, 2004 12:48 am

yeah,
Sorry, I should have been more clear. There's like four Ej20G conversion threads on Nabisco's conversions forum right now...

mTk · Post by **mTk** » Sun May 02, 2004 1:33 am

I swapped the engine witing harness, didn't have to remove the intake manifold, just unbolted it and lifted up a few inches. The car harness i added the turbo specific wires to, (6 total i think?) and swapped some pins on the harness side of the ecu connector.

MK

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