Welcome to the North American Subaru Impreza Owners Club Saturday November 28, 2020
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Built Motor Discussion

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 08-06-2010, 05:04 PM   #1
ASF Machine
Former Vendor
 
Member#: 236349
Join Date: Jan 2010
Location: Western Colorado
Vehicle:
1993 Impreza
OD Green

Lightbulb Subaru Cylinder Head Flow Database

I thought I'd start a thread for cylinder head flow numbers, feel free to add to it. Please include mods, flow depression and any other pertinent info.

Disclaimer: I don't drive a train or have an engineering degree, I am simply an engine machinist who enjoys Subies trying to share some info with the community.
Disclaimer 2: Flow CFM is only part of the cylinder head equation but knowing these numbers aid some us greatly when modeling combinations. (I know Subies don't ever get .50" lift but I like to go there just to see "what if")

What Head:
Valves & Size of Valves:
Port Work:
Chamber Work:
Type or Model of Bench:
Flow Depression:
Notes:



*All intakes done with clay radius stack on intake.*
*No pipe on the exhaust*
*4" Polycarbonate bore fixture*



JDM EJ207 Big Port AVCS RHS20V Casting
Stock Valves
Stock Ports
Stock Chambers
SF-110
7" H2O corrected to 28"
Mighty Impressed by "as cast" heads, especially mid lift from .250" to .350".


Code:
Lift    Intake Flow             Exhaust Flow Non-Dogleg Port 
.050           44                                 31
.100           86                                 67
.150          142                                114
.200          178                                150
.250          232                                156
.300          262                                178
.350          281                                188
.400          283                                191
.450          283                                194
.500          283                                197
JDM Version 4 EJ20K
Stock Valves
Stock Ports
Stock Chambers
SF-110
7" H2O corrected to 28"
Somewhat disappointed as people often tout these as super-awesome.


Code:
Lift    Intake Flow             Exhaust Flow Non-Dogleg Port
.050           30                                 31
.100           87                                 69
.150          138                                103
.200          179                                132
.250          214                                152
.300          241                                165
.350          245                                177
.400          249                                185
.450          249                                193
.500          251                                194
EJ251 SOHC
Stock Valves
Stock Ports
Stock Chambers
SF-110
7" H2O corrected to 28"
Cleanest factory casting I've ever seen.
Surprised as many folks on the forums discount these heads as inferior to anything DOHC. I haven't flow tested the exhaust yet.


Code:
Lift    Intake Flow             
.050           48                                
.100           84                                 
.150          143                                
.200          188                                
.250          222                                
.300          239                                
.350          253                                
.400          253                                
.450          260                                
.500          264
EJ251 SOHC
Stock Valves
Port Matched to TGV (yep empty TGVs on a SOHC) + full ASF port & polish
Polished chambers
SF-110
7" H2O corrected to 28"

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              -                    -
* Registered users of the site do not see these ads.

Last edited by ASF Machine; 04-26-2011 at 09:07 PM. Reason: added info
ASF Machine is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 08-06-2010, 05:33 PM   #2
ZeroDrift
Scooby Specialist
 
Member#: 184324
Join Date: Jul 2008
Chapter/Region: RMIC
Location: Colorado
Vehicle:
1999 Impreza 2.5RS
Black

Default

Interesting finds! I've long been a fan of SOHC heads, albeit mostly because its much easier to change plugs while the engine is in the car. Good to know that they flow well! Curious as to how much they flow when they have been ported...
ZeroDrift is offline   Reply With Quote
Old 08-06-2010, 06:25 PM   #3
Matt Monson
Scooby Guru
 
Member#: 832
Join Date: Jan 2000
Chapter/Region: RMIC
Location: Teh Ghetto Garage, CO
Vehicle:
99 2.5RS, '85 911
'73 914 and 2012 BRZ

Default

http://www.chrracingproducts.com/flow-test-data

If you click the flow test date button for Subaru on this site, those are my heads listed. SOHC heads really open up nicely on the exhaust side. You can go further than they did on my heads, but my car is NA with a hopped up street cam and we didn't want to kill the port velocity and low end. My redline is only 6400 rpm. For different applications like a high revving race motor or FI you could port them more.
Matt Monson is offline   Reply With Quote
Old 08-14-2010, 12:52 AM   #4
ASF Machine
Former Vendor
 
Member#: 236349
Join Date: Jan 2010
Location: Western Colorado
Vehicle:
1993 Impreza
OD Green

Default More...

JDM EJ207 Big Port AVCS RHS20V Casting
+1mm Supertech Valves with radius into tangent valve job
ASF Ported & Polished with minimal port volume increases (yay for velocity!)
Chambers deshrouded to 99.5 Bore, Valves deshrouded individually
SF-110
7" H2O corrected to 28"
Notes: Noticeable gains at higher lift, extraordinary low to mid lift; I cannot wait to see the power under the curve on this build. Customer's knowledge and planning on this build are unparalleled.


Code:
Lift    Intake Flow             Exhaust Flow Non-Dogleg Port
.050           49                                 37
.100           98                                 78
.150          151                                121
.200          199                                165
.250          237                                196
.300          272                                210
.350          291                                216
.400          297                                217
.450          301                                217
.500          302                                219

Last edited by ASF Machine; 10-28-2010 at 07:38 PM.
ASF Machine is offline   Reply With Quote
Old 08-14-2010, 04:57 AM   #5
kenikh
Scooby Newbie
 
Member#: 212677
Join Date: May 2009
Chapter/Region: NWIC
Location: King County East, WA
Vehicle:
1999 Forester S
Bone stock...for now

Default

Here are mine:

JDM Version 4 EJ20K
Stock Valves
Hand Ported and Polished
Chambers Deshrouded & Polished
Stock cams and valvetrain with shim under bucket follower setup
5 angle into radius valve job, decked to clean
SF-110
28" H2O
Code:
Lift    Intake Flow             Exhaust Flow Non-Dogleg Port
.050    42                                     35
.100    89                                     70
.150    140                                  115
.200    188                                  150
.250    226                                  167
.300    257                                  180
.350    264                                  191
.400    264                                  197
.450    268                                  201
.500    276                                  203
kenikh is offline   Reply With Quote
Old 08-14-2010, 05:23 AM   #6
iana
Scooby Newbie
 
Member#: 252934
Join Date: Jul 2010
Location: Island Gaol
Vehicle:
99

Default

JDM V7 STI
Tony Knight Race Engines, Adelaide Australia.
Chambers modified by JHH, Brisbane Australia.
Stud bores and oiling opened up by me.
Ferrera catalogue, manganese guides etc.
CNC profile and hand finished.
Chambers to suit 100mm custom CP's
Kelford 264's etc
Drilled to suit 12.7mm head studs with sleeved stud bores to limit distortion.
You get the drill. They flow better than Cosworth big port heads do at all points of lift @ 28in. (Cosworth figures are a joke, at 28in of water they flow terribly compared to these, nearly 17cfm lower at 400thou.)

Flow testing was done on an SF600 superflow bench
The bench has been calibrated with tractorsport orifice plates
Tested at 28" depression


Inlet/Exhaust Ratio
Lift 0.100 0.200 0.300 0.400 0.500
Ratio Ported 86.0 86.2 82.0 81.6 78.4

Code:
Lift    Intake Flow     Exhaust Flow Straight     Exhaust Dogleg
.100    98                                84.5                              84
.200    195                               169                              167     
.300    281                               232                              229
.400    315                               258                              256
.500    335                               263                              262 
iana is offline   Reply With Quote
Old 08-14-2010, 07:06 AM   #7
iana
Scooby Newbie
 
Member#: 252934
Join Date: Jul 2010
Location: Island Gaol
Vehicle:
99

Default

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.
iana is offline   Reply With Quote
Old 08-14-2010, 12:37 PM   #8
ASF Machine
Former Vendor
 
Member#: 236349
Join Date: Jan 2010
Location: Western Colorado
Vehicle:
1993 Impreza
OD Green

Default

Yes, Cosworth uses a bench at 50" H2O. It produces super inflated flow numbers but to their credit it also better at uncovering flow deficiencies than the standard 28". To convert depressions Take the dep. you want to convert to / your dep. and fin that number's square root. Example 50/28=1.7857 That square root of that is 1.3363, now multiply this against your old flow numbers at 28" H2O.

Quote:
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.
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.
ASF Machine is offline   Reply With Quote
Old 08-16-2010, 01:24 AM   #9
frankenwagon
Scooby Newbie
 
Member#: 166132
Join Date: Dec 2007
Location: Earf
Vehicle:
1888 Horse
Brown

Default

double true^
frankenwagon is offline   Reply With Quote
Old 08-16-2010, 01:26 AM   #10
FuJi K
Scooby Guru
 
Member#: 3687
Join Date: Jan 2001
Chapter/Region: MWSOC
Location: St. Paul, MN
Vehicle:
MY99 GF4 JDM 6spd
NF Performance

Default

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.
you are not gonna kill a subaru head making them big. they cant get all that big.
nice numbers btw
FuJi K is offline   Reply With Quote
Old 08-16-2010, 12:17 PM   #11
ASF Machine
Former Vendor
 
Member#: 236349
Join Date: Jan 2010
Location: Western Colorado
Vehicle:
1993 Impreza
OD Green

Default

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
Put your numbers in here, this isn't just an ASF-whoring thread.

Once I have my Pitot, I'll rebut you guys on the velocity thing.
ASF Machine is offline   Reply With Quote
Old 08-16-2010, 02:11 PM   #12
Homemade WRX
Scooby Guru
 
Member#: 33782
Join Date: Mar 2003
Chapter/Region: MAIC
Location: Mooresville, NC
Vehicle:
96 3MI Racing
search FIRST, then PM!!!

Default

been there and played with a pitot using Performance Trends port flow analyzer. You'll find some good stuff for sure!
Homemade WRX is offline   Reply With Quote
Old 08-17-2010, 12:01 AM   #13
FuJi K
Scooby Guru
 
Member#: 3687
Join Date: Jan 2001
Chapter/Region: MWSOC
Location: St. Paul, MN
Vehicle:
MY99 GF4 JDM 6spd
NF Performance

Default

Quote:
Originally Posted by ASF Machine View Post
Put your numbers in here, this isn't just an ASF-whoring thread.
hahahaha I was gonna let you have all the fun because I had a thread of my own.

but here we go for data's sake.

STOCK B25 STi head
Code:
Lift          Intake       Straight        Dogleg
.100           81             84               78
.200          166            166             155
.300          231            188             174
.400          248            195             178




What Head: '06 EJ257
Valves & Size of Valves: SuperTech +1mm
Port Work: Double-D intake and enlarged exhausts
Chamber Work: Stock
Type or Model of Bench: SuperFlow600
Flow Depression: 28"
Notes: 5angle valve job with seat blending. Clayed intake and 2" dia x 3" length exhaust pipe clayed on. Removed valve guide and supports. Intake ports 3mm larger port runners.
http://forums.nasioc.com/forums/show...&postcount=166

Code:
Lift          Intake       Straight        Dogleg
.100           87             88               88
.200          177            183             186
.300          262            235             227
.400          294            247             235



What Head: '04 EJ257
Valves & Size of Valves: Stock
Port Work: Baby-D intake and enlarged exhausts
Chamber Work: Stock
Type or Model of Bench: SuperFlow600
Flow Depression: 28"
Notes: stock valve angles with seat blending. Clayed intake and 2" dia x 3" length exhaust pipe clayed on. Removed valve guide and supports. Intake ports 1mm larger port runners.
http://forums.nasioc.com/forums/show...&postcount=195

Code:
Lift          Intake       Straight        Dogleg
.100           86             78               81
.200          170            159             159
.300          241            217             210
.400          267            239             228


What Head: '06 EJ255
Valves & Size of Valves: Stock
Port Work: STOCK
Chamber Work: Stock
Type or Model of Bench: SuperFlow600
Flow Depression: 28"
Notes: Clayed intake and 2" dia x 3" length exhaust pipe clayed on.
http://forums.nasioc.com/forums/show...81&postcount=1

Code:
Lift          Intake       Straight        Dogleg
.100           86             72               72
.200          177            145             142
.300          237            185             180
.400          253            203             192







http://forums.nasioc.com/forums/show....php?t=1728481
http://forums.nasioc.com/forums/showthread.php?t=903873
FuJi K is offline   Reply With Quote
Old 08-17-2010, 12:15 AM   #14
wrxwhat
Scooby Specialist
 
Member#: 87653
Join Date: May 2005
Chapter/Region: South East
Location: Long Island NY
Vehicle:
97 Supra / 17 GTR
16 Z06 / 07 STI / 05 Evo

Default

I'll have mine up fairly soon, intake is over 300 cfm at .400
wrxwhat is offline   Reply With Quote
Old 10-28-2010, 03:37 PM   #15
Homemade WRX
Scooby Guru
 
Member#: 33782
Join Date: Mar 2003
Chapter/Region: MAIC
Location: Mooresville, NC
Vehicle:
96 3MI Racing
search FIRST, then PM!!!

Default

bump for a revival...

ALSO, I didn't realize this until now but everyone should really mention what bore diameter they are flowbenching on because it does make a difference. If you get into charge/discharge coefficients, you'll really notice.

**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.


ASF Machine: how are you making a Superflow SF110 flow 28" at those flowrates?...isn't it only rated to like 15" H2O and like 180 or so cfm...

Last edited by Homemade WRX; 10-28-2010 at 03:45 PM.
Homemade WRX is offline   Reply With Quote
Old 10-28-2010, 07:43 PM   #16
ASF Machine
Former Vendor
 
Member#: 236349
Join Date: Jan 2010
Location: Western Colorado
Vehicle:
1993 Impreza
OD Green

Default

Good point on the bore fixture.

You are correct on bench flow capacity.

I've amended the above listings to show heads were physically tested at 7" and corrected to 28". I realize this is less than ideal when uncovering flow deficiencies but I am currently only doing what I know works(and many others that have come before me that are a lot smarter than I am.)
ASF Machine is offline   Reply With Quote
Old 10-29-2010, 12:40 PM   #17
Homemade WRX
Scooby Guru
 
Member#: 33782
Join Date: Mar 2003
Chapter/Region: MAIC
Location: Mooresville, NC
Vehicle:
96 3MI Racing
search FIRST, then PM!!!

Default

Quote:
Originally Posted by ASF Machine View Post
Good point on the bore fixture.

You are correct on bench flow capacity.

I've amended the above listings to show heads were physically tested at 7" and corrected to 28". I realize this is less than ideal when uncovering flow deficiencies but I am currently only doing what I know works(and many others that have come before me that are a lot smarter than I am.)
ok, cool. Yeah being able to run the heads at higher pressure will help in 'tuning' the ports (hence Cossie's higher flow pressures and thus rates) but for getting the base flowrates, I'd say you're good to go
Homemade WRX is offline   Reply With Quote
Old 10-30-2010, 01:16 AM   #18
FuJi K
Scooby Guru
 
Member#: 3687
Join Date: Jan 2001
Chapter/Region: MWSOC
Location: St. Paul, MN
Vehicle:
MY99 GF4 JDM 6spd
NF Performance

Default

I'm trying to get good flow numbers on stock valves. I can't seem to hit 300CFM with the bore size I'm using; 4". Came close with this head. Pictures are as seen in my posts somewhere in this forum.


FuJi K is offline   Reply With Quote
Old 11-04-2010, 09:54 PM   #19
ASF Machine
Former Vendor
 
Member#: 236349
Join Date: Jan 2010
Location: Western Colorado
Vehicle:
1993 Impreza
OD Green

Default

Quote:
Originally Posted by FuJi K View Post
I'm trying to get good flow numbers on stock valves. I can't seem to hit 300CFM with the bore size I'm using; 4". Came close with this head. Pictures are as seen in my posts somewhere in this forum.

Have you tried putting a big 30 degree backcut (almost all the way to the lap/interference line) on the intake valves?

I can usually pick up a bunch at low lift and smidge up high even on valves that have a "backcut" already on them.
ASF Machine is offline   Reply With Quote
Old 03-10-2011, 07:11 PM   #20
Nisstrust
Scooby Newbie
 
Member#: 255202
Join Date: Aug 2010
Chapter/Region: International
Default

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

Nisstrust is offline   Reply With Quote
Old 03-10-2011, 07:37 PM   #21
Homemade WRX
Scooby Guru
 
Member#: 33782
Join Date: Mar 2003
Chapter/Region: MAIC
Location: Mooresville, NC
Vehicle:
96 3MI Racing
search FIRST, then PM!!!

Default

so you can expect a little over 270 cfm intake and about 250 cfm exhaust from that setup.
Homemade WRX is offline   Reply With Quote
Old 04-26-2011, 08:43 PM   #22
ASF Machine
Former Vendor
 
Member#: 236349
Join Date: Jan 2010
Location: Western Colorado
Vehicle:
1993 Impreza
OD Green

Default

Updated more SOHC weirdness to post #1.





EJ251 SOHC "Polyquad"
Staggered Valve sizes Intake: 35.05mm @ 45* seat into radius & 36.05mm @ 30* seat into radius w/ 6* deshroud
Exhaust: 30.5mm & 31.5mm 45* seats into radius
Port Matched to TGV (yep empty TGVs on a SOHC) + asymmetrical ASF Port & Polish
Polished & staggered deshrouded chambers
SF-110
7" H2O corrected to 28"
Comments: Intake is EXTREMELY turbulent in both directions, I was after some "twirl" to aid in ethanol atomization for better burn but this seems a bit extreme. This turbulence is what I attribute the loss of intake flow to... as an added odd note; peak flow in reverse on the intake was 306 CFM from .400-.500".
I can only speculate that these heads would be a poor pairing with an NA setup & bunches of overlap, the dyno will tell us how they do with some FI goodness.



Code:
Lift    Intake Flow    Dogleg Exhaust   Straight Exhaust         
.050           51              31                  50
.100           98              88                  93 
.150          143            125                 129 
.200          188            161                 174  
.250          218            183                 204   
.300          241            194                 225  
.350          253            199                 230    
.400          257            203                 244   
.450          268            205                 246  
.500          276              -                    -



Last edited by ASF Machine; 04-26-2011 at 09:11 PM.
ASF Machine is offline   Reply With Quote
Old 04-26-2011, 10:16 PM   #23
Homemade WRX
Scooby Guru
 
Member#: 33782
Join Date: Mar 2003
Chapter/Region: MAIC
Location: Mooresville, NC
Vehicle:
96 3MI Racing
search FIRST, then PM!!!

Default

I'm thinking blower heads or low boost from a turbo.

I'm going to guess that higher pressure manifold ratios (exh/int) and overlap will probably hinder power (potential) from reversion.
Homemade WRX is offline   Reply With Quote
Old 04-26-2011, 11:12 PM   #24
ASF Machine
Former Vendor
 
Member#: 236349
Join Date: Jan 2010
Location: Western Colorado
Vehicle:
1993 Impreza
OD Green

Default

Quote:
Originally Posted by Homemade WRX View Post
I'm thinking blower heads or low boost from a turbo.

I'm going to guess that higher pressure manifold ratios (exh/int) and overlap will probably hinder power (potential) from reversion.
I was thinking these would need a big hotside on the turbo to really shine.
ASF Machine is offline   Reply With Quote
Old 04-26-2011, 11:22 PM   #25
Homemade WRX
Scooby Guru
 
Member#: 33782
Join Date: Mar 2003
Chapter/Region: MAIC
Location: Mooresville, NC
Vehicle:
96 3MI Racing
search FIRST, then PM!!!

Default

yup and little overlap on the cams. Keep us posted on how it turns out. Should be interesting.

Did you think of deshrouding the otherside to help increase flow and reduce some of the turbulence?
Homemade WRX is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Subaru Cylinder Head Info+ Specs cribbie Built Motor Discussion 7 11-22-2018 12:53 AM
EJ205 heads flow? leighton1245 Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 3 08-06-2010 10:34 AM
subaru cylinder heads TimBeeno Private 'Wanted' Classifieds 2 09-28-2007 12:45 AM
Cylinder Head Flow Bench nkeehn Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 1 03-18-2003 06:34 AM
Air flow data - Cylinder Heads Trey Technical Forum Archive 16 08-10-2000 12:38 PM

All times are GMT -4. The time now is 09:22 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2020 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.