DUMPVALVE

[gafvts]

just added dump valve to the car,sounds very nice,but when you let the car come down in gear you can hear it hissing away,is this normal on the supercharged cars,i did not expect it to sound the same as a turbo car so i thought that is why it does it

[Scott]

possibly because the super charger is still making some boost as it runs of the crank as the engine revs down?

[gafvts]

just as long as it is ok smileys/smiley17.gif

[Dan]

How much did that set you back craig? If you dont mind me asking?

[Simo]

just added dump valve to the car,sounds very nice,but when you let the car come down in gear you can hear it hissing away,is this normal on the supercharged cars,i did not expect it to sound the same as a turbo car so i thought that is why it does it

It's hissing as you are letting boost out of your charge pipes...

The vacuum in the inlet manifold is opening up the dump valve. Your charger is still creating bosot as the engine is turning, so some of this boost is expelled through the dump valve.

If youre happy with the sound, fair enough, but on a supercharger youre actually losing one of its benefits...

[Awretham]

Yea was about to say the same, a DV on a s/c setup won't do you any favours.
You'll only benefit from it with a turbo, even then its really only to reduce the strain on the commonents caused by the excess pressure (when the throttle is closed,) and the lag between gear changes due to compressor shaft stalling.

[gafvts]

took the dumpvalve off after 2 hours,started to do my head in,i would not recommend fitting dump valve to supercharged saxo.dan i got the dumpvalve given to me by my local garage cos i do some work there sometimes

[Dan]

Did it affect the performance of the car at all?

[gafvts]

did not seem to effect performance of car dan

[Mr_Hush]

what did it sound like? lol

[gafvts]

when not driving the car it sounded pretty much like a normal dumpvalve,but when driving it sounded crap