I may be senile, but I remember reading in a homebuilt airplane magazine years ago about an HO pushrod motor installed in Japan-market trucks that came with special heads and maybe some other parts. They said it had dual ports, and made more horsepower than the car motor. Anybody know what it was called, and where I might look for one?

That special ea81 usually came with the dual hitachi carbs in the subies outside of the united states.

The ea81 heads on that motor have swapped ports. Meaning the exhaust valve is where the intake valve usually sits on the standard ea81 head for a much better flowing head. The heads usually are called dual port heads which is really ill named when they are essentially a siamese port head.

The only place where I have seen these heads available is from some of the homebuilt aircraft shops that deal with subaru engines.

A good place to start would be with stratus aircraft co. They are located in oregon I believe. That is the same place I bought couple of my dual carb intakes from.

 

Just a side note if you are planning to build a jdm spec ea81 you will need to make sure and get the: heads, pushrods and rocker shafts, and cam as the standard ea81 parts are quite a bit different than that one.

I have one of these EA81's. I believe they were nick named dual port heads due to the split exhaust port. Theres a thin wall in the middle of the port that goes right until the end of the head, the std EA81 ports join up in the head and are don't look like "dual port"

 

There is however two places I know of (SUB4 in NZ and RAM in USA) that make new heads for EA81s which use real Dual Port design. RAM Engines were doing a super charged EA81 which was pushing 200chp I believe not so long ago.

 

The Jap spec dual port EA81's like I have came factory with 101hp (I think there was two models and one was slightly more, I just say 101). The Standard EA81's came with about 78hp. You can feel the difference, and when mine was running well it happily reved over 8k RPM. Something the dual carbs have to thank for I think.

Just a shot in the dark, but can this setup be adapted to an EA81T? (What custom fab. would it require?)

Just a shot in the dark, but can this setup be adapted to an EA81T? (What custom fab. would it require?)

 

Ya you could adapt it to the ea81t,but you would need to make up some mounting bosses on the heads for the injectors.

Does this engine have a special designation other than EA81? EA81 HO somehow sticks in my mind, but it could be a figment of my imagination, its been about 10 years since I read about it.

No, has no special name. Well not that Ive found anyhow. I just call it EA81dc (dual carb). When I first signed up here 3 years ago everyone just thought the dual carbs were the special part and putting the manifold and carbs on would give you those power figures. But it is a whole engine deal. 9.5:1 comp, reversed vavles and performance reversed cam to go with it. larger exhaust diameter out of the head. And of cause the dual carbs.

No, has no special name. Well not that Ive found anyhow. I just call it EA81dc (dual carb). When I first signed up here 3 years ago everyone just thought the dual carbs were the special part and putting the manifold and carbs on would give you those power figures. But it is a whole engine deal. 9.5:1 comp, reversed vavles and performance reversed cam to go with it. larger exhaust diameter out of the head. And of cause the dual carbs.

 

 

Hmmm Sounds like the motor for me. Anybody know how I can get on in (or to) the U.S.?

They are pretty rare here in Australia (at least the full deal is rare, the carb setups aren't so rare). I think NZ has a more or at least easier to get. Most of them I tihnk have been used in ultralites. As those guys have known that they are a great engine for years and bought most of them up.

They are pretty rare here in Australia (at least the full deal is rare, the carb setups aren't so rare). I think NZ has a more or at least easier to get. Most of them I tihnk have been used in ultralites. As those guys have known that they are a great engine for years and bought most of them up.

 

 

yea they very rare here to aye. found out they only brought 14 of that model here brand new. ive never seen one here yet. i wanas 1

As far as I know all the ones Australia got were imports. Probably all from Japan.

Wasn't there a EA81 hatch in Japan called the SRX or something? Was that what this engine came in?

They are pretty rare here in Australia (at least the full deal is rare, the carb setups aren't so rare). I think NZ has a more or at least easier to get. Most of them I tihnk have been used in ultralites. As those guys have known that they are a great engine for years and bought most of them up.

 

 

Care to sell yours?

Care to sell yours?

Sorry, the EA81 is still my favourite motor and I'm keeping mine for a future project. For now I'm going to put it in another Subaru, put waist spark total electronic ignition (like the EJs have, no disty) and rebuild the carbs. Then go have fun offroad. But I really want to build it up with high comp and twin webers one day. I would like to get it to be reliable at 10K RPM and maybe 140hp NA.. But that will be a while down the track for sure.