Hi,
I\'ve been looking into buying a Skyline or an Rx7...
A question that\'s been bothering me recently, but I don\'t now much about turbo technicalities or dump valves etc...
Most Skyline (and other turbo\'ed cars) give off a loud hiss when you lift off - the dump valve \'dumping\' right?
But looking at the MRC London Tunnel run vids and other RX7 vids I\'ve seen, most RX7\'s seem to give off a kind of chirping sound, or purring sound, and not a hiss like other turbos..
what gives?
Is it just a special kind of dump valve, or what?
You can here the chrip i mean here: at about 07min35secs to 07min45secs
http://video.google.co.uk/videoplay?docid=-2049615832735105543&q=tunnel+run
Hi Red Rummy
The sound varies on what dump valve you use, my rx7 has the hiss sound your talking about (apexi), whereas my friend with a supra has the chirpy one (HKS one I think he has).
the chirpy noise is the waste gate chatter let off by your wastegate actuator...get it on my fd3 with a blitz super sound...
Sounds like compressor surge, anyone know who\'s RX7 that is and if it\'s a single?
That\'s Laeeq\'s car with smallish single turbo.
ok, cheers guys :))
Sorry I replied to your post without listening to the sound clip, was talking about a totally different chirp :)
Some dump valves are more chirpy than other, my apexi was adjustable until the adjusting thingy broke, but like Prince says thats wastegate chatter
There\'s no such thing as \'wastegate chatter\'. That chirrupy noise is in fact compressed air passing back through the compressor housing of the turbo due to the closed throttle plates. Found a pic of Laeeq\'s engine bay and there was no dump valve, which would explain the compressor surge.
Fair enough, that sounds always been described to me as wastegate chatter so thought thats what it was, definately not a dump valve which is what I basically meant.
Does an external wastegate make a similar noise as well then? phrase has gotta have come from somewhere
Yeah, I\'ve seen the term used quite often (usually in reference to compressor surge), not sure where it\'s come from. Sometimes you\'ll get compressor surge even when there\'s a dump valve fitted, so perhaps that\'s why people blame the wastegate. Can\'t think of a reason why a wastegate would ever \'chatter\' on the overrun.
You can still get the flutter from the surge with a DV if the spring in the DV is too tight (high boost applications) Then when you boost small ammounts the DV cant open thus you get the flutter. :cool
ok, guys, thanks...
I like the chirpy noise and would much prefer it than the hissing of normal turbos....
Just wondered if it was a specific kind of turbo / dump valve... sounds like its more complicated that that tho :rolleyes:
:3gears-lh
How about the HKS SSQV - what do they sound / preform like on an FD?
but laeeqs car does have a blow-off valve...the chirp is the the wate gate opening allowing instant boost release leading to the chatter...
personally i h8 of the hks on a sequential set-up...
Quote from: prince_of_tokyobut laeeqs car does have a blow-off valve...the chirp is the the wate gate opening allowing instant boost release leading to the chatter...
Alright then mate, it is wastegate chatter :rolleyes: