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ea81 mpfi build


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has anyone done this before I am thinking about building a motor for our touring wagon which will be a hydro ea81 WITH TURBO HEADS so can I use the FI the wagon already has I know the injectors are in the heads on the ea81 and in the intake on the ea82 but using the ea81 intake and changing over the senors and engine harness will it work?

 

I'm tried of the ea82t and have all the parts I think to build the EA81 I am asking about

 

and I AM NOT EJING THIS THING OK SO DON'T ASK

 

I have luck out ej cars owned five and have all leaved me stranded water pumps locked, tbelts,bad heads,crank keyways

 

its ea81 mpfi or ea81 spfi

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Its def an interesting idea. Im not sure its do-able or not but i will be keeping a close eye on this thread and see where it goes. I have a Solid lifter EA81 apart in my basement waiting to be built up and if you find there is a somewhat simple way of doing a MPFI EA81 then by all means do it and report back.

 

I will add that you will most likely be using some sort of hybrid harness to run it since the EA81T computer is not calibrated correctly for running N/A applications. Also the EA81T used a flapper style maf and you would be much better off using a hotwire maf like the 86 on EA82 SPFI engines did. As i said..mixing and matching parts to come to a combination that works on that motor.

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I have luck out ej cars owned five and have all leaved me stranded water pumps locked, tbelts,bad heads,crank keyways

 

You aren't doing the proper maintenance then. They don't just run forever without being touched. Everything you mention is bad maintenance or assembly problems and that can and does happen to all engines including EA81's.

 

And for the record I've replaced more EA81 water pumps for actual *failure* than I have EJ water pumps. The saving grace is that it takes all of 15 minutes to change the EA81 pump.

 

EA81's are good engines, but I wouldn't put a lot of time and energy into making one MPFI - the parts, such as the heads, are too rare to consider running them on a daily.

 

SPFI is capable of 16 more HP than a stock EA81 is rated for and there's likely a little bit of overhead on top of that. Why go to the added complexity and use of rare parts in order to gain basically nothing?

 

GD

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Because I have kept the parts over the years I've owned 2 rusted out 84 turbo wagons. and the touring wagon was a stock turbo car I got out of FL. with a thrown rod so, I swooped in a xt mpfi N/A motor and ecm 3 years ago I wrote a thread on It.

I just want to know any one else thoughts about it. The motor will be a 86 hydro low mile short block with 84 turbo heads and intake It look like all the sensers on the intake will switch for the ones 89 turbo intake

 

oh GD the ejs I've owned were almost new mile cars 2003 up and when I had them they were under warranty the first one happen while I was in college 04 and was working at a subaru dealer at the time it was a 03 wrx wagon

I take better care of my fleet of cars than most people you will find for that matter I've been drive my rx turbo for 11 years I know what I am doing

 

right now I own 7 subarus all running from a 76 FE coupe to a 91 xt6 and thats not counting the almost 30 rust buckets I have on my farm thats what normally kills subarus here in the southeast they were cheap 4wds were drove in salt, snow, mud, dirt roads and NEVER WASHED my family has own subarus since 1974

I know how to fit them

 

the new ones just aren't as good as the 70s a 80s

Edited by 84gl
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SPFI is capable of 16 more HP than a stock EA81 is rated for and there's likely a little bit of overhead on top of that. Why go to the added complexity and use of rare parts in order to gain basically nothing?Quote GD

 

the car is already mpfi on wiring needed less work going to have too build a motor anyway

 

My Brats already spfi would like to try something differant for a change

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2003 and up is your problem - those are crap.

 

Get yourself a 90 to 94 EJ22 for the car. Trust me - it's a much better swap and the early EJ22 doesn't have the problems of the later EJ's. They cost-cut them to oblivion in '95+ cars. Even the EJ22 suffered in some ways. The original EJ22 design is yet to be surpassed by later generations of the EJ engine. It's a high-water mark for the Subaru brand in general.

 

I would argue that the EJ22 is just as reliable as the EA81. And the benefits are worth the little bit of trouble to do timing belts now and then. Plus they are totally easy to do belts on.

 

GD

Edited by GeneralDisorder
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well I've never owned a 89-94 legacy or the 95-99 legacy or outback you might be right about them but I still have every part I'll need to build this engine if I was to ej it I would have to get a parts car for the harness,engine and make an adapter plate weld up and redrill a flywheel. Thats more work, time, mods and money than I want to spend. besides finding a good low mile 89-96 ej22 is almost impossable down here for less than $1500

 

People crushed everything they could get there hands two years ago when metal was high there is almost on cars older than 97 around here. heck I ran one guy off the farm for trying to buy or still my junk I had to move them out of sight

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Heh - I understand what you mean. The old stuff is getting scarce - though I have no trouble finding 90 to 94's here - other parts of the country differ and I know that.

 

As to if it will work - I'm sure it will given enough fidling about. If it were me, I would do something like MegaSquirt on such a thing. That way I wouldn't be limited to running what the EA82's ECU wanted. I could mix/match at will and simplify. You could even build an adaptor harness to use the car's existing wireing since there will be enough wires to do the job.

 

GD

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  • 3 years later...

Thread dig:

 

I'm wondering if you've got any pics of this conversion, I'm namely after how you mounted the injectors as I too am interested in doing this to an EA81.  The subaru MPFI system works fine for what I want and I think that and the EA81 should make for an interesting combination for a cheap daily driver.

 

Regards

Bennie

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He was going to use ea81t heads.  The injectors would have mounted just like stock.  If you want to see a picture I'll try to remember to snap a few when I get home. 

 

 

Side note, I may have asked this before but 84gl, where in southwest VA are you?

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That's awesome mate!

 

Could I please be a pain and ask for the last photo to be reshot and have one from the front and rear of the head to look at angles a bit better?

 

I'm also keen to see what the factory fuel lines look like since you've got them in that last pic; and the last thing, a measurement for the face of the injector boss that's cast into the heads, how high it sits off the outside of the casting.  This is pretty exciting stuff for me over here as we never got the EA81T from factory, even their heads are super rare!

Does anyone know of injector bosses that can be purchased to have welded in place like the above?  I'm wanting to do this to a set of NA heads as a shits and giggle project.  If not I guess I'll have to machine up a set.

 

Thanks heaps for the pics and help so far BRATMAN!


Cheers

Bennie

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I'll do my best to remember to get these measurements and some extra pictures for you this evening.  I snapped those real quick as we were going out the door for dinner last night.  I'll get as much detail as possible for you.

 

It's greatly appreciated!  

 

I have done it have to modify disstrubutor drive gear and power strering is pain use ea 81 intake with ea82 wire harness need a 85 ea82 throttle body rest should work fairly easy need to use a lower rad hose from a 94 loyale the s hose

 

Sounds about right Ivan, I didn't know the trick with the lower radiator hose.  Why do you specifically need an '85 EA82 throttle body?  I was going to adapt an MPFI one to keep it all related to the wiring harness and associated sensors...

 

Regards

 

Bennie

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That's awesome mate!

 

Could I please be a pain and ask for the last photo to be reshot and have one from the front and rear of the head to look at angles a bit better?

 

I'm also keen to see what the factory fuel lines look like since you've got them in that last pic; and the last thing, a measurement for the face of the injector boss that's cast into the heads, how high it sits off the outside of the casting.  This is pretty exciting stuff for me over here as we never got the EA81T from factory, even their heads are super rare!

 

Does anyone know of injector bosses that can be purchased to have welded in place like the above?  I'm wanting to do this to a set of NA heads as a shits and giggle project.  If not I guess I'll have to machine up a set.

 

Thanks heaps for the pics and help so far BRATMAN!

 

Cheers

 

Bennie

There are some pictures of EA81T heads in this thread,

 

http://www.ultimatesubaru.org/forum/topic/119688-ea81-swaps-and-ac/

 

I have enough extra EA parts (2 complete EA81Ts) to build a N/A MPFI and a stock water cooled turbo version. I would need stand-alone for the N/A EA81T because I don't want to cut down my only good stock wiring harness.

Edited by Crazyeights
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I thought the ea82 tb gos in at angle and the ea81 gos strait in could be wrong also thought was somthing with the throttle pos senser the 85 ea82 used the same mangment as ea 81 well close thiss tb bolts up and plugs in. On the one i biult we used a soilid lifter block with turbo ea81 heads this setup reved realy good and no ticky ticky if i biult one again i will use wrx 2.0 pistons or 89-94 ea82 gl10 pistons with drilled oil feed holes and pin rings way stronger and can rev and boost it to the moon

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I thought the ea82 tb gos in at angle and the ea81 gos strait in could be wrong also thought was somthing with the throttle pos senser the 85 ea82 used the same mangment as ea 81 well close thiss tb bolts up and plugs in. On the one i biult we used a soilid lifter block with turbo ea81 heads this setup reved realy good and no ticky ticky if i biult one again i will use wrx 2.0 pistons or 89-94 ea82 gl10 pistons with drilled oil feed holes and pin rings way stronger and can rev and boost it to the moon

 

There is an EA82 MPFI "spider manifold" that points the throttle body towards the firewall much like the EJ's do.  But that should be able to be unbolted and placed where ever you want.  With the NA and turbo MPFI "run of the mill" EA82s the throttle body is positioned straight up.  This part should be relatively easy to move to where I want it come the day I get to this point.

 

I would be using the hot wire MPFI system for the management on this engine - only because I've got a couple of setups stashed in the shed.

 

Will EJ20 pistons actually fit in an EA81?  I'd reckon that the EJ18 would be more like the go due to the same capacities if they were to fit at all - or do you have to more out the EA81 block for them to fit?  Drilled oil feed holes - on the piston head or for the turbo?  Just curious!

 

The tick tick ticky tick drives me nuts with the EA82s!  I love how EFI setups look after them selves, return good fuel economy and good performance when needed.  I'm hoping the EA81 MPFI will do the same thing with the same EA81 reliability they're known for!  That's the aim.

 

Cheers

 

Bennie

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No worries, I've been trolling Google images and have found a few good ones.  But if you could still take those pics and get those measurements that would be awesome help in working out what I'm going to do.

 

Been looking for injector bosses but can't find anything that looks like it would suit my needs.

Cheers

Bennie

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the ea 81 pistons have sloted oil ring feed the 2.0 and late ea82 turbo pistons have drilled oil ring feed holes this makes piston stronger. The 2.0 pistons will fitt but must press wristpin bushings out and use 2.0 wristpin. I think you will find that the hot wire tb dosent bolt up very easy could be wrong has been a while since last ea81 turbo engine. PS have 4 ea81 turbo long blocks and 12 crank and rod assemblys from ea81 saved for the airplane guys

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