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Guest Message by DevFuse
 

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EA81T to MPFI EA81 :)


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25 replies to this topic

#1 TheSubaruJunkie

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Posted 10 March 2005 - 01:30 AM

I might have found a '84 Turbo Wagon that I'd like to transfer my lift into. I dont want to use a turbo engine for off-road use, but I would love to keep the MPFI.

I have a spare carbbed EA81 to use, for the block and pistons... Im thinking I'll need to have the heads shaved alittle to help the compression.

The only thing im unsure of is the ECU and everything. Does the EA81T run with a MAF like the EA82T's? Will the ECU miss the turbo and cause other problems?

-Brian

#2 baccaruda

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Posted 10 March 2005 - 01:46 AM

neat project.. i'd think that you could try swapping EA82 MPFI electroguts onto it if nothing else.

#3 MilesFox

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Posted 10 March 2005 - 02:56 AM

the ea81 mpfi should be compatible electrically with 85-86 ea82 mpfi components, the maf, disty, knock control, ecu. just so long as you get the wiring inb between. its speculated to be plug-and-play between ea81 mpfi and 85-86 ea82 mpfi

#4 TheSubaruJunkie

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Posted 10 March 2005 - 10:02 PM

Does anyone have the stock CR on a EA81T? I was thinking of trying to get it up to 10:1 to run w/out the turbo.

Also, is there any shadetree way of calculating the CR on an engine, maybe with a compression tester?

-Brian

#5 Ross

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Posted 10 March 2005 - 11:08 PM

7.7:1 (pretty sure). Its just a VAF sensor on the ea81t, should work fine without the turbo. the computer wont even know its not there.

#6 carfreak85

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Posted 11 March 2005 - 12:06 AM

Yeah, 7.7 is the EA81T CR.

#7 TheSubaruJunkie

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Posted 11 March 2005 - 12:22 AM

Cool. Wonder what a Carbed block and Turbo heads would make for CR? Anyone know of a way to calculate the compression?

-Brian

#8 Ross

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Posted 11 March 2005 - 12:27 AM

The ea81t heads don't change the compression as far as i know. The difference is all in the pistons!

#9 TheSubaruJunkie

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Posted 11 March 2005 - 12:29 AM

Really?

I was still thinking of having the heads shaved alittle to help. And maybe get a cam for it as well.

-Brian

#10 Ross

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Posted 11 March 2005 - 12:33 AM

I can't remember who told me that, and i don't know how they would have known, but.....sounds feasable anyway.
you should be able to run a much higher compresison ratio than the carb'd ones, since it'll have the knock control unit and so on. Sounds nice!
I was thinking of putting N/A pistons in my ea81t to give it some extra oomphh, but well see!

#11 TheSubaruJunkie

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Posted 11 March 2005 - 01:51 AM

Where is the knock control unit mounted?

-Brian

#12 Ross

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Posted 11 March 2005 - 01:53 AM

Inside the left hand fender (yes inside!). You have to take the fender off to get to it. I think its the same on early ea82ts.

#13 TheSubaruJunkie

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Posted 13 March 2005 - 03:20 AM

I went and test drove the donar car today. Its a '84 Turbo Wagon, with EA81T and auto.

The engine sounded and felt real solid. Car ran great, so i think i'll get it and work on it before the heads crack. I noticed there's alot of stuff in the engine compartment, not sure what most of it does but hope i can streamline it alittle :)


-Brian

#14 mudrat79

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Posted 13 March 2005 - 02:36 PM

As far as running the Turbo motor Off-Road......I built one last Winter, And Noah ( MSLGECKO ) over in Montana Bought it....IT is Running Just fine, and is Doing great Off-Road......I stuffed a 5 speed Hi-Lo behind it and Opened the Exhaust up of Coarse..:)

If you decide to run it Non Turbo with a Carbed Block.....

Compression is all in the Pistons as Someone stated above.....
If you decide to shave the heads , Don't Go more than 20 thousands.....That will bring your Compression up to a Nice respectable 9.2-9.6 to one I can't remember specifics.....

And the MPFI heads will still go on the Block well.....And all Turbo wiring will run it without the turbo Just fine.....

One thing to remember The Turbo motor should be a Hydralic Lifter Motor.....The Carb'ed Block you use Needs to be hydralic as well......

Another thing to check If you keep the turbo unit for now....Verify if the Turbo unit is Oil Cooled only or if it's been upgraded to the Oil and Water Cooled version.....If it is not Water Cooled Stick an Ea-82 Turbo on it.....

E-mail me if needed......I can walk you through what I did to the One I built.....

Later, John......

#15 TheSubaruJunkie

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Posted 13 March 2005 - 05:23 PM

John, thanks! I will definatly be needing some assistance. Im not sure if the Turbo is Oil/Water or just Oil. I think i'll use this EA81T wagon for transportation until my RX is all fixed up, then I will go to town on the EA81T and convert it.

Im glad to hear the comp is all in the pistons. The Carb block is a '84 so it will be hydro as well, no problems there.

-Brian

#16 TheSubaruJunkie

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Posted 14 March 2005 - 01:36 AM

One other thing... Im going to need to use the EA81T Distributor, right? Just sorting out little details.

-Brian

#17 Qman

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Posted 14 March 2005 - 03:30 AM

'84 doesn't guarantee hydraulic. '83/'84 with autos are hydraulic and anything from '85 on.

#18 Ross

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Posted 14 March 2005 - 05:34 AM

One other thing... Im going to need to use the EA81T Distributor, right? Just sorting out little details.

-Brian


Yeah, use the ea81t distributor. It has a different ignition module in it for the knock control system.

#19 TheSubaruJunkie

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Posted 14 March 2005 - 07:29 PM

Ken, what is a surefire way of knowing wether or not my EA81 Carbbed from my '84 is Hydro or not?

-Brian

#20 jeffroid

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Posted 14 March 2005 - 07:42 PM

I'm not Ken, but someone much wiser than myself in regards to Subarus pointed out to me in a post a while back that all you had to do was look for the boss for the knock sensor. Just behind the carb (towards the rear of the engine) there will be a raised boss casted in to the engine block if the engine has hydro lifters. This raised boss is for the knock sensor on the turbo motor. If you don't have a turbo, you won't have the knock sensor of course, but if you have the raised boss, you do have hydro lifters.

At least that's what I was told.

I've been following along because I am facing a similar delimma. I just picked up a near cherry '84 turbo wagon with a toasted motor. I can't decide whether to rebuild it or drop in a spare EA81 non turbo block, use the turbo heads and nuke the turbo. I'm curios to see how your situation turns out.

Anyway, sorry for hijicking your thread.

#21 Ross

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Posted 14 March 2005 - 07:48 PM

I have also heard that all hydro lifter engines will have the knock sensor boss. The push rods also have different ends, someone posted a page from a manual showing the difference, but i can't remember who.....

#22 TheSubaruJunkie

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Posted 14 March 2005 - 08:00 PM

Jeff, no worries mate :) That info is exactly what i was looking for.

If I put a non-hydro block with hydro heads... what can I expect to go wrong?

-Brian

#23 GLCraig

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Posted 15 March 2005 - 01:08 AM

Jeff, no worries mate :) That info is exactly what i was looking for.

If I put a non-hydro block with hydro heads... what can I expect to go wrong?

-Brian


I don't know, but back when I was working at a Subaru shop, they never had a problem when the put N/A heads that were origionaly on a hydro engine on a non-hydro block.

#24 Ross

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Posted 15 March 2005 - 01:43 AM

I cant think of any reason why there would be a problem either. The rocker assembly looks the same. :-\

#25 TheSubaruJunkie

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Posted 15 March 2005 - 02:05 AM

Yeah, and if I use the pushrods from the non-hydro engine, i dont see how the pushrods will know.

I cant wait to get started. Im waiting for the owner of the 84 to get it smogged. If it fails, I'll be at ground zero.

Im crossing my fingers.

-Brian




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