vacuum sources\compressor surge

[thebeewantsboost]

my camaro has been sitting for about a year. when i drove it recently i was getting compressor surge. a nice little flutter and then the bov would finally let out some air. the best i can remember i've never had any issues like this. i'm using a turboxs RFL bov. i took it apart and cleaned/lubed it. there was quite a bit of what i'm assuming is oxidation inside. kinda looked like tasty stuff that grows on your battery cables. cleaning helped a little but i still had the same issue. i then removed all of the washers/shims from the bov. and it works tons better. meaning there is a loud bov sound. but i still here a little bit of flutter. it might not be anything to worry about, but if i can get rid of it, i would like to... currently i have my boost gauge and my bov plumbed into a vacuum line from the map sensor. wastegate is plumped to the turbo itself. is there a better vacuum source? i'd go with a bigger vacuum hose but its the correct size for the nipple on the bov. also with the way the bov is "tuned" currently with no shims/washers, the bov is slightly open at idle.

[ssms5411]

Re: vacuum sources\compressor surge

I would have the BOV closed at idle, might be why its surging.

[thebeewantsboost]

Re: vacuum sources\compressor surge

the way its setup now,with the bov cracked at idle is the best it has performed as far as less fluttering and more "whoosh". i could probably put a washer/shim in and have it closed at idle with the same or similar performance. I was running the bov with 4 washers last summer(more spring pressure) and i don't recall it ever fluttering. Not sure what has changed. i'm just looking to see if there's a stronger source for vacuum for a possible faster response. the car is running extremely well, i don't suspect any vacuum leaks. but i will look.

[3.4grapeofwrath]

Re: vacuum sources\compressor surge

Bov should be closed at idle. I would be concerned about dirt coming through the bov since you now have a fresh air opening in the intake side. The vacuum source for the map sensor should have it's own line. The wastegate boost line should be connected to the intake manifold to get a more accurate reading. Coming off the turbo directly will always give you a higher boost reading.
I like to add vacuum/boost fittings on the intake.

[thebeewantsboost]

Re: vacuum sources\compressor surge

i know that about the wastegate. but theres not alot of vacuum sources on the intake from the factory so it seemed like a better idea than tee'ing more off the map sensor. i read something somewhere about wanting the waste gate on a boost only source. but the closer to the intake the better to make up for any boost drop after the intercooler.
Theres a block off plate on the top of the intake. i'm not sure what its for. and i've also blocked off my egr. so i think i'll be making a seperate vacuum source for the gauge and bov i read something somewhere about wanting the waste gate on a boost only source. but the closer to the intake the better to make up for any boost drop after the intercooler. Of course when i hook up a boost controller, as long as their is a reference thats consistent it doesn't really matter if its dead on accurate.

[thebeewantsboost]

Re: vacuum sources\compressor surge

so until just now i had no idea where our pcv valves were located. i thought the plate on top of our intakes was just something because of different models of our engine in different vehicles. i had thought about using it as a vacuum source but it looks to get a lilttle oily. i'm not sure if we actually need the pcv valve installed or not since our turbo cars are using breathers and have the pcv blocked off at the intake. think im going to just use the egr port, that i blocked off that should be sufficient right?

[thebeewantsboost]

Re: vacuum sources\compressor surge

egr port worked like a dream completely fixed my compressor surge. just made a new plate out of 1/8" steel tapped it for a 1/4" npt fitting to 1/4" barbed.
i added 2 washers and may add another to the bov. it sounds pretty bad ***. and its soooo much fun driving it again.

[3.4grapeofwrath]

Re: vacuum sources\compressor surge

Glad it worked out for you. Watch you don't add too much pressure to the bov spring. You want the bov to open up just at zero boost or zero vacuum to protect the turbo from back pressure.