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Old 03-31-2009, 04:36 PM   #1
CKxx
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Your BOV sounds lame
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Default I need some head advice.

Background....
Right now I've got a stroked EJ205 block (2.12L) with stock 2002 WRX heads. My head gasket just crapped out and I'll be removing the motor shortly. Since I don't like to make an everyday habit of removing my motor, I was considering doing some work to the heads while it is apart. My question for you guys is, what do you think should be my course of action? I'm not made of money, so that is a concern, but I do have a little bit saved up. I am also in the process of swapping to a larger turbo, a 30R, and would love to see 400+whp. If I can rev higher, maybe a 35R? Anyway...

A few options:
1) USDM STi Heads
I have seen a few sets of stock STi heads around for a decent price, but I'm not familiar with AVCS or how its controlled. What all is involved in that? Is it even possible to put a 2.5 head on my 2.0 block? My bore is 99.5 for reference, only 0.5 over stock. What can these rev to? My block is supposed to be A-OK to 8kRPM. Could I get away with adding some springs to the otherwise stock STi heads and running with a higher rev limit? What else do I need? Oil pump?

2) JDM STi heads
These I can't seem to find anywhere. I know they rev to 8kRPM, which is a plus. How is their cam profile and flow in comparison to USDM STi heads? I'm inclined to believe it is probably better.

3) Stock heads
Save that money, and buy some cams and springs for my current 2.0 heads. This way seems that I'll still be very limited by the size of the ports. I've been told they don't flow well past 400whp.

4) Any other ideas?


Sorry for writing a book, but I have a ton of questions and no one around here to ask. If you have any other info to throw in, let me know. Also, if you have some heads for sale, or know anyone that's got something lying around...well, you know the deal.
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Old 04-01-2009, 09:28 AM   #2
CKxx
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Bump....because I need to choose one soon...
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Old 04-01-2009, 09:48 AM   #3
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"head" advice? Get as much as u can as often as u can.

j/k. Sorry I've got nothing to add, that was just wide open for me. Hey, free bump for u though.

EDIT: I would definitely try to call Dave @ Defiant Autospeed. He loves talking about this stuff whether it's a sale for him or not (and in most cases, it's not b/c he seems to suggest stuff he can't even sell ) and is very knowledgeable. Not just "I read on the internetz...."
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Old 04-01-2009, 10:52 AM   #4
sopmoney
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head advice? i like it when they do the twist with the hand myself. hope that helps
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Old 04-01-2009, 10:55 AM   #5
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^^ yes. That's a nice "touch," if u will.

It's all about the technique.
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Old 04-01-2009, 04:27 PM   #6
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Not to be a prick but..if you dont have an answer for this guy then **** and dont post in his thread. I know alot of people like to post just to see themselves post but this isnt OT or General. If you dont have a question or any valuable information to add to a discussion then dont come here.


Anyways....if i was you I would try to find a set of 04-05 WRX heads, they are shimless and take revs better from what I see on here. Using STi heads or any 2.5L head will probably lower your CR, however I am not sure if it is possible.

I would also use these as a base for potentially camming/porting the heads as well. There is a company that does CNC milling on USDM wrx heads that mimmick the jdm ej207 porting...

In all honesty it seems like head porting is kind of pointless unless you're going for huge horsepower and or using the engine for a race application where you need to make x amount of power over a certain rpm range...

For pure street use stock heads are good enough. Alot of people get caught up spending big money on their subarus and not getting alot of result.


I am going through the same thing in a way, and I concluded for how I drive and how often the power I want to make will be used, its not worth it to invest $$ in building the heads.

May I ask what are you using the car for?

Last edited by mxpunk; 04-01-2009 at 04:52 PM.
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Old 04-01-2009, 07:52 PM   #7
CKxx
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Quote:
Originally Posted by mxpunk View Post
Not to be a prick but..if you dont have an answer for this guy then **** and dont post in his thread. I know alot of people like to post just to see themselves post but this isnt OT or General. If you dont have a question or any valuable information to add to a discussion then dont come here.

Anyways....if i was you I would try to find a set of 04-05 WRX heads, they are shimless and take revs better from what I see on here. Using STi heads or any 2.5L head will probably lower your CR, however I am not sure if it is possible.

I would also use these as a base for potentially camming/porting the heads as well. There is a company that does CNC milling on USDM wrx heads that mimmick the jdm ej207 porting...

In all honesty it seems like head porting is kind of pointless unless you're going for huge horsepower and or using the engine for a race application where you need to make x amount of power over a certain rpm range...

For pure street use stock heads are good enough. Alot of people get caught up spending big money on their subarus and not getting alot of result.


I am going through the same thing in a way, and I concluded for how I drive and how often the power I want to make will be used, its not worth it to invest $$ in building the heads.

May I ask what are you using the car for?
I suppose the best explanation would be "street/strip." I'm not really into drag racing, but I would certainly take it out to get a nice number and then be happy with it. Mostly I just like to fiddle with the car and make it quicker. The reason I'm interested in the heads all of a sudden is because I my headgasket blew (as you saw in my other thread) and I'd like to get a better flowing setup while the motor is out. Also, I have a stroked block that is safe to 8K, so I'd like to take advantage of it by doing some work to the heads. Additionally, I have a 30R sitting on my night-table, so I figure the extra flow will help get me over 400whp (my general goal) much easier. If I can spin to 8K and have cams, maybe I'd do a 35R next season? Who knows. I just like smashing 350Z's with a stock-looking bugeye.


Anyway...heads...

There is a chart floating around with a lot of hybrid swap info and it list only a 1cc difference in head volume between the 02-05wrx heads and 06+ heads, and a 7cc difference between the 04-07 sti heads and my current ones. If this is a case, I guess I only need to figure out if it is even possible to use the 2.5 heads (99.5 bore) on my block (92.5 bore).

ETA: I've talked to a few people and I just looks like I'm going to try a set of Sti v7 or v8 heads. They seem to have all the features I need (high rpm, hotter cams, good ports) but I won't have to pay anyone to build them for me. Also turns out that 2.5 heads would suck on my 2.0 block.

Last edited by CKxx; 04-01-2009 at 11:16 PM.
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Old 04-02-2009, 12:46 AM   #8
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Quote:
Originally Posted by CKxx View Post
There is a chart floating around with a lot of hybrid swap info and it list only a 1cc difference in head volume between the 02-05wrx heads and 06+ heads, and a 7cc difference between the 04-07 sti heads and my current ones. If this is a case, I guess I only need to figure out if it is even possible to use the 2.5 heads (99.5 bore) on my block (92.5 bore).

ETA: I've talked to a few people and I just looks like I'm going to try a set of Sti v7 or v8 heads. They seem to have all the features I need (high rpm, hotter cams, good ports) but I won't have to pay anyone to build them for me. Also turns out that 2.5 heads would suck on my 2.0 block.
im running a hybrid 2.5 with 2.0 heads.
i had the combustion chamber modified to fit the bigger bore of the 2.5 cylinder and had a 3 angle valve job. my engine spins nicely to 7800 rpm.
im also running a gt30 turbo. never been on the dyno though.
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Old 04-02-2009, 09:06 AM   #9
kevinh211
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if i were you i'd just find a cheap set of wrx heads for sale. send them out to be ported and larger valves installed. put in larger cams, new valves, and springs.
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Old 04-02-2009, 12:40 PM   #10
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Have the WRX 205 heads worked over or run JDM 207 heads. Chamber on the 2.5 heads is too big for your bore.
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Old 04-02-2009, 12:48 PM   #11
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jdm 207 heads are huge compared to wrx, and you can probably buy two heads for the same price or cheaper than you can get the wrx heads build and ported and polished, plus you have the option of avcs which is so nice
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Old 04-02-2009, 01:00 PM   #12
CKxx
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Your BOV sounds lame
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Quote:
Originally Posted by seanathanq83 View Post
jdm 207 heads are huge compared to wrx, and you can probably buy two heads for the same price or cheaper than you can get the wrx heads build and ported and polished, plus you have the option of avcs which is so nice
I've been searching around and haven't found any v7/v8 heads for sale yet, only old *sold* ads, so I'm not sure what they cost. The only prices I have seen though was for either complete RAW heads (very expensive) or porting on the 205 heads (expensive) and that was w/o cams+springs+assembly cost.

It seems like finding some v7/v8 heads would be a cheaper option...If I can find them.


EDIT: Sorry, I misinterpreted your post. You are saying the v7/v8 ARE a good idea.
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Old 04-02-2009, 01:47 PM   #13
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Plan on spending around $2k for 207 heads that still need a refresh($500) and are not plug and play or spend $3000 to PnP stock 205 heads, cams, and valves and have heads that will outflow stock 207 heads.
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Old 04-02-2009, 03:59 PM   #14
CKxx
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Quote:
Originally Posted by kellygnsd View Post
Plan on spending around $2k for 207 heads that still need a refresh($500) and are not plug and play or spend $3000 to PnP stock 205 heads, cams, and valves and have heads that will outflow stock 207 heads.
I'm told they used to be plentiful at $1K. I guess that is no longer the case.


A friend of a friend works for Subaru in Japan...I've got him on the lookout.
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Old 04-02-2009, 09:36 PM   #15
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207 SB's used to be plentiful for around 1K but I've never seen heads that cheap unless they where damaged.
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Old 04-06-2009, 02:05 AM   #16
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port, polish, cams, valves and springs on your factory heads.

They'll flow like crazy and give you everything you could ever want.... except the hand twist... that's all you.

If you can't swing the 3500 ish for all that work, just do the cams and springs. Still makes a huge difference. Try to keep them reasonable and not too lumpy. Something with 225-230 @ 0.050" and 10.5mm lift would be plenty for a DD and still give huge performance gains.
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Old 04-13-2009, 07:16 PM   #17
CKxx
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Quote:
Originally Posted by Maxwell Power View Post
If you can't swing the 3500 ish for all that work, just do the cams and springs. Still makes a huge difference. Try to keep them reasonable and not too lumpy. Something with 225-230 @ 0.050" and 10.5mm lift would be plenty for a DD and still give huge performance gains.
Any reason you don't recommend something like the Crower 272* cams? Motor is a 2.12L w/GT30R. Non-DD.
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Old 04-13-2009, 11:09 PM   #18
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Quote:
Originally Posted by CKxx View Post
Any reason you don't recommend something like the Crower 272* cams? Motor is a 2.12L w/GT30R. Non-DD.

I think the crowers actually match what I described in that post. I think they're a 10.5 lift with 225 duration at .050" (or something close to that)

I'm actually thinking of running them in my STi because they aren't too aggressive.
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Old 04-14-2009, 03:03 PM   #19
CKxx
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Quote:
Originally Posted by Maxwell Power View Post
I think the crowers actually match what I described in that post. I think they're a 10.5 lift with 225 duration at .050" (or something close to that)

I'm actually thinking of running them in my STi because they aren't too aggressive.
O ok, I see what you meant there. I'm not too familiar yet will all the cam terminology.

I'm having some trouble finding the heads I originally wanted (JDM Big-port) but I did find someone who can CNC port my 205 heads for a very reasonable price, as well as install some BC cams/springs/retainers + assy work. Is there some unforeseen negative consequence to using 205 heads as a starting point rather than 207, AVCS aside? I wouldn't have the money to run the AVCS for a while anyway. I only need to rev to 8K. My stroked block can't take much more.
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Old 04-14-2009, 05:02 PM   #20
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Properly ported 205 heads will outflow stock big ports heads so unless you plan on picking up some big port 207 heads for $2K then spending $3.5K for a good PnP with cams you should just stick with the 205 heads and get them ported.
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