Jump to content
SAU Community

Recommended Posts

Is it better to block it off at the base of the intake hose or at the end of the recirculation pipe?

and if the recirculation pipe is the way to go were should i Mount/hide/place it so it dosnt look in the way or stupid?

cheers :D

Link to comment
https://www.sau.com.au/forums/topic/284525-diy-bov/
Share on other sites

Step 1, undo rubber recirc pipe and remove from BOV.

Step 2, insert plastic softdrink bottle lid

Step 3, reconnect rubber recirc pipe to BOV.

Or if you don't like that, remove the BOV, trace and cut out a piece of sheet tin, reinstall BOV with sheet tin sandwiched underneath it.

Both methods look factory and undetectable without tools.

Link to comment
https://www.sau.com.au/forums/topic/284525-diy-bov/#findComment-4786501
Share on other sites

If I were to cut out a metal 'gasket' like you described Luke, but then drilled a few small holes in it, would that essentially allow for flutter at low RPM, but it would still dump properly when boosting? I remember being told this by several people, and saw it on the net somewhere ages ago but can't for the life of me find any information about it now.

Quite keen to do this actually.

Link to comment
https://www.sau.com.au/forums/topic/284525-diy-bov/#findComment-4786776
Share on other sites

If I were to cut out a metal 'gasket' like you described Luke, but then drilled a few small holes in it, would that essentially allow for flutter at low RPM, but it would still dump properly when boosting? I remember being told this by several people, and saw it on the net somewhere ages ago but can't for the life of me find any information about it now.

Quite keen to do this actually.

No, you're essentially disabling the BOV by doing there, there's no way for air to be released from the cross over pipe back into the intake side of the turbo.

If you want that low RPM flutter but still a BOV that works, go get an aftermarket plumb back bov and tighten it till it flutters at low rpm but still releases pressure at higher rpms.

Link to comment
https://www.sau.com.au/forums/topic/284525-diy-bov/#findComment-4786914
Share on other sites

Ive searched heaps but am still unsure/confused,

Can someone please clarify for me the pros/ cons of blocking that tiny little 5mm hole with a flush screw on the inside base of the stock r33 (rb25det) BOV

Thanks :)

That hole is there to aid smooth transition from boost to vaccum and vice versa. i.e. smoother transition between acceleration and deceliration. When blocked, the transition is a bit harsher.

Thanks for the info guys... is there a way of modifying the stock BOV spring to increase tension? Yes I'm being incredibly tight-arsed hahah

I've heard of people squashing the top of the BOV to increase the resitance of the spring.....but it's far from perfect.

The piece of material (more commonly steel or alloy) cut to shape and sandwiched bewteen the BOV and the intake pipe flange would be the most suitable and most effective sollution. blocking it fully will cause deceleration/idle issues with any AFM engine..........of which the RB is one.

Link to comment
https://www.sau.com.au/forums/topic/284525-diy-bov/#findComment-4787531
Share on other sites

I tore up a beer can and stuck a piece under the BOV on mine with a bit of gasket goo, easy done.

Best way to block the stock BOV imo... beer can, coke can whatever you like... trace it out then cut it out with scissors and a hole punch and bolt it back up. perfect.

I wouldn't bother with the holes in it though. have the BOV or don't have it.

Link to comment
https://www.sau.com.au/forums/topic/284525-diy-bov/#findComment-4791548
Share on other sites

Thanks for the info guys... is there a way of modifying the stock BOV spring to increase tension? Yes I'm being incredibly tight-arsed hahah
That hole is there to aid smooth transition from boost to vaccum and vice versa. i.e. smoother transition between acceleration and deceliration. When blocked, the transition is a bit harsher.

I've heard of people squashing the top of the BOV to increase the resitance of the spring.....but it's far from perfect.

The piece of material (more commonly steel or alloy) cut to shape and sandwiched bewteen the BOV and the intake pipe flange would be the most suitable and most effective sollution. blocking it fully will cause deceleration/idle issues with any AFM engine..........of which the RB is one.

*sheepishly puts up hand

i did that. combined with putting a screw into the hole that jase also mentioned you got a bit of a flutter when lifting off from light throttle. but it was only like half a flutter. it was sort of a FFFT FFFT FSSSSSHH. so it fluttered once or twice then just dumped as normal. if you do decide to squash it in, you sit a socket on it (i think about a 21mm is about the right size) and then give it a few gentle yet firm hits. be warned that you can squash it too much. it is best to measure the height of the hat before you start so that after each hit you know how much you have squashed it. you only need to squash it a few mm.

other than that, if you want the full hektic flutters then you need to go aftermarket bov.

Link to comment
https://www.sau.com.au/forums/topic/284525-diy-bov/#findComment-4792023
Share on other sites

The best way as said is to stick a gasket of whatever coke can in between and you can leave the other hoses running on it to make it look stock, stalling wont be to bad just the only problem is if u for example take off in gear one den dont shift and dump the clutch itll stall but adjusting driving style can elimnate the stalling or raise your idle by a couple of 100 revs

Mine has never stalled with the BOV blocked off.

Link to comment
https://www.sau.com.au/forums/topic/284525-diy-bov/#findComment-4792640
Share on other sites

The best way as said is to stick a gasket of whatever coke can in between and you can leave the other hoses running on it to make it look stock, stalling wont be to bad just the only problem is if u for example take off in gear one den dont shift and dump the clutch itll stall but adjusting driving style can elimnate the stalling or raise your idle by a couple of 100 revs

Link to comment
https://www.sau.com.au/forums/topic/284525-diy-bov/#findComment-4792555
Share on other sites

Thanks for the info guys... is there a way of modifying the stock BOV spring to increase tension? Yes I'm being incredibly tight-arsed hahah

I have one of these, i squashed it in the vice and concaved he top in. Flutters on light throttle back off. I got sick of it and took it off. I'm willing to give it you for the price of postage :P :P PM me if you want it

Link to comment
https://www.sau.com.au/forums/topic/284525-diy-bov/#findComment-4793684
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Welcome to !
    • As I've said elsewhere, I am using the stock intercooler piping path in the engine bay, and a return flow cooler, and making ~250 rwkW (without any effort put into trying to turn it up past there just yet) and expect to be able to make some more, and frankly, I would be perfectly happy with 260-270rwKW. This is peak road Skyline usability territory. You go past there and, sure, the car will snap necks more when it's on boost, but it will also break shit all the time, cost a (even larger) fortune in tyres, etc etc. Anyway, I also do not like the over-the-fan pipe path, and you don't have to do it.
    • I see, honestly I’m not too fussed about the looks. The only reason to go plenum is to make the piping easier instead of the classic over the rad etc. 
    • Not easy to quantify wrt something like how many fractions of a second slower it would be over 0-100. But given that a 250-300rwkW car is able to do that launch sprint in 5-6 sec (and faster with appropriate tyres, and surface)..... giving up as much as a second would feel like torture. A ~450HP capable turbo is not going to make lots of boost in the 2000-3000 rpm range. So, whilst with some boost on hand it will be faster accelerating in that rev range than your engine currently is NA, it will not feel like a fast car until the boost is solidly in. You know what your car feels like right now when you open it up at 2000rpm. if you've ever been in an actual fast car, you will appreciate that the NARB25 is.... not exciting. Well, add some boost and it will be better. But shorten the intake runners and it might not be better at all. It might come out better, but it could end up feeling the same. For me, it's not the 0-X km/h sprints that matter. It is easy to fry the tyres with anything over 200 rwkW. You can't use all the power available in 1st and 2nd anyway, you have to modulate the throttle. What matters is how the car reacts when you're driving in traffic in 4th or 5th and have maybe 2000 rpm on board, and you want/need to add some speed quickly, and don't have time for the downshift. It won't make boost, it will be all NA (at the speeds we're talking about - remember how fast you're going at 2000 in 4th! and don't plan on breaking the limit by too much.) So giving away NA torque is not what I would consider practical for a street car. And retaining that NA torque builds boost faster which makes the car faster. The flashy plenum is not actually better, unless you're looking at a track car where you can keep it on the boil all the time.  
    • So how much difference does it make you think? Like 1 second in the 0-100?  I was have smaller turbo so hopefully that spools quick GTX2871.  currently it’s NA so you can imagine pretty slow, but I do want fast accusation a little as there’s not many places I’ll be driving where I go over 80 even near me. So 0-60 and 0-80 targets   
×
×
  • Create New...