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Old 09-21-2006, 03:01 PM   #49
FuJi K
Scooby Guru
Member#: 3687
Join Date: Jan 2001
Chapter/Region: MWSOC
Location: St. Paul, MN
MY99 GF4 JDM 6spd
NF Performance


Originally Posted by Matt Monson View Post
Fuji K,
I have stopped participating because as far as I am concerned this has become a bunch of mental masturbation. Xephyr has shown that you can make BIG power on the DOHC Ej25 '98 heads. He put down over 400whp on a very conservative dyno. The heads were unported and used stock cams and valves. The only changes to them were upgraded springs. And because they are from very similar castings to the Ej20K/EJ20H/EJ20R heads, it's very easy to tap out the fittings for the turbo oil and coolant stuff that is lacking on them from the factory. They are cast into them (which is a tell that they are based upon a turbo head) and just haven't been drilled out and tapped. Beyond that, I don't need to know anything else about it.

I did recieve 2 longblocks last night. One is an Ej20G from '96 and the other is an Ej20K from '97. I will be measuring them and taking pictures of them for my own database of information. The '96 has HLA's under buckets, like the '96 USDM Ej25s. The '97 I expect to be nearly identical to the '97-99 DOHC Ej25's. But it still doesn't "proove" anything. I am still unsure what you are trying to proove in this thread and stand by my assessment that it's a bunch of irrelevant mental masturbation. At this rate, I will have my engine rebuilt from the ground up, and installed in my car while you are still arguing on the intraweb about irrelevant details...
I look forward to seeing some pictures if you're willing to share.

I was just very curious because of the port runner casting style, which was of a D-style runner. This just got me to think that the 2.5L DOHC could be watered down turbo heads. I've asked around which got a good bunch of answers to find out where these heads are based off of. I don't know if you guys paid attention to them because I didn't get much feedback from you guys about the D-style port runner castings until now.

Then of course comparing them to the NEW BIG PORTS to see where they stand and what things we're looking at.

Like..something I was looking getting was:
Yes, the BIG PORT heads and the 2.5L DOHC NA head share the D-style port castings, but the port inlet is not as tall due to being filled in to help increase air speed into the cylinder. The 2.5L DOHC NA head is slightly smaller in port runner. They are based on the EJ20R w/ same combustion chamber but smaller inlet like said above. This engine is also found on overseas 2.5L NA Subarus of the same year. These heads perform very well for what they are and can be greatly improved on with porting.

BUT REALLY I want this thread to be filled with info on all heads if possible so we can all compare/learn about each one whether new or old style heads.
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FuJi K is offline   Reply With Quote