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Old 03-06-2008, 06:38 PM   #151
Hurley 2.5 WRS
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wrx are very similar if not the same casting on K's
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Old 03-06-2008, 06:43 PM   #152
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sorry i meant a WRX K(ported)vs. of STi K(stock). didn't mean WRX(USDM) if thats what you thought. i know the castings are the 2.5 RS/V3-4(5?) style, just wondered what they were.

--keith
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Old 03-06-2008, 08:58 PM   #153
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Quote:
Originally Posted by kheff46 View Post
do you have this one measured? is it stock or ported? i know STi's are "massaged" but a stock WRX K isn't. what K is it btw?
They are ported and those heads are from a wrx ra.
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Old 03-06-2008, 09:48 PM   #154
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Quote:
Originally Posted by kike_ej20 View Post
They are ported and those heads are from a wrx ra.

Who ported them?
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Old 03-06-2008, 10:43 PM   #155
kike_ej20
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Who ported them?
Not me...Lol
Thats a japanese friend's car.
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Old 03-06-2008, 11:50 PM   #156
Hurley 2.5 WRS
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Quote:
Originally Posted by kheff46 View Post
sorry i meant a WRX K(ported)vs. of STi K(stock). didn't mean WRX(USDM) if thats what you thought. i know the castings are the 2.5 RS/V3-4(5?) style, just wondered what they were.

--keith
nope, thats what i was saying, WRX K's are very similar to STi K castings

usdm WRX is nowhere close
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Old 03-06-2008, 11:54 PM   #157
Matt Monson
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Quote:
Originally Posted by kike_ej20 View Post
Not me...Lol
Thats a japanese friend's car.
That's a very important distinction. Any of these heads can be ported and manipulated for more flow and bigger ports. The primary purpose of the this thread is to find the similarities and differences in the factory heads and their castings...
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Old 03-09-2008, 12:24 PM   #158
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Quote:
Originally Posted by Hurley 2.5 WRS View Post
nope, thats what i was saying, WRX K's are very similar to STi K castings

usdm WRX is nowhere close
OK. just wanted to clarify. i figured our WRX's were different generation all together anyway.

--keith
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Old 03-23-2008, 06:48 PM   #159
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heres a few pics of my mystery heads, maybe we car figure exactly what they came out of.....








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Old 03-23-2008, 10:34 PM   #160
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That clover style combustion chamber and valve cover design is usually found on the EJ20H Legacy twin turbo heads. If you pull the cams and find direct acting HLA (hydraulic lash adjusters) then they are most likley the EJ20H twin turbo's.

Want to sell 'em? I'm looking for a set...

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heres a few pics of my mystery heads, maybe we car figure exactly what they came out of.....








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Old 03-24-2008, 10:24 AM   #161
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I also am looking for a good low mileage set.
Charliew
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Old 03-24-2008, 10:08 PM   #162
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how do the 20h heads flow? hmmm I hope these work on my t-leg
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Old 03-24-2008, 10:10 PM   #163
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also, they do have HLAs.
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Old 03-24-2008, 11:20 PM   #164
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actually they have the "buckets" idk if thats the same or not.
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Old 03-25-2008, 12:31 PM   #165
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If I ever find the time to make a fixture for my EJ20K heads I'll throw them on the bench and see what they flow. Don't look at your heads and assume a gasket mismatch needs to be removed. This is probably one of the most common and worst things people do. Making a head perform better is a very complex and scientific task and unfortunately for a lot of years backyard "head porters" have become "professionals" by just hogging stuff out bigger. This too is seldom the right answer for a street driven car. Subaru knew what they were doing when they designed the heads.

-Michael
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Old 03-25-2008, 12:58 PM   #166
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Quote:
Originally Posted by d00f View Post
If I ever find the time to make a fixture for my EJ20K heads I'll throw them on the bench and see what they flow. Don't look at your heads and assume a gasket mismatch needs to be removed. This is probably one of the most common and worst things people do. Making a head perform better is a very complex and scientific task and unfortunately for a lot of years backyard "head porters" have become "professionals" by just hogging stuff out bigger. This too is seldom the right answer for a street driven car. Subaru knew what they were doing when they designed the heads.

-Michael
Hey Michael,

Has it been established that most of the JDM Ej20 heads (later G's,H,R, K) heads all flow well and pretty much the same? I believe the only significant difference is the valve actuation type and cam profiles, correct?
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Old 03-25-2008, 01:10 PM   #167
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Quote:
Originally Posted by Ej22Tim View Post
actually they have the "buckets" idk if thats the same or not.
Twin turbo heads (ej20H) have the bucket style HLA's, so it's pretty certain that's what you have there.
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Old 03-26-2008, 11:13 AM   #168
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Quote:
Originally Posted by manxaru View Post
Hey Michael,

Has it been established that most of the JDM Ej20 heads (later G's,H,R, K) heads all flow well and pretty much the same? I believe the only significant difference is the valve actuation type and cam profiles, correct?
Yes, but if I go through the trouble of building a fixture to put the head on the flow bench then I'll be casting the runners, making measurements and playing with them. If anyone has any blown up heads with at least 1 good cylinder I'd be more than happy to buy them as well

-Michael
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Old 03-31-2008, 12:24 PM   #169
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Michael Hi, when you cast the ports do you use a silicone of some sort and how do you get it out without tearing it up? It seems like the guides would need to be out also. If I had some junk heads I could saw them up I guess but there must be an easier way. I bought some 3/8 thick pvc sheet and used some 4 inch pvc for my adapter. I also made a 1.5 x 2.0 x 1.5 longer than the head (don't remember exactly) nylon block. It has two holes out past the head to screw to the bench plate. I use .250 x 20 all thread as hold downs threaded into the bench plate with wing nuts. It also holds the valve positioning screws and two dial indicators to set the lift of either the intakes or exhausts. You just turn the head around to suck or blow to flow. Of course you switch air flow. Harbor Freight dial ind.s and .250 all thread for adjusting screws. I also use HF fender protector material for the gaskets. The dial ind.s are on the end of the screws. The block sets over the sparkplug cavities and once we forgot the plugs and it still worked, we went back and reflowed it. Probably a piece of hardwood would work just as well as the nylon it was what I had laying around.
Charliew

Last edited by charliew; 03-31-2008 at 12:39 PM.
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Old 04-02-2008, 11:44 AM   #170
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There are some complex formulas that say you need a fixture that is at least 1/3 the stroke or some such thing. Has to do with the airflow - I went through them a few years back said yeah that makes sense so all my fixtures have been about 3" in height minimum.

For the molding process I use a releasing agent and spray the runners down before pouring and the silicone based stuff just pops out. The trick is to find the material with a low enough shore rating that it's deformable but not so low you can't cast it. I leave the valve guides in but sometimes it does rip the silicone when it's removed.

-Michael
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Old 04-02-2008, 01:07 PM   #171
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Quote:
Originally Posted by d00f View Post
There are some complex formulas that say you need a fixture that is at least 1/3 the stroke or some such thing. Has to do with the airflow - I went through them a few years back said yeah that makes sense so all my fixtures have been about 3" in height minimum.

For the molding process I use a releasing agent and spray the runners down before pouring and the silicone based stuff just pops out. The trick is to find the material with a low enough shore rating that it's deformable but not so low you can't cast it. I leave the valve guides in but sometimes it does rip the silicone when it's removed.

-Michael
Hey Michael,

I have a question about "amateur home porting". As I believe you have pointed out in other posts, porting is a science, and going at it with a dremel and making everything bigger is no guarantee of getting a better performing head.

Since my heads are off and apart, however, I'm think about just putting a little more of a knife edge on the intake "splitter" and maybe just polishing out any rough spots I see (if any). In you opinion, is there any benefit to a "light tough up" like that or better to just leave them alone?

Thanks!
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Old 04-02-2008, 07:32 PM   #172
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Chances are you will hurt things more than you will help them. The best gains are made on what's called the short side radius - that's where the machined area just below the valve seat matches the casting. Generally there is a ridge here. On subaru heads they do a pretty good job of this.

Using sandpaper rolls and small flap wheels you can smooth out the casting on the entire intake runners - this will help a small bit but you shouldn't make it too smooth or you will run into fuel pooling problems.

You can also deshroud the valves. Again, Subaru did a pretty good job on this as well but there should be some gains available.

I will have to do some work and measure a bunch of the cross-sectional areas before being able to tell you for sure what will make our heads flow better. The major areas where gains are made on other heads are pretty good already.

Unfortunately in the head porting industry the guys who are good generally work for the high end race teams. The shops with deep pockets pay them to do some work on a head then get it digitized and do the jobs production. Many of the "rest" are snake oil salespeople. People generally don't have flow benches to verify the work so I've seen a large number of cases where a head flowed 5-7% over stock while the company selling the service provided flow bench sheets showing 35% gains. Buyer beware.

-Michael
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Old 04-07-2008, 11:31 PM   #173
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Quote:
Originally Posted by d00f View Post
There are some complex formulas that say you need a fixture that is at least 1/3 the stroke or some such thing. Has to do with the airflow - I went through them a few years back said yeah that makes sense so all my fixtures have been about 3" in height minimum.

For the molding process I use a releasing agent and spray the runners down before pouring and the silicone based stuff just pops out. The trick is to find the material with a low enough shore rating that it's deformable but not so low you can't cast it. I leave the valve guides in but sometimes it does rip the silicone when it's removed.

-Michael
I made my adapter 4 inches deep and 4 inch bore, ( 4 inch pvc and pvc sheet) I think it should approximate the stroke. You are creating the cylinder relationship to the head. I also used a tgv valve assy. that had the delete mod and on the exhaust I made a 2 inch long exhaust pipe and flange out of pvc tubing and pvc sheet.

Charliew
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Old 04-08-2008, 09:52 PM   #174
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Quote:
Originally Posted by manxaru View Post
Hey Michael,

I have a question about "amateur home porting". As I believe you have pointed out in other posts, porting is a science, and going at it with a dremel and making everything bigger is no guarantee of getting a better performing head.

Since my heads are off and apart, however, I'm think about just putting a little more of a knife edge on the intake "splitter" and maybe just polishing out any rough spots I see (if any). In you opinion, is there any benefit to a "light tough up" like that or better to just leave them alone?

Thanks!
it depends what areas you're touching. My WRX heads I just D'd thhe port runners from the slippter and little ways down. I tried to mimmic the JDM heads as there was something good there. I didn't touch the valve throat at all, just the floor and the splitter. For someone to say my ports don't flow would be their opinion. I didn't try to make the port look weird or anything at all. Just mirroring the JDM heads.
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Old 06-13-2008, 01:28 AM   #175
FuJi K
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Here are a few pics of a freshly aquired '96 2.5L DOHC from a '96 USDM Legacy Outback. Noticed how much BIGGER the combustion chamber is. This has the LARGE intake ports w/ matching intake manifold and is HLA. The OLDER model HLA where a little different.

I'll get some pics of the set of heads in the near future; EJ22T, '97-'99 EJ25D, '96 EJ25D, EJ205 USDM, EJ207 JDM.

But here are the pics of the '96 2.5L DOHC.

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