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EA81 Performance Mods--Best Bang for the Buck?


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30 replies to this topic

#1 Dante

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Posted 23 October 2003 - 04:10 PM

What are the best performance mods for the ea81 in order of hp or torque added per dollar (or hour spent)?

Here is what is on my list (in no particular order):

Weber and K&N or Piper Cross filter

EA71 pistons UPDATE: Or ea82 SPFI pistons

UPDATE: EA82 SPFI exhaust manifold?

Exhaust mods (less restrictive muffler and 2" pipe from the restriction in front of the muffler back and maybe drill the cat or replace with 3-way)

New or reprofiled cam

Port/Head work (e.g. bigger valves, port, polish and/or shave)

Upgrade ignition components (coil, wires, 2WD distributor, plugs)

Replace belt-driven fan with electric one (said to free-up hp)

Lower-temp thermostat (said to increase responsiveness and permit use of lower-grade fuel)

Anything else?

#2 Hondasucks

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Posted 23 October 2003 - 05:43 PM

If you are going to have head work done, get a set of 84 or later EA81 heads, I read somewhere that they have bigger valves.

#3 Dante

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Posted 23 October 2003 - 05:55 PM

Originally posted by Hondasucks
If you are going to have head work done, get a set of 84 or later EA81 heads, I read somewhere that they have bigger valves.



Hopefully, I'll be building an '84. That's the year I'd prefer anyway.

If I get an '84, I'll probably only clean up the ports when I put in ea71 pistons...

#4 AKIRA

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Posted 23 October 2003 - 06:48 PM

EA82 SPFI pistons give better compression.
1600 pistons are only 9.0:1, the SPFI are 9.5:1.

1984+ EA81s also have better exhaust manifolds, more flow.

check out my brat page at the bottom, I have a list of EA81 engine mods on the second page.

you can modify the hitachi until you get the webber, just use a piece of coat hanger-not sure where the link to the page is though.

AK

#5 Snowman

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Posted 23 October 2003 - 07:02 PM

No matter what you do with the Hitachi, it's still not a weber. The bores are still smaller.

#6 PHATBRAT

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Posted 23 October 2003 - 08:26 PM

Just for the record, For years, no one has ever doubted the 2wd disty swap until recently. Skip said he looked up the 2wd vs the 4wd and they have the same advance curve. Now I don't doubt him for a minute with the facts that he has brought to our attention because he looked them up in a book (Which could be wrong) , He seems to be a pretty smart guy, however, I have done the swap and I still say I notice the difference. And up until he said anything, everyone who has done it has also stated a noted difference but since he said this no one has said a word about it except for me. Just thought I would share this fact with you. That way, If you decide to proceed with the swap you can let us know what you find. Boz

#7 PHATBRAT

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Posted 23 October 2003 - 08:35 PM

Here's a link to another post with some people's opinions on the disty.

http://usmb.ultimate...s=&threadid=380

#8 AKIRA

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Posted 23 October 2003 - 09:52 PM

I said untill he gets a webber, a hitachi will never be as good as a webber but if you don't have the money or if you want more power while the webber is in the mail you do this. use a piece of coat hanger to wire the secondary barrel so that it opens when the pedal is a third of the way down instead of when the pedal is all the way down and some vacuum has formed, which is the stock way.

I still can't find the page that describes this, sorry.

#9 Dante

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Posted 24 October 2003 - 11:47 AM

Thanks everyone! Here's a list I found on Akira's page. Looks similar to mine, except for a few items.

modify the Hitachi then 32/36 Webber Carb or Webber 38
1600cc pistons or EA82 SPFI pistons
custom manifold
EA82 SPFI exhaust manifold (no cat)
exhaust Manifold wrap
Ported heads
bigger radiator (it will fit in with the lift)
170 degree thermostat
on/off switch for hot air pipe
2WD distributer
new spark plugs with bigger gap

The SPFI pistons will give me just the CR I want for decent performance with cheap regular unleaded. If I use them I should not have to shave the head. I can just clean up the ports when I do the pistons.

I didn't know about the SPFI exhaust manifold. Will it bolt right up? What is the upside?

#10 AKIRA

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Posted 25 October 2003 - 11:23 AM

Iam not totally sure, but I read somewhere that the exhaust manifold on an EA82 has no catilitic converter and bolts rightup.
no cat = better flow.

I would check on that better before you get one though.

#11 archemitis

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Posted 25 October 2003 - 03:10 PM

false info. they all have cats.

engine swap to an ea82 is cheaper than a weber.:banana:

#12 Dante

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Posted 25 October 2003 - 06:27 PM

I shot an e-mail to Ron at www.ramengines.com and asked him a few questions. When I find the right car, I'll buy a cam and probably some other products and/or services from him. Anyway, he was nice enought to respond and had some interesting things to say. I'll try to cut-and-paste his e-mail, but here's the jist of it:

1. The stock intake manifold sucks (I think we all know that). I followed-up by asking him if there are any affordable alternatives that will install easily and work well in a car.

2. I don't want to start a flame war or for anyone to give Ron a bunch of B.S., but FWIW he questioned the EA71/EA81SPFI piston info. He decks the block to get higher compression.

3. He also mentioned the importance of proper header lengths to maximize performance. I followed-up by asking him if anyone makes an affordable header for these cars and, if not, how much it would cost to have one made.

4. He also said something about "recurving" the distributor. He said that was good for 13 ft/lb of torque.

That's all I can remember off the top of my head. Again, I'll try to cut and past the response when I get to my other PC.

Originally posted by archemitis
engine swap to an ea82 is cheaper than a weber.:banana:



I'd rather have an ea81 (hence the subject). Just my $0.02. To each his own.

#13 AKIRA

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Posted 25 October 2003 - 08:31 PM

sorry about the manifold, my bad.:boohoo:

#14 AKIRA

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Posted 25 October 2003 - 08:43 PM

Wait, is the EA82 manifold larger in diameter and bolts up?
thats what I could have read and screwed it up.

instead of no cat, it would flow better because of the larger diameter?

am I still wrong?

#15 Dante

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Posted 25 October 2003 - 10:00 PM

IIRC at least one member has cut out the cat and welded pipe in its place. I think he also did something to the pipes just ahead of where they go into the cat to make them flow better...

#16 Dante

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Posted 27 October 2003 - 02:11 PM

Here are those e-mails from Ron:

Dante

Please let me address some of your questions;

1) The use of this [Weber] carb is a good idea but the short comming is the intake. The cross sectional area of this intake is very high inertia and will restrict hp.
2) This is a falsafication! The ea71 piston has the same compression height as the ea81 but the block is 1" shorter. The ea82 piston is the same as used in the ea81 but has 2 large eyebrows in it. I make the forged hp pistons , which is 88 grams lighter, but have retained the compression height and deck the block for higher compressions. Note; this engine will require 100 octane at 9.5:1 compression.
3)can do. This [port/head work] is where the hp is made.
4) can do [cam] to match the heads
5) Header primary length is critical to this engine, you need 1.625 od tubing (1.5 id) off the head 28" long into a collector from there on your 2" will work.
6) This [lower temp. thermostat] is a good idea but the engine makes best power at 170.
7) Recurve the distributor and you will pick up 13 ft. lbs. torque.

Please don't bore and hone the engine block without a deck plate, this is absolutely a must!!!!
Ron
RAM Performance

Your Welcome!

1) I build and intake system which comes with the weber, water system, intake. This bolt-on system is $1059.If you would like to build your own water system and supply your weber, just the intake will cost $350.
2) your welcome. The highest comp. ratio on pumped gas is 8.89:1 and still build 115 hp. 130 ft.lbs.
3) I recommend for your application the stage 1 port. I also recommend guides and stainless valves (1.660\1.400).
4) Yes, this is the price for a new RAM cam. You will need to send your lifters for refacing this cost is 67.00
5) I can build it [header] for you but this will require some photos and specs. If you have a mig welder I can send a pipe kit with collector and flanges.This tubing is stainless and will require finish tig welding.
6)your welcome
8) that is correct, [new recurve distributor is $360] if you buy a car and it has a nippondenso distributor I can recurve yours and it will cost 160.

Yes it is a good buy and I do offer core values.
Ron

NOTE: I am just posting this for the information of other members. Please don't give Ron a bag of sh*t if you disagree with something. I want to be able to work with him when I find my car.

#17 Dante

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Posted 01 November 2003 - 01:36 PM

Qman, if you read this, would you please tell me what you did to the motor you built for torque? Where did you get your cam profiled?

#18 GeneralDisorder

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Posted 01 November 2003 - 02:42 PM

I have heard a LOT of reputable people around here say that the EA71 pistons DO inscrease compression..... and I know that CCR will put them in a rebuilt engine for you - talk to them and see what they say.

$160 for a disty recurve??!?!

These guys:

http://www.philbingr...al_services.htm

Do awsome work, and will do it for $40. They are local in Portland. They rebuilt my ND disty for me. They can even rebuild vac advance units.

I have talked with Qman and others about the cam regrind - and the general consensus was that it cost around $80 - maybe a little more, but under $100.

I don't know about the other things he's talking about, but you should talk to Qman - he's built several H.O. EA81's.

GD

#19 beauregaardhooligan

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Posted 01 November 2003 - 05:18 PM

The best Bang-for-buck with the least effort I've done to FERTHER is the Accel SuperStock coil and opening the gap to .050.
That, and advancing the timing to run 93 octane.

#20 Tom63050

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Posted 01 November 2003 - 05:34 PM

What's a good safe number to advance the timing to?

#21 Hodaka Rider

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Posted 01 November 2003 - 05:43 PM

Distributor: the 2WD disty swap was a tip from a page on EA-82 performance. I can't comment personally on whether or not it makes a difference on those engines (completely different disty) but on the EA-81 cars, the 2WD curve is not necesarily better.
I have graphs of the different EA-71/EA-81 curves available (and I believe I posted them at one point). If you are running too much initial advance then you probably will get more low end with a 2WD disty, because it won't start to preiginite as easily. The 4WD disty curve shows more advance at lower RPM's, which will give you more output when properly tuned.
High RPM's may be a different story. Haven't really checked that.


Tom: start with stock specs, then advance a couple degrees at a time until you hear pinging when you floor it under load at low (1700-2500 or so) rpm's. When you get to the point where it's pinging, back it off a degree or two. My car is in serious need of a rebuild, and I was only able to get about 4 degrees extra before it started pinging. I switched back to 87 octane since, and my timing is back pretty much to stock because of it. I did notice a nice increase with 92 octane and extra advance, but gas is too pricey right now.

#22 Snowman

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Posted 01 November 2003 - 06:54 PM

I've recently been running mine at 14 degrees with 88 octane gas. Interestingly, the guy that put my engine in must have looked up the wrong spec when he did the timing, because when I checked it for the first time, this fall, it was set at nearly 20 degrees! Amazingly, if I just ran premium gas, knocking was never a real problem. So apparently there is a lot of room to play with here if you take the time to do it right.

#23 Qman

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Posted 01 November 2003 - 09:34 PM

Dante, I will talk to you on Saturday, I will come up and meet you in person and hang out with you, John and Eric for a while. What time are you guys planning on getting together?

#24 Dante

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Posted 03 November 2003 - 12:26 PM

Originally posted by Qman
Dante, I will talk to you on Saturday, I will come up and meet you in person and hang out with you, John and Eric for a while. What time are you guys planning on getting together?



Thanks Qman! I'll be calling John today. Based on our previous conversation, I think we'll be meeting Saturday morning. I cna't be more specific than that at this point.

GD, FWIW Ram says their cams are new--not regrinds.

Dante

P.S. I had planned on the Accel Superstock coil, and etc. under "upgrade ignition components" in my list...

P.P.S. Since I got a lifted wagon with big tires I want to build the engine for torque.

#25 Dante

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Posted 04 November 2003 - 02:44 PM

OK, I have about a grand or so to spend on engine mods.

I've been told intake, exhaust and ignition mods are the way to go. Maybe next year I can spend some more to upgrade the cam, port the heads and do something to increase the C/R.

Here is my revised list and my questions:

1. K&N or Pipercross air filter
2. Buy and rebuild used Weber.
3. Upgrade intake? I can get Ram's Weber intake without the carb and water system for $350. I'd have to build the water system and I don't know how difficult that would be. The intake with a weber and water system costs $1,059. There's also another intake for $495 HERE I just don't know what kind of torque or horsepower improvements I can expect from upgrading the intake manifold.
4. If I don't do the intake, I'll need a Weber adapter plate.
5. Upgrade exhaust from the restriction in front of the muffler back. Maybe replace the two two-way cats with one high-flow three-way.
6. Header? Would having one build be worthwhile? How much would it cost?
7. Ignition modifications--Accel Superstock Coil, recurve distributor, upgrade wires and spark plugs and run wider gap.

I suppose I could just do the air filter, carb, exhaust and ignition upgrades to my ea81 and save any money left over until I have enough for internal mods (or for rear discs, a 5-speed D/R, etc.) :brow:




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