Explain this sound

[TurboSmoke]

firstly, excuse my feeble grasp of the internal workings of race car engines....


okay the Lancia Delta rally car (and others in the game), keep making a soung like a pneumatic valve opening and shutting, its quite loud and i originally thought it was the gears....but the sound seems to be random so i think its the cars clutch since you cant control that in the game....

there is a guy in my home town with an EVO 5 and it does the same thing and its loud when you hear it outside the game...

you also hear it in WRC & WRC II and other games....

wtf is it?

 

[kodiak]

B.O.V. or Blow-Off-Valve.

A pressure relief valve on turbocharged (some supercharged) engines that prevents compressor surge. Due to inertia, turbos will continue to build boost for a moment after the throttle has been closed. This boost is no longer able to get to the engine because the throttle plate is now closed. This creates a pressure wave that hits the throttle plate and bounces back toward the turbo. This could damage the compressor so a relief valve is needed.

In real life, they can be quite loud. I scare the be-jeebus out of pedestrians with my Talon.

Try the Toyota GT-One race car or road car... loudest B.O.V. in the game.

 

[TurboSmoke]

Cheers Kodiak....


yes they can be loud....when a car drives past you on a quiet road it can startle you...there must be a lot of pressure in those valves...

 

[Solid Lifters]

Originally posted by kodiak
B.O.V. or Blow-Off-Valve.

A pressure relief valve on turbocharged (some supercharged) engines that prevents compressor surge. Due to inertia, turbos will continue to build boost for a moment after the throttle has been closed. This boost is no longer able to get to the engine because the throttle plate is now closed. This creates a pressure wave that hits the throttle plate and bounces back toward the turbo. This could damage the compressor so a relief valve is needed.

In real life, they can be quite loud. I scare the be-jeebus out of pedestrians with my Talon.

Try the Toyota GT-One race car or road car... loudest B.O.V. in the game.

Good explanation. 👍

Now, please explain to me why Rally race cars, IRL, make a quick "chirpping" sound when they downshift. WTF is that? It can't be from the tires, they're in contact with dirt. I thought it might be something similar with the POV, but maybe the pressure is much lower or something and it comes out sounding like a chirp instead.

 

[phillip]

its called Back-Fire... its when you Downshift, there comes Un-Burned fuel out.. tat then gets heated in the Exhoust, and Explodes..

 

[eddieturner2002]

Originally posted by phillip
its called Back-Fire... its when you Downshift, there comes Un-Burned fuel out.. tat then gets heated in the Exhoust, and Explodes..

no what solid lifters is talkin about is also the pressure being let out of the blow off valve/dump valve/wastegate but just sounds different. Get some really knowledgable person in here to explain why......like famine or someone

 

[DoZeRxXx]

Originally posted by kodiak
Try the Toyota GT-One race car or road car... loudest B.O.V. in the game.

Thats what that was. I always hated that car just because that noise was so bad. its always like pshew pshew pshew

 

[TurboSmoke]

Originally posted by DoZeRxXx
Thats what that was. I always hated that car just because that noise was so bad. its always like pshew pshew pshew

i think its a great sound...i wish my car in real life made that sound.....

 

[eddieturner2002]

Originally posted by eddieturner2002
no what solid lifters is talkin about is also the pressure being let out of the blow off valve/dump valve/wastegate but just sounds different. Get some really knowledgable person in here to explain why......like famine or someone

its a bypass valve sound
bosch bypass valve sound (wav)
listen to that......i think thats the sound solid lifters means....the difference between blow off valves and bypass valves is that a bypass valve will release turbo pressure between shifts. The term "bypass" relates to the idea that the turbo air is then rerouted back into the intake. These valves are designed to be fully open in any amount of vacuum, so they can only be routed back into the intake, otherwise stalling would occur. It can be argued this is the "proper" way to release turbo pressure so that no air is ever lost from the intake system. This is also the same setup that the ST205 GT-four and Supra Turbos use

or Solid Lifters are you talking about a BOV with a high pitched whistle like some of the HKS BOVs's on low pressure do.
HKS Whistle BOV (wav)


and TurboSmoke if ya want your car to sound like that buy a nice turbo and stick a blow off valve or bypass valve on it

 

[Tuned]

Ive always wondered what that sound from the rally car was aswell, the one I am thinking of doesnt sound like that, I cant really put my finger on what it sounds like.

I like the blow of valve sound personally, ive only heard a few cars that sound like that, one of which was a Lotus Esprit, I was on a driving lesson with the windows closed and still heard it. V.V nice car, the game just doesnt do it justice.

 

[DoZeRxXx]

i think its a great sound...i wish my car in real life made that sound.....

I like the sound too but when your doing a track like grand valley it is doing it all the time. Then it started bothering me

 

[Boost Lee]

Originally posted by Solid Lifters
Good explanation. 👍

Now, please explain to me why Rally race cars, IRL, make a quick "chirpping" sound when they downshift. WTF is that? It can't be from the tires, they're in contact with dirt. I thought it might be something similar with the POV, but maybe the pressure is much lower or something and it comes out sounding like a chirp instead.

Multiple chirp's = The car has an external wastegate
Single chirp = B.O.V

 

[2005McLarenF1]

Is that what you always hear when you watch videos of Skylines? They always sound weird when the shift.

 

[Solid Lifters]

Originally posted by Monster7
Multiple chirp's = The car has an external wastegate
Single chirp = B.O.V

Yes, it is usually multiple chirps, but not always. An external wastegate, huh? Never heard of that before. Do you know much about them? Oh, btw, the chirp is very fast, and very quiet. It sounds like a gun silencer from those cheesy late 70's spy movies, but at a much higher pitch. There is no way I could confuse that with exhaust "pops."

 

[Solid Lifters]

Originally posted by eddieturner2002
its a bypass valve sound
bosch bypass valve sound (wav)
listen to that......i think thats the sound solid lifters means....the difference between blow off valves and bypass valves is that a bypass valve will release turbo pressure between shifts. The term "bypass" relates to the idea that the turbo air is then rerouted back into the intake. These valves are designed to be fully open in any amount of vacuum, so they can only be routed back into the intake, otherwise stalling would occur. It can be argued this is the "proper" way to release turbo pressure so that no air is ever lost from the intake system. This is also the same setup that the ST205 GT-four and Supra Turbos use

or Solid Lifters are you talking about a BOV with a high pitched whistle like some of the HKS BOVs's on low pressure do.
HKS Whistle BOV (wav)


and TurboSmoke if ya want your car to sound like that buy a nice turbo and stick a blow off valve or bypass valve on it

No, cool clips, but that's not it at all. Those cars are upshifting, and the sound happens when Rally Cars downshift. I'm beginning to think it's coming from the drive train. Maybe the clutch is making a very quick chirp sound when it grabs the flywheel, or something.

I need to hear the external wastegate that Monster7 mentioned. Sorry, I didn't mean for this question to be such a pain.

 

[Hot4]

Most WRX's have monster sounding BOV. zzzzz CHOOOOF

 

[eddieturner2002]

Originally posted by Solid Lifters
No, cool clips, but that's not it at all. Those cars are upshifting, and the sound happens when Rally Cars downshift. I'm beginning to think it's coming from the drive train. Maybe the clutch is making a very quick chirp sound when it grabs the flywheel, or something.

I need to hear the external wastegate that Monster7 mentioned. Sorry, I didn't mean for this question to be such a pain.

Where's Petter Solberg when ya need him?

 

[Jugend]

It has nothing to do with the engine. I think the chirp you're talking about is the differentials in the transmission working. I think there are like 3 of them and especially on asphalt they have to work really hard.

 

[Jugend]

looks like I was biking in the ditch..

this link explains it:

http://www.thecheckeredflag.com/rallye/wholestory.asp?10

 

[Boost Lee]

Originally posted by Monster7
Multiple chirp's = The car has an external wastegate
Single chirp = B.O.V

"That “chirping” sound comes from the waste gate. Every time the engine reaches a certain boost (On WRC cars boost is usually 1.9-2.0 bar except for the Subaru which is lower) level, and or the pilot lets off the throttle the waste gate opens sending a “whoosh” of air out of the engines system. That is what makes the “chirping.” - thecheckeredflag.com

 

[19xx]

sucks that GT3 only has one BOV sound... that must be the universal one

 

[Drifty_McDrift]

The sound in the game is the Blow Off Valve.

Yes Rally cars make a chirping sound too. That sound, however, is not from the BOV. That sound has to do with the sequential gearbox on downshifting. Watch WRC on speed channel they tell you a lot of cool $h!t

 

[anthonysinatra]

theres mainly 3 diff types of bov's, adjustable, hard, and soft, the hard bovs, make the single sounding whistle, the soft, is more of a fluttering sound, and the adjustable combines the two.

 

[VG30DETT]

My friend had a turbocharged Plymoth Lazer, it had a pretty cool blow of valve. At one point him and couple friends started thinking how they could get it so the air would go through a train whistle.

WRC = God.

 

[Delphic Reason]

Originally posted by GTJugend
It has nothing to do with the engine. I think the chirp you're talking about is the differentials in the transmission working. I think there are like 3 of them and especially on asphalt they have to work really hard.

Good call, GTjugend. This is the sound that he is talking about. Rally car transmissions tend to be very loud, and are known to produce a chirping sound.

 

[Jugend]

silviadrifter:
Good call, GTjugend. This is the sound that he is talking about. Rally car transmissions tend to be very loud, and are known to produce a chirping sound.

Hmm.. I thought I was way off in that post.. We'll see if this thread turns into a drift/grip never ending discussion..

 

[drift_prophet]

sequential bovs allow a "chirping" sound. these devices dont let the inlet pressure out in one hit, rather stream it out.. thus the sqwirreling chirping sound. this occurs to keep some air pressure in the inlet pipe, so the turbo doesnt have to build up a whole lot of boost again. rally cars also use an anti-lag system, which essentially keeps the turbo spinning through the apllication of unburnt fuel... keeping the turbine spinning after the throttle has been let off, so that the boost pressure never has to built up from vaccum at least. this is the crackle and popping sounds that you hear in rally games. i keep losing my train of thought typing this post, so ill leave it at that. gt3 lacks the crackle and grumble that occurs when the throttle is let off in these cars, slightly dissapointing, considering the realism of every other aspect. i hope number 4 fufills my desire for realistic sounds...

 

[Boost Lee]

The never ending thread....

The answer to this question has been explained every way possible.

 

[Tofu4G63]

Ok...... In regards to the noise in GT3 in rally cars when you are downshifting. Every time you shift gears guess what happens..... the throttle plate closes anytime you shift up or down....... and when the throttle plate closes what happens? Voila. And if it is doing it very repeatedly, either you are downshifting multiple gears..... or you downshifted to quickly and are bouncing off of the rev limiter cause hell on your car trying to slow down and getting a very very crazy sound of the BOV letting out all the air. Go to the in car view...... downshift to first gear unnecisarly at say 100 mph.... then you will hear this sound and watch the boost gauge at the same time and see how it goes from vaccum to boost like 100 times.

 

[Bahbo]

BOV Sound clip