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advise on turbo sets on ea81 1800cc motor.


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43 replies to this topic

#1 ryer_s

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Posted 05 November 2003 - 12:28 PM

hey im in the process of buy a 84 subaru awd car with a ea81 1800cc motor. My friends and i have always turbo charge all of our cars. hondas nissions ect.. and when i saw this little sh*t box i knew what was my next project. but i have only worked with fuel injection and turbos. so im pretty lost on the whole idea of turbos and carbs. i have already got 2 weber dcoes side draft carbs and they are set up as a primary and secondary. that is just how i bought them. well my point is how do you build that motor to handle boost and not be tearing the motor up. do ya have a site with a lot of history and information about my motor. when im done with this project i want to be running about 15lbs of boost. the idea is fun little rally car. thanks for the info -ryer

#2 JonOfScio

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Posted 05 November 2003 - 12:54 PM

there is a turbo EA81 engine, it was stock MPFI (EA81T). Then there is the EA82T engine stock with a turbo (MPFI as well)

There's been discussion on turboing a carbureted car off and on for a long time, and recently I've brought it back up...

It doesn't look like it's been done to our subies yet, but I hope to change that. (EA82 engine BTW is overhead cam.)

stock EA81 engine has 8.7:1 CR. the cam probably needs to be changed for something beefier, and a better breathing cam wouldn't hurt either. Then there is springs, and the rest of the drivetrain.

As far as parts, Ramengines.com has parts listed for this engine for the airplane crowd, but it's expensive. Do a search of the forums to find more manufacturers of stuff.

The EA81T engine has 7.7:1 CR, so you could grab those pistons if you needed to. Or put pistons in from a EA71 (1.6L) and raise it to 9.5:1. There already is a man with an EA82 that has pistons from an EA82 SPFI block in there. (9.5:1 for the EA82) and hasn't had much trouble with his car.

As far as carb'd turbos... I say do it, I'm going to try in time if $$$ permits.


PS: no '84 subaru has AWD. not unless it's been transplanted there from an EA82 RX, XT6, or Loyale. It's most likely 4WD or possibly FT4WD, but that would also have to come from a different model later year'd car. It's definately either FWD or 4WD if it's stock.

#3 ryer_s

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Posted 05 November 2003 - 01:12 PM

hmm im going to go back to the guy and ask about that then. because im very sure its and 84 and it had 4wd in. when i was checking it out it the man selling it enaged it. and that is the only reason why i caught my eye because its a 4wd. thanks for the info. so im guess that the duel over head cam from a ea82 will not fit on a ea81. and you cant swap the motors because of the bolt pattern. do you know if the weber dcoe's is a good carb to turbo. i bought them from this guy a long time ago and just had them inside my garage just waiting for them to go on something. who knew my dad would be right in telling me to buy them even tho i didnt have anything for them to go on. i was wondering if the're different cranks and rods the ea81. some thing that is either strong or has along stroke to raise the cc. or since the motor is a flat 4 motor it will be fine. thanks

and were can i find an lsd for both rear and front diff.

#4 calebz

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Posted 05 November 2003 - 01:16 PM

so im guess that the duel over head cam from a ea82 will not fit on a ea81. and you cant swap the motors because of the bolt pattern.



EA82 doesn't have dual OHC. And yes, the motors can be swapped.. but it isn't a direct bolt in.

Where in texas are you?

#5 ryer_s

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Posted 05 November 2003 - 01:23 PM

hey calebz im in san antonio. were are you. oh i thought the other post said the're was.

#6 JonOfScio

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Posted 05 November 2003 - 01:56 PM

the engine mounts are the same between EA81 and EA82, as far as I know. the EA81 is pushrod and the EA82 is SOHC.

The EA82 into EA81 body is a little hard depending on the car, because the engine compartment may need some work to fit it in.

as far as rods and cranks, you can change the rods and pistons out for ones from an EA71 (1600cc engine) and get more compression ratio, but I haven't ever seen anything on different cranks.

Theoretically, you could turbo those carbs. They're good carbs, but I don't know of anybody with DCOEs on their sube. DG and DF (DGAV, DGEV, DFAV, DFEV) 32/36 carb swap is common.

#7 soobme

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Posted 05 November 2003 - 02:13 PM

From what the "fly boys" say, the stock crank and rods are good for 6300RPM all day long. If U use stock Subaru EA81T pistons they are forged (Nitrous any one:brow: ) There is a place up north ( Portland or Seattle) that grinds cams for the Subarus (but I can't remember the name)
I have used that carb on a draw through turbo sys. before with good results on an air cooled VW T1 engine, so I don't know why U couldn't use it. The turbo exaust man. from a stock Subaru turbo from '83 or '84(EA81) to '91(EA82) WILL fit that engine, as will the down pipe.
I would go the wrecking yards and find a stock turbo Subaru and get the turbo, exaust man, the aluminum intake to turbo pipe, and the oil and water(if so equipt) lines.

#8 ryer_s

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Posted 05 November 2003 - 08:55 PM

is there a dohc head that will bolt onto a ea81 motor?

#9 calebz

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Posted 05 November 2003 - 08:57 PM

Nope

#10 GeneralDisorder

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Posted 05 November 2003 - 10:19 PM

In my opinion, if your looking to run 15 lbs of boost, drop in an EA82T. There's people on here that run at least 14 on those with intercoolers and boost controllers. Trying to build a turbo EA81 from a non-turbo EA81 is certainly going to cost a lot more than simply getting your hands on an EA82T, and doing a little frame rail cutting to get it in. The EA81 was not designed to be turbo'd, and the turbo version of it (the EA81T) is considerably different. And while turbo'd carbs have been done, it sure is a lot simpler to run MPFI with a turbo. In short - it might be fun to try if you have lots of money to throw away, but there are SOOOOO many EA82T's out there in the JY's for cheap that you would never be able to do it for less, and the same amount of money put into an EA82T would yeild more HP anyway. If you really want power, drop in an EJ20T or EJ22T and an EJ series AWD tranny. More expensive, but since these are the WRX style engines (the EJ22T anyway - the EJ20 being similar in design), there's TONS of aftermarket parts for them.

At least once a week someone asks about this - to date, no one has done it (for a car). There's a reason. I bet you can guess what it is.

GD

#11 calebz

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Posted 05 November 2003 - 10:53 PM

Rick pretty much summed it all up.

I only disagree with one thing:

there are SOOOOO many EA82T's out there in the JY's



This isn't the NW rick.. we don't have Turbo soobs falling out of our asses down here.. trust me.. I have looked(eww):lol:

There a few SPFI and carb cars..

and very few EA81 and earlier cars..

Soobs just aren't plentiful here.. Thats bad, because it makes it hard to find parts. But its good because you don't have competition from 3/4 of the board when you do find something

#12 GeneralDisorder

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Posted 05 November 2003 - 11:27 PM

Yeah - your right, we are blessed up here. Went to the yard today, and since it's been cold here, there was three EA81 wagons, and a coupe there. And I don't even count EA82's there are so many - probably 15 or more in just that yard.

Too bad they aren't poular down there, but I don't suppose you have much snow or wet weather either - probably why you don't see a lot of them. (the older ones anyway)

GD

#13 ryer_s

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Posted 06 November 2003 - 11:06 PM

well GeneralDisorder the thing is i have never turboed a carbed motor and would like to. yes fi is very easy to turbo and yes it is better to turbo a fi then carb just because on how much more perfect the fuel is delieverd. but i like to learn new things. if the ea81t is so much better to turbo then i will go find one and swap it out. i was told that the ea82 will not bolt up and due to the fact i dont have a lot of the machines to make my own adaptors and what not im am limited to what i can make. basically i just have a pipe bender welder grinder torch and chop saw so i can only make exhuasts, manifolds and some suspension parts. if the crank is forged in the ea81t motors. i just have to find some better rods and better pistons. i dont know how much boost the block can handle. i just want to know what will it take to get a ea81t motor a solid turboed block. for the carbs i have a set of weber dcoes. i just want to know they are a good carb to turbo. i like them so far because they handle better then a normal carb on corners because they are side drafts. or that is what i was told. i dont know why you brought up this post comes up every week. i dont know i guess you just had to bring that in. but you should also since this is a forum people go there for help and if all they are going to get is bull**** about this and that then that is a really sorry forum. honda civics were never a turboed car but its not hard to get them boosting

#14 calebz

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Posted 07 November 2003 - 12:29 AM

i dont know why you brought up this post comes up every week. i dont know i guess you just had to bring that in. but you should also since this is a forum people go there for help and if all they are going to get is bull**** about this and that then that is a really sorry forum



Perhaps this was a backhanded way of suggesting you use the search function of the forum, that way you would be armed with as much info as possible before you started asking questions.

if the ea81t is so much better to turbo then i will go find one and swap it out



The EA81T is not so much better to turbo.. it is turbo'd.. (thus the T in its designation)

i was told that the ea82 will not bolt up and due to the fact i dont have a lot of the machines to make my own adaptors and what not im am limited to what i can make.



Whoever is giving you info about soobs has absolutely no idea what they are talking about and should stick with hondas(or what ever)

i just want to know what will it take to get a ea81t motor a solid turboed block. for the carbs i have a set of weber dcoes



As stated above, the EA81T is a turbo motor already(Thus the T in the designation).. There will be no need to carb it.. it is an EA81 with Multi point fuel injection and a turbo.. just get the ECU and wiring harness and bolt it in.

#15 GeneralDisorder

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Posted 07 November 2003 - 01:46 AM

Caleb has the idea. Read the previous post.

I'm not giving you bullsh!t, I'm just telling you that you are wasting your time and money trying to turbo a carbed EA81 that was never meant for it. It is my opinion - please treat it as such. And please don't compare soobs to civics - they are competely different - they have little more in common besides being 4 cylinder passenger cars.

You CAN bolt an EA82 to your car - in fact it's so easy it's almost pathetic. There will be about 1/2" between the cam covers and your frame rails - you don't even need to cut, it's just a drop in conversion, using the same engine mounts, and just a mix/match of clutch components. This goes for the EA82T (Turbo version) as well.

If you really want to turbo a carb - go ahead, but please start with an EA82 turbo block. It's built for it already. Make yourself a custom intake for it to mount those side drafts, and go to town. Trying to use an EA81 would be a waste of your money as you would have to completely redesign the entire motor. The EA82T block is already running boost friendly components, and has the correct compression ratio for boosting. Not to mention the overhead cams.

I agree that it's cool to learn new things. I don't personally feel that turboing a carb is worth the trouble, as it's really just as easy to run a small supercharger with a carb, and you'll get more power, and easier tuning. The Turbo is really meant for MPFI. If your going to the trouble of manufacturing manifolds, why not do it right, and go with a blower?

GD

Oh - and Caleb - "Just bolting in" the EA81T (if you can find one) sounds simpler than it really is...... You really need the whole front clip of the car for that conversion....... Just sent one to John (Mudrat) so he can build a turbo Brat :-)

#16 Caboobaroo

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Posted 07 November 2003 - 06:17 AM

and were can i find an lsd for both rear and front diff.


you can get a stock LSD for the rear from an RX but you'll have to change out the front diff as well. Unfortunatly, there is no LSD for the front and so it'll always be an open diff. But good luck in finding a rear LSD because a lot of the people on the board go and grab these as soon as they hit the yard

#17 WJM

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Posted 07 November 2003 - 06:52 AM

there was a place that converted open diffs to LSD, we talked aobut it a while back. We send open diff to them, and $300 later, an LSD is born.

I'm the dude with 9.5:1 turbo.

#18 ryer_s

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Posted 07 November 2003 - 10:36 AM

well i dont like reading though other peoples posts when the information im looking for is here and there and i have to go through a bunch of threads. and i had already asked if someone could tell me a reliable site about these motors. hey Caboobaroo do I have to change out the whole pumpkin or will the ls pull out. and if i do have to change the pumpkin that means the gear ratio is going to change. or are all subarus have the same gear ratio. because if you change the gear ratio in rear how would change it in the front?

"As stated above, the EA81T is a turbo motor already(Thus the T in the designation).. There will be no need to carb it.. it is an EA81 with Multi point fuel injection and a turbo.. just get the ECU and wiring harness and bolt it in."
so the ea81t came with fuel injection. i didnt know that. but the ea81t will not just slip in it? and what cars came with the ea82t. thanks for information

#19 Snowman

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Posted 07 November 2003 - 11:43 AM

EA81T bolts up to everything, but you also have to swap in all of the computer stuff, wiring, fuel system, etc. That's why it's a good idea to get a complete car to take one from.

The EA82T was offered starting in 1985, and can be found in a wide variety of cars. I think they were at least an option in the entire lineup of ea82 body style cars up through the early 90's, but I am not certain of that.

#20 GeneralDisorder

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Posted 07 November 2003 - 01:22 PM

The EA81T is a RARE engine - came in only 83 and 84 wagons, Brats, and coupes - and only some of them. It's VERY different than a regular EA81 car. The battery is on the other side, the cross-member is different, etc. etc.

It will bolt to the trans, but that is about the only thing it will bolt to. You'll want the whole car for an EA81T conversion.

The engine is so rare, that even finding replacement parts is nearly impossible, so it really isn't such a good choice.

The EA82T came in cars from 85 to 91 (?) here in the states. Tons of them out there in the yards for cheap - replacement parts are easy to get.

Oh - and the LSD's were 3.7 - you have to convert them to 3.9 using a ring gear from a normal rear end. There's a bit of grinding and fitting involved, but it will go in. The company he refers to is Phantom Grip I belive that does the front diffs.

GD

#21 ryer_s

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Posted 07 November 2003 - 01:30 PM

what makes the ea81 1600cc and 1800cc different motors. is it the bore sizes or stroke?

#22 GeneralDisorder

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Posted 07 November 2003 - 01:49 PM

The EA81 is the 1800cc - the EA71 is the 1600cc.

It's the stroke - the bore sizes are the same. You can use EA71 pistons and rods in an EA81 to increase compression.

GD

#23 Adam N.D.J.

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Posted 07 November 2003 - 04:55 PM

Turboing the NA EA81 is something that I've been looking into for a long time now, since I had my first EA81 car (1997). Here's whot you do. Your going to need quite a few parts from an EA82 (85 n newer) car, you need the pistons from a turbo car, that will drop your compression, making it easier to run boost to it. once the pistons are in it, get the crossover pipe from the EA82T, it will bolt right up to the motor, you may need to move the exhaust studs around though. Modify the crossmember to put the pipe in. Then bolt on the turbo from the EA82T. You will notice the inlet pipe to the turbo bolts to the turbo. So just make a new inlet pipe that has a mounting flange for the carbs on it. Now get an intake manifold from an SPFI EA82, remove the throttle plate from the shaft. Use the intake tube from the EA82T to run straight from the turbo, or, you can add in an intercooler easily at this point. For the turbo oiling, just add in a supply feed from one of the plugs in the oil pump, you can take off the supply from a T in the sender, or there is a plug in the side of the block, right behind the pump that you can use to supply oil. For the return, drill a hole in the head where there is a flat spot on the back side, and press in a piece of 1/2" pipe, then run a hose with a 90 in it to this, this is exactly how the EA81T has it. As for the water lines, you can run a line from the heater core to it, the best way to do this is to run the line from the heater supply line to the turbo, then to the heater core, then back to the engine. That way you can cool the coolant from the turbo off faster with the heater core before it gets to the engine. I would highly recommend putting in an A/F meter so that you can tune in the carbs correctly for it. A boost guage is also a good thing to have.
A lot of this I got from helping some friends that owned Caprice turbo's, this was a 2.3 turbo with a carb, the carb is a draw through, so the carb sits before the turbo, it can be done, it's just a matter of how time do you want to put into it. I really don't have a good candidate any more, cause 3 outa my 4 vehicles are already fuel injected, and the 4th is a restoration project, it's going to be all stock.

P.S: I would really like to see some of my idea's put to work, I know that I can't do everything that I come up with, so I'm presenting my designs for others to use. If someone can test em out for me, that makes me more confident in all my work.

P.S.S: Tony, the pistons in the EA81T are NOT forged. I have one that you have to check out, it's pretty bad, it has one of the ring lands between the top and bottom compression rings snapped off. They are definatly cast.

#24 WJM

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Posted 07 November 2003 - 07:18 PM

I think 92 was the last year for the turbo EA82. Coupes (also know as the 3 door, or 3 Door Coupe *not to be confused with "hatchback"(EA81/71 powered car)* ), Sedans, Wagons. Mainly found in the GL-10 sedans and wagons from 85 to 89. Some Coupes from 87 to 89. ALL RX's, sedans and coupes, from 85 to 89, but RX coupes were only from 87 to 89. Ive personally NEVER seen a turbo in a "Loyale"...aka, 1990 and up EA82 cars.

edit: Some GL models came with Turbo too, mainly wagons. Ive never seen/heard of a GL sedan or ANY DL with EA82T.

Id go with the EA82T, and not the EA81T. More parts.

#25 ryer_s

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Posted 08 November 2003 - 01:37 AM

ok here is my question. ok lets say i get the turbo pistons and put them in my n/a motor. and boost it. my question is what is the first thing that is going to give. is it going to be the crank rods pistons or cylender walls. and are all the ea81s cranks forged? if not which crank is forged and which will fit the motor. im not to worry about dropping the cr to much. because you just have to replace the lower cr with boost to gain the hp you lost. so i would rather drop it a little bit and have that same boost be added hp instead of replaceing. and less boost is easyier to mange. and if the ciseasy as is the one web page i read then i will fi my motor. thank you Adam N.D.J. for tell me the place for the turbo cooling and oil lines. one less thing to think about.




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