Phase 1 ej25d head flow numbers

Heads, valves, pistons, rods, crankshaft, etc...

Moderators: Helpinators, Moderators

Post Reply
dankberries
Second Gear
Posts: 506
Joined: Thu Oct 27, 2011 5:09 am
Location: Dirt Roads, Colorado

Phase 1 ej25d head flow numbers

Post by dankberries »

The chart below show's flow numbers for phase 1 DOHC ej25d heads.

Shown is before and after, stock OEM unmodified head flow numbers vs. Port and Polish, deshroud, +1mm ex. & In. Valves.

Heads where purchased brand new from Subaru and then sent to ASF machine for modifications/flow testing.
1998 ej25d. Parts #: 11063AA762, 11039AB123.

Image

I've been catching alot of flack from people for my interest in the phase 1 heads, but these numbers help to show that the ej25d heads are very much capable of making some big power. While most people's logic is to go for phase 2 big port heads, I've chosen to step away from the norm and see how far I can take the ej25d heads.

I'm extremely happy to finally have flow numbers for these heads, I hope it aids as a comparative data point for the community.
93 impreza rally muffin
93 legacy ss Tarmac Terminator
89 Nissan 240sx sr20
90 Nissan 240sx 2jz
killajamal wrote:Dank is actually German for "silly term which the kids have come up with to describe exceptionally choice marijuana.''
BiNiaRiS
First Gear
Posts: 128
Joined: Fri Mar 15, 2013 10:47 am
Location: Portland, OR

Re: Phase 1 ej25d head flow numbers

Post by BiNiaRiS »

Anyone that has used 25D heads know they are very capable. I have them mated to a 257 shortblock and they run really well. A few mechanics that drove my car estimated 330whp or so. I had dyno numbers close to that as well but they have a lot more room for more power I think.

Hopefully next year I'll be able to get some actually numbers once my SS is out of the shop.
EJ22D
In Neutral
Posts: 7
Joined: Thu Mar 02, 2017 5:19 pm

Re: Phase 1 ej25d head flow numbers

Post by EJ22D »

Slightly worked over EJ25D heads are practically equivalent to EJ20D heads. I have a thread two positions below this one that display what stock EJ20D heads can do on the dyno when paired to an EJ222 block through a 4eat, naturally aspirated. The number will surprise you and solidify any confidence you have with EJ25D heads.
beatersubi
Fifth Gear
Posts: 2385
Joined: Tue Mar 13, 2007 12:56 am
Location: 10-9-oh(!), wa

Re: Phase 1 ej25d head flow numbers

Post by beatersubi »

That's really impressive. I've been confident in 25d head flow but it's good to see it in real numbers.
How much valve lift are your going to be running with these heads?
93 legacy wagon L, 22T swapped (TW imitator) now with five forward speeds. (Gone, but never forgotten)
johndrivesabox wrote: Rally, my kyboard is brok, his has nohing o do wih h liquor.
Originalcyn wrote:Apparently everyone hates Gabe.
dankberries
Second Gear
Posts: 506
Joined: Thu Oct 27, 2011 5:09 am
Location: Dirt Roads, Colorado

Re: Phase 1 ej25d head flow numbers

Post by dankberries »

beatersubi wrote:How much valve lift are your going to be running with these heads?
Will be running 11mm/.433in of valve lift.
93 impreza rally muffin
93 legacy ss Tarmac Terminator
89 Nissan 240sx sr20
90 Nissan 240sx 2jz
killajamal wrote:Dank is actually German for "silly term which the kids have come up with to describe exceptionally choice marijuana.''
Post Reply