Welcome to the North American Subaru Impreza Owners Club Friday July 25, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
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.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 09-30-2007, 08:16 AM   #1
saintluciascooby
Scooby Specialist
 
Member#: 109527
Join Date: Mar 2006
Location: Chicago
Vehicle:
1997 GC8 8.38@165Mph
blue

Default Ported head flow #s are these good?

go some head flow numbers back from a porting job , curious to know what the consensous is?



Lift inches Stock intake Ported intake Stock exhaust Ported exhaust
0.100 97.4 113.3 93.6 120.2
0.200 195.1 200.8 162.5 202.8
0.300 233.5 260.9 166.5 214.7
0.400 246.2 280.9 169 219.5
0.500 249.6 286.5 168.8 222.8
* Registered users of the site do not see these ads.
saintluciascooby is offline   Reply With Quote
Old 09-30-2007, 09:09 AM   #2
hotrod
Scooby Specialist
 
Member#: 14141
Join Date: Jan 2002
Location: 13.239@102.85 @ 5800 ft on 13T
Vehicle:
2002 Impreza WRX
e85forum.net

Default

what depression was used to get the flow numbers. Without that the numbers are totally meaningless.

What cylinder bore were the heads flowed on?
Where they flowed with the intake manifiolds and exhaust manifolds bolted on?
Were they flowed bare (square flanges with no entry smoothing)?
Were they flowed with short stubs on the ports,or with smooth radiused openings?

The problem with head flow numbers is people thow out the gross flow numbers without the slightest bit of info regarding the test conditions. Some of the changes in flow procedure mentioned above can change the numbers by 10% or more.

Larry
hotrod is offline   Reply With Quote
Old 09-30-2007, 10:00 AM   #3
Homemade WRX
Scooby Guru
 
Member#: 33782
Join Date: Mar 2003
Chapter/Region: MAIC
Location: 3MI Racing LLC
Vehicle:
96 bastard child
search FIRST, then PM!!!

Default

look at how your exhaust flow is higher than your intake flow at low lift adn then at 0.300" your intake skyrockets 60cfm!!
Homemade WRX is offline   Reply With Quote
Old 09-30-2007, 10:45 AM   #4
saintluciascooby
Scooby Specialist
 
Member#: 109527
Join Date: Mar 2006
Location: Chicago
Vehicle:
1997 GC8 8.38@165Mph
blue

Default

These numbers are from a set of heads that I am looking to buy and this is the info I was given. I will ask for more detail now I know what to ask.
homemade wrx I assume the 60cfm # must be wrong?
saintluciascooby is offline   Reply With Quote
Old 09-30-2007, 01:15 PM   #5
Homemade WRX
Scooby Guru
 
Member#: 33782
Join Date: Mar 2003
Chapter/Region: MAIC
Location: 3MI Racing LLC
Vehicle:
96 bastard child
search FIRST, then PM!!!

Default

not saying wrong but seems more like an error in taking the data...
Homemade WRX is offline   Reply With Quote
Old 09-30-2007, 04:13 PM   #6
_Ai_
Scooby Newbie
 
Member#: 70714
Join Date: Sep 2004
Location: Charlotte, NC
Vehicle:
2005 STi
Crystal Grey

Default

Quote:
Originally Posted by saintluciascooby View Post
These numbers are from a set of heads that I am looking to buy and this is the info I was given. I will ask for more detail now I know what to ask.
homemade wrx I assume the 60cfm # must be wrong?
The probability is that you will be far better served to ask for references that exemplify actual performance (i.e. customers who have shown real world performance gains). As Larry mentioned, attempting to gauge the quality of a job based on incomplete data is in most cases a waste of time. Consider that even provided more information on the test setup, you still need to know what was altered dimensionally to gauge the efficiency of the gains in measured CFM. Far more relevant (to most applications) than flow numbers is the quality and consistency of the machinework performed. If the shop has a good reputation for quality work, customer service, and references demonstrating the success of their customers then I would suggest ignoring the marketing all together.

Homemade WRX: Gains in the lower l/d ranges are greatly/primarily affected by valve and seat prep. For reference, a factory stock EJ257 casting at 28" shows .200-.300" gains on the order of 50-52cfm at 28" on our test setup (3.910"/99.3mm bore) depending on inlet entry form. Depending on valve & valvejob we have commonly seen gains in excess of 85cfm from .100-.200" and over 70cfm from .200-.300" at 28" depression. Using those datapoints as a gauge, his 60cfm gain would appear reasonable. I would personally agree that something appears lost in translation regarding the exhaust numbers, but as we know nothing about the head, test setup, procedures or conditions it's all an excercise in futility. Invariably the shop is likely to say "it is what it is" as there is typically little benefit in publicizing a great deal of information in this regard.

Good luck with your project.
_Ai_ is offline   Reply With Quote
Old 09-30-2007, 04:51 PM   #7
Homemade WRX
Scooby Guru
 
Member#: 33782
Join Date: Mar 2003
Chapter/Region: MAIC
Location: 3MI Racing LLC
Vehicle:
96 bastard child
search FIRST, then PM!!!

Default

yeah, I was reffereing to the exhaust outflowing the intake as being possibly wrong...or un-favorable design IMO. I would hope that it is a recording error.
Also, reviewing there factory numbers between .2-.3 I can completely see 60cfm being dead on. I'm still use to motorcycle, honda and SBC heads
Homemade WRX is offline   Reply With Quote
Old 09-30-2007, 07:07 PM   #8
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

why no one takes pics of their PORTED heads......
FuJi K is online now   Reply With Quote
Old 09-30-2007, 11:18 PM   #9
Kosmic
Scooby Specialist
 
Member#: 99140
Join Date: Oct 2005
Chapter/Region: E. Canada
Location: Montreal, Canada
Vehicle:
GD Racing chassis
Slowly in construction

Default

Any link on a good thread about stock wrx/sti heads ported, before and after results?
Kosmic is offline   Reply With Quote
Old 09-30-2007, 11:19 PM   #10
bjm
Scooby Newbie
 
Member#: 87090
Join Date: May 2005
Default

All depends on the heads to what they will look like in the end...



bjm 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
s13 silvia injectors... what flow rate are these? IllNastyImpreza Normally Aspirated with bolt-on Forced Induction Powertrain 8 10-07-2005 12:41 AM
Ported Heads - Flow Information 2000vfr800 Factory 2.0L Turbo Powertrain 6 10-17-2003 10:11 AM
Are these good? Dre2932 General Community 3 01-02-2002 01:52 AM
Are these good Subs? Dre2932 Car Audio, Video & Security 10 09-08-2001 03:23 AM
('93-'01) Are these good?? STi_22B Impreza Forum 1 04-29-2001 08:10 PM


All times are GMT -4. The time now is 10:01 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.