I just got everything set up, and am quite happy with the 5psi I am running, but there is a fluttering sound coming from the engine bay when I let off the throttle to shift. I am using a cheap *** Bosch BOV for the time being, and I have heard that sometimes BOV's do make a fluttering sound, but I am worried that it could be something else. Any ideas?

 

You can get a one-way valve at Lowe's Hardware to put at the end of they Bosch bypass valve. They seem to leak and have no adjustment on them. There is a good Miata site with the instructions and pictures. Excellent site that should be in the FAQ but I can't find it right now.

 

If you can, you need to loosen the spring a little on your blow off thats what the noise is.

 

wastegates make a fluttering sound. have you seen 2 fast 2 furious. if you did, remember the skyline. it had that flutter to it. i think the internal wastegates arent that loud. but if you have an external wastegate, then thats what it is.

 

That fluttering sound is the backspin from the wastegate/turbine...that fluttering gets louder with the more boost you run. Thats not something that you want to hear and it will hurt your bearings. Your BOV isn't letting out enough pressure. Check to see if its opening all the way...sometimes they get stuck from moisture

 

basically your bov is junked. Start looking at a new one. The fluttering is happening because when you are leting off the gas the turbo is still spinning and the air is bouncing off of the throttle body and reversing the air to the turbo and spinning the blade backwards. You definetly need to get a new bov and when your driving now be careful when your letting off the gas.

 

2 words; Compressor surge

 

that only with deltagate wastegates that make that loud *** fluttering noice

 

I was afraid that this was the case. Looks like I am going to have to make myself poorerer and go get a new BOV.

 

That was a ------- movie .You must be the only person on this site to of have seen that gay *** movie!I smell a ------- ricer who believes that fast and furious ---- is real!