bov actually do any thing?
 

besides the ever delightful swish noise that is delivered from the contraption......does it do any noticable or signifigant work?......i didnt care.....i bought the hks SSqv (super Squeak) --but honestly......wats the deal....show me i did good in buying it.....:D

If you have a stock turbo there wasnt really any point in buying it for anything else then just makin people that dont know anything about FD's, look at you funny and say what the fuck was that noise. Belive me, when i came to this one guy in a mustsang and let my BOV go he said "Woah buddy ez on the shifting" But if you ever plan on getting a bigger turbo (with more boost) you will need it.

Do a search on www.ausrotary.com.au for bov's and you will see many arguments...sorry discussions have risen about this apparently required device....

your site doesnt work:mad: lol....o and to the guy with the first post.i dont have different turbos or a single conv. but i do have the bnr stage 1 upgrade...clipped fans n watnot

The function of a BOV is to save your turbos when you shift. Generally when shifting a turbo car with a manual transmission, you take your foot off the gas pedal which slams the throttle shut. The turbo doesn't immediately run out of boost, so excess pressure builds up in the intake pipes which can make its way back to the turbo. If this happens often, it can shorten the life of the turbo. What a BOV does is when the throttle is slammed shut under boost (i.e. you shift while there's a decent amount of acceleration required) the valve opens up to relieve the pressure in the intake pipes thus preventing it from building its way back to the turbo.

The FD has a BOV stock. It works just fine without making any discernable noise. There is a way to disconnect a hose that will make the characteristic Fast & Furious™ BOV sound. However this does nothing to increase performance and only announces that your car is not stock to others on the street. It might get a couple of oohs and ahhs from the crowd of teenagers at the local Starbucks but in the long run it's kind of pointless if ya ask me.

try this http://www.ausrotary.com/ look for ... no bov

Plus stock BOV's are not messy. Disconnect the hose or add an aftermarket and you will have a nice mess of oil all over everything around it in the engine bay.

ahh much better..seems im a moron and for got the au thing was there.......got my thinking cap on backwards i guess:withstupi

actually not when you shift just when you let off the gas, but this mostly happens when you shift at higher rpm's. It protects the turbos from compressor surge which is when the intake pressure goes back on the turbo compressor and stops it suddenly causing serious damage to the turbo internals. That is why you have a bov, now as to why you upgrade, its mainly for when you start setting your boost levels higher. You can run stock turbos and still NEED an upgraded bov, like when you start boosting really high as in 20+ pounds because the stock bov can't handle those high boost levels for that long (they will fail in other words). But I don't know if this is possible with stock twins, is this even possible on the bnr stage 2 or even 3's to boost to 20+? Anyone know?

yeah 20 psi is doable on stage 3s
spoautos is running 19 daily on pump gas
he was doing fine with a stock bov

remember 19psi on twins is not the same as 19 on a big single...it flows a lot more air

ive never seen a bov wear out or break...usually the problem is that it cant flow enough raw air out but the stock ones are very very good so i see no need for an upgrade unless you have a single turbo

Are you guys simply disconnecting them, because i did that today and i love it, because i am easily amused, but i would like to support them somewhere somehow so they are not just layign there. What did some of you do?

Except to the cops in a smog-nazi state. Any intake mod, even disconnecting the stock BOV hose from the stock airbox, can get you unwanted hood-up attention from the local Po-Po. Trust me.
:mad:

what if im going to upgrade to single turbo but dont want a ricey high pitched whoosh... i just want the stock breathing sound!

You could still use the stocker if you welded a bung for the piping somewhere on the intake track. It'd look kinda weird, but it'd work.

you can always feed it back to the intake like a stock one... this will keep it relativly quiet.... im planning on doing this

Oil in the intake to the point that it spills all over the place, is usually a sign of a turbo gone bad.. so Unless you stick your BOV at the lowest point on the hoses, you souldn't get all messy... and the Woosh sound is tuneable, and even Elliminatebale, via a recirculation pipe from the BOV back into the airbox...

Messing with you intake is concidered bad in Cali, the thing taht you can argue in court, if you're armed with the knowledge and not just talking out of your ass... is that a BOV, vented to atmosphere will change the Airflow to the engine, the thing is this engine used a MAF sensor and therefore reads Airflow, to adjust it's tune, and therefore will compensate automatically, unlike other systems...

That and it's going into the airbox, at which point it could make it's way back through the intake shroud, and back to the front of the car, (Theoretically) If going bcakwards under boost and you let off the throttle maybe :D

hmmm, i dont see how you could run 19psi on pump gas... shouldnt you end up with detonation because of the much higher compression ratio you are causing in your combustuin chamber? im just not understanding how you can run 91octane @19psi w/out blowing your motor. can anyone comment???

as far as the single flowing more air, im not sure if i believe that either (sorry for being such a skeptic)... if you are seing 19psi at the throttle body using a single turbo, and using some BNR stahe 3's you can also make 19psi at the throtle body (assuming both motors are the same etc) then your total air flow should be the same in either case, no?? if someone could comment i'd appreciate it. thanks heath

Even a brand new perfect condition turbo will get some oil blow-by. It is a very light mist that eventually builds up on anything that gets in its way. Venting a BOV will vent this mist and will cause some oil to build up no matter what, not to mention the environmental effects fo spraying hot oil into the air. This is why all stock cars from FD's to DSM's to Supras have a BOV that recirculates back into the intake instead of venting to atmosphere. Cars such as DSM's with a MAF instead of MAP could have been tuned to vent to atmosphere, but because of the oil in the intake the boost charge is just recycled back into the intake and the ECU is tuned to run that way.

I agree.

So the ECU is factory tuned to compensate for oil in the intake???

Only us poor Cali folk get the 91 octane gas.... :doh:
...besides, it's all in the tuning :doh: x 2

ugh... psi is relative

look at a garden hose

there is a nice steady flow of water.........

but u want more force b/c you tires on your car are really dirty.......

so u put your thumb over the end. This decreases the area and increases it's velocity which is realated to the force or "psi". It hits the car so hard it splashes on your shoes :(

The same amount of water is flowing through the hose. Just at a different psi.

a larger turbo has a bigger "hose" so it can flow more at the same psi.

It's all about the size of the hose my friends..........

but you cant tune out detonation. detonation occurs when your fuel mixture gets to a pressure that it can not withstand. thats why we have to run premium in our cars.... because it will detonate when the pressure increases (under boost). otherwise mazda would have just "tuned" the car to run at 10psi on 87 octane!!

as far as octanes are concerned, do other states have higher octanes for "premium" cause in CA the highest ive seen is 91. if so why is that?

that's what oil catch cans are for though.......

run the blow by through the filter

atmospheric bov should not vent oil - if setup for a recirculating bov it might.

the ecu thinks it has more air than it does (by recirc methods). That is what causes the flames at high boost levels :) I'm for the flames.

exactly my point a few posts up... if we are measuring the psi @ the TB for a single, and a set of twins that can both make 19psi @ the TB... then dont we have the same amount of air being pushed?

i dont think this is true if it is vented *before* the air flow meter like in the stock setup... then the air flow meter can register a change in flow and inform the ecu to compensate. heath

you can run crazy high boost levels.

some VW or sumtihg runs like 56 psi or sumthing.

detonation is great.......it makes my car move....pre-detonation makes my car not move.........

intake temps go up with higher psi.......Think of the compresses air bottle for your pc's........

when u use them they get really cold.......reverse the process.......

that usually is the killer and reason for not running high psi. That will cause pre-detonation easier since it's closer to the flash point.......

eh....

yeah could be RotorMotor

not sure on this density map bs they changed to.

some day i'll have the gumtion to learn it.

it works that way on a maf

That's correct you wouldnt' be running the same amount of air even though u have the same psi.

well if you tell me your running 10 psi i'm like ok...that doesn't tell me anythign about the CFM's.

but if you telling me ur running 10psi on a t88 i'm like......wow. That's a lot of air.

b/c 10psi on a T88 is more than those hitachi's are capable of putting out at the same psi.

just look at it like that.

i have to respectfully disagree good sir :biggrin: :wink: haha. think about it from the perspective of measuring all pressure right before the TB. If your seeing 19psi at the throttle body and all your intake piping is the same length/diameter after the turbo then you have the same flow of air... am i right? sure those hittachi's are screaming away, while the huge t88 blades are leisurely spinning away, but no matter how its made its still the same PSI. if a cow could fart into your intake and you see a sustained 19psi at the TB then you should have the same flow rate as the beloved t78.

EDIT: ah i may see what your saying.... your thinking about it as measuring the PSI right after the turbo.... maybe some stage 3's would have to register 22psi right after the turbo to make 19psi at the throttle body... but to have a constant measuerment of flow, think about measuring everything from the TB. if your saying that the hitachi's would run out of volume (cant mov enough air) then you would see your psi at the throttle body drop. BNR claims however that their stage 3's can cut it in the flow department, and i believe them. i think that a set of stage 3's would be better than a single cause you can make the same psi but spool faster. heath

i know this may be off topic but does anybody know if they make the turbo xs rfl blow off valve for the fd and how much does it cost and is it a kit or does it require welding

pv=nrt

If the manifold (volume) and intercooler (temperature) remain unchanged, then 19psi from twins or 19psi from a single is the same amount of airflow per minute, right?

You upgrade your intercooler in order to decrease the air temperature (and thus density) so if you have the same 19psi at a lower temperature, now you are moving more air than before, because it's more dense.

But should an upgraded intercooler create more lag? I think no... the psi may be lower because the density is higher, but you still have the same amount of air and thus same power. But with an upgraded intercooler you and same 19psi, now you have more air (power) than 19psi at a higher temperature (because of the air density).

ahhh....

Theoretical numbers:
Twins making 19psi at the TB: spinning at 10,000rpm
Huge single making 19psi at the TB: spinning at 5,000rpm

Now your turbo is not "working" as hard. Thus not as much heat is being generated, and thus being transfered to the intake air.
So, a single turbo at 19psi may have slightly higher density than the twins at 19psi, and thus more power.
I'm droppin' $3k on a huge single for the extra 10hp!!!

***highjacked thread***

Does the BOV do anything? No, you can just use a hose to connect them to each other... the air pressures will cancel each other out.:wink:

PSI = Voltage = Pressue
CFM = Amperage = Volume

2 different measures...

This also is proven by the fact that some people lean out in cold weather, because cold air is denser than warm air, even though Atmospheric pressure stays the same.. There is more Oxygen per Cubic Centimeter...

Dcrosby is right

the diameter of the hose effected the PSI (pressure) and the water was the CFM

or as he puts Voltage is the hose and amperage is the water.

that's why there' independand

P=VA

if you have a large voltage it takes less current for same power (small turbo high psi, low CFM)

but u can have a small voltage and a large current to do the same power (big turbo, low psi, big CFM)

but then again if there was a cow farting and no one was there.........does it really make a sound?

holy ass crap i started a nutty disscussion!

Ass crap might be a hazard in cow farting situation :rlaugh: :rlaugh:

detbryon.....ugh...u scared me with that damn formula....i thought i could for get that after my damn chemistry class

well from that i guess u can say then

p1v1=p2v2

this would relate the psi and cfm for the turbos

p=nrt/v

if you increase the pressure then u decrease the volume. Like squez'n a jar of air so you can fit it in your pocket.....i guess they call them air compressors nowadays.

anyway.....its' that damn conservation of mass that gets in my way........if i could break that law and create a friction less surface i'd be rich.

yeah all things turn to nothing in time

even intelligent ppl

are we talking about chemistry/voltages/bovs or was it washing cars? No wait....it was turbos......

nm......i forgot.

I don't understand what your saying at all with the voltage / current V=IR

CFM = volumetric flow = VA
V = velocity
A = cross-sectional area (TB) = constant

P1/d1 + (V1)^2 = P2/d2 + (V2)^2
P = pressure
d = density
1 = huge single turbo
2 = stock twins

If velocity increases, then pressure decreases. Like lift on an airplane wing.

But my colleague is telling me that even with same pressure, the velocity is still dependant on the suction velocity. So I'm actually just talking out of my ass.

I thought we were talking about Ass Crap and Cow Farts ! :D

Re: Nutty Discussion
I belive squirrel turds have come into the whole mix as well ! :rlaugh:

P= Power (Watts) (HP)
V= Voltage(Volts) (Pressure -> PSI)
A= Amperage (Amps) (Volume -> CFM)

P=V*A

Also Known as
P = I(times)E or P=IE
In this case P=Watts I=Amps E=Volts (don't ask)

The issue is that in reality CFM's are fixed, unless you change intake pipeing and / or Intercooler, etc... since all that has to do with volume...

And usually we change the PSI...

And what that formula states is that you can doubble the pressure and half the volume and still end up with the same amount of work done.. (power)

p1v1=p2v2

only holds true if the intake temps are the same

pv=nrt

so when i meant comparing the turbos i was talking at same temps too.

if the temps were teh same at the tb and the pressure was the same and the volume was.

yeah i'll buy it :)

gah!

u beat me to it.......but my computer restarted :(

i musta missed the squirel turds thing.

do they look like rabbit turds?

Yeah just nuttier :D

wow thats more physics than i care to know.

anyway here in jersey we have 92-93 octane.

huh.........

i guess u learn something everday.......

but then again.... i don't know why i would need to know the consistancy of squirel dung.........

but if i was a stranded and hungry........

Did we ever answer the question?
what was the question?

to end the thread...

the three reasons an upgraded BOV would be necessary...

1. defective stock BOV
2. you are using a turbo the size of an aircraft carrier
3. you want to make high schoolers squeel

If a blow off valve served a purpose... :D
As to the Consitancy of squirrel turds, it's a phrase, "he's nuttier than squirrel turds, I guess it's pretty nutty since, nuts are all squirrels eats" eh, humor is a bit tougher over the message boards :D

i debated on the mean of "nuttier".

but couldn't determine if it was to be witty or descriptive. I suppose it doesn't matter too much.

oh and to answer the question

do bov serve a purpose? ............. yes :)