Compressor surge vs fluttering
 

I fired up the car for the first time since the clutch and turbo install this morning just to check for leaks and problems. Didn't drive it since I don't have an ECU or injectors yet.

While revving it lightly, I do hear some turbo noises when I close the throttle and I'm trying to figure out what it is. I found this thread:

https://www.miataturbo.net/forum/sho...V+sound&page=2

It sounds more like the fluttering. I'm only at idle and not building any boost. I'm using the FM aluminum BOV which routes things back into the intake.

http://www.flyinmiata.com/depts/images/05-90105.jpg

I suppose I should wait until I drive it to figure out if it makes the same noise when I'm actually boosting under load.

On a side note, what's the purpose for the one way check-valve for the carbon canister? I purchased this kit used and it wasn't included. Thanks!

edit:
don't know if you can view the video without an account
http://vids.myspace.com/index.cfm?fu...deoID=33145867

Put the video on youtube.

http://www.youtube.com/watch?v=VamebVaP0SI

Unfortunately it's a huge file because of the digicam. You can hear it in the beginning and end of the video when I'm revving it.

A friend said he can make his Evo do that when he's driving with low load and low boost and let off the throttle quickly.

That's not the sort of thing that's usually included, not that I've seen anyway.

The check valve is meant to keep from pressurizing the charcoal canister.

My car makes a similar sound that kind of sounds like a cricket. I think it is from the valve being slightly open when coming down from a light rev. I notice it when i am driving slowly around parking lots and stuff.

edit: I dont have sound at work so i didnt actually listen to the video, so i am just guessing.

my car also "flutters" on low speed driving, i dont think it has too much of an effect on the turbo, i would think that extreme pressures would cause problems (i.e. compressor surge due to lack of a BOV).

is BOV flutter, no worries. loosen the valve if you can.

Thanks all!