Big Bubba question
Thread Starter
Melting Slicks
Joined: Nov 2017
Posts: 2,306
Likes: 747
Big Bubba question
I finally got my car back and swapped the filterless 38mm bypass valve out for the filtered Big Bubba 52mm. Definitely more sound when out of boost, although not as dramatic of a difference as I expected from past posts. One of the reasons I swapped it out was to eliminate the flutter/compressor surge I was getting when shifting in the mid-high rpms at WOT. I was surprised to see that didn't change much in going to the Big Bubba, so I'm thinking something else is a little off. It's definitely not as fluttered sounding as the 38mm, but when it first opens in between shifts, there's a slight flutter/whipping noise as opposed to the clean low pitched "purge" sound I was expecting. Is this normal? If not, the only thing I can think of is the vacuum line ID appears to be pretty small. It's a thick wall silicon line, but the ID is pretty tiny. Could that still be collapsing under high vacuum, not letting the piston open quickly enough? i'm hoping it's just normal, but if not, that's the only thing I can think of. The unit itself is in very good condition and the large o-ring is still in tact.
Thread Starter
Melting Slicks
Joined: Nov 2017
Posts: 2,306
Likes: 747
So no flutter even pushing way more air, that's what I was afraid of. It definitely looks like the raceport design would flow much better, I just have a hard time believing the Big Bubba wouldn't be able to push 10 psi from a S trim with no flutter if it opens fast enough. Guess I'll look for some larger vacuum line and see!
Thread Starter
Melting Slicks
Joined: Nov 2017
Posts: 2,306
Likes: 747
Just an update: replaced the vacuum line with regular old 7/32" from Autozone and all is well now. If I would have replaced $20 in vacuum line first, I would probably still be running the 38mm valve lol. Kind of frustrating the installer used that vacuum line to begin with.
Instructor
Joined: Dec 2015
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From: Florence South Carolina
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