1. Join the Community!

    DSMtuners is a massive archive of DSM information - but more importantly, it's a COMMUNITY! Join in and participate with other DSMers, and invite all of your DSM friends to make this place their home. Chat with others, create a build thread, post questions and answers. Get involved! Logging in will also remove many of the advertisements, along with this notice. ;)

Holset (7 blade hx35) turbing housings

Posted by jpmxrider489, Sep 18, 2020

Please Support STM Tuned
Please Support Fuel Injector Clinic
  1. jpmxrider489

    jpmxrider489 Supporting VIP

    2,150
    39
    Joined Apr 4, 2010
    pittsburgh, Pennsylvania
    So i recently come to the conclusion that my divided 12cm housing was my restriction. I was only able to flow 45lb/min and after porting the housing, I noticed flowing 47, which is much lower from other peoples reports.

    So I have a divided 16cm housing that I plan on installing. Issues I ran into is the 16cm housing has only a 2.5 outlet instead of the 3 my 12cm had. With that being said, I welded my 3 inch vband flange to the outlet. My question is what should I expect from this?
    Also, with the 3 inch flange welded on, there is plenty of materical I can take away from the outlet to make it a actual 3 inch outlet. Is this something I should do? Should I also port the divided part of the housing? I know its not reccomended but I saw a very small difference when porting the divided 12.

    Like i said, I welded the 3 inch vband to the 2.5 section. I can open it up so it is the same diameter of the vband. Should this help with power, backpressure and overall performance?
     

    Attached Files:

    Street Build 364  1

    1995 Eagle Talon TSi
    fwd · automatic · 2G DSM

    Street Build 2K  3

    1995 Eagle Talon TSi
    fwd · automatic · 2G DSM
    Loading...
  2. Mello

    Mello Proven Member

    1,194
    355
    Joined Jul 4, 2003
    Albuquerque, New Mexico
    Opening up the V-Band flange will help when you move closer to maxing out the turbo. I would open it up now to save having to do it later.
     
  3. jpmxrider489

    jpmxrider489 Supporting VIP

    2,150
    39
    Joined Apr 4, 2010
    pittsburgh, Pennsylvania
    What about opening up the divided section to match the gasket? Everything I read was that these housings should be ported. I was also unaware that there were some housings with 2.5 and 3 inch outlet.

    I wish there was a true list that is applicable to our cars that talk about the housings and outlets. I know there is a list of part numbers but would be nice to simplify that. Especially since there are hybrid holsets. Some with gates and some without.
     

    Street Build 364  1

    1995 Eagle Talon TSi
    fwd · automatic · 2G DSM

    Street Build 2K  3

    1995 Eagle Talon TSi
    fwd · automatic · 2G DSM
    Loading...
  4. RWD4G63

    RWD4G63 Proven Member

    420
    94
    Joined Dec 7, 2011
    Paw Paw, Michigan
    Are you using this on a non-divided manifold? The 12cm housing isn't a restriction until 500whp or more.
     

    Road Race Build 363  3

    1997 Eagle Talon TSi AWD
    awd · manual · 2G DSM
    Loading...
  5. jpmxrider489

    jpmxrider489 Supporting VIP

    2,150
    39
    Joined Apr 4, 2010
    pittsburgh, Pennsylvania
    Im am using a divided manifold with the divided 12 housing previously and on average I saw 45-47 lb/min at 33psi. I recently upgraded to the divided 16 and see 47lb/min at 28 psi.
     

    Street Build 364  1

    1995 Eagle Talon TSi
    fwd · automatic · 2G DSM

    Street Build 2K  3

    1995 Eagle Talon TSi
    fwd · automatic · 2G DSM
    Loading...
  6. RWD4G63

    RWD4G63 Proven Member

    420
    94
    Joined Dec 7, 2011
    Paw Paw, Michigan
    Well if you port the turbine housing like your pictures you're going to destroy the twin-scroll effect. Do not remove the center divider.
     

    Road Race Build 363  3

    1997 Eagle Talon TSi AWD
    awd · manual · 2G DSM
    Loading...
  7. jpmxrider489

    jpmxrider489 Supporting VIP

    2,150
    39
    Joined Apr 4, 2010
    pittsburgh, Pennsylvania
    I never said I was removing the center divider. Simply matching it to the gasket. As far as the twin scroll effect, I cant see any more than 45lb/min for airflow. So how the heck are other people getting above 50 for airflow. Even in a bolt on housing. I saw minimum changed results in my 16cm without porting. Im about to port it to see it it helps.
     

    Street Build 364  1

    1995 Eagle Talon TSi
    fwd · automatic · 2G DSM

    Street Build 2K  3

    1995 Eagle Talon TSi
    fwd · automatic · 2G DSM
    Loading...
  8. RWD4G63

    RWD4G63 Proven Member

    420
    94
    Joined Dec 7, 2011
    Paw Paw, Michigan
    What cams do you have? What intake manifold? What intercooler? All these things affect your total mass airflow.
     

    Road Race Build 363  3

    1997 Eagle Talon TSi AWD
    awd · manual · 2G DSM
    Loading...
  9. jpmxrider489

    jpmxrider489 Supporting VIP

    2,150
    39
    Joined Apr 4, 2010
    pittsburgh, Pennsylvania
    Hks 272 regrinds, and vrsf intercooler. The intercooler has 2.25 outlets. My jmfab mani I believe is the street version because its smaller. I would have to to through my purchase history. S90 throttle body.

    In my opinion these might be minimal factors in why I'm seeing low airflow? I see many people with more airflow.

    It was also recommended by a non dsmer to adjust my cam gears a little. I read one post about it regarding this issue but many people run cams on stock gears.
     

    Street Build 364  1

    1995 Eagle Talon TSi
    fwd · automatic · 2G DSM

    Street Build 2K  3

    1995 Eagle Talon TSi
    fwd · automatic · 2G DSM
    Loading...
  10. RWD4G63

    RWD4G63 Proven Member

    420
    94
    Joined Dec 7, 2011
    Paw Paw, Michigan
    Every bend and every restriction adds up in the system. I can tell you right now that 272 regrinds are garbage, people like them because they're cheap, and that is their only redeeming quality. A real cam will make more power and torque.

    You should adjust cam gears on the dyno.

    As an example of what a 12cm twin-scroll housing can do, here's a good setup:

    http://morrisonfabrications.com/tech/mr-peepers-twin-scroll-t3/
     

    Road Race Build 363  3

    1997 Eagle Talon TSi AWD
    awd · manual · 2G DSM
    Loading...
  11. jpmxrider489

    jpmxrider489 Supporting VIP

    2,150
    39
    Joined Apr 4, 2010
    pittsburgh, Pennsylvania
    Just dynod at 530
     

    Attached Files:

    • 530.pdf
      File size:
      713.2 KB
      Views:
      14

    Street Build 364  1

    1995 Eagle Talon TSi
    fwd · automatic · 2G DSM

    Street Build 2K  3

    1995 Eagle Talon TSi
    fwd · automatic · 2G DSM
    Loading...

Share This Page

Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Feal Suspension Fuel Injector Clinic Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications OHM Racing Raven Fabrication RixRacing RockAuto RTM Racing SouthBay Fuel Injectors STM Tuned Track Decals Track Sculptures VR Speed Factory