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 Post subject: Boost drop off
PostPosted: Fri Oct 31, 2014 9:15 pm 
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Joined: Thu Jan 16, 2014 10:24 pm
Posts: 18
Location: Canada
Car Model: ST185
Hey guys just had a question about a possible boost leak on my 185.

Currently I have a turbosmart manual boost controller installed and set to 14-15 psi (~1bar). I am able to easily hit the full 15 psi of boost...however, by the time I hit red line I am down to about 7 psi(~.5bar). Right now I am running the stock ct26 turbo and all of the connections to the inter cooler are tight. My thoughts are that either the blow off valve is leaking under the higher pressure or that the waste get is opening due to the increased boost pressure....any other thoughts as to what might be causing this?

Thanks in advance.


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 Post subject: Re: Boost drop off
PostPosted: Sun Nov 02, 2014 11:51 pm 
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WRC
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Joined: Tue Dec 09, 2008 6:51 pm
Posts: 1397
Location: Austria
Car Model: None
Hi,

sounds like the turbo is not able to delivery any more air, when the point is reached where it drops down

try 0,7bar or something else and look for it again....

greetz

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 Post subject: Re: Boost drop off
PostPosted: Mon Nov 03, 2014 5:30 pm 
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Joined: Thu Jan 16, 2014 10:24 pm
Posts: 18
Location: Canada
Car Model: ST185
Sunny wrote:
Hi,

sounds like the turbo is not able to delivery any more air, when the point is reached where it drops down

try 0,7bar or something else and look for it again....

greetz



Worth a shot thanks for the idea


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 Post subject: Re: Boost drop off
PostPosted: Tue Nov 04, 2014 12:31 pm 
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Club Staff
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Joined: Wed Jul 13, 2005 12:06 am
Posts: 4743
Location: Perth, Western Australia
Car Model: ST205
In addition to Sunny's suggestion, have you pressure tested the actuator to confirm it is working to specification? Also worth checking the wastegate spindle to make sure it's moving freely and not partly stuck open. You are running a downpipe so there should be no downstream restriction to the exhaust gas flow which could cause the compressor to 'choke' at higher rpm.

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1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
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1989 Van Diemen RF88/89 Formula Ford 1600
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 Post subject: Re: Boost drop off
PostPosted: Tue Nov 04, 2014 5:28 pm 
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Joined: Thu Jan 16, 2014 10:24 pm
Posts: 18
Location: Canada
Car Model: ST185
I haven't pressure tested the actuator yet but when I remove the manual boost controller and go off of the wastegate spring pressure I run a constant 5 psi boost. I am pretty sure the spindle is moving freely but I will double check its movement.

Thanks


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 Post subject: Re: Boost drop off
PostPosted: Tue Nov 04, 2014 11:10 pm 
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Group B
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Joined: Sat Sep 02, 2006 3:13 pm
Posts: 3679
Location: Bournemouth
Car Model: None
Double check the vac pipe from the inlet manifold to the top of the dump valve is present and not blocked / kinked. Without this, the DV will act as a pressure relief valve.

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 Post subject: Re: Boost drop off
PostPosted: Thu Dec 18, 2014 3:10 pm 
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Junior WRC

Joined: Fri Mar 27, 2009 9:39 pm
Posts: 838
Car Model: None
if you still running a stock ct26 then the boost will not hold any more then .8bar over 5-5.5krpm it will spool upto 1-1.2bar be for 5k but the nit just can not flow after 5-5.5k and this is why it drops off,

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