how do you make turbo cars make the cool chirping sounds like race cars
11-05-2003, 11:41 AM
#1
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how do you make turbo cars make the cool chirping sounds like race cars
You know
waaaaah
chirp.. chirp... chirp
waaaaah
chirp.. chirp... chirp
that type of noise on up and or downshifts
yeah I'm a newbdweeb
waaaaah
chirp.. chirp... chirp
waaaaah
chirp.. chirp... chirp
that type of noise on up and or downshifts
yeah I'm a newbdweeb
11-05-2003, 01:41 PM
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Re: how do you make turbo cars make the cool chirping sounds like race cars
My understanding is that the cars did not have a bypass valve or a blowoff valve since the large intercooler acted as a buffer for the turbo. The chirping was the actual valve opening and closing as boost danced along that threshold in the intake manifold. Once the throttle opened back up again, the compressed air in the IC would rush into the manifold. I think the S1s did not have a MAF/MAS type of sensor so this type of boost control was adequate.
Any good incar video of a true S1 will have that distinctive vrroooommm squeak squeak squeak vrrrrrrroooommmmmmm squek squeek squeek...
Any good incar video of a true S1 will have that distinctive vrroooommm squeak squeak squeak vrrrrrrroooommmmmmm squek squeek squeek...
11-05-2003, 02:39 PM
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It's also attributable to the anti-lag program that a particular car is running...
...Raw fuel is sprayed into the hot IM. This in turn combusts, and keeps the turbo spinning at a pre-determined RPM, thus there's usually always pressure bleeding out of the exhaust BOV.
11-05-2003, 07:06 PM
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Re: how do you make turbo cars make the cool chirping sounds like race cars
The noise that the WRC cars make is a sequential blow off valve. It doesn't release all the pressure at once but in stages.
Is that the sound you are talking about?
Crayfish
Is that the sound you are talking about?
Crayfish
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11-05-2003, 07:37 PM
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wasn't that only on the hillclimb specials?
Bruno told me that "constant air" setup would burn out the exhaust valves in about 30 minutes. Enough for a hillclimb.
It was in his words "Terrific power" when it was working.
It was in his words "Terrific power" when it was working.
11-07-2003, 04:24 AM
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Re: That's correct James, and Chirping defined
The antilag was considered by audisport to have a complete motor service life of less than 1 hour. This was only used on Hillclimb cars. I believe Ned still owns one of those manifolds. The S1 and PP at Monterey 99 both had the bungs welded over (read: deleted). I'd also venture, if you saw one installed or in action, you should consider yourself lucky.
IME with the "chirping", this is they wastegate relieving pressure at part throttle boost conditions. The turbo is spinning up, and before vacuum (part throttle "hold") the wastegate will open slightly and "bounce" the excess pressure. In MAC 11 cars you can get this pretty easily because of how WGFV is designed.
Since "overboost" (increased effective spring pressure) only happens with WOT activation, you put your foot to the floor, the WGFV holds the WG shut, then lift a bit as the turbo is spooling, and the reduced spring effective pressure causes the WG to chatter. I do this all the time with my old CIS wagon (it has BPV installed as well, different sound). In the rally cars, you could here the cars coming with the chirpping sounds before you ever saw them. Listening to the exhaust note, it was before lift. I attribute this to leaving the throttle slightly cracked with a big turbo spooling up, blowing the WG open slightly.
I remember having this discussion with Ned a few times. I proposed the above, I remember he was more inclined to think it was compressor stall. I discount that because you can hear it on cars with BPV installed before "vacuum" on full lift throttle.
HTH
Scott Justusson
QSHIPQ Performance Tuning
Chirping k24 just yesterday....
IME with the "chirping", this is they wastegate relieving pressure at part throttle boost conditions. The turbo is spinning up, and before vacuum (part throttle "hold") the wastegate will open slightly and "bounce" the excess pressure. In MAC 11 cars you can get this pretty easily because of how WGFV is designed.
Since "overboost" (increased effective spring pressure) only happens with WOT activation, you put your foot to the floor, the WGFV holds the WG shut, then lift a bit as the turbo is spooling, and the reduced spring effective pressure causes the WG to chatter. I do this all the time with my old CIS wagon (it has BPV installed as well, different sound). In the rally cars, you could here the cars coming with the chirpping sounds before you ever saw them. Listening to the exhaust note, it was before lift. I attribute this to leaving the throttle slightly cracked with a big turbo spooling up, blowing the WG open slightly.
I remember having this discussion with Ned a few times. I proposed the above, I remember he was more inclined to think it was compressor stall. I discount that because you can hear it on cars with BPV installed before "vacuum" on full lift throttle.
HTH
Scott Justusson
QSHIPQ Performance Tuning
Chirping k24 just yesterday....