ECU Swap 1997 Impreza

Bradenrm · Post by **Bradenrm** » Thu Jan 13, 2011 10:05 pm

G'day guys;

I've got a 1997 Subaru sportswagon. Good for about 85kw...Yeah. Nuff said.

5sp manual and dual range. Running a stock EJ20 with 150k on it. Like all subie owners say, just broken in.

Now; heres my thought process.

The Jap domestic market Subaru Legacy, with the same motor does the following:
(Naturally aspirated)
1998-2004 155 hp (116 kW) BE - BH series

And heres mine:
Power 85kW @ 5600rpm
Torque 170Nm @ 4000-4400rpm

Historically manufacturers use the same platform engine with different tuning to gradually unlock the potential on an engine over time and models. Increased output=renewed interest with less development costs. And given that the engines are the same, one would assume mine is pretty de-tuned.

So, if I happened to have access to a JDM Be5 Legacy ECU for an EJ20 5sp manual, Naturally aspirated, would it work?

As I understand, there would be an issue with coded keys/engine immobiliser/Alarm system.

I don't have any of those.

The most mods I am/are doing performance wise are Resonator removal and a full exhaust system. It's gunna stay NA.

d_generate · Post by **d_generate** » Fri Jan 14, 2011 2:19 am

Aren't the Legacy 2L n/a's quad cam? I know my 92 Legacy wagon was, they are also tuned for 100 octane fuel so you'd need to use a minimum of 98 at all times, if you find a computer and it has the right amount of plugs I guess your best bet would be to plug it in and see what happens.

Gannon · Post by **Gannon** » Fri Jan 14, 2011 5:31 am

The NA EJ25 makes 116kW

I know the JDM BE/BH models had a DOHC EJ25 that had AVCS and made 123kW

If there was an EJ20 that was built like the above, i doubt it would it would make 31 more kW over the normal one.

Even if it did, its not in the tuning, the engine had a different heads and cams which flow a lot of air, if you did just change the ECU, you might actually make it worse.

damo666 · Post by **damo666** » Fri Jan 14, 2011 8:12 am

According to Google, there was a Legacy 'R' released in Japan with a hot n/a EJ20 -140kw!!
It was a DOHC engine with AVCS and ran 11.5:1 compression, so yes, a little more than just an ECU swap.

Bradenrm · Post by **Bradenrm** » Fri Jan 14, 2011 10:31 am

Thanks for clearing that up guys. Next time I'll verify my sources better.
For now I'm going to finish my intake, and look at getting the exhaust done. I've just discovered an obd1 plug as well as the ssm port so I'm going to look into a reflash. Previous research told me its ssm only and not able to be flashed. But none of it said anything about obd1..

Post by **Alex** » Fri Jan 14, 2011 10:58 am

mate, take the car as it is.

dont waste your money on little things here and there, by the time youre done you could have done a turbo conversion and you still wont have as much power as a turbo.

my 2002 2.0l lib has 98kw. She is, but isnt a slug at the same time.

the fuel usage of 7-8l/100km is what keeps me pretty. Also the utter reliabilty.

the cheap upgrades are the only things slightly worth it...ie, $20 on a new intake. Iridium plugs etc. The rest like exhaust, wont make 2/5ths of **** all difference. Save your money(unless you want the noise)

alex

d_generate · Post by **d_generate** » Fri Jan 14, 2011 3:28 pm

Chuck a 3L H6 in it if you want more non turbo grunt, it's been done before.