Turbo and Dump Valve Advice
 

Hey guys,

I've just picked up my second Impreza after my 1994 STi RA was 'borrowed' so I'm very excited to be able to get onto this forum.

I'm looking for a spot of advice on turbos and dump valves and wondered if any of you knowledgeable chaps could help...

My car is a 1998 UK Turbo 2000 (GC8).
It's standard apart from a 3" de-cat exhaust, a K&N induction kit and a noisy Bailey Motorsport dump-valve.

The turbo is pretty noisy and can very easily be heard winding-up from the driver's seat. It makes a slightly unhealthy grinding sound so I'm not sure if the bearings may be worn?

Also, the dump valve sounds terrible. Apart from being generally far too loud for my liking, it can be heard dumping pressure when the throttle is on and before the turbo starts spinning up. Taking a closer look, it seems that when the dump valve drops pressure, it stays open and doesn't close properly. I'm wondering if this means that the dump valve is screwed or that the turbo isn't generating enough suction to close the dump valve?

Does this all point towards a knackered turbo?
If so, how would you rate a VF34 as a direct replacement to get a power gain at the same time?

Your thoughts would be much appreciated.

Cheers

Spratty

Hi Mate,

1) Loose the VTA dump valve and just get the std Subaru recirculating one put back on

2) If you're going to replace the turbo, I'd really also budget for a ECU replacement and map (e.g. Apexi Power FC). I say replacement as yours can't be remapped using Ecutek. There are folks on here who've upped the turbo sans remap and got away with it. If you must do this, you should at least get the fueling checked by someone with an wideband AFR guage and det cans to make sure the engine isn't detting itself to bits under boost. In any case, to get the most from the turbo you want the car mapped to suit. VF34 seems like good option, spools later than TD04 but hits harder and longer. VF24 or 28 also similar IIRC and might be had for less dosh. You could help in this respect by getting your headers ported. Alternatively, Andy F sells a TDo4 hybrid, that can hold higher boost longer than std, but retains the excellent low down response.

Are you signed up to Kent Scoobies yet?

Ns04

Thanks for the advice, NS04.

I think I'll start off with getting an Apexi FC (possibly from Andy F as I like his site and from what I can gather he seems like a decent guy) and then upgrade the turbo later (can't afford both at once and I'm rubbish at saving!).

I'll get straight onto getting a std dump valve...I'm fed up with my Scoob sounding like a steam train!

I'm not registered with Kent Scoobies as I actually spend most of my time in Leeds (that's where I work). Might look to join a bunch of Scooby-nuts up this way if I relocate permanently.

Cheers

Spratty