OT: Why do WRC cars chirp?

Even tho it's at least a week delayed now, we still get pretty thorough race recaps of the World Rallye Championship. In many of the exterior shots of the cars you can hear them chip/squeak as they navigate the corners. What is the cause of this noise? Springs? Brakes? dave henrie

Yeah, that's a good question actually.. I really noticed it last year, especially with the Peugeot! Also, I noticed that the in-car camera in the Peugeot the whole thing sounds like it whistles really loudly, I'm guessing it is the turbo, although I don't know much about cars. I always just assumed that the little chirps and squeaks were from the suspension or even the brakes. If someone makes a modern day WRC game (pleeeaaaaaaaaseee), I'd love to be able to hear these same noises during replays. Mike http://mikebeauchamp.com "Dave Henrie" <[email hidden]> wrote in message news:[email hidden]... > Even tho it's at least a week delayed now, we still get pretty thorough > race recaps of the World Rallye Championship. In many of the exterior > shots of the cars you can hear them chip/squeak as they navigate the > corners. What is the cause of this noise? Springs? Brakes? > dave henrie

Dave Henrie wrote: > Even tho it's at least a week delayed now, we still get pretty thorough > race recaps of the World Rallye Championship. In many of the exterior > shots of the cars you can hear them chip/squeak as they navigate the > corners. What is the cause of this noise? Springs? Brakes? > dave henrie Dave, I'm not 100% sure, but I'm thinking that it's the ABS kicking in. Aibhne

It is the engine backfiring through the exhaust and also the turbo spooling up and down (which happens a lot more "violently" than on a street car with a turbo). The sound on the Speed Channel coverage is 90% backfiring, which happens very often at gear change, but can also happen just from rapid throttle input change. Marc "Dave Henrie" <[email hidden]> wrote in message news:[email hidden]... > Even tho it's at least a week delayed now, we still get pretty thorough > race recaps of the World Rallye Championship. In many of the exterior > shots of the cars you can hear them chip/squeak as they navigate the > corners. What is the cause of this noise? Springs? Brakes? > dave henrie

Actually, I thought about it some more and you are likely aware of what a backfire sounds like, in which case the unidentified sound is the transmission changing gears. These cars use sequential electronically shifted trannies (a scaled down version of what an F1 car uses), which make a significant noise when being shifted up or down the range. Marc "Marc Collins" <[email hidden]> wrote in message news:Ne_3a.430$[email hidden]... > It is the engine backfiring through the exhaust and also the turbospooling > up and down (which happens a lot more "violently" than on a street carwith > a turbo). The sound on the Speed Channel coverage is 90% backfiring,which

Quoted text (8 lines)

> happens very often at gear change, but can also happen just from rapid > throttle input change. > > Marc > > "Dave Henrie" <[email hidden]> wrote in message > news:[email hidden]... > > Even tho it's at least a week delayed now, we still get pretty

thorough > > race recaps of the World Rallye Championship. In many of the exterior > > shots of the cars you can hear them chip/squeak as they navigate the > > corners. What is the cause of this noise? Springs? Brakes? > > dave henrie > >

I'm fairly certain it is the turbo. I remember it most prominently on the Audi Quattro's that were run in the late 80's Trans Am. The sound was also heard in the CART Indy cars, but not to the same degree. What little Ralley car footage I see, I hear the same thing on all the Turbo assisted cars. Jeff H. "Dave Henrie" <[email hidden]> wrote in message news:[email hidden]... > Even tho it's at least a week delayed now, we still get pretty thorough > race recaps of the World Rallye Championship. In many of the exterior > shots of the cars you can hear them chip/squeak as they navigate the > corners. What is the cause of this noise? Springs? Brakes? > dave henrie

In article <A1%3a.7900$[email hidden]>, [email hidden] says... > I'm fairly certain it is the turbo. I remember it most prominently on the > Audi Quattro's that were run in the late 80's Trans Am. The sound was also > heard in the CART Indy cars, but not to the same degree. What little Ralley > car footage I see, I hear the same thing on all the Turbo assisted cars. > It's the turbo. More accurately, it's the wastegate bleeding off excess boost. I used to own a slightly modified '86 Buick T-Type that ran the 1/4 mile in the mid-12 second range and in it, you could hear the wastegate operating when you let off the gas. The Buick had a fairly large (by today's standards) aftermarket turbo and wastegate so the sound was more pronounced than it is in a factory stock turbo car. -- __________________________ Todd Walker http://twalker.d2g.com __________________________

Dave Henrie wrote: > Even tho it's at least a week delayed now, we still get pretty thorough > race recaps of the World Rallye Championship. In many of the exterior > shots of the cars you can hear them chip/squeak as they navigate the > corners. What is the cause of this noise? Springs? Brakes? > dave henrie

It's most likely the turbo blow off valve... it releases the pressure from the intake manifold when the driver lifts his foot off the accelerator. AFAIK the only game that has this modelled is netKar (Supra TT). -- - JKo -

Jussi Koukku <[email hidden]> wrote in news:[email hidden]: > It's most likely the turbo blow off valve... it releases the pressure > from the intake manifold when the driver lifts his foot off the > accelerator. AFAIK the only game that has this modelled is netKar > (Supra TT). > -- > - JKo - But isn't the turbo waste=gate a popping noise? pop pop this is more like a bird chirp or a metal on metal squeak. Do the turbos really sound like that? dave henrie

"Dave Henrie" <[email hidden]> wrote in message news:[email hidden]... > Even tho it's at least a week delayed now, we still get pretty thorough > race recaps of the World Rallye Championship. In many of the exterior > shots of the cars you can hear them chip/squeak as they navigate the > corners. What is the cause of this noise? Springs? Brakes? > dave henrie Its the wastegate on the Turbo its as they come off the throttle and IIRC - a valve released pressure from the turbo system to stop it trying to 'push' the fuel/air mix into the cylinders after the driver has come off the throttle Doug

On Mon, 17 Feb 2003 09:03:25 GMT, Dave Henrie <[email hidden]> wrote something like this:

Quoted text (14 lines)

>Jussi Koukku <[email hidden]> wrote in >news:[email hidden]: > >> It's most likely the turbo blow off valve... it releases the pressure >> from the intake manifold when the driver lifts his foot off the >> accelerator. AFAIK the only game that has this modelled is netKar >> (Supra TT). >> -- >> - JKo - > > But isn't the turbo waste=gate a popping noise? pop pop this is more >like a bird chirp or a metal on metal squeak. Do the turbos really sound >like that? >dave henrie

The popping noise is probably coming from the ignition system. It cuts off the ignition while shifting to allow shifting without using the clutch (semi-automatic transmission, clutch used only for standing starts). It could also be the system that is used to spool up the turbo (or rather to keep it spinning) while lifting off the throttle... I don't know if this system is currently used in WRC cars though; small amount gasoline is ignited in the exhaust manifold, which causes pressure in the manifold and spins the turbo. This also causes the flames you see coming out of the tail pipe sometimes. This is done to reduce the turbo lag. -- - JKo -

"Jussi Koukku" <[email hidden]> schrieb im Newsbeitrag news:[email hidden]...

Quoted text (30 lines)

> On Mon, 17 Feb 2003 09:03:25 GMT, Dave Henrie <[email hidden]> wrote > something like this: > > >Jussi Koukku <[email hidden]> wrote in > >news:[email hidden]: > > > >> It's most likely the turbo blow off valve... it releases the pressure > >> from the intake manifold when the driver lifts his foot off the > >> accelerator. AFAIK the only game that has this modelled is netKar > >> (Supra TT). > >> -- > >> - JKo - > > > > But isn't the turbo waste=gate a popping noise? pop pop this is more > >like a bird chirp or a metal on metal squeak. Do the turbos really sound > >like that? > >dave henrie > > The popping noise is probably coming from the ignition system. It cuts > off the ignition while shifting to allow shifting without using the > clutch (semi-automatic transmission, clutch used only for standing > starts). > > It could also be the system that is used to spool up the turbo (or > rather to keep it spinning) while lifting off the throttle... I don't > know if this system is currently used in WRC cars though; small amount > gasoline is ignited in the exhaust manifold, which causes pressure in > the manifold and spins the turbo. This also causes the flames you see > coming out of the tail pipe sometimes. This is done to reduce the > turbo lag.

You are absolutely right, 100%. That�s the case for the noises. > - JKo -

"Jussi Koukku" <[email hidden]> wrote in message news:[email hidden]...

Quoted text (13 lines)

> > The popping noise is probably coming from the ignition system. It cuts > off the ignition while shifting to allow shifting without using the > clutch (semi-automatic transmission, clutch used only for standing > starts). > > It could also be the system that is used to spool up the turbo (or > rather to keep it spinning) while lifting off the throttle... I don't > know if this system is currently used in WRC cars though; small amount > gasoline is ignited in the exhaust manifold, which causes pressure in > the manifold and spins the turbo. This also causes the flames you see > coming out of the tail pipe sometimes. This is done to reduce the > turbo lag.

A modern WRC car sounds pretty much like an episode of the Three Stooges. You've got the anti-lag system sounding like Moe going at it with the slap of his hand (Bang... Bang... grrrr...) followed shortly thereafter by the distinctive sound of the wastegate, sounding like Curly at his best (Wooo woo woo woo)... Even the street-legal Cossie I once drove sounded a treat working its way up and down a Swiss mountain pass. Stephen

In article <[email hidden]>, [email hidden] says... > Even tho it's at least a week delayed now, we still get pretty thorough > race recaps of the World Rallye Championship. In many of the exterior > shots of the cars you can hear them chip/squeak as they navigate the > corners. What is the cause of this noise? Springs? Brakes? > dave henrie > It's the rear end. They use a "limited slip" differential.

says... It's the rear end. They use a "limited slip" differential.

Todd Walker <[email hidden]> wrote in message news:<[email hidden]>... > It's the turbo. More accurately, it's the wastegate bleeding off excess > boost. I used to own a slightly modified '86 Buick T-Type that ran the > 1/4 mile in the mid-12 second range and in it, you could hear the > wastegate operating when you let off the gas. The Buick had a fairly > large (by today's standards) aftermarket turbo and wastegate so the > sound was more pronounced than it is in a factory stock turbo car. Yes, it's the wastegate flutter. I was almost run over by a modded (are any not?) Renault 5 Turbo "Raider" on my way to work that sounded just like this! Regards, Mark

What a marvellous thread! Might help zero in on the definitive answer, Dave, if you described when, exactly, the chirp occurs. Stephen F. is right; WRC cars--real and virtual--are a delightful collection of chirps, bangs, boinks, clunks, pops, growls, whizzes, and screeches. "Dave Henrie" <[email hidden]> wrote in message news:[email hidden]... > Even tho it's at least a week delayed now, we still get pretty thorough > race recaps of the World Rallye Championship. In many of the exterior > shots of the cars you can hear them chip/squeak as they navigate the > corners. What is the cause of this noise? Springs? Brakes? > dave henrie

"Doug Ellison" <[email hidden]> writes:

Quoted text (12 lines)

> "Dave Henrie" <[email hidden]> wrote in message > news:[email hidden]... > > Even tho it's at least a week delayed now, we still get pretty thorough > > race recaps of the World Rallye Championship. In many of the exterior > > shots of the cars you can hear them chip/squeak as they navigate the > > corners. What is the cause of this noise? Springs? Brakes? > > dave henrie > > Its the wastegate on the Turbo its as they come off the throttle and IIRC - > a valve released pressure from the turbo system to stop it trying to 'push' > the fuel/air mix into the cylinders after the driver has come off the > throttle

that's how one of the team mechanics explained it sometime in the previos season. IIRC he also said the waste gate on WRC turbos are in the engine intake, since they run at warp 10 continuously. -- Gunnar Cougar#02748 #31 SUCKS#015 Tupperware MC#002 DoD#0x1B DoDRT#003 DoD:CT#4,8 Kibo�: 2 myk, trygg og god.

Not to mention the hooting and hollering of Jeff Gordon when he goes upside down... "Steve Smith" <[email hidden]> wrote in message news:Gi44a.78563$[email hidden]...

Quoted text (8 lines)

> What a marvellous thread! Might help zero in on the definitive answer, > Dave, if you described when, exactly, the chirp occurs. Stephen F. is > right; WRC cars--real and virtual--are a delightful collection of chirps, > bangs, boinks, clunks, pops, growls, whizzes, and screeches. > > "Dave Henrie" <[email hidden]> wrote in message > news:[email hidden]... > > Even tho it's at least a week delayed now, we still get pretty

thorough > > race recaps of the World Rallye Championship. In many of the exterior > > shots of the cars you can hear them chip/squeak as they navigate the > > corners. What is the cause of this noise? Springs? Brakes? > > dave henrie > >

Todd Walker <[email hidden]> wrote in message news:<[email hidden]>...

Quoted text (14 lines)

> In article <A1%3a.7900$[email hidden]>, > [email hidden] says... > > I'm fairly certain it is the turbo. I remember it most prominently on the > > Audi Quattro's that were run in the late 80's Trans Am. The sound was also > > heard in the CART Indy cars, but not to the same degree. What little Ralley > > car footage I see, I hear the same thing on all the Turbo assisted cars. > > > > It's the turbo. More accurately, it's the wastegate bleeding off excess > boost. I used to own a slightly modified '86 Buick T-Type that ran the > 1/4 mile in the mid-12 second range and in it, you could hear the > wastegate operating when you let off the gas. The Buick had a fairly > large (by today's standards) aftermarket turbo and wastegate so the > sound was more pronounced than it is in a factory stock turbo car.

Yes Todd, you are correct. It's more pronounced on the rally cars 'cause they use the misfire/bang bang/anti lag system. Info. here: http://www.rallycars.com/Cars/bangbang.html

Dave Henrie <[email hidden]> wrote in message news:<[email hidden]>... > Even tho it's at least a week delayed now, we still get pretty thorough > race recaps of the World Rallye Championship. In many of the exterior > shots of the cars you can hear them chip/squeak as they navigate the > corners. What is the cause of this noise? Springs? Brakes? > dave henrie Hi Dave, what you are hearing is the turbo blow off. It's more pronounced on WRC cars 'cause they use the anti-lag/bang bang/misfire system (tho not unique to WRC cars). Check out this article for info: http://www.rallycars.com/Cars/bangbang.html hope this answers your question ot: would you happen to know the "secret" project SBDT is currently whipping up??? :) cheers mike

"Steve Smith" <[email hidden]> wrote in news:Gi44a.78563$[email hidden]: > What a marvellous thread! Might help zero in on the definitive > answer, Dave, if you described when, exactly, the chirp occurs. > Stephen F. is right; WRC cars--real and virtual--are a delightful > collection of chirps, bangs, boinks, clunks, pops, growls, whizzes, > and screeches. > Boy that is tough...it's only heard on the trackside cameras. I think I notice it the most on slower corners I assumed it was the suspension working. The trouble is...because of camera/microphone placement it is not always easy to tell the exact status of the car. Do they drift through off throttle? Or do they keep some trail braking going? I'm pretty sure I don't hear it much on the hand-brake turns so I'm assuming it is when the throttle is off or relaxed. dave(here birdy birdy)henrie

"John Simmons" <[email hidden]> schreef in bericht news:[email hidden]... > It's the rear end. They use a "limited slip" differential. Actually they use 3 diffs: front, rear and one in between. But the sound is the turbo wastegate. Bye, Leo

Hi Dave, This excerpt is from the Subaru Impreza Owners Group website... "...the main advantage of the blow off valve is to reduce stress upon the turbo blades when you lift off of the accelerator to lets say change gear. The turbine is still spinning and thus pumping gas into the input...but the engine is off power. So what to do with the excess. A blow off valve set to a certain pressure releases this excess. A vent to atmosphere allows it to go to air giving the characteristic pfffft, a recirculating one feeds it back into the input of the turbo thus keeping the system pressurised. When you hit the accelerator the vented system then needs to momentarily build up the pressure again whilst the recirculating system doesn't. Without a BOV the turbine can actually stall or air is drawn back through the wastegate in the wrong direction. The turbine is spinning but there are no exhaust gases coming out of the engine, so it either stalls or draws airthrough the wastegate from the exhaust side.This is the chirp you hear on the WRC cars. The stress on the bearings is quite substantial and in a completely different direction to that which the turbo is designed. The turbo in the WRC cars has a 360 degree bearing surface to counter this (and the turbo is changed and refurbished per rally if not sooner), the road going turbo does not." Regards, KWS "Dave Henrie" <[email hidden]> wrote in message news:[email hidden]... > Even tho it's at least a week delayed now, we still get pretty thorough > race recaps of the World Rallye Championship. In many of the exterior > shots of the cars you can hear them chip/squeak as they navigate the > corners. What is the cause of this noise? Springs? Brakes? > dave henrie

On Mon, 17 Feb 2003 23:16:17 GMT, "KWS" <[email hidden]> wrote something like this: >This excerpt is from the Subaru Impreza Owners Group website...<snip> >a certain pressure releases this excess. A vent to atmosphere allows it to >go to air giving the characteristic pfffft, a recirculating one feeds it >back into the input of the turbo thus keeping the system pressurised. When >you hit the accelerator the vented system then needs to momentarily build up >the pressure again whilst the recirculating system doesn't. So they are saying that the recirculating system is some sort of perpetual-motion machine? I wonder why they don't use it in WRC cars or in tuned up street machines if it actually reduces lag... :P -- - JKo -

That's what I thought. Suspension, or maybe body parts. Larry "Mike Beauchamp" <[email hidden]> wrote in message news:z9_3a.5284$[email hidden]... > Yeah, that's a good question actually.. I really noticed it last year, > especially with the Peugeot! Also, I noticed that the in-car camera in the > Peugeot the whole thing sounds like it whistles really loudly, I'mguessing

Quoted text (13 lines)

> it is the turbo, although I don't know much about cars. > > I always just assumed that the little chirps and squeaks were from the > suspension or even the brakes. If someone makes a modern day WRC game > (pleeeaaaaaaaaseee), I'd love to be able to hear these same noises during > replays. > > Mike > http://mikebeauchamp.com > > "Dave Henrie" <[email hidden]> wrote in message > news:[email hidden]... > > Even tho it's at least a week delayed now, we still get pretty

thorough > > race recaps of the World Rallye Championship. In many of the exterior > > shots of the cars you can hear them chip/squeak as they navigate the > > corners. What is the cause of this noise? Springs? Brakes? > > dave henrie > >

On Mon, 17 Feb 2003 09:03:25 GMT, Dave Henrie <[email hidden]> wrote: I seem to remember the announcers mentioning this on the first race of the year at Monte Carlo. One of the drivers was at the starting line revving the engine and it was chirping away. He mentioned that it was the turbo waste gates making the noise.

Quoted text (14 lines)

>Jussi Koukku <[email hidden]> wrote in >news:[email hidden]: > >> It's most likely the turbo blow off valve... it releases the pressure >> from the intake manifold when the driver lifts his foot off the >> accelerator. AFAIK the only game that has this modelled is netKar >> (Supra TT). >> -- >> - JKo - > > But isn't the turbo waste=gate a popping noise? pop pop this is more >like a bird chirp or a metal on metal squeak. Do the turbos really sound >like that? >dave henrie

"Mike Beauchamp" <[email hidden]> wrote in message news:z9_3a.5284$[email hidden]... > I always just assumed that the little chirps and squeaks were from the > suspension or even the brakes. If someone makes a modern day WRC game > (pleeeaaaaaaaaseee), I'd love to be able to hear these same noises during > replays. Have you tried netKar? It has a Toyota Supra TT (Twin Turbo) that has this nice pfffft/chirp sound when you lift your foot off the accelerator =) http://driving.multiplayer.it/netkar/home.htm -- - JKo -

[email hidden]

Quoted text (7 lines)

> ot: would you happen to know the "secret" project SBDT is currently > whipping up??? :) > > cheers > > mike >

uhhh no...why do you ask? :) (you think they'd trust me to keep my yapper shut??) dave henrie