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PostPosted: Mon Jan 23, 2006 7:34 pm 
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Location: Evesham, Worcestershire
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I have been having a bit of a problem with boost cut lately.

My TVSV is disconnected, no relief valve or boost controller is fitted (haven't got round to it yet! :oops: )
I finally fitted my boost gauge yesterday, way better than the standard one as I can now see what is going on.

I seem to be getting some variation in max boost.
Most of the time it hits 6psi as expected, but occasionally it hits 9psi and has even boost cut.
The 9psi has happened in 2nd, 3rd and 4th, so I don't think it has anything to do with the TVSV.

Anyone got any idea what is going on? :?

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PostPosted: Mon Jan 23, 2006 8:05 pm 
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Location: Sunny Fareham, UK
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Sounds a bit odd...

DO you think it could be a bit of boost creep?

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95 ST205 - slept for 10 years, now waking up...
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PostPosted: Mon Jan 23, 2006 10:49 pm 
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No idea to be honest.
How does boost creep manifest itself?

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1991 Jap ST185A
ST205 Head Gasket.
Some random RV & no-name BOV
Blitz Nur-spec SS backbox
Apexi Air Filter

ST205 Front Calipers - Yes, really!


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PostPosted: Mon Jan 23, 2006 10:54 pm 
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Location: Auckland, NZ
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Faulty wastegate or actuator?
Gary

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PostPosted: Mon Jan 23, 2006 11:16 pm 
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Location: Haywards Heath
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have you been able to spot any kind of pattern to when it happens?

IE when booting it at high revs, within first 20 minutes of a journey, when engine is really hot after a blat.

Ay of these could help pinpoint what is causing the problem.

Boost creep will manifest as the boost level rising to its desired position (is 0.6bar) and then gradually creeping higher as the revs increase. Almost olways on WOT.

With the downpipe in place I'd say that creep is quite possible.

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PostPosted: Tue Jan 24, 2006 6:03 pm 
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Location: Sunny Fareham, UK
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As Gary says a duff actuator may also give these symptoms. Blow into the pipe feeding the actuator and it shouldn't pass any air, if it does, it is knackered.

Actuators do fail!

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95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
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Turbocharging - the replacement for displacement


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