XtremeVette

Hey guys got an a@a kit and just downgraded from a 50 MN blow off valve to a 38 mm. I love how it is much quieter. I can here my corsa exhaust again. No street sweeper noise. But I have a fluttering noise at above 4000 rpms. Andy said turn the dial to just before seeing the o ring which I did. Didn't help. I then tried it more toward the softer side...no difference. I went full hard. No difference. Is this sound normal? Did I get a defective unit? Any help kindly appreciated. Been working on it for 2 hours now. Andy's closed now so turning to the forum for advise. Thanks

realcanuk

It's not normal. I had a fluttering sound and it turned out to be a leak in the vacuum hose to the BOV.

XtremeVette

Yup, Andy was really cool and just gave me a call. How's that for customer service! He was thinking maybe the same thing at first. Only I have good vacuum as the 50mm Raceport worked fine prior to this swap to the 38mm. I did what he said and took the spring and piston out. The piston wasn't moving very freely so I cleaned it out and re-lubed it with WD-40 per Andy's recommendations. Seemed to be moving better. I'll let it sit overnight and take it out tomorrow for a test drive. See if it improved anything. Crossing fingers.

ss4luck

I assume you're talking about when you're out of the throttle? My new phew says my BOV sounds like one of my rattle snakes when I back out of the throttle, I just assumed that was normal. Now I'm questioning it haha

XtremeVette

Yes exactly. I was getting a loud street sweeping whoosh with the 50mm. That got old really quick. I then spoke to Josh at A@A who said for me to go with the 38mm with built in filter. As told it worked as expected except for the loud fluttering noise when I decelerate at anything greater then 4000rpm.

SmoothFRC

I have this same issue - I spoke to Josh before picking up a used 38mm A&A BOV, as i had the stock Prochager BOV and had this same issue.

He mentioned this should work fine, which it does for the most part.

When letting off at HIGH RPM (as you mentioned, anything above 4) I still get the fluttering, and Josh mentioned that i may need the 50mm to stop this.

Curious how you make out with it, I've cleaned mine, put a larger hose on the BOV (that was another recommendation)... still has the issue. I find if I stab the throttle again, it usually stops the flutter.

Maybe you can swap a 50mm with someone whom has the non race port to put a filter on it and keep it a little quiet?

XtremeVette

Yup no change after the cleaning and re-lube. I'll be talking to Andy on Tuesday to change it out to the 52 Big Bubba version with filter. Maybe it's just a bad design from Turbosmart on 38? I found that the design of the Raceport was much better. The piston does not move inside the cylinder. Way less friction and potential for jamming up. The Raceport has it suspended to a rubber diaphragm that moves back and forth. If the Big Bubba is made this way Iam sure it will fix the problem. My guess is that with the 38 mm version the air and turbulence causes the piston to jog violently from side to side very rapidly causing it to chatter against the inside walls of the chamber and thus a fluttering type of sound when high amounts of air are moving it. No proof of that just my common sense logic after looking at how both are made.

Chevy Guy

What head unit/pulley are you using? You could have stepped down to a valve that is too small.

stevieturbo

The fluttering noise means you need to vent more air. Plain and simple.

You will be doing the blower no good whatsoever by allowing this to happen.

realcanuk

In this video you can hear the "fluttering" noise that alerted me to check things out. Found the vacuum line leaking. Make sure its getting enough vacuum, and if not I guess the valve is bad. I now run a Big Bubba with the filter and you will get the street sweeper sound but not as much as the procharger big red.

stevieturbo

I went from a Vortech Mondo to a Big Red.

No idea why people think the big red is loud...the Mondo was far far worse on mine !

realcanuk

That's actually crazy. I went from a Mondo, which was very quiet, to the Big Bubba which is louder. LOL

Only changed the mondo because it kept losting the oring. Was a good BOV other than that.

stevieturbo

Not really.

Lots of air through a small hole...it'll scream ( and it did ! )

Lots of air through a huge hole....quieter.

realcanuk

Yeah. I meant crazy because my mondo was so quiet. Almost sorry I changed it after.

XtremeVette

just running a v3si. They ship with the 38 mm. My installer thought it would be cool to order and install the 50 mm Raceport that comes wide open in the middle. No filter. It's very loud and got old real quick with me. The 38 as mentioned above definitely quieted the street sweeper whoosh noise down a lot but the fluttering noise above 4000 rpm upon a deceleration had me concerned. Anybody take apart to see what the big Bubba with the filter on it looks like for the inside? Is it more similar to the Raceport with a rubber diaphragm or is it like the turbo smart and has a piston inside the chamber?