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Old 04-26-2011, 10:35 PM   #26
ASF Machine
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Yeah and I was really thinking we'd see 300 CFM in the proper direction but it's this weird valve job that seems to have muffed the flow. It's for my own parts hauler so I've been trying to convince myself that somehow the improved fuel atomization will somehow trump airflow. The "twirl" turbulence should rival that of a "fast burn" GM 185 runner SBC. I'm still convinced with a symmetrical 45* into radius VJ, light unshroud & backcut the overall flow in the right direction would've been more impressive from an airflow standpoint.

Here are the flow numbers pre-weirdo valve job, low and mid-lift are outright awesome.


Code:
Lift    Intake Flow    Dogleg Exhaust   Straight Exhaust         
.050           58              31                  37
.100          103             68                  72 
.150          156            108                 113 
.200          214            147                 160  
.250          249            176                 196   
.300          268            193                 222  
.350          280            201                 235    
.400          280            204                 245   
.450          281            206                 246  
.500          281              -                    -
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Old 05-07-2011, 12:35 AM   #27
Nisstrust
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Quote:
Originally Posted by Homemade WRX View Post
so you can expect a little over 270 cfm intake and about 250 cfm exhaust from that setup.
thnks
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Old 01-12-2012, 08:56 PM   #28
ASF Machine
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Training a new porter...

Had him try his hand at mimicking a big port EJ207 on junk D25 casting.

EJ255 D25 Junk Casting
ASF Ported & Polished
SF-110
7" H2O corrected to 28"
No valve or chamber work.



Code:
Lift    Intake Flow             Exhaust not tested yet.
.050           47                                 -
.100           93                                 -
.150          148                                -
.200          191                                -
.250          237                                -
.300          262                                -
.350          276                                -
.400          283                                -
.450          289                                -
.500          289                                -
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Old 01-12-2012, 10:51 PM   #29
squarebush
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Again, you guys are GREAT for posting this stuff up! and I hate to be "That guy" but where is the EJ205 info? I only ask because I was considering machinging a set of 205 heads to match the 2.5 block but picked up a set of 255 heads instead, so I was wondering what the difference in flow would be.
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Old 01-17-2012, 05:42 PM   #30
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Patience young padowan.
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Old 01-17-2012, 11:35 PM   #31
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Quote:
Originally Posted by ASF Machine View Post
Patience young padowan.

But... but... I need to know
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Old 01-18-2012, 01:17 AM   #32
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Quote:
Originally Posted by squarebush
Again, you guys are GREAT for posting this stuff up! and I hate to be "That guy" but where is the EJ205 info? I only ask because I was considering machinging a set of 205 heads to match the 2.5 block but picked up a set of 255 heads instead, so I was wondering what the difference in flow would be.
Which are they, B25 or D25? All the USDM turbo 02+ have the same intake port design. There are the exhaust ports of the B25 and the others which are the same; S20/D25/V25B/W25.
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Old 01-18-2012, 05:02 PM   #33
subaroket
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Its great that you posted the flow of both exhaust ports.

Would it be too much to ask for the numbers on the single port 2.2 heads? I always wonder if they have terrible flow even though the single port 2.2 had higher peak HP than the dual port 2.2
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Old 02-06-2012, 10:01 PM   #34
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What is the difference in a EJ251 head, both styles of EJ253's and the EJ254 heads?
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Old 02-06-2012, 10:17 PM   #35
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Quote:
Originally Posted by fateo66
What is the difference in a EJ251 head, both styles of EJ253's and the EJ254 heads?
Intake runners are the same, AVLS models have a different chamber, more Honda-like if you will (read: quench pads recessed into chamber instead of being deck surface). I don't have any pictures on my phone here. I'm guessing you of all people have seen them.
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Old 04-12-2012, 02:23 PM   #36
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maybe this is the right place to ask. I'm planing on picking up a cheap used na 2.5 from a 96 or 98 legacy to temporarily replace the avcs heads i have for my wrx. i was hoping they would be close enough to use as normal 02 wrx heads while I build/fix the heads I have now. any info would help alot.
I'm running a ej207 that came from a jdm twin turbo legacy so I'm not even sure that they match any of the usdm STI heads.
on cobb 16g map.
just need them to work in the short term while building second motor......
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Old 04-12-2012, 03:02 PM   #37
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Phase I heads will not work in your situation.
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Old 04-12-2012, 04:33 PM   #38
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Quote:
Originally Posted by FuJi K View Post
you are not gonna kill a subaru head making them big. they cant get all that big.
nice numbers btw
I've seen more than one head fail due to over porting so yes you can port them too much especially in the exhaust ports. Road racing with 1000C exhaust gas temps over time will pretty much warrants OEM thickness ports. We don't touch them for reliability sake.

Quote:
Originally Posted by iana View Post
This 'yay for velocity' stuff is a bit of a laugh. We're talking subaru head castings here, you cant physically go to big. Its just impossible.
It may not matter for maximum flow purposes but it matters for an overall great package. Why ruin the idle and low RPM performance when very little if any measurable gains are made on the top end or risk port failure? There's a balance that needs to be achieved for a "great" head package.


Quote:
Originally Posted by Homemade WRX View Post
bump for a revival...


**I also kind of toss flowbench values from one to the other out the window as how tests are conducted can vary and that it is much like comparing dyno numbers in that each bench is calibrated and things can vary. In conducting tests, my dislike with 'claying' is the question of repeatability throughout testing, which brings about the question of what inlet do they use if they aren't claying.
I agree which is mainly why I don't share our flow test numbers because they are not comparable to other machines or heads. Just for the OEM to modified test on the same machine and testing equipment. Flow bench numbers get very exaggerated when tested with high water. I can't tell you how many times someone brags about their flow bench numbers that don't equate to more power on the dyno.

Look at the SOHC flow bench number and tell me why they repeatedly fail to make huge power? It's strange for sure but this is why real world testing and dyno work just can't be replaced by flow bench numbers.

My 2c. LOL!

Phil Grabow
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Old 04-12-2012, 09:15 PM   #39
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Quote:
Originally Posted by Element Tuning

I've seen more than one head fail due to over porting so yes you can port them too much especially in the exhaust ports. Road racing with 1000C exhaust gas temps over time will pretty much warrants OEM thickness ports. We don't touch them for reliability sake.

someone must of over done them. we where referring to too large killing velocity. If it isn't as big as a JDM big port, you can't say it too big. A S2000 had sports larger intake ports than us. The exhaust ports, there isn't much room to play with. I know, I play with them all the time; B25, D25, S20. Seen V25B, W25...
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Old 05-22-2012, 07:21 PM   #40
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Hey Guys,

Does anyone have flowbench results of the Dual AVCS heads, i want to compare against my ported setup to see if there is any significant difference between a stock Dual AVCS head setup and mine below?

Quote:
Originally Posted by Nisstrust View Post
Hey Guys, Great i have been looking for a reference point like this thread.

i recently had my heads ported, but don't have much info re data points, fairly new to all the field values so please educate me on terminology regarding my table below.

Pics below is all that i got from shop re flow bench test results.

What Head: EJ255 heads
Valves & Size of Valves: BC Springs and Retainers and 1mm oversized BC valves
Port Work: Yes
Chamber Work: not known
Type or Model of Bench: not known
Flow Depression: not known
Notes: installed with Kelford 264 intake and 260 exhaust cams

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Old 05-23-2012, 03:13 AM   #41
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Quote:
Originally Posted by ASF Machine View Post
The point I was making there is that there is alot more to porting than just making holes big; velocity is extremely important, forced induction or not.
As anyone with a good engine simulation program, a flowbench, or just good old experimentation can tell you. Oval port vs Rect port BBC? 2bbl / 4 bbl Cleveland?

What's the average CSA of the intake on these heads ASF?

S.
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Old 07-15-2012, 09:24 AM   #42
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am i missing something but does it seem that the NA heads flow quite well?
Was thinking of changing my ej253 sohcs to ej205 dohc to get more flow, but seems that i might aswell just out some better cams in my sohc heads that will cope with the turbo better.
Am i right in saying that??
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Old 07-15-2012, 10:00 AM   #43
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Single cam heads work well for being single cam.
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Old 07-29-2012, 04:16 PM   #44
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EJ257 V25B ('07 STi casting)
Stock valves - refaced and back-cut
Valve Job (Newen EPOC), bowl blend, smoothed STR (short turn radius) on int + exh, lowered intake floor .020" - nothing else
No chamber work
SF-1020
28" H2O
95.5mm aluminum bore fixture - o-ring sealed top and bottom
Plastic intake entry, no pipe on exhaust
All work done by myself




Exhaust

Exhaust

Exhaust

Intake

Intake

Intake

Both + valves

The bench

*these heads might soon be for sale - pm me if interested*

EDIT: They are now for sale here http://forums.nasioc.com/forums/show....php?t=2407476

Last edited by BallPeenHamr; 09-14-2012 at 09:51 AM.
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Old 07-29-2012, 04:39 PM   #45
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What can the EJ205s be opened up to? Kind of looking at stuff, and wondering if it's feasible to get them out to flowing similarly to 207 heads or if it's not even worth the trouble.
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Old 07-30-2012, 02:10 AM   #46
FuJi K
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Quote:
Originally Posted by mekilljoydammit
What can the EJ205s be opened up to? Kind of looking at stuff, and wondering if it's feasible to get them out to flowing similarly to 207 heads or if it's not even worth the trouble.
they can be ported to flow the same if not more.
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Old 09-16-2014, 01:44 AM   #47
ranger23
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Bumping this to the top any new info on the 205 heads
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Old 05-18-2015, 04:58 PM   #48
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For those buying STI heads, you may want to look into the Z20 heads from the legacy as they might flow somewhere between the 257 and 207, and probably cheaper
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Old 08-23-2015, 05:05 PM   #49
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these questions could be answered somewhere [ i have spent a good time looking ] but as with the bore size , i have a question with regards to troth size , on std valves size are you increasing it if so how much [ some might not like to say by how much ] we usually get to open them by 1mm on std valves on other brand engines / and this is where i wonder does everyone increase troth size when using bigger valves or are new bigger seats or keeping std troth to increase venturi ,

i seen someone rote that the newer std heads are flowing near b16a head figures , this is a point where i see subaru lacking as these cfm figures obivouslly flow perfectlly adiquatlly for 16-1800cc and the increase in subaru cc only increase the restriction and therfore the hugh fall off in what we see the graphs , cam are really only an attempt to sort the issue
has anyone got a set of cams cut to suit the head they have flowed

Cheers
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Old 02-21-2019, 04:57 PM   #50
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I know this is ancient, but based on your flow test data is there any reason an EJ251 couldn't make, say, 650hp?
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