I want to change the standard dump valve on MY02 STI Prodrive, I want one which works well and makes a noise, which one would you recommend and why?

TIA

Nick

 

Would also be interested in peoples thoughts - looking todo the same on my 02 WRX with PPP.

So far I have it narrored down to a GFB Hybrid or a Forge VTA (dual piston type to even out the idle and mixture).

Anyone used the Go Fast Bits Hybrid WRX (spring pre-set for the WRX) - like the idea of it both recirculating at lower power but VTA for the noise at higher boost). I think MRT sell these in the UK through a couple of different companies - Jap Innovations springs to mind.

For me, I want the noise, but am hoping it will smooth out the gear changes a tad under hard acceleration.

 

you might be interested to know that we've just had the first batch of Bailey DV's for the New Age cars in today. Will install on our WRX03 later and post some pics up.

Neil
www.scoobyworld.co.uk

 

All I can say is that I have had no problems with the Forge one (£70-ish) or the HKS SSQ (£250). Performance-wise they were equal and neither had a detrimental effect on the cars running. HKS made more 'interesting' sounds, though perhaps not £180-worth of interestingness LOL
Chuck

 

Call me a bore, but surely these are a waste of money?
The only thing they do is make a noise, the Impreza already has a perfectly good re-circulating dump valve (hence no noise) so why bother changing it?

 

Call me a tart but I want some noise - but I also believe that a VTA can smooth out some of the lag during hard acceleration and gear changes?

Be interested in your thoughts on the Bailey unit.

 

They are only really worth it if:

a) your existing re-circulating dump valve is broken, or you are running serious levels of boost causing the standard one to leak.
b) you specifically want the "pssht" noise when you lift off.

If you fit a vent to atmosphere one, then there is a chance that your car may actually perform worse, use more fuel and idle poorly. The reason for this is that the air coming into the engine is measured by the ECU, and if you vent some of this to the atmosphere, then the ECU gets the calculations wrong (more air coming in than expected), so it adds loads more fuel to compensate. This can cause the car to run rich for a second or so on each gearchange, and also cuase poor idling when coming to a stop.

If you have a replacement ECU which doesn't use the measured air mass as an input, then you probably won't have these problems.

 

John, my thoughts exactly. I wanted the noise, but have since got tired of it as in most cases it just sounds like trucks air-brakes. Went back to recirc recently and noticed no difference in power delivery/running.
C