JT20's Subaru

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Yup, just wish it was as simple and well documented as on the EEC-IV Ford stuff, I've done two MAF conversions on that system and it's quite straight-forward for the most part.

MAF would be ideal, it would just "work".

If he downsized injectors he risks leaning it out at low load where fuelling requirements are lower and the maps will be closer.

agreed,

probably any attempt to “fool” it is going to work over the entire rev range. It might also figure out something is up and set a code. Much safer for it to be rich than lean.

I guess a logging wideband could help determine if it’s a huge issue, but they are not cheap and then you are right back to what to do about it...

I guess I should stop throwing ideas out since I still think just leave it alone is the best plan.

Subies are kinda known for crummy fuel mileage anyway aren’t they...
 

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agreed,

probably any attempt to “fool” it is going to work over the entire rev range. It might also figure out something is up and set a code. Much safer for it to be rich than lean.

I guess a logging wideband could help determine if it’s a huge issue, but they are not cheap and then you are right back to what to do about it...

I guess I should stop throwing ideas out since I still think just leave it alone is the best plan.

Subies are kinda known for crummy fuel mileage anyway aren’t they...

Yup, I have a wideband rig kicking around here from back in my 5.0L days but I'm not even sure if I have all the parts for it now. It was an Innovate LM-2 I think? It wasn't an overly inexpensive kit, but as you note, the bigger issue is of course that once you've done the datalogging, you are no further ahead, lol.
 

JT20

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Yup, I have a wideband rig kicking around here from back in my 5.0L days but I'm not even sure if I have all the parts for it now. It was an Innovate LM-2 I think? It wasn't an overly inexpensive kit, but as you note, the bigger issue is of course that once you've done the datalogging, you are no further ahead, lol.

I know its being suggested to just leave it be, but apparently a 1993 or 1994 EJ22 (which is MAF) can go in, just cutting away half of something or another and welding the old stuff on.. if I'm seeing this right?
I of course have the same exact car as he starts out with.


 

JT20

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^ "Weld the 2-5 throttle body plate, I guess you could call it, onto the 2-2 intake."
 

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I know its being suggested to just leave it be, but apparently a 1993 or 1994 EJ22 (which is MAF) can go in, just cutting away half of something or another and welding the old stuff on.. if I'm seeing this right?
I of course have the same exact car as he starts out with.



Nooooooo, dude, you are over-thinking this or not understanding what's being advocated. It has NOTHING to do with the engine, you don't need to touch that. What would be ideal is if you could get the MAF ECM and harness bit from a year or two earlier that was MAF and "convert" your existing setup. Then you just put the mass air meter in your intake tract after integrating the wiring and swapping the ECM and you'd be good to go.

HOWEVER

I doubt this is that easy with the Subaru. On the Ford stuff, it was very well documented as to what needed to be done, I did a quick search this is not something that the Scoobie-Doo boys do.
 

JT20

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Nooooooo, dude, you are over-thinking this or not understanding what's being advocated. It has NOTHING to do with the engine, you don't need to touch that. What would be ideal is if you could get the MAF ECM and harness bit from a year or two earlier that was MAF and "convert" your existing setup. Then you just put the mass air meter in your intake tract after integrating the wiring and swapping the ECM and you'd be good to go.

HOWEVER

I doubt this is that easy with the Subaru. On the Ford stuff, it was very well documented as to what needed to be done, I did a quick search this is not something that the Scoobie-Doo boys do.

Oh. I see.

Also... it really appears different depending on who you ask.. apparently WRXs had 2.5s (2.5RS) and Turbo cars had MAF *and* MAP *in the same engine* if I read it right.

Ehhhhhhhhhh.

There must be something can be done...
 

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Oh. I see.

Also... it really appears different depending on who you ask.. apparently WRXs had 2.5s (2.5RS) and Turbo cars had MAF *and* MAP *in the same engine* if I read it right.

Ehhhhhhhhhh.

There must be something can be done...

The MAF Ford stuff had a MAP sensor to, but it was to atmosphere to track barometric pressure. Some boosted cars use both so they know boost as well as air ingestion.
 

JT20

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The MAF Ford stuff had a MAP sensor to, but it was to atmosphere to track barometric pressure. Some boosted cars use both so they know boost as well as air ingestion.

I wonder, then, if some kind of turbo ECU could.. hmm, no, maybe not, since it wou... actually.

Yeah.

What about a Turbo ECU?

MAP is there...
Add MAF..

????
 

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I wonder, then, if some kind of turbo ECU could.. hmm, no, maybe not, since it wou... actually.

Yeah.

What about a Turbo ECU?

MAP is there...
Add MAF..

????
No, you'd just want a naturally aspirated MAF ECM that's setup for the same injectors and sensors you are currently running + MAF.
 

JT20

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No, you'd just want a naturally aspirated MAF ECM that's setup for the same injectors and sensors you are currently running + MAF.

I. See.

I'm most disheartened to be hearing that the EJ20 ECU may not work..?

Haven't found a tuner interested in this yet.

Let me go look at to see if I can even get a Cobb unit that hides in the glovebox...
 

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I. See.

I'm most disheartened to be hearing that the EJ20 ECU may not work..?

Haven't found a tuner interested in this yet.

Let me go look at to see if I can even get a Cobb unit that hides in the glovebox...

The risk is that, as has been noted, the wiring may be significantly different for the Japanese cars, which would making it an extremely expensive task to make work in your application.

The Cobb stuff is not inexpensive from my understanding.
 

JT20

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Cobb looks like it's available for 2002 WRX 2.0 but I wonder if that would even work.

Screenshot_20210130-162043_Chrome.jpg
 

JT20

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The risk is that, as has been noted, the wiring may be significantly different for the Japanese cars, which would making it an extremely expensive task to make work in your application.

The Cobb stuff is not inexpensive from my understanding.

I mean.... Okay, real quick.. I hear what you're saying?? But, in the week or so of using this, my MPGs i may as well be driving a Ford Explorer. So I'm interested in getting it right. I get maybe slightly better mileage than your Expedition right now.

Yeah, expense, I feel we are past that.

Would a Cobb port even fit? I'm having a little difficulty getting an answer by searching, seems the 05s and later have turbos and if the WRX was like a USDM version of JDM, if that mathats sense.. if it was really 2.0, which I now have...
 

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I mean.... Okay, real quick.. I hear what you're saying?? But, in the week or so of using this, my MPGs i may as well be driving a Ford Explorer. So I'm interested in getting it right. I get maybe slightly better mileage than your Expedition right now.

Yeah, expense, I feel we are past that.

Would a Cobb port even fit? I'm having a little difficulty getting an answer by searching, seems the 05s and later have turbos and if the WRX was like a USDM version of JDM, if that mathats sense.. if it was really 2.0, which I now have...

I assume somebody makes a tuner that fits. If you can afford it, getting it tuned is definitely the "right" way to use your existing ECM.

BTW, this looks promising:
 

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What about an EJ20 MAP sensor?
No.

No sensor change is going to fix anything, you need a different (proper) fuel map for the engine you have in your ECM. I suggest contacting the people in the link I just provided.
 
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You mentioned using a 2.0L impreza computer. That would work without other problems ONLY if:
1) It was a 2.0 4-EAT setup
2) The computers are pinned EXACTLY the same -- some brands you can do this , some brands you cannot. Do not know about Subaru.
3) The gearing is the same
4) It's also MAP

With that said, you aren't going to find a NA 2.0L impreza with 4.44 gears. So you'll have all sorts of speed sensor codes. So the impreza computer would be a no-go. You can get away with this on vehicles that use the tailshaft to set the speed, but something that runs off of the ABS sensors will have problems

The gas mileage you were posting isn't really terrible for a 2002 outback. Subaru's AWD system is not the most fuel efficient and the gearing causes it to scream on the highway.
 
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