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compressor surge and BOV problems

5035 Views 45 Replies 17 Participants Last post by  Black Stallion
well, guys, some of you may have had the "gobbling turkey" no matter how soft you adjust your BOV. i have a solution.

if you have all your turbo accessories running off the same vacumm port, you are asking too much of that one vacuum line.

here's what i did:

Bought a 3 way 1/8" NPT female T from Pep Boys in the "Help!" section.
Bought 2 3/8" barb to 1/8" NPT fittings
Bought 1 1/4" barb to 1/8" NPT fitting.

i assembled the fittings so that the 3/8" barb fittings are on the top and bottom, opposite each other and the 1/4" is sticking out the side. i then ran some 5/16" vacuum hose (aka windshield washer hose) directly to the BOV, and the other 2 were plugged into the brake booster. so, basically, you T the brake booster and the BOV together. this makes it so that you only are feeding 2 things with this vacuum port, and the fact that it is a giant 3/8" hose, you arent taxing it by putting the BOV on there. this is an easier solution to trying to drill/tap the manifold, as that pretty much requires removal.

now, my previously impossible to open GReddy Type R blows off quite easily, with a satisfying "whoosh" instead of the turkey gobble.
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are you losing any power braking ability?
I was actually thinking about ordering one of the vaccum blocks that alot of the honda guys run and run it in-line with the brake booster hose. You really shouldnt have any issues with braking, seeing as it is a closed system and the extra volume the BOV housing and additional hoses add is next to nothing.
yeah, this wont affect braking. as long as it doesnt leak.

besides, under boost, you arent boosting your brakes anyway.
WOW...Thanks...i actually do have the wastegate and BOV on the same line!!! I'll fix that!!!! Thanks again
My hks ssq valve just flutters, or thats what it sounds like, i dont really know if its a problem. The ar drives great and doesnt stall, and it makes good power.

Any suggestions/ideas?
I had the same issue with my ssq hks, no matter how I adjusted it it sounded like it was sneezing rather than a continuous whoosh. I swaped it out for a greddy type-S, which is a lot quieter so I'm not sure if it's fluttering but I'll have to try HotshtSR20's suggestion to see how that works. I was always wary of having my wastegate, bov and boost gauge on the same vacuum line. I was also thinking of getting a vacuum manifold to run all those littel lines off of
HotshtSR20 said:
well, guys, some of you may have had the "gobbling turkey" no matter how soft you adjust your BOV.
lol :tongue: ......ive heard it before....a lot of turbo'd cars sound like that. i drilled and tapped my IM and ran a barb'd fitting/line for my tial bov. works great, even with a "stiff" spring in the bov.
this is a good idea do you have any pics of this setup? i need to do this with my greddy type r bov. it always flutters under low boost. i need to cut the spring in there also when i get a chance and a "c" clamp pliers

LOL.... i like the turkey sound effects :)
HotshtSR20 said:
well, guys, some of you may have had the "gobbling turkey" no matter how soft you adjust your BOV. i have a solution.
yeah i use vaccum blocks on my customers cars

its right behind the intake manifold in black
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ooooh, vacuum blocks... looks nice.

Where can I pick some of these up?
so if i have a vacumm block spliced into my brake booster vac hose then i can run my BOV,WASTEGATE and Boost controler supply vac from there??With no worries?? I wanna get rid of this surging before i do damage, not driving car now so it would be nice to get this done ASAP. Thanks Tom
i have em, i need to devise a price for them however. will be avail next week or i might just give you guys some part numbers if you're nice enough hehehe
Dist. block

I posted this a while back when I was doing my turbo install. Here is a pic. of my setup, the line on the far left comes directly off the intake manifold it works perfectly.

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Could it be making that noise because its so close to the TB? I have it on its own vac line coming straight from the intake manifold. Or is the spring in it just to tight for low boost?

At higher boost (11-15psi)the fluttering sound just gets louder. I never tried adjusting it though.

I am gonna mount the bov further from the tb this spring when i have the IC piping made for my pwr water to air IC.

it's been posted before, but has the vacuum manifolds in many different styles and you can get all the fittings from them too
yes, but with a vacuum manifold, you are still running into the same problem. vacuum must be applied to the entire line and the boost must first be sucked out of it before vacuum will hit the BOV. you will still have a delay. you will still risk having compressor surge, esp with some of the harder to open BOVs, like the GReddy Type R.

i posted this as a solution to all of us with the gobbling turkey noise (some louder than others) as this can kill a turbo FAST. You NEED to segregate the BOV and other turbo vacuum/boost lines. i used to have something similiar to a "vacuum maifold" basically, a 4 way brass split with 1/4" NPT fittings and had about the same internal volume as the vacuum manifold. you'd swear there was an ANGRY thanksgiving turkey under the hood, as 20 psi of compressor surge isnt too subtle sounding.

oh, as an amendment, dont forget to hose clamp the vacuum fitting of your BOV, otherwise you will have a nasty boost/vacuum leak because the 5/16" line is larger than your BOV fitting. also, its a 3 way 1/8" NPT fitting, i fixed that too.
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I guess mine is different in that the only thing srun off the dist. block are the charcoal cannister, BOV, and boost gauge.
thanks for the info HotshtSR20. I guess I'll have to get under the hood and redo some of my vacuum lines. I presume I can use the vacuum manifold for all other lines of the intake manifold, for example, and just have the vacuum line for the bov run off the brake booster line?
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