is this normal?

[ScuttleRX]

since having my apexi intake fitted, i can hear what sounds the dump valve hissing when on about half throttle, no noise when on full boost or no boost(slow acceleration) just when its making about 0.3-0.5 bar.

Is this normal, venting the excess air or something?

[bnaellis]

Yep it\'s normal I think you will probably find it\'s the nosie of the induction kit actually but yep it\'s fine.

rgds

[ScuttleRX]

Cheers Bri, any idea why it dont make the noise at full throttle, or is it cos theres excess air at half throttle

[bnaellis]

Tell you while the engine is running pop the bonnet pull the throttle linkage to rev it up a bit and you will hear where the sound is coming from. Maybe it\'s the bleed valve  too.
Different indcution kits sound quite different. I find the apexi to loud I found the hks and blitz quite lod for example.

rgds

[Squealy]

The Apexi unit will probably give quite an audible sucking noise at some point up the rev range.  I had one on my MR2 non turbo and it did this between about 5 - 6 thousand revs.  I got to quite like it.  Only way I can think to desribe it is as a frantic gulp for air.  Umm...sort of!  Apparently it is due to the way the filter is made.  If you look inside it, it has a little black tapered plastic cone.  It is part of the cap if you look at the top.  This is supposed to spin air into a sort of vortex to smooth airflow into the intake.  The noise you hear is apparently where the vortex is at its most violent hence the noise.  If you blip the throttle from idle you should also get a weird wee sucky whistly noise.  Sort of SHHHUP. Odd but nice.
This is just what I was told by the dealer I bought it from.  Could be bull. Dunno!  Anyway.  Hope it sheds a bit of light.

Neil

[antnicuk]

If you have standard BOV\'s, then you can probably only hear the primary BOV, hence half throttle!