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Old 10-12-2018, 04:46 PM   #1
Dlawson20
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Default Is Head work worth it on a DD? EJ205

I was just wondering to what extent I should build my 02 WRX 205 heads. Im planning a 300-350 wheel DD with a 20g and meth injection. Just curios to hear your guys thoughts. Thanks in advance!
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Old 10-12-2018, 05:04 PM   #2
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Isn't needed for those power goals.

Depending on what your definition of head work is, it'll allow you to make that power with less boost and little trade off. Or you make the same power with more margin of safety.

What size turbine housing; 7cm or 8cm?
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Old 10-12-2018, 05:08 PM   #3
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As mentioned, what kind of head work are you thinking?

I'll second that, you can easily achieve those power goals without touching the heads. The factory heads are good for around 450hp.
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Old 10-12-2018, 05:46 PM   #4
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Originally Posted by viper_crazy View Post
As mentioned, what kind of head work are you thinking?

I'll second that, you can easily achieve those power goals without touching the heads. The factory heads are good for around 450hp.


What about ej20x heads?
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Old 10-12-2018, 06:56 PM   #5
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Originally Posted by batesd1994 View Post
What about ej20x heads?


On what car? They're dual avcs and need the 32bit ecu to take advantage of their benefits.
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Old 10-12-2018, 07:44 PM   #6
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Talking having them ported. Obviously better using their dual avcs feature
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Old 10-12-2018, 08:14 PM   #7
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I was saying more so on matching the flow characteristics of ej20x heads which are supposedly Jdm better flowing heads
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Old 10-12-2018, 08:53 PM   #8
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Spend the money on proper EL headers & good TMIC instead...and do TGV delete/porting.
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Old 10-12-2018, 09:52 PM   #9
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Quote:
Originally Posted by batesd1994 View Post
What about ej20x heads?
Roughly the same. Maybe a bit less but 300-350 hp would be easily achieved.
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Old 10-13-2018, 09:22 AM   #10
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Quote:
Originally Posted by batesd1994 View Post
I was saying more so on matching the flow characteristics of ej20x heads which are supposedly Jdm better flowing heads
Very few heads, JDM or not, are actually big port heads.

Example, I have two sets of EJ20Y/X (manual vs auto) heads in my garage and they're not big port but are DAVCS.

Last edited by Homemade WRX; 10-17-2018 at 12:09 PM.
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Old 10-13-2018, 07:53 PM   #11
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Which ports do EJ20X heads have? I'm not familiar with these. Very few heads, JDM or not, are actually big port heads.



Example, I have two sets of EJ20Y heads in my garage and they're not big port but are DAVCS.


Do you happen to have the casting numbers?
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Old 10-14-2018, 04:11 PM   #12
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Don't waste your money on head work at that power level. Stock heads are plenty capable at that power level.
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Old 10-15-2018, 09:30 AM   #13
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Quote:
Originally Posted by batesd1994 View Post
Do you happen to have the casting numbers?
Z20 heads.
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Old 10-15-2018, 10:27 AM   #14
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Hello everyone!
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Old 10-15-2018, 10:32 AM   #15
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Don't waste your money on head work at that power level. Stock heads are plenty capable at that power level.


Doesn’t head work make the turbo do less work?
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Old 10-15-2018, 11:52 AM   #16
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head work does make the engine breath better up top, but it doesnt necessarily mean that it will work well with the turbo you have. to make power, you need to match components to what you are trying to achieve and where you want your power band to be. Ie if you have a 16g turbo that doesnt make power above 6500 why try to make power above that. Now if you have a 3076 then yes it makes sense cause it can make power above that point.
Also if you get head work, you will loose velocity on the bottom end so it will lag a little more.
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Old 10-16-2018, 05:06 PM   #17
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head work does make the engine breath better up top, but it doesnt necessarily mean that it will work well with the turbo you have. to make power, you need to match components to what you are trying to achieve and where you want your power band to be. Ie if you have a 16g turbo that doesnt make power above 6500 why try to make power above that. Now if you have a 3076 then yes it makes sense cause it can make power above that point.
Also if you get head work, you will loose velocity on the bottom end so it will lag a little more.
Big ports and small cams is become common place for modern OEM engine development. I'm sure mekilljoydammit will pop in soon and give us all a good lesson on modern cylinder port and cam interactions for street applications.

On my personal 2.1 stroker build, I'm using stock EJ255/7 exhaust cam and ported heads. I didn't want a big lope in my daily driver. I also wanted to keep low end spool for the .64 6758 setup and have flow for the .83 7163 (interchangeable EFRs).

I did go ahead and toss some left over sodium filled STi valves in there and some old BC springs and retainers, as I'll be spinning over 8k on the 7163.
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Old 10-16-2018, 11:09 PM   #18
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Quote:
Originally Posted by Homemade WRX View Post
Big ports and small cams is become common place for modern OEM engine development. I'm sure mekilljoydammit will pop in soon and give us all a good lesson on modern cylinder port and cam interactions for street applications.



On my personal 2.1 stroker build, I'm using stock EJ255/7 exhaust cam and ported heads. I didn't want a big lope in my daily driver. I also wanted to keep low end spool for the .64 6758 setup and have flow for the .83 7163 (interchangeable EFRs).



I did go ahead and toss some left over sodium filled STi valves in there and some old BC springs and retainers, as I'll be spinning over 8k on the 7163.


Are you keeping the 205 intake cam?!
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Old 10-16-2018, 11:38 PM   #19
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Default Is Head work worth it on a DD? EJ205

Quote:
Originally Posted by Homemade WRX View Post
Which ports do EJ20X heads have? I'm not familiar with these. Very few heads, JDM or not, are actually big port heads.



Example, I have two sets of EJ20Y heads in my garage and they're not big port but are DAVCS.


Have you flow tested these by any chance? I'm getting myself an older Impreza to turn into my track specific car and am thinking about an EJ20x/y for it. I know they spin to 7500 and have a forged crown/cast piston and according to a few Aussie posts that they do flow better then the S20 heads. But since you have them in hand, any specific differences that stand out to you?

Last edited by snow_bound26; 10-17-2018 at 08:53 AM.
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Old 10-17-2018, 12:05 PM   #20
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I haven't compared them. One set of heads were development heads and the the other set is still part of an assembled EJ20X, that will be going up for sale.
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Old 10-19-2018, 01:08 AM   #21
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I get about 360 whp out of my 22T/205 hybrid with stock heads running a Blouch 20G-XT. I did chamber match them for the 22T bore and threw in some STi cams, but other than that they are stock and work great. Like others have said, no need for head work to reach those power goals. If you can afford it and want to do it, that's another story.
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Old 10-19-2018, 09:01 AM   #22
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Quote:
Originally Posted by Homemade WRX View Post
Big ports and small cams is become common place for modern OEM engine development. I'm sure mekilljoydammit will pop in soon and give us all a good lesson on modern cylinder port and cam interactions for street applications.


I don't have a 1d simulation that I trust the output of so I won't go much further into it other than the very basics. Besides, we both know despite the stuff I'm messing with for fun, you've done a lot more stuff focused on modern engine packages.

Anyway, quickie guide for those in the audience, for a given amount of air trapped in the cylinder (volumetric efficiency) the more air the ports flow, the less time you need the valves open. The less time you need the valves open the less you compromise part of the powerband by having them open at times you don't want. AVCS is sort of another way of doing that, but for something that makes power at high RPM, you're still going to be basically saying "OK, at this point do I want the valve to open too early or close too late?" On the other hand, it gets to be a challenge to have ports that flow well but still produce good in-cylinder motion (just hogging out to big holes isn't necessarily the best) but it'd be a boring world if it was easy.

If I had a big budget for an "ultimate" street EJ, I'd probably reshape the ports a lot (might not fit in the stock castings) and go with cams with a lot of lift but relatively mild duration. OK, for a given horsepower level (300-350 at the wheels, whatever) you can just throw more boost at it to get there, but I feel like by reworking more you can get a lot more out of the engine at a given boost level.
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Old 10-19-2018, 11:28 AM   #23
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Yeah, I wished I'd just forked over the money for +1 valves on this street set up but my Bugeye is the beater, so it was mostly hand me down parts.

I was going for good flowing heads and small cams to keep a more livable powerband, idle, and better fuel economy. Thanks tiny overlap and little cams. Went with the larger STi exhaust cam to see how it behaves with the torque curve. I think it'll help mid range.
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