Impreza WRC cars don't have a dump valve. There's some debate about exactly what causes the chirping on the WR Cars, but either way it's going to be difficult to reproduce (and keep your car reliable), as it's partly a result of the high boost pressures and anti-lag the WR Cars run.

It is possible to produce a similar sound by greatly increasing the spring strength, or completely removing the dump valve on a standard car, thus forcing air to pulse back past the compressor instead of being dumped.

You'll get better throttle response in this circumstance, but the working life of your turbo will be reduced as a result (WRC turbochargers go a maximum of 500 stage kilometres before being rebuilt!).

There are supposedly also some dumpvalves designed to mimic the noise, but I don't profess to know much about these!

[Edited by greasemonkey - 10/6/2003 10:20:38 PM]

 

what sort of dump valve / induction / wastegate do the WRC Imprezas use to get the chirping on lift-off?

I'm sick of whooshy noises

 

fair enough- thanks for the reply.
I suspected it was going to be expensive
would be interested in that dump valve tho

simon

 

Smart cars have the wastegate chatter

Don't ask me how though

 

Oh, don't get me wrong, you can achieve a similar noise for just the price of a blanking plate/bung where your dump valve should be. The problem then is that it's going to cost you money in terms of turbo wear (and possible engine damage if you don't catch a failing one early enough!).

Dumpvalves, I'm not really the person to ask regarding current aftermarket products, although I thought the Blitz was supposed to have a "chirpy" mode.

Incidentally, I've often thought that an electronically commanded, solenoid controlled dump valve would provide the best compromise between turbo safety and throttle response, and a design of this sort would coincidentally produce a "chirp-like" sound. If only I could find someone to manufacture it...

 

forge one with the correct spring makes a chirpy sound...

 

Is it the dumpvalve chirping or the turbo chirping cos the dump valve doesn't open though?

 

The chirping IMHO is caused by the turbo stalling, which as greasemonkey has said will lead to an expensive bill very quickly

 

Smart cars don't have dump valves... IIRC... hence the chirpy noises. The rumours of the chirps being a canarie powered engine are unfounded.

 

A chirping td05 is not as expensive as a vf23 with a similar habit

Richard

 

A-ha, so the conclusion is obvious. If you want that "chirpy" lift-off sound without damaging your Impreza's turbo, buy a Smart and make your missus drive round everywhere behind you.

Even better, remove the engine, put it in the boot of your Scoob (it'll probably fit in the spare wheel well), and link the throttle cable to the accelerator!

 

Record the chirping the WRC cars make, put a loud speaker under the bonnet, burn the sound on an NVchip with a button on the dash to run it.

"cchhiirrpp"

 

Why not fit one that plays ring tones from your favourate boy band.

 

Fit a bigger Turbo & FMIC

 

Ran My TD05 at up to 1.8bar with no DV at all for 7 months, still going now... 4 months later with another owner.

Rob

 

you're all making me feel like a right **** now