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Tranny options for an EA81 T


harpua
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Being a turbo, you'll want your rev's to be in the higher range. the 5spd will give you a closer shift range and should keep the power where you want it. I know with my 4spd, after shifting i often find myself below 2500rpm which would probably make your EA81T choke. With the 5spd, your revs should be alot higher out of the shift.

 

-Brian

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This all depends on *which* 4 speed you use - there were two, not sure on the years exaclty, but I'm pretty sure that 83+ was the lower 3rd and 4th gears. Junkie - that's why your revs are so high in 4th - you have a pre-83 4 speed. The 83 and up 4 speeds are higher geared in 3rd and 4th. For example - my wagon (pre 83 4 speed) runs 75 MPH at 4,000 RPM in 4th. But my Brat (85) runs at 75 MPH at 3,000 RPM in 4th. Both EA81's with the 4 speed D/R.

 

GD

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Your right about the different 4speeds, but i think the years are different. My '84 GL Wagon has the higher range tranny with the revs at 4500rpm at 80mph and my '86 Brat rev's at 4000rpm. My old '83's tranny rev'd at 4000rpm at 80mph as well. So im not sure if its year dependant rather than the area the cars were sold in. Flatland's probably got the higher gear ratio while mountainous ranges got the lower ratio.

 

-Brian

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What We are trying to figure out is this....?

 

EA-81T is Running an Auto Trany and 3:70 final gears,

 

We are looking to stuff a 3:90 tranny in behind the Turbo, and the problem I am thinking of is that if the EA-81T has as much or more bottom end Torque as the Normally carbed EA-81 then we are going to run out of Motor around 60 or 70 mph.....?

 

So what I want to know is if anyone has ACTUALLY in REAL LIFE Installed and Ran a 3:90 tranny behind the EA-81T.....???????

 

I already know From Experience that An EA-82T with 3:90 gears Behind it runs AWESOME right up to about 100 mph then flattens out real fast......?

 

So I don't want to stuff one behind a Lower Reving motor to find out it won't work well for HWY driving......?

 

Let me Know,

 

Later , John in Oregon....

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I have driven a Turbo Brat with a 4spd Dual range tranny 3.90 installed. It drove it fine, and it held its own on hills really nicely.

 

I am working on my wagon which is getting an RX FT4wd trans. Im not the first to do this and it should drive just about like an RX would have as the motor isn't much different power wise from an ea82t.

 

You really can't go wrong with any of the Subaru 4wd manual transmissions, you just need to pick what kind of driving you plan to do with it. For highway I recommend a 3.70, for lots of city and 4x4'ing I think the 3.90 is better.

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John, i think i have to rebuild your account. I will PM you shortly.

 

Ive driven IN a EA81T with a FT4WD RX tranny and LSD behind it. The thing was a rocket. Didnt get past 100mph cause we were doing some urban rally'n. But damn that thing got UP and WENT! The driver liked to take the revs past 6000 alot. Probably why the heads cracked :) hehe

 

-Brian

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i put a 5spd behind an ea81t. i tried a 4wheel burnout, spun all four tires, but i was actually in 2nd gear high.

 

much faster off the line, and sine the turbo will pull rpm's, it will get you top mph.

 

but the turbo doesnt have bottom end torque, it had high end horsepower. but it will pull throughout its rpm range!, picking up at about 2500 rpm.

 

it will fit with slight tunnel mods, but i had a lift in mine. but i do have a 5spd in a normal 83 wagon with an ea82 motor......no lift, got it to fit!

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well, my 83 wagon was originally a 2wd 5spd. i had to cut away a but for the 4wd lever on the side, and the big square part on the back.

But ask General Disorder and he will tell you that a 4wd tunnel is bigger. he put a 4spd in a 2wd's tunnel, with just a little beating of the metal(i think) and dropping the crossmsmber down by stacking washers between it and the frame, giving more clearance

 

a 4s0d d/r in a ea81 bodt that is already 4wd wouldnt be as difficult as mine was.

if you stack the washers as general disorder did, it mgnt be rel close. expect to massage the tunnel. you may have to cut the shifter hole to get the 5spd lever to fit. there is a stud for a 12mm nut under the tunnel behind the shifter hole, you an use it to mount the 5spds shift lever with the hardware that heldit to the ea82 it came from.

 

the ea82 flywheel will fit on the ea81t only without mods. the flyeheel holes will be larger, but it will still center up on the back of the crank

 

you will ahve to the 2pc driveshaft-------the typical 5spd conversion jive. if you dont know that already it shoul be archived all over the place.

 

either way, 4 or 5spd, you will need to get rid of your existing driveshaft and rear diff.

 

what else do you need to know. will be glad to answer

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The 2WD 5 spd tunnel Miles is refering to is a LOT smaller than the tunnel in the automatic 4WD you'll be working with. The 5 speed will be a much easier fit in the auto. I have looked at both tunnels many times. My tunnel required beating, and some washers as Miles said - but it went together, so there's no reason why the auto, with it's bigger tunnel, couldn't accomidate the 4 spd, or even the 5 spd. John will sort all that out I'm sure. And I think that as long as he doesn't run it up over 6k RPM's (holy s#@t!!!??!!) all the time, the engine will be just fine. I think that's why Subaru didn't put this engine in front of a manual to begin with - they didn't want people blowing them like that.

 

GD

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