Ea81 increase in power

[YaBoyKingsley]

Hey guys I’m building a brat with a ea81 (150k on it) and wanted some extra ponies in case of an emergency I’m going to polish the intake and open the exhaust a little are there any ways to get a significant boost without turboing and making it a fuel injection thanks in advance

Edited December 6, 2017 by YaBoyKingsley

[DaveT]

Polishing it won't do anything noticable. Too many other design factors limit the air flow. Lots and I mean lots of old threads on this forum about such things.

 

Weber carb or convert to spfi are safe mods. But realize thus is a 30+ year old machine, and parts may be scarce.

[Knucklehead Saloon]

Biggest differences made to mine :

 

K730M weber kit from redline.

 

MSD blaster 45000v coil.

 

Plugs gapped to 1mm.

 

Delete EGR.

 

Custom headers with 1-3/4" primaries into a narrow angle 2" collector (like a 2cyl motorcycle exhaust). From there a 2" system through to back of car.

 

Make sure your distributor is in good condition with no side play on the top of the shaft or you'll get erratic ignition timing. I got a reman unit from cardmon in mine.

 

Advance ignition timing more than standard. I took mine out on the road on a hot day and kept advancing the timing until I could hear pinging. Then backed it off 3 degrees. No pinging and revs higher, makes more power.

 

I've also been rejetting the weber. It'll run ok with the stock jets supplied by redline but won't realise its full power potential.

Replaced the stock 140 secondary main jet with a 155. Also will replace secondary idle jet with a 55 when it turns up. Had a flat spot in power delivery when the secondary barrel opens up(its a lean hole). Also about to order a 150 primary main jet (stock 140).

 

All that ^ made a huge difference to the car. It'll hold freeway speeds in top gear now and runs neck and neck with a mates 3liter turbo diesel pickup in a drag.

 

Power mods I've got planned include porting a set of heads and shaving them for more compression. Also the stock intake manifold sucks donkey balls. Man what a crap design. In the future I'm gonna build something way better thats tuned length and doesnt carry the coolant inside it.

 

Hope this helps!

[GeneralDisorder]

EA82 SPFI pistons, and swap the cam for an RV torque grind.

 

That's really all you need to push it up to around 90 HP.

 

GD

[YaBoyKingsley]

EA82 SPFI pistons, and swap the cam for an RV torque grind.

 

That's really all you need to push it up to around 90 HP.

 

GD

Could you link your sources or the forum this is from so I can check it out

[CWAIS]

Look up ea81 stratus engine. There should be some sites that will help you with info. They say it will put out about 110 hp but I think it is more like 100 hp. I think the cam is the key, Weber carb, larger exhaust headers ( h- pipe just below the oil pan) 1.75" and a ea82 intake. I think that is most of it off the top of my head. Good luck

[GeneralDisorder]

Could you link your sources or the forum this is from so I can check it out

There aren't any links. The source is my own experience. It's not difficult to search and find this info based on what I've given you. You split the case, swap the cam, install new bearings, etc, and install 86 to 94 SPFI pistons. Compression goes up to 9.5 from 8.7 and the cam does the rest.

 

And even if you did this - 90 HP is not at all impressive. If you want power swap in an EJ22 or EJ25. Instant 135-165 HP. You'll never get even close to this with an EA.

 

GD

Edited December 6, 2017 by GeneralDisorder

[YaBoyKingsley]

There aren't any links. The source is my own experience. It's not difficult to search and find this info based on what I've given you. You split the case, swap the cam, install new bearings, etc, and install 86 to 94 SPFI pistons. Compression goes up to 9.5 from 8.7 and the cam does the rest.

 

And even if you did this - 90 HP is not at all impressive. If you want power swap in an EJ22 or EJ25. Instant 135-165 HP. You'll never get even close to this with an EA.

 

GD

Do you know we’re i can get those pistons and crankshaft

[iceageg]

I just did the webber and cam replacement on my rebuild a few months ago.  Made a huge difference between 1500-4400RPM.  Above that it isn't noticeable.  I will eventually open up the exhaust a bit (it does need replaced) but I haven't got there yet.  I didn't take the time to source SPFI pistons but I am still happy with the result.  As I understand it the head design is the main limiting factor.  For all the improved air in and exhaust out work you can do, the heads are still the roadblock to performance on this engine.

 

Polishing the intake may actually hurt your performance.  The way the theory goes, you need a thin layer of turbulent air to keep the fuel from sticking to the walls of the manifold.  Like the dimples on the outside of a golf ball.  If your engine was fuel injected and only air was passing through the manifold then a polished intake would undoubtedly be effective.  Something to keep in mind.  Do share the results if you decide to polish yours though.

[Naked Buell]

As much as you want to rebuild the ea81, speaking from experience, I am doing the ej swap just for what you are searching for.

More power plus you get fuel injection and the parts are way easier to get. My 2 cents.

[GeneralDisorder]

http://www.rockauto.com/, and http://www.deltacam.com/

[jono]

I am always suspicious of those claiming an EGR delete making any power unless egr gunked up and leaking somehow. Egr only meant to work when you have manifold vacuum. You don't have that when foot flat to the floor asking for more power.

 

No ooffence knucklehead

[jono]

I also thought I found the more base advance I ran the less willing to rev out...but not the case with my EA82.

 

Now, that's what you want...an efi EA82 from an XT non turbo! Two intake ports per head, a manifold to match, ohc willingness to rev.

 

I have almost enough go to consider not fitting my EA82 turbo ...but I have to in order to complete a decade long project. My other Brumby to get this ball tearer

[ferp420]

What gd sead also port and polish your heads custom power grind the valves deburr the intake manifold add spacers between the manifold and heads port match all your intake and ehaust gaskets add a spacer under the carb get a better carb plug the egr ports as they create turbulance in the exhaust flow that robs power use better gas and advance the timing and grind the 1/4" welded bead out of the inside of the ehaust manifold were it bolts on and go with a 2" cat back exhaust or drop in a ej2.2

[sparkyboy]

+1 on the ej22 swap for the easiest way to have more power. It'll make your brat scream i promise! I did it on my 86 gl and don't regret it for a second.

I can't speak on building up an ea81 as i have never done it myself, it would be cool and pretty sleeper but if i were to guess the swap would be less work and money. In fact you can probably at least break even for selling a good factory ea81. I got a donor car (t bone accident) for $500, parted the rest and came out even. With the adapter plate, fuel pump, new clutch, head gaskets and timing belt it cost me about $500. I drilled the flywheel myself.

I see you are in AZ, if you are ever tooling around in CO, i have a good phase one ej22 and wiring harness (complete uncut, hardest part of the swap) i will sell you for cheap, $500. I have a video of the engine running before i pulled it.

If i can do it anyone can.

Food for thought, it would be cool to take your brat on a little road trip to get her a new engine, and trust me people will be geeked when you open the hood.

http://www.ultimatesubaru.org/forum/topic/162423-respect-for-the-ea81-and-performance-mods/?fromsearch=1

Remember this guy fellas? This is a funny read

[Knucklehead Saloon]

Jono: no offence taken at all mate.

 

I imagine everyone else's ea81 egr system is as stuffed as mine was after 26 yrs of use. I was getting wayyyyyy too much crap going into the intake.

[wagons]

Ea81 mods should be replaced with EJ22 swap. $500-1000 for an EJ22 swap and it will make way more power than an ea81 ever will. If I ever get to the point of splitting a block I'm trashing it an doin an ej swap

[Knucklehead Saloon]

True Wagons... however at heart I'm a carburetor man. Cut my teeth on that stuff over 30 years ago and been spinning spanners on them ever since. Sure I've had injected and forced induction machines over the years and learned thay stuff inside out too.

 

Just really digging the ultra simplicity and reliability of a well set up computer free car right now. Yep.. later model injected motors make more power, better economy etc but relaibility ?? In my experience old school carb 'n' dizzy kicks their rump roast when the motors get past 10 to 12 yrs old.

[wagons]

Get an SJR intake manifold and modified escort dizzy, then add Weber 3236 and have the best of both worlds, power of an EJ22 and simplicity of a carburetor. Carb ej22 sound and look menacing, and are just AWESOME! Reliability has nothing to do with a carb or fuel injection, its maintenance and sometimes luck. My 2003 Bonneville has 289,000 and I beat on it because it's a super charged engine and it has perfect compression and leak down.

Edited December 8, 2017 by wagons

[Twitch de la Brat]

Check out this thread for building an EA81 for power.

http://www.ultimatesubaru.org/forum/topic/137196-the-blu-bomb/

I did it, and it was worth the time and effort, for me, but your experience may vary.

Power is probably well under the 150hp mark and no where near a racecar, but a fun car to drive nonetheless.

 

Twitch