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Loss of Power - Dump Valve?

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Old 12 January 2000, 06:11 PM
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Yosser
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Unhappy

Help!
At about 4000 rpm there is sometimes a deep turbo type sound. This only happens occasionally. However I've been out in the car today and the turbo is spinning up ok and all the sounds are usual (apart from the occasional noise mentioned before) - there now seems to be a complete loss of turbo power. It was suggested to me that a leaky dump valve might be causing the noise. If this had now gone completley would this be causeing the loss of power??
96 STI3 Wagon.
Thanks in advance
One Worried owner.
Yos
Old 12 January 2000, 06:36 PM
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MorayMackenzie
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Hi Yosser,

Congratulations on choosing the best STI vintage!

I had a similar problem on my STI3 V-Ltd, I managed to cure it by replacing the 97 model subaru blow-off valve with the 98 model. The units appear identical, but the part number has advanced by 1. Probably just a stronger spring in the unit, but it cured my noisey bov problem. It was about £57 quid for the part at GGR or from my local subaru dealer. Said it was for a 97 model car and I didn't have the chassis number, they (subaru dealer) sold me the bit anyway (top marks for not being ****).

Moray
Old 12 January 2000, 06:38 PM
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Area 52 Autosport
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Sounds logical Yos based on what you have said. The 97MY are renowned for this (FAQ).

No real dramas as a replacement is not the most expensive part in the world!! Just make sure you don't get one that vents to atmosphere

Laters

Ben
Old 12 January 2000, 10:14 PM
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Yosser
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Cool

Thanks for the response guys
I'll get it sorted out ASAP.
Only bought it in November (import) and I was a bit concerned.
I don't want to take it back to where I bought it - just incase they botch it. So Scoobysport here i come.
I was booked in on 4th Feb anyway for Brembo's but i cant wait that long with the loss of power - I'm just one of those people that has to feel confident in a car, that it will get me to where I want to go, I spent 16,500 on it, well you know what i mean.
thanks
Yos
Old 13 January 2000, 01:32 AM
  #5  
Lee
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Thats funny cos I picked it up off his shelf and asked what he was doing with vent to atmosphere valves....apparently those were sent through for trial.

they are naff though..apparently they open on any vacuum, even at idle/cruise....
Old 13 January 2000, 10:39 AM
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MorayMackenzie
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Exclamation

The BOV is fairly easy to replace, asuming you can source the replacement. The 98 model is externally identical to your 97 model (except part no! ). Have a look under your bonnet and you may decide you can do the job yourself! If you do this it should take all of 10 - 15 minutes (doing it carefully) and you should make sure that all 3 hoses (in, out and vacuum) are securely clipped to the unit when you've finished.

Handy hint: however convinient the intercooler looks for storing little bits and screwdrivers or leaning on, DON'T! The intercooler fins are VERY soft and fragile, so anything in contact with them can damage the intercooler fins and restrict it's efficiency.

Moray
Old 13 January 2000, 12:22 PM
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pat
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Until you get to Scoobysport, you can just blank off the dump valve to stop it leaking. This will give you better pickup than with a dumpvalve fitted, but will cause higher shock load on the turbo bearings (but if it's only for a day or two.....)

I was at Scoobysport yesterday, and IIRC, Pete still had one of those sexy uprated dump valves on the shelf (the type that would fit your car). But check with him first...

Cheers,

Pat.
Old 14 January 2000, 12:56 PM
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pat
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Lee,

There were originally four dump valves and two plugs. Two of these were recirculatory and two non-recirculatory. Of the lot, I think the only one left now is the non-recirculatory one which fits onto a hose rather than the intercooler.

As for opening up under light vacuum... err, well it takes a bit more vacuum to open these than the standard ones.

Cheers,

Pat.
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