Welcome to the North American Subaru Impreza Owners Club Thursday October 23, 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 12-11-2012, 10:17 PM   #1
Scubynubie
Scooby Newbie
 
Member#: 103757
Join Date: Dec 2005
Default Is there a purpose to the dog-leg port on the Subaru heads?

After reading Crawford's analysis of the new FA BRZ and hearing that even the new BRZ heads have a dog-leg port, I have really been wondering if there is a purpose to having them.

You have to figure that if they could have gained some efficiency, or a gain in power, they could have easily designed a head that didn't have them with the 2007 STI, the 2008+ STI with Dual AVCS, and especially the FA BRZ engine that is trying to make a lot of NA hp where I would assume that efficiency would be paramount.

Part of the purpose of this thread is that before this point, I have been thinking of porting a head only enough to match the flow of the dog-leg and straight port, and pairing that with an EL headder. But now I wonder if that would actually not be an ideal set-up compared to leaving the dog-leg port different.

In a nut shell, if the dog-leg port was bad/less efficient, wouldn't they have remove it by now?
* Registered users of the site do not see these ads.
Scubynubie is offline   Reply With Quote
Old 12-12-2012, 12:05 PM   #2
Storm
Scooby Guru
 
Member#: 5218
Join Date: Mar 2001
Chapter/Region: MWSOC
Location: SAUL'S Motorsports
Vehicle:
96L Most Over-
Developed Beater

Default

My understanding is a simple packaging restraint. The engine subframe occupies the space where the dogleg exhaust port would exit if it werent turned and routed closer to the other port.

Jay
Storm is offline   Reply With Quote
Old 12-12-2012, 12:24 PM   #3
CatfaceType-R
Scooby Guru
 
Member#: 81102
Join Date: Feb 2005
Chapter/Region: MWSOC
Location: I sell platinum cat jewelry.co
Default

idk how we can match the ports with that dogleg...

matched airflow+matched (cc) injectors+matched gap in spark plugs in between cylinders=good. Ability for your tune to be pertinent...
CatfaceType-R is online now   Reply With Quote
Old 12-12-2012, 02:09 PM   #4
tja1618
Scooby Newbie
 
Member#: 181995
Join Date: Jun 2008
Chapter/Region: Tri-State
Location: Rochester, NY
Vehicle:
2003 WRX
WRB

Default

Can someone point out what you mean by dog-leg ports? Does this refer to the shape of the ports as they curve up/down to the intake/header? As opposed to something straight up and down?
tja1618 is offline   Reply With Quote
Old 12-12-2012, 02:12 PM   #5
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 tja1618
Can someone point out what you mean by dog-leg ports? Does this refer to the shape of the ports as they curve up/down to the intake/header? As opposed to something straight up and down?
FuJi K is offline   Reply With Quote
Old 12-19-2012, 01:40 PM   #6
spoolinsti05
Scooby Specialist
 
Member#: 108051
Join Date: Feb 2006
Chapter/Region: Tri-State
Location: NY
Vehicle:
2005 TickingTimeBomb
Jr tuned TT Sleeved

Default

Exactly how mine look^ Besides for the valve seat blend you had done.

The dog leg will always be their. Matching it's flow is what you need to aim for.
spoolinsti05 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


All times are GMT -4. The time now is 12:59 PM.


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.