To BOV or Not to BOV! [Archive] - calaisturbo.com.au

1ShyVL

08-10-05, 16:51

Hey guys :)
Firstly, thanks for reading and any advice! :)
I am getting my new intercooler piped up in the next 2 weeks... I got a turbosmart type 3 supersonic BOV (got it with the car) and im wondering if i should ditch it when i get this new piping put on?
Will it damage the turbo without having one? (its a highflow turbo)
And ALSO... what are the positive and negative affects of having the AFM in the cooler piping?
Thanks for any help :)

DarkJedi

08-10-05, 17:43

Having the AFM just gives you better air flow to the turbo.. to it doesn't shutter and when you back off at boost (think thats a good way to explain it).. if i where you ditch the BOV, sell it to a mate .. or even on here..

Miz_VL_Turbo

08-10-05, 19:30

ah the BOV vs no BOV argument again, it all comes down to personal preference and what you think works, everyone will tell you a different story based on their opinion, if you want to sell the type III i will buy it.

1ShyVL

08-10-05, 19:31

Im not after peoples opinion if i should have it or not.. im trying to find out if it will do any damage to my turbo if i dont have one..

Miz_VL_Turbo

08-10-05, 19:51

you didnt read what i said, based on previous debates everyone will tell you something different, therefore it is their opinion, do you understand what im saying? From personal experience, i would not run my vlt without a BOV. When the compressor is spinning, when making boost, and you take your foot off the throttle, the butterfly shuts, and thus the compressor surges because of the air in your pipes that has no where to go - it can damage your turbo, more so when the compressor is spinning faster, but others believe it doesnt do any damage to the turbo at all.

1ShyVL

08-10-05, 20:00

I was thinking the exact same thing Erin :) Thanks for the reply. It sure makes sence :)

duz360

08-10-05, 20:18

in am manual car the compressor will slow down when changing gears with no bov.
i recommend the bov

furryfrog

08-10-05, 20:24

Morgz

08-10-05, 22:02

personally i wouldnt go the BOV but it all comes down to what you want.

people will tell you the turbo is going to get stuffed without one, maybe put one on if you plan to run big boost.

there are many vlts that are running stock gear with no BOV.

There are a lot of high Hp cars not running BOV's as they can be prone to leaking at high boost..

I can't say I have personally known anyone breaking a turbo coz a bov was not fitted..

Krieger

08-10-05, 22:11

VLB-57A

08-10-05, 22:48

my personal opinion is that you should run a bov, but plumb back of course which im sure you realize is necessary for a car with an afm. think of any pressurized system and you will notice that they all have some way of venting excess pressure, so why should your intake be any different? the pressure has to go somewhere, and that is back through the compressor, causing cavitation which is no good for any kind of pump. you say it probably wont do any damage, but at a very minimum the compressor will keep spinning freely giving you faster wind up when you get back on boost. at least it gives you some peace of mind that if there is any damage that could occur from it, then you are already preventing it,.. if you get me.

-jimmy

Why is it necessary to run a plum back bov when running an afm?
Also, you say bov's prevent cavitation? How does this happen in a turbo?
I know cavitation can happen in power steering pumps, water pumps,any type of hydraulic pump, that is a "spinning" pump, but how could you get cavitation in something that only has air running through it such as a turbo does?

Not trying to be a smart arse, just intrested for my own learning/curiousity.
Cheers, Brad.

RB26DETT

08-10-05, 22:58

If your going to use a BOV, why not get one of the ones that you can swith between venting and plumb back?

david85dc

08-10-05, 23:15

bov not required. if a turbo can last 17 years of thrashing, and then u rebuild/ highflow u wont need a bov

sure in a manual when u take ur foot off the compressor it slows down, but it wont spin backwards. the turbo will always be spinning foward even on idle.

the amount of damage it does when not running a bov is very very minimal anyway. just dose it man

Torcida

09-10-05, 06:45

what about ppl who own External WASTEGATE setup on their manifolds ?? do we need bov ?

7FOUR7

09-10-05, 10:14

i dont run one with my xtrnl gate

ATMO_BT1

09-10-05, 10:34

in theory you need a bov, but in reality no one has actually ever said in one of these arguments that they ACTUALLY know someone who blew up their turbo due to not running a bov.
I dont run a bov, 15psi and neither did the owner who had it for 10 years before me and no dramas (highflow t3).
For piece of mind, if you just HAVE to, then run a bov....my plan is (because i looove the dose lol) to run no bov with my highflow and if it does ever blow up then il just upgrade to a gt35, then run a plumb back bov (none of that psssht bull****) that is wound up nice and tight so that it only kicks in at say 15psi....so i can still dose it up on 5 or 10 or whateva.
The reason for me wanting a plumb back bov with the gt35 is because to me, with an expensive turbo (as opposed to a run of the mill highflow t3), it is worth it for piece of mind as ball bearing turbos such as the 35 spin much more freely and hence i believe in my opinion that compressor surge would be much more damaging to one of them as opposed to a sleeve bearing turbo such as the vlt t3.

my 2c, Jack

Midz

09-10-05, 10:53

I know someone who has blown 3 turbo's with an innocorrectly functioning bov.

Well I don't know if that was the cause, but 2 blew then he removed the BOV and found it was stuck replaced it with a new one and no more turbo problems?

That was 1 2nd hand turbo and the other 2 were brand new.

I got a bov and its the illest out bro, seriously.

ATMO_BT1

09-10-05, 10:57

I got a bov and its the illest out bro, seriously.

haha funny as, you coming on the cruise mate?

Krieger

09-10-05, 12:14

Why is it necessary to run a plum back bov when running an afm?

because your dumping air that is already measured by the afm. if you dump it to atmosphere, then the computer is adding fuel for air that is not there so you get overfuelling and stalling.

I know cavitation can happen in power steering pumps, water pumps,any type of hydraulic pump, that is a "spinning" pump, but how could you get cavitation in something that only has air running through it such as a turbo does?

forcing air back through the compressor the wrong way.

-jimmy

88vl

09-10-05, 20:31

wat would happen if u had the afm after the bov..like have the afm right next to the trottle body..and have the bov back further say 300mm or wat ever..??

Petros

09-10-05, 20:55

its just w@nk factor unless you are that paranoid - have it recirced

1ShyVL

10-10-05, 07:25

Ok i think im going to go NO BOV and see how it goes and i will hold onto the BOV incase i wanna put it on further down the track...
What is everyones thoughts about the AFM in the intercooler piping? i heard people say its ok, but reduces the life of the AFM :S

FRCED-6

10-10-05, 08:09

pannic runs 32psi... doesnt run a bov :)

david85dc

10-10-05, 09:12

if u really care about ur turbo, get a plump back

i got some loud bov on my new vl and let me tell u, there r sh!t i wish it wasnt there

ATMO_BT1

10-10-05, 11:06

haha dave you BOV wanker!

LTHLRB

10-10-05, 12:25

pannic runs 32psi... doesnt run a bov :)
although he does run a bleed valve.

david85dc

10-10-05, 13:12

how u get a bleed valve to hold 32 psi without spikin?

Krieger

10-10-05, 13:23

wat would happen if u had the afm after the bov..like have the afm right next to the trottle body..and have the bov back further say 300mm or wat ever..??

you would get a lot of reversion through the afm causing rough running and stalling.

Proph

10-10-05, 13:48

pannic runs 32psi... doesnt run a bov :)

i also think he's probably using a different turbo to a T03, and is expecting rebuilds more than us anyway with it being a purpose built drag car and all.

furryfrog

10-10-05, 17:44

if u really care about ur turbo, get a plump back

i got some loud bov on my new vl and let me tell u, there r sh!t i wish it wasnt there

haha why lie for di(khead you vent that thing every chance you get. playin musical notes and all, think you're so good with the auto.

:p

VLB-57A

10-10-05, 18:59

because your dumping air that is already measured by the afm. if you dump it to atmosphere, then the computer is adding fuel for air that is not there so you get overfuelling and stalling.

forcing air back through the compressor the wrong way.

-jimmy
Ah ok, fair enough.

Krieger

10-10-05, 23:57

no prob

251NFL

11-10-05, 01:01

id go bov that way u get a nice flutter which ends in a big bang LOL :)

nah in all honesty runnin high boost i have been told to run a bov...and on big turbos ie gt3540 run 2 bovs

ATMO_BT1

11-10-05, 01:17

haha why lie for di(khead you vent that thing every chance you get. playin musical notes and all, think you're so good with the auto.

:p

busted!

HYBRID VL

11-10-05, 04:06

look all turbo cars have some sort of pressure releif vavle its just not made as noticeable as a big whhhhooooosh you dig?

i dont really like cause round here every man and his wrx has 1 and its the most anoying piece of craftsmanship machined metal that has sold millions and is a waste if you ask me get a plumbacksame thing no noise.

i have a HKS BOV i wind it so it dosnet open.

FRCED-6

11-10-05, 07:11

i also think he's probably using a different turbo to a T03, and is expecting rebuilds more than us anyway with it being a purpose built drag car and all.

ye, nah thats understandable, like the car was built mainly for track