DS-MAP

porting turbine housing and a/r ratio

epinephiend

  • **
  • 9
    • Talon TSI AWD
    • 1992
    • Head: 1G (large ports)
    • Motor: 4G63 2.0L
    • Turbo: evo3 16g
porting turbine housing and a/r ratio
« on: May 14, 2013, 09:56:20 PM »
Correct me if i am wrong but when we (yes i did it too) port the step out of the turbine housing aren't we changing the area in the area to radius ratio of the housing? I tried to keep the porting to minimal and taper it out but not sure how this affects spool up or overall flow if at all. Just curious what some intelligent dsmer's thought maybe we shouldn't port the step out?
Stock 6-bolt, evo3 16g, evo3 o2 pipe, wally 255lph hp pump, aeromotive afpr, vr-speed 2g fmic, fp race exh manifold, denso 660cc inj, 2g mas, k&n,pos 3" tbe, es poly lca bushings and front and rear motor mounts, gvr-4 switchable trans and t-case, fidanza alum flywheel, sbc kevlar street clutch

Re: porting turbine housing and a/r ratio
« Reply #1 on: May 14, 2013, 10:24:36 PM »
I'm not a guru by any means, but unless you're going to measure backpressure or having creep there really is much to be had by porting.

You won't really know what you did unless you have some type of measurable result. I've never found it useful. When my old 60-1 wastegate kept blowing open, I just welded the gate shut and added an external gate. Found that extremely more versatile in boost control.
AMP 2 Corinthians 8:21
For we take thought beforehand and aim to be honest and absolutely above suspicion, not only in the sight of the Lord but also in the sight of men.


epinephiend

  • **
  • 9
    • Talon TSI AWD
    • 1992
    • Head: 1G (large ports)
    • Motor: 4G63 2.0L
    • Turbo: evo3 16g
Re: porting turbine housing and a/r ratio
« Reply #2 on: May 18, 2014, 04:36:43 PM »
Yea that's kind of what I'm getting at, I think there are a few "tips" like this in the dsm community that, while not harmful, probably aren't useful. I did out because my turbo was out and it was kind of fun, but I could have easily messed up something. Looking back on it now it was noob move and its just a friendly heads up to any one who is considering doing this.
Stock 6-bolt, evo3 16g, evo3 o2 pipe, wally 255lph hp pump, aeromotive afpr, vr-speed 2g fmic, fp race exh manifold, denso 660cc inj, 2g mas, k&n,pos 3" tbe, es poly lca bushings and front and rear motor mounts, gvr-4 switchable trans and t-case, fidanza alum flywheel, sbc kevlar street clutch

SOB Racing

  • *
  • 57
    • Other
    • 87
    • Head: 1G (large ports)
    • Motor: 4G63 2.0L
    • Turbo: S16g
Re: porting turbine housing and a/r ratio
« Reply #3 on: May 22, 2014, 12:32:53 PM »
Porting helps smooth airflow (I beleive my porting allows boost to build very early 3000 rpm) but mainly with combat creep in my experience.   I have an external on my 20g (using the stock waste gate port).    It was uncontrollable unported.