What is this car modification?

Iwannahurl

When crossing the road recently, pushing child in buggy, I had just about got the two front wheels up on the pavement on the opposite side when a modified car came around the corner very fast.

The driver was clearly accelerating hard for effect. The desired effect was a loud noise like air brakes on a truck or bus, which occurred just after each acceleration/gear change.

I have encountered cars with this modification before on a few occasions and it seems to be associated with a driving style mainly characterised by hard acceleration. The drivers seem to like the loud intermittent 'air brakes' effect, so they drive in a way that produces the sound as often as possible.

What is this modification, and am I the only one that finds it bloody irritating?




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Voodoomelon

Dump valves.

Retarded sounding.

challengemaster

dump valve

http://www.youtube.com/watch?v=HblCEQXQ8Q4&feature=related

Iwannahurl

Thanks for that.

This bit of the Wikipedia entry on dump/blowoff valves is probably close to what I have encountered:

Some blowoff valves are sold with a trumpet-shaped exit that intentionally amplifies the sound. Some turbocharged vehicle owners may purchase a blowoff valve solely for the auditory effect even when the function is not required by normal engine operation.

At least I'll hear them coming I suppose, which will give me a chance to run...

hi.im.fred

Well its not actually a modification on some cars..

Sometimes you hear it louder than other cars..
Every Turbo Car has to release air

Better than this noise
http://www.youtube.com/watch?v=Erjhkv9AzKY

Absurdum

it could be a Dump Valve Simulator!!

Nonoperational

If I push on I hear it too and I have the standard "dump" valve on my car.

Mycroft H

Absurdum wrote: »

it could be a Dump Valve Simulator!!

My god that is stupid