^^^ what… it’s the right opinion , not just ‘an’ opinion…
where whould you put a BOV and please explian your reasons for it…
Why don’t you explain your reasons since you are positive on which side it should be. I never in my post said where it should go, I just stated that’s his opinion since the topic of BOV placement has been argued over and over and there are pros and cons for both. But in the end it doesn’t really matter because it works perfectly fine both ways.
your BOV needs to be adjusted to the amount of vaccum you have at or near idle… it can only be done with a vacumm gauge tool… its easy to do…
otherwise it will not work right…
I have the tools up at ORF, if you want to come over in the spring…
^^^
Can I have this post bronzed or in some way e-laminated?
I think hell just froze over LOL
^^^
Can I have this post bronzed or in some way e-laminated?
I think hell just froze over LOL[/quote]
its true, so many kids on here have no clue what they are talking about!
I see a lot of bullshit but no discussion as to why exactly cold side is better placement than hot.
I also remember “to lazy to search” that BAS stated in a post once that IF you do place the BOV on the cold side that you must mount it a proper distance away from the TB as it could effect its funcition if mounted to close to the TB ?
spd-dmn wrote:
I see a lot of bullshit but no discussion as to why exactly cold side is better placement than hot.I also remember “to lazy to search” that BAS stated in a post once that IF you do place the BOV on the cold side that you must mount it a proper distance away from the TB as it could effect its funcition if mounted to close to the TB ?
care to explain???
Pressure difference.
Your throttle body closes.
Your BOV vents.
Your piping is only vented from the BOV to the pressure source (ie the turbo)
If you put the BOV on the hot side, when it vents, your intercooler and cold pipe will not vent well.
Since the motor is not under load, it is no longer filling your pipes with pressure (boost)
The pressurized air in the piping/intercooler will try to move to the low pressure zone (where the air has been vented)
You get back on the throttle, TB opens, and the turbo has to overcome the pressure difference.
If you put it on the hot side … it will be louder.
:dunno:
I’ve heard that supposedly, some guy in Japan at some point tested his Skyline, and got an extra like .5 psi of boost by mounting the BOV on the hot side. But all I’ve heard is the rumor, repeated in a hundred different forums … strangely no one can explain why.
I guess if you’re pushing weaksauce 7 psi through an intercooler the size of your front fascia, you don’t want to have to fill that giant IC again, so by putting the BOV next to the turbo, you’ll actually be able to hear it.
6-14" from the TB seems to be the best location to let the BOV do its job.
what we should do this summer
is hook up my EMS to log boost and RPM
leave the bov on the hot side and do 3 passes down the strip
put it on the cold side and do 3 passes down the strip
compare the 2-3 and 3-4 shifts in each pass and measure the time it takes for boost to come back up on each shift
average the shit
and see if we have bullshit or fact.
I think that sounds like a good idea
Also wanted to mention that if the “cold side” was such a better location then would Nissan not have mounted the BOV there as its stock location rather then on the hot side ? (usually the manufactures R&D is up there) I’m sure they didnt just say you know what… likes stick it here!
also greddy puts them on the Hot side.
… because everything else is PLASTIC and moulded into a space that leaves no room, the hot side pipe between the turbo and pipe going to the SMIC is an easy spot and the only place to put an aftermarket part… that’s why you see blitz and others put it there.
The reason (s) why you don’t put a BOV on the hot side;
it puts the BOV in between the TB and the IC, the IC passeges are very soft alloy and it is brazed togher with the fins and end plates… aluminum solder is not strong the sum of the parts hold the unit along with the strong top/bottom backbones and end tanks. ( in whatever form).
If you place the BOV on the hot pipe side you are allowing a considerable ammont of pressure cycling to occour in the metal that combines with the heat cycling between running temps and cool down will cause the joints to fatigue and crack. as your boost goes up, so does the pressure spike when the TB closes. IF the BOV is infront of the IC on the cold side pipe. then the build up of pressure is released before it gets to the IC…
Hot air, compared to cold air requires more volume for the same ammount of air molecules; this can cause piston creep/bypass as the aluminum expands at a greater rate then the brass or ferrous piston. As Heat changes from BOV setup conditions this will cause the piston to flutter. as the hotter air has expanded putting ‘+’ pressure condition ont he piston. compared to the cool side
However too close to the TB and you run the risk of blowing too soon, the added build up of pressure in the IC piping acts to refil the manifold quicker reducing the apparent ‘lag’ conditions. Unfortunately in some setups like the 240 FMIC with batter placment still up front, the placement of the BOV, so it’s within reach… is a bit close to the TB for my liking… however, the setting the BOV spring to a bit firmer setting does help in this condition. V mounts I don’t worry about as the ‘lag’ conditon is almost non exsistant in the IC / IC piping short run system.
Check out an OEM SMIC … the BOV is on the cool side… aftermarket wise… they probably said that “it’s the only place we can put it…”
Most companies put the BOV ont he cold side… Subrau went so far as to put it ON the cold side tank of the IC becuse thiere is no pipe betwen TB and IC however there is more then enough space to put it on the hot side. Given a chioce the BOV will be on the cool side.
the way I always pictured it is that when you close the throttle plate that rush of air stops and starts to build up pressure starting from the tb slowly moving towards the turbo
in the case of the bov on the cold side the it doesn’t allow the rest of the system to fill up with this stagnant air. on the hot side the whole system needs to pressurize before reaching the bov
although absolute pressure isn’t increasing in this case I think it’s bernoulli’s principle or something like that which stats that the faster a fluid (in this case, air) is flowing through a pipe the less pressure it exerts on the pipe itself… you know… the same idea that makes planes possible.
so when you’re wot there little is pressure on the actual ic system because of the flow or air while with the plate closed there is no flow.
but going back to the flutter. no bov that I’ve ever heard of makes a fluttering noise, any flutter is definitely compressor surge. your bov is probably cack. and I wouldn’t recommend taking it apart. if it in fact is diaphram you’ll destroy it; you’ll never get it to seat properly again.
it should have a screw on the top that allows you to adjust from soft to hard, are you sure you got a true megan and not a replica ie didn’t meet megan racing quality standards so some baught their trash and is now reselling it?
and if it is a true megan racing bov then you probably aren’t running enough boost to get it to open. also, with your thumbs work the piston a little bit it; could be stuck/stiff from sitting on the shelf.
i had this problem a while back. if you have vacuum, if you have no other vacuum leaks (usually this will cause a weird funky blow off), if you’ve tried adjusting the spring…
then it’s time to open up the bov if it’s a diaphragm type bov, and check the diaphragm for rips. this will greatly impact the bov’s ability to open.
luka: i dunno about the megan racing bov, but why do you think the diaphragm won’t seat properly? usually the screws that hold it down are the reason to properly seal the diaphragm when they’re torqued down
Because a lot of knock-off companies use cheap diaphrams that are not oil or heat resistant. The diaphram gets brittle and stops doing what it’s supposed to, especially if the BOV is at about -10ºC when you fire it up. Heat cycling anything is a good way to fatigue it.
And paper power is a weak reason to bother trying.
Whether or not it makes 1/3 of a cunthair worth of spool, or 3/5s of an asshair worth of horsepower isn’t really what should be the issue here.
If you found 15 hp, then it would be worth it. Anything under that becomes very irrelevant.
BOVs are primarily used to reduce stress and damage to components. Everything else is just a bonus.
My S12 didn’t even come with a BOV or any kind of bypass valve. So I wouldn’t be inlcined to agree that the OEMs really know best.
turbozee,
it’s like a condom… you can only put it on once… and you should never buy it used.
mr200, BOV’s were made for reason… same reason why each car after the s12 came with a bov…
then there is a the question whether to vent or recirc… you can argue both ways.
ok so the BOV is brand new bought off of varun did he sell me busted product…lol like how do i tell when i rev at idle i can feel the air coming out but i always get flutter. the BOV only wrk at higher rpm so when i really give’r, which i prolly should’nt do, i dont really hear the flutter because the BOV is opening up properly almost…so how do i tell if the BOV is bust and prove it to the seller…and i know varun stands by his products he sells…so wut do i do…lol thanks guys for all the imput.