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Old 11-04-2008, 01:56 AM   #1
macaws
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Default At my wits end with T04z- need advice

My previous issues are documented here: http://forums.nasioc.com/forums/show...highlight=t04z

In summary, I could boost over 30 psi but no returns beyond 23 psi, even with the significantly larger turbine housing.

So we put in a bigger twin uppipe (41mmx2), GT heads (best flowing Subaru head ever) and radical cams.

Peak power was the same at 510whp but now on less boost, 22psi previous 23-24 psi.

BUT ..... now cannot boost beyond 22psi.
There are no boost leaks located yet, air filter off makes no difference, suspected Synapse 50mm wastegate but sealed it shut with still no difference.

Am I looking at A TURBO ISSUE OR WHAT ?
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Old 11-04-2008, 09:37 AM   #2
wcbjr
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I would have to assume it's the turbo. Can't believe you haven't tried another one yet.
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Old 11-04-2008, 10:51 AM   #3
macaws
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There is a small leak from the intake manifold. Doubt it can have such a drastic effect.
I have to persist until I get this turbo to sing !
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Old 11-04-2008, 11:04 AM   #4
wcbjr
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What intake manifold do you have? magnus?
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Old 11-04-2008, 01:13 PM   #5
macaws
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Yip Magnus.
Manifold itself seems fine- the leak is between the mani and phenolic spacers.
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Old 11-04-2008, 01:23 PM   #6
wcbjr
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Oh ok, Magnus is known for leaking though.
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Old 11-04-2008, 01:30 PM   #7
fujiillin
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Have you been using OEM tgv gaskets on both sides of the phenolics? I wouldn't trust metal/phenolic/metal for a reliable seal at those pressures.

What kind of plugs and gap?
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Old 11-04-2008, 04:18 PM   #8
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Try use studs and nuts on the intake manifold as opposed to the stock bolts. That helps keep everything tight. Have you measured pressure drop? Perhaps an IC problem?
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Old 11-04-2008, 07:05 PM   #9
rjrutzky
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Quote:
Originally Posted by macaws View Post
Am I looking at A TURBO ISSUE OR WHAT ?
Change the turbo and find out Are you sponsored by HKS or did you just want to try something different? I'd go with a full Garrett unit.
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Old 11-04-2008, 07:11 PM   #10
WhiteKnight
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What do you use for boost control?

Manual or electrical controller?
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Old 11-04-2008, 07:58 PM   #11
Phatron
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Can you please go back to your first post and edit it and include the following

- Complete Mod List, especially items relating to boost control
- List of trouble shooting you have done so far, things you have ruled out (i mean you found a leak less than 12 hrs after your first post, so have you done any troubleshooting at all yet)
- ECU? What are you using to tune?
- Boost plots
- are your headers wrapped? are you sure they arent cracked?
- do you have an EGT gauge? if you have a leak and the turbo is having to work harder to compensate for the leak then it could be turning into a big hairdryer...and you may be able to see it in the egt's

IMO running with the wastegate shut proves that its a boost leak. if nothing you do to the wgdc, boost control, etc changes the boost, then you probably have a leak or leaks.

And since you were able to get over 30psi before you changed some of the parts, I would say that rules out the turbo being bad.

the simplest way to check for leaks is to start at the turbo and work your way to the throttle body double & triple checking every flange, screw, nut, bolt, hose, clamp, etc.
Once you're done there, start at the headers and work your way back to the turbo.

Last edited by Phatron; 11-04-2008 at 08:32 PM.
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Old 11-04-2008, 08:06 PM   #12
WhiteKnight
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Also if you are using HKS EVC 6, there is a bug in the software, which causes boost not to raise as you wish. I experienced this on my car.

There is a simple solution for that.

Thats why i asked your boost controller.
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