prodriva

Can you get the above device, BUT NOT GIVING THE USUAL RS TURBO Psssst/Whoooosh sound. I'm after the sound the WRC cars make, a flutter/chirping sound. I've done a search and of all the threads ive looked at my question remains unanswered. I watched a show on men-and-motors a while back and saw a white bugeye fitted with a "Blitz Blow-off valve" and that created the sound I'm after. Any help would be greatly appreciated.

logiclee

No you can't get a WRC dump valve because they dont fit them on the WRC cars.

On the road car the dump valve dumps the boost pressure to mainly protect the turbo and prevent the turbo stalling when you lift off.
On the wrc car the pressure in the plenumn inlet is kept at full boost even when you lift off so full boost is available all the time. The antilag sytem keeps the boost pressure at maximum, pressure is regulated by the wastegate and its the wastegate you hear chattering as it slams open and closed.

Lee

MorayMackenzie

I have a WRC specification dump valve fitted. It cost me nothing.

SecretAgentMan

I've got it as well - major improvement to response and virtually no lag between gearchanges.

/J

prodriva

Would anybody care to mention the make of them and where I can purchase/obtain one??? MY97 Wagon if that helps.

EvilBevel

Prodriva, I think Moray and /J may be on about removing the dumpvalve altogether

As Lee says, no DV on a WRC car.

Don't do this without asking advice first mind, depending on what turbo you have, you could seriously reduce it's lifespan.

prodriva

Let me get this straight, Subaru design a car WITH a DV as standard after months if not years of research and development and people are removing them!?! WTF!!! Come on people, I know its Friday and that means the pub at lunch time but this is a serious question. I'm sure there are DV's out there on the market that replicate the WRC style chirp and my first port of call was this BBS to get some real world advice!?! And just for the record WRC Impreza's make the same chirp with the Stage switch switched off so it cant be anything to do with the anti-lag system and waste-gate.

logiclee

even when the antilag is off the turbo boosts normaly. On lifting off the boost that the turbo is producing can't go any where and the pressure rise is sudden, the wastegate snaps open to let the exhaust gases bypass the turbo. This is what most of the sound is although the sudden shock on the turbo blades and the sudden stall of the airflow produces noise.

On road cars, upgraded turbo's with 360 degree thrust bearings will take the abuse of no dump valve. The sound is not full WRC noise as the road car will probably have 14psi and the wrc 40+psi of boost.

Closest I have heard was Dingy's Mk11 Escort Cosworth.

Lee

DocJock

Prodriva

You say yours is a serious question yet when people give you a serious answer you belittle them.

If you are not going to listen, don't ask the question in the first place.

Cheers

DJ

logiclee

Found This!!!!

Rally sound thread

Lee

MorayMackenzie

prodriva,

"Let me get this straight, Subaru design a car WITH a DV as standard after months if not years of research and development and people are removing them!?! WTF!!! Come on people, I know its Friday and that means the pub at lunch time but this is a serious question."

Hum. Taking your argument, why on earth are you even considering changing the OE dump valve? If subaru sold you the perfect vehicle, and they spent many many hours choosing everything for it, why are you even considering changing anything?

I was being serious. I run a WRC spec BOV and it cost nothing because it is nothing. It does reduce gearchange lag and improve throttle response significantly. I suspect part of the noise you want is actually the WRC cars ALS system. I have this also, despite subaru not selling me the car with it. Oh how I have erred in my ways and bless you for showing me the light.

If you want the authentic rally sound, then start by running motorsports engine management, fitting tubular exhaust headers, fitting a turbo with a decent sized compressor wheel and removing your blow of valve.

However, If you want to make your car sound a little bit more agressive and "special" for not much money, then I would suggest you might be better of spending your money on a K+N 57i induction cone kit. This way you actually do get an improvement in throttle response and possibly a tiny bit more power _and_ the standard dump valve noise will become more audible to you as it recirculates into the inlet tract. Even better, the noises the turbo is making when on boost will be much more audible too. Generally a better investment, imho, than a dump valve that merely makes noise. Even if subaru didn't fit one as standard to your car.

MorayMackenzie

PS: thanks for the kind support there DJ.

prodriva

DocJock,

So your one of those, thanks for the helpful, constructive comments!!! I have in no way belittle'd anybody so dont put words into my mouth/keyboard. No doubt your 1000ish posts have all been along the lines of flaming someone for the sake of flaming!?! I getcha. I thought this was a BBS where freedom of speech was the case!?! I welcome all comments and maybe my responses are typed in a harsh way sometimes but not in anyway to BELITTLE anyone. Thanks for your help mate, its people like you who make me wonder why BBS's exist if all your going to get is flamedfor speaking your mind. Take a chill pill mate, all i'm after is a bit of freindly advice. RANT OVER. PLEASE NOTE THE SMILE IN THE MESSAGE ICON AS I HAVE TAKEN THIS ON THE CHIN SO TO SPEAK.

DocJock

???
>>Come on people, I know its Friday and that means the pub at lunch time but this is a serious question.

People gave you friendly advice and you didn't believe them.
I'm not the one needs to chill pal.....

MorayMackenzie

prodriva,

"I watched a show on men-and-motors a while back and saw a white bugeye fitted with a "Blitz Blow-off valve" and that created the sound I'm after."

Heres a bright idea... why not just buy a Blitz Blow-off valve?

"Any help would be greatly appreciated. "

Really? You could have fooled me.

Notice tounge firmly in cheek.

prodriva

Appologies to all who I have obviously offended. I dont set out to offend but sometimes my style of typing can be a bit to the point if not harsh at times. Please accept my sincere appologies. I'll get me coat.

Turbo_Steve

ProDriva, as they say, if you like the Blitz....buy a blitz.
The nearest thing to it is probably the HKS SQV Sequential blow off valve. It "flutters" rather than chatters.

Alternatively, you can put on a forge dump valve with a stronger spring. This will slam the valve closed quicker and chatter (if you boost is high enough). This is in no way guaranteed, but is cheaper than a Blitz or HKS.

The guys without dumpvalve's know what they are doing.

You should also be aware that running a Vent To Atmosphere dump valve WILL make your car run rich on overrun.

pat

There are many noises that the WRC makes, all of which my car has made in the past, and will make in duplicate in the future given that it'll be running twin ball bearing turbos

For the record, given a sufficiently strong turbocharger, the best dump valve is no dump valve at all. Its *ONLY* function is to protect the turbo, anyone who tells you otherwise is either pulling a fast one, just plain mistaken, or a tart looking for extra noises.

If you want pops and bangs then you want an antilag system. This allows unburnt fuel to exit the cylinders and light up in the exhaust system, which imparts significant energy to the turbine keeping it running. It also imparts significant heat into the turbo; an aggressive ALS system will literally melt your stock turbo in a matter of minutes. When I was running somewhat milder antilag on my car, I installed a temperature probe in my turbo exhaust housing so the engine management could monitor it to make sure it didn't fry it. At 950 degrees I had it switch to an even less agressive ALS mode. On Knockhill I managed to find about 2 seconds per lap by running the ALS! The torque out of the hairpin caught me off guard first time I used the ALS. I was very wary of what the ALS would do to my engine and turbo, so I was concentrating on the road, the rev counter, the air fuel ratio meter, the knock meter, the boost gauge all at the same time. Anyways, I slid clean across the track as all four tyres lit up Hard ALS is a turbo destroyer, make no mistake. It is no coincidence that Prodrive replace the turbo on the WRC every day!

If you want the chirp then you need to run without a dump valve and use a compressor which chirps when it crosses the surge line high up the pressure ratio scale. For example the MHI TD series compressors (TD-05H 16G, 18G, TD-06 20G etc) don't seem to chirp regardless of the boost employed... at least I could never get any of mine to chirp at high boost. At lower boost they do "flutter" though Some of the IHI turbos do chirp a little, but the cores are not as strong as the MHI, so proceed with caution. In addition the VF22 has a notoroiously weak compressor wheel, it's not uncommon to rip vanes clean off it without a dump valve. The best chirp I've come across is from the Garrett GT series turbos, they sound evil when you lift off with no dump valve fitted Running 40 PSI on one of these and lifting off will remind you of some of the noises the awesome Group B rally cars used to make. In any event, the lack of a dump valve will impart significant shock loading (more violent than hitting the compressor with a hammer!) to the turbo, and it will shorten its life. The degree of this reduction of life is a function of the basic strength of the turbo. For example, the shaft and bearings in the Garrett GT35 or GT40 series are so large that they will survive this type of abuse pretty much indefinitely, yet a VF22 compressor wheel will shatter quite soon.

There have been attempts to replicate these noises by various companies using devices that wouldn't normally make that type of sound. Personally I don't see the point, just like I can't see the point of having a loud dump valve. The noise will just get irritating after a while, unless it serves a purpose. A loud dump valve serves no purpose other than to say "I've got a loud dump valve"; it doesn't improve the performance of the car, nor does it improve upon the stock item's ability to protect the turbo. In a similar way, a dump valve which sounds like compressor stall serves no purpose; running no dump valve on the other hand does serve a purpose... it improves throttle response between gears, and as an added bonus you get the WRC chirp. As a downside you may shorten the life of the turbo.

Cheers,

Pat.

prodriva

Pat, you are a star. Thanks for the information, the DV issue is now a lot clearer.

My final comment on this thread is that I hope the people I offended earlier (you know who you are) have accepted my sincere apologies as I havent heard from you since!!!!!!!! BBS buddies again???

stellaFella

I have just fitted a K+N 57i and a Bailey Evo piston D/V to a MY97 Turbo i does the chatter thing when you lift off but when you change gear it blows kids off their bikes.

siwrx

ive run mine without a dumpvalve for ages, much prefer the wastegate chatter and i dont trust dumpvalves as they leak and cause the engine to over fuel.

Mine isnt stupidly modified either

Turbo_Steve

Yeah, but it is a laugh having one.

As they are driven from the vacuum system, a solenoid in the vaccuum line with enable / disable it with a switch on the dashboard. This enables you to drive around normally without it. A pressure driven switch in paralell with this will also ensure that the dumpvalve operates should your boost increase over 0.4Bar. This means you can be a tart, be subtle AND protect your turbo all at once.