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ea71 engine mods


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The real problem with making them uber powerful is airflow. The heads just can't handle much, and unlike VW's, we can't just go get some dual port heads for reasonable $$ (not sure theres any at all for the EA71 - EA81's do have a following in the aircraft crowd. $2000 for a set of dual-port heads for an EA81.....

 

Get a 32/36 Weber DGV and you will gain some low end. High end is pretty much a matter of porting the wimpy heads you have, decking them a bit, and getting a custom cam.... probably a custom manifold too at that point. I'm afraid it will never make much over 100 HP tho without new heads.

 

GD

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Its like making any other car more powerful. Exhaust, intake, carb, coil, plug wires, new sparkplugs, disty cap and rotor (its amazing what a tune-up can do). Basically just start with the general basics and then if you have lots of money left over, you can start on what GD was sayin; heads ported and polished, intake and hedas port matched, and a custom cam.

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Take a look at what I've done with "frankinintake" and the exaust work on the Solo Subie--The exaust would be louder than you would want on a daily streeter--but flow in & out of the engine helps alot--I'd do the basics first like the other guys said--then open your flow up--you still most likely won't net over 100hp, but it will perform better---:D

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If you are interested in developing an intake manifold to accept a Weber 32/36 then you may want to take the same approach that I did. I took an EA82 Carbureted manifold and modified as follows.

 

1. Remove all non-essential vacuum port tubes by physically pulling them out of the manifold. (you will have the holes welded up).

2. Cut or grind off all non-essential "bolt and screw bosses" and sand the areas where they were at, smooth.

3. Turn the manifold upside down so that the bottom, where the hot water passes underneath the manifold, is accessible and easy to get at with a "Sawzall" or a high speed cutter with a thin carbide cutting disk.

4. CAREFULLY cut a slot through the water passage area only. You will make 2 of these cuts. One of the cuts will be about 1.5's from the NON THERMOSTAT end and the other in a diagonal manner running parallel to the "heater feed water pipe boss" on the end that has the thermostat housing. The cutts should be clean and wide enough to insert a piece of aluminum bar stock to act as a water passage dam. Note that the cut on the thermostat end of the manifold will be on the side CLOSEST to the center of the manifold "carberator intake bowl" where the water heats the intake plenum.

5. Take the intake manifold to a shop that performs aluminum welding and have the 2 "DAM PLATES" welding into place so that there are no water leaks. Have all of the vacuum port opening, that you are not going to use, welded up also.

6. Take a can of "LOW EXPANSION" POLYURETHANE INSULATION and carefully fill the void BETWEEN the 2 "dam plates" with this insulation material. I used the snorkle tube that came with the insulation inserted in the hole in the carb mounting area where the water came up to heat the lower edge of the carb body. Let this cure for 24-48 hours to make sure that it is well cured.

7. Have a hole drilled in the WATER PASSAGE ELBOW area of the manifold, in the bend if you can(that is where miine is at) and have it threaded to receive a "pipe nipple" suitable to permit a good flow of coolant out of the the drivers side head. Plumb this into the heater supply pipe which is still on the manifold. The permits a coolant flow in the same manner that existed prior to your intake modifications.

 

You have, in effect, created a "cold air intake carburetor manifold". It is a fact that Subarus have a horsepower drop between a cold engine and a hot engine due to the heating of the "Intake plenum bowl" with hot coolant. You now have a cold intake plenum bowl and therefor will realize a gain in power when using a Werber Carb with the set up.

 

I know that it is a long post but I felt compeled to post something after looking at the engineering feat of the FRANKINTAKE.

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Thank You!! One of the reasons behind Frankinintake was to reduce the time that the fuel charge was exposed to hot water heating--you do need some to prevent intake iceing (when it happens-your power drops WAAAAA off:))--but the amount that Subaru included was over the top by a fair amount.

 

I also wanted the tuneability of a side-draft carb--yes, they are more work to keep in tune---but when you hit the "sweet spot"--all hell cuts loose!!

 

Also making the intake runners longer promoted a better powerband higher up--I find that my power comes in all at once at 2500/2800 and starts to fall off at 5500/6000--will work better when I run a hotter cam to take advantage of it--

 

Didn't mean to hijack the topic--just like spreading info as far as possible--WE HAVE HONDAS TO SLAY!!!:lol:

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I have an ea81 '81 Wagon GL 4WD and was considering an electronic distributor, since a stock used one goes for 75 bucks anyways. Could you please tell me where you bought yours? Something really weird happened one day while I was replacing the alternator and I am pretty sure my angle sensor took a dump in the process. I found out that means pretty much a new distributor, so here I am in search of a remedy and you may have the answer to giving life to Diamond. Thanks...xenongod

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Start asking around on the board. I got mine from Hondasucks for helping him on his 1982 4wd sedan. He had it out of the old motor because it was originally a 2wd auto car. I can keep an eye open but I usually don't see any in the yards around here that still have motors in them.

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Caboobaroo...there are a couple junkyards near me and was going to go take a gander. What other years and models would work for mine? Does anyone even know why there even is a cam angle sensor? Have they been known to go bad by just "accidently" grounding the alternator circuit? In my case accidently=brain fart..but...I only make one mistake once. Anyways...just wondering if you could give me some extra info on my options...Thanks.

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