# R35 "Blow off Valves" (BOV) hehehe



## Titanium GTR (Sep 27, 2009)

found this and thought it might make good convo, anyone got BOV's on their GTR yet? Do you just want it for noise? or performance? Personally i love the noise they make :clap:

YouTube - Go Fast Bits Stealth FX / Deceptor BOV on Nissan GT-R R35


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## Titanium GTR (Sep 27, 2009)

ohhh forge do some BOV's, they look so niceeeeee

"I want themmmmmmmmmmm"

Forge Motorsport | Alloy Fabrication


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## robsm (Jul 22, 2008)

Hope4Sun from Norwich has BOV's

Its OK, bit chavy though lol

They wont improve performance at all


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## Titanium GTR (Sep 27, 2009)

i dont care if its chavy sounds sweettttttt, i will make a GTR Chav mobil lol (Get a burberry wrap done on it lol)


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## Zed Ed (Oct 24, 2007)

Titanium GTR said:


> i dont care if its chavy sounds sweettttttt, i will make a GTR Chav mobil lol (Get a burberry wrap done on it lol)


and a nice blue light for underneath


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## _shaun_ (Jan 16, 2007)

LOL I think Steve has some of the Forge ones.....

Steve you a Chav?

I not heard them on the r35 yet, but think i'll like/want them lol


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## Gatling (Jun 16, 2010)

Leave these to the MacDonalds car park brigade!


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## GTRSTAR (Nov 26, 2009)

As far as Im aware the GTR has BOVs as standard, theyre recirculating not to atmosphere so they dont make the wooshy noise (which I think is cool BTW although it might get on my nerves after a while)

My BOVs have been removed all together, its supposed to improve something or other, only now I get this pathetic low level pu pu pu pu and the throttle response is like an on off switch, good for track not great for cruising..

Kev I want my BOVs back!


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## Mookistar (Feb 5, 2004)

nothing wrong with BOV's imho. They just add another dimension to driving.

they're fine

mook


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## Gatling (Jun 16, 2010)

Mookistar said:


> nothing wrong with BOV's imho. They just add another dimension to driving.
> 
> they're fine
> 
> mook


Atmospheric BOV's do add another dimension to driving, looking like a right tit!


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## Steve (Sep 21, 2001)

_shaun_ said:


> LOL I think Steve has some of the Forge ones.....
> 
> Steve you a Chav?
> 
> I not heard them on the r35 yet, but think i'll like/want them lol


Sh*t I have been sussed !! LOL Yes, I have some Forge BOV's ------err you understand that they are ready for the next big modification only (+ the lovely swoooooooooooooosh noise they make when you nail it in 2nd gear and come off the gas hard!) LOL


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## _shaun_ (Jan 16, 2007)

Steve said:


> Sh*t I have been sussed !! LOL Yes, I have some Forge BOV's ------err you understand that they are ready for the next big modification only (+ the lovely swoooooooooooooosh noise they make when you nail it in 2nd gear and come off the gas hard!) LOL


:thumbsup:

I might get these for the R35

I have a "pigeon" mod on my 200SX and love it!


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## andrew186 (May 3, 2010)

steve, how easily adjustable are the Forge BOV's?

and do you have a sound clip??


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## Steve (Sep 21, 2001)

andrew186 said:


> steve, how easily adjustable are the Forge BOV's?
> 
> and do you have a sound clip??


Easy peesy, a thumbscrew, but I just have them opened full LOL

Ah, sound clip, best if you come to Castle Comb on Saturday and hear the BEAST's for your self


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## GTRSTAR (Nov 26, 2009)

andrew186 said:


> steve, how easily adjustable are the Forge BOV's?
> 
> and do you have a sound clip??


lol ye it goes PTSCHE!


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## Mookistar (Feb 5, 2004)

Gatling said:


> Atmospheric BOV's do add another dimension to driving, looking like a right tit!


on a cool summer evening, empty B-road , windows down, Throttle, lift PSCCHTT, pop. it's hella fun

mook


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## Gatling (Jun 16, 2010)

Mookistar said:


> on a cool summer evening, empty B-road , windows down, Throttle, lift PSCCHTT, pop. it's hella fun
> 
> mook


Hella chav! :chairshot


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## andrew186 (May 3, 2010)

i think BOVs are fine.. leave us alone!


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## Steve (Sep 21, 2001)

God, steady on guys some of you are agreeing with me !!!!


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## Titanium GTR (Sep 27, 2009)

i think it makes your engine sound more powerfull than it really is hehe. and it does sound cool.


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## Bajie (Dec 13, 2001)

Bastids ...
Imagine the disappointed faces when they hear you coming, hear the dump valves then the hugely anticipated citrofoxhall doesn't appear !


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## Hope4Sun (Jul 28, 2003)

robsm said:


> Hope4Sun from Norwich has BOV's
> 
> Its OK, bit chavy though lol
> 
> They wont improve performance at all



Chavy lol, don't get me started on how much I hate them!!!, it was the R34 that made me do it,, honest. The lovely sound of the air filters and waste gate chatter etc, the 35 just sounded so dull, hell a stock 350 sounds better than a standard GTR Lol. I'm a happy enough when I get time to drive her (though they are now turned right down hehehe)

I can still try and nab some clips if you want, combined with the exhaust sounded good IMHO, but getting the balance of receculation and atmosphere (hence volume) is key, I get just enough pssst to make me smile when i want (small things hey lol)


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## Hope4Sun (Jul 28, 2003)

Steve said:


> Easy peesy, a thumbscrew, but I just have them opened full LOL
> 
> Ah, sound clip, best if you come to Castle Comb on Saturday and hear the BEAST's for your self


Lol just reread the thread, opened on full!! Steve ya nutter lol, when I did that the day fitted them, my mate said it sounded like fleet of buses (that coming from someone with a turbo on his Supra that would not look out of place ontop of a DunKin Donuts), but i bet on the track on coming of hard throttle must sound crazy


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## andrew186 (May 3, 2010)

i emailed a forge dealer about the bov's and he says its either full atmosphere or full recirc (different unit) :O is he talkin thru his a$$?


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## _shaun_ (Jan 16, 2007)

Might have to add these to my list of bits to get form the USA


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## andrew186 (May 3, 2010)

_shaun_ said:


> Might have to add these to my list of bits to get form the USA


well the forge ones you can get from the UK 

the GFB Stealth FX (the one in the OP video) is one of the popular ones on NAGTROC.. Its an aussie brand.. Available in UK too via Graham Goode (Leicester) at around £600! Can be had for half the price from the US :runaway: might have to call up Graham Goode and ask why they are so expensive :chairshot


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## _shaun_ (Jan 16, 2007)

andrew186 said:


> well the forge ones you can get from the UK
> 
> the GFB Stealth FX (the one in the OP video) is one of the popular ones on NAGTROC.. Its an aussie brand.. Available in UK too via Graham Goode (Leicester) at around £600! Can be had for half the price from the US :runaway: might have to call up Graham Goode and ask why they are so expensive :chairshot


OK great. Need to find out which it "better" and then find somewhere in the States that sell it :thumbsup:


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## Hope4Sun (Jul 28, 2003)

Got mine from the States, just asked the guys on NAGTROC and one of them shipped directly to me  From all the research I did the stealths are best suited to the car because you can ensure most of the air is recirculated and then not causing any potential issues, but then again a lot of the US guys are running there's fully open with out issue ether, I like to mother mine though


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## Titanium GTR (Sep 27, 2009)

some one With Forge one has to put a Video Clip on here. well anyone with them on pleaseeee get film ing show us what they are like?


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## Fuggles (Jul 3, 2001)

BOVs that vent to atmosphere create a minor amount of lag. Excesss pressure is released into the atmnosphere so, when you want to get the turbines up to pressure again the resevoir has to be refilled. BOVs that recirculate store the pressured air in a chanber and, as soon as you apply acceleration to the turbines the air is released back into the system.


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## David.Yu (Jun 28, 2001)

GTRSTAR said:


> As far as Im aware the GTR has BOVs as standard, theyre recirculating not to atmosphere so they dont make the wooshy noise (which I think is cool BTW although it might get on my nerves after a while)
> 
> My BOVs have been removed all together, its supposed to improve something or other, only now I get this pathetic low level pu pu pu pu and the throttle response is like an on off switch, good for track not great for cruising..
> 
> Kev I want my BOVs back!


Yeah I never understood that. What advantage is there to removing the BOV altogether?

For those of you who think they are just for making chavvy noises (I know, I had HKS SSQs on my R33 12 years ago!), the main function of any BOV is to prevent compressor surge on lifting off the throttle, i.e. keep the turbines spinning, hence reducing lag and preventing long term damage to the turbos by slamming them to a halt every time you lift off.

So what is the thinking behind losing BOVs altogether?


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## Steve (Sep 21, 2001)

Thought that was / is the job of recirculating valves ?? ie to keep the pressure up and the turbines spinning


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## David.Yu (Jun 28, 2001)

Steve said:


> Thought that was / is the job of recirculating valves ?? ie to keep the pressure up and the turbines spinning


Both versions, i.e. recirc (like the stock ones) or atmospheric are designed to do the same thing, i.e. keep the turbines spinning.

Hence I cannot see how ditching them altogether can be a good thing.

I'm guessing in very high boost installations, the valve can leak some boost, but I'd rather have less lag and longer-lived turbos!


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## Bajie (Dec 13, 2001)

I had HKS SSQs om my Subaru.
Only problem I ever had with them was if it was a really hot day, the car would sometimes stall and not start till it cooled down again.
Quite a few threads on Scoobynet about it way back then.
Out of interest, do the standard BOVs get louder [more audible] as you up the power?


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## Steve (Sep 21, 2001)

David.Yu said:


> Both versions, i.e. recirc (like the stock ones) or atmospheric are designed to do the same thing, i.e. keep the turbines spinning.
> 
> Hence I cannot see how ditching them altogether can be a good thing.
> 
> I'm guessing in very high boost installations, the valve can leak some boost, but I'd rather have less lag and longer-lived turbos!


Yep, me too !!! (mind you, an excuse if there was one needed to upgrade the Turbo's !) LOL


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## David.Yu (Jun 28, 2001)

Bajie said:


> I had HKS SSQs om my Subaru.
> Only problem I ever had with them was if it was a really hot day, the car would sometimes stall and not start till it cooled down again.
> Quite a few threads on Scoobynet about it way back then.
> Out of interest, do the standard BOVs get louder [more audible] as you up the power?


Main problem I had with the SSQs is that they would vent oil as well as air...

Just upping the boost won't make the stock valves operate noticeably louder, but fitting an air intake certainly does!

I have a Cobb intake and now there are lovely sucky intake noises on boost and a discreet but noticeable whoosh on lifting off. Car sounds great now!


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## GTR ally (May 19, 2008)

David.Yu said:


> Main problem I had with the SSQs is that they would vent oil as well as air...
> 
> Just upping the boost won't make the stock valves operate noticeably louder, but fitting an air intake certainly does!
> 
> I have a Cobb intake and now there are lovely sucky intake noises on boost and a discreet but noticeable whoosh on lifting off. Car sounds great now!


What all have you done to the car now David?


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## Titanium GTR (Sep 27, 2009)

i heard David Yu's car last week and saw the COBB intakes and it does sound sweet. and his acceleration is amazinglyyyy quick, and VERY VERY scarey (especially on unbeded brakes lol)

All i like the BOVs for is the WHOOSHHHH noise. so how much power would you lose for the noise aspect?


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## kevan kemp (Jan 27, 2010)

David.Yu said:


> Both versions, i.e. recirc (like the stock ones) or atmospheric are designed to do the same thing, i.e. keep the turbines spinning.
> 
> Hence I cannot see how ditching them altogether can be a good thing.
> 
> I'm guessing in very high boost installations, the valve can leak some boost, but I'd rather have less lag and longer-lived turbos!


Hi Dave 

always work like that
My car has no bye pass valves or blow off valves
And I will keep it like this

Like anything their are pros and cons
I feel a very slight advantage keeping boos their on full throttle runs
Running now 800bhp the turbos are under more stress at this boost level
But they are built to stand this

Basically if you keep the oem design this is called a bye pass valve
Yes it reduces pressure upon lift off. Helping re spool and protecting compressor down side ,dumps all the pre heated charged air back into the system again resulting in slightly higher induction temps

The blow off valve design dosnt suffer from this ,because it dumps the charged air too atmosphere. Hence the whoosh sound.
Not all good news here on r35s. Immediately it does this the injectors over rich themselves because the ecu is expecting the dumped air "in" the system
And releases the extra fuel. You will find hydro carbons rise
Also now you've dumped the air. You have to re boost the system nip and tuck on your extra lag theory 

It's all down to preferences in set up My 10.3 isn't too bad and 0 -110 in 6.3 seconds and has nice road manners to boot (no bovs fitted)
They all have pros and cons we could debate

Having said all that I'm now testing bovs and bye pass valves and bov less set ups all over again to perfect the next stages of tune

When I've hit 150mph in the 9second bracket. And mook allows me to post the data I will let you know bye pass/bovs/or bov less lol

Hope this helps kk


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## NickTO (Sep 26, 2007)

Fuggles said:


> BOVs that recirculate store the pressured air in a chanber and, as soon as you apply acceleration to the turbines the air is released back into the system.


Sorry, but that's not accurate.

BOVs that recirculate just dump the air back into the uncompressed portion of the intake runner, post air-filter and MAF.. While the vented air does not get re-measured by the electronics, it does need to go through the turbo again to be compressed.

It's not like there's a balloon hanging off the BOVs.

There are efficiencies gained by changing to an aftermarket BOV. The stock units (mitsu) on the R35 bleed a notable amount of air back into the intake when they are closed through a channel running from the pressurized side of the intake to the dump port. Despite what others may have posted, there are power gains (especially if the car's been tuned up in power) to be had with an aftermarket BOV that seals properly, especially during throttle modulation.

PS. I'm the author of the video in the OP post.


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## Titanium GTR (Sep 27, 2009)

Great Video by the way "NickTo" hope you didnt mind me posting it on here, its started a good thread. What do you recon of Forges BOV's???


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## Steve (Sep 21, 2001)

Titanium GTR said:


> Great Video by the way "NickTo" hope you didnt mind me posting it on here, its started a good thread. What do you recon of Forges BOV's???


Got em, brilliant !!!


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## andrew186 (May 3, 2010)

steve any chance we can get a vid?


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## GTRSTAR (Nov 26, 2009)

David.Yu said:


> Yeah I never understood that. What advantage is there to removing the BOV altogether?
> 
> For those of you who think they are just for making chavvy noises (I know, I had HKS SSQs on my R33 12 years ago!), the main function of any BOV is to prevent compressor surge on lifting off the throttle, i.e. keep the turbines spinning, hence reducing lag and preventing long term damage to the turbos by slamming them to a halt every time you lift off.
> 
> So what is the thinking behind losing BOVs altogether?


All I can say is that without BOVs the throttle repsonce is very sharpe and the acceleration relentless, only draw back that I can see is the sharp engine breaking when coming off throttle, it takes some getting used to, perhaps it will make me a smoother driver, like you


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## kevan kemp (Jan 27, 2010)

GTRSTAR said:


> All I can say is that without BOVs the throttle repsonce is very sharpe and the acceleration relentless, only draw back that I can see is the sharp engine breaking when coming off throttle, it takes some getting used to, perhaps it will make me a smoother driver, like you


Alex mate if you want to go for a dump

Just let me know. 

Kk:flame:


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## NickTO (Sep 26, 2007)

Titanium GTR said:


> Great Video by the way "NickTo" hope you didnt mind me posting it on here, its started a good thread. What do you recon of Forges BOV's???


I think they're a fine piece of kit. From what I gather, they will do 100% VTA or Recirculation but not a combination of both.

Ultimately, the BOV helps prevent compressor surge which is beneficial to the life of the system. The GFB unit is particularly good as it has some design cues (like asymetric vent ports and spring adjustability) that gives you the best combination possible: hybrid venting (where majority of air charge is recirculated, some is vented) and air charge (tighter spring keeps some of the air charge compressed in the intake, similar to a BOV delete setup)....

There are quite a few companies that make good BOVs, ultimately it's a decision on design , feature and obviously price


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## GTRSTAR (Nov 26, 2009)

kevan kemp said:


> Alex mate if you want to go for a dump
> 
> Just let me know.
> 
> Kk:flame:


You lead Kev, I'll follow, let's tango :flame:


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## MiKy-HuT (Mar 7, 2012)

sorry to bring up an old thread.

i've just had these delivered today. i plan on fitting them later, anybody on here who has had them fitted know of a good amount of clicks in on the adjuster to start? i understand that you wind them in untill you here the flutter then wind them one back? just wondered if anyone has counted their clicks so i have a good start point?

thanks


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## DWC (May 18, 2009)

It does'nt click it just winds like a bolt. I spent ages setting mine up but in the end found that a strong spring rate ie wound right in works best as i was getting some funny very low speed strange stuff when coming of the gas. I do get quite a bit of flutter some times but at least the car is running well now. You'll find yourself Dumping on purpose for a while then the shine wears off & you start driving it normally again ! The valves sound great when your not expecting it. As in flying up slip roads and stuff. Frightens the life out of padestrians too.

Let us know how you get on

Enjoy


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## Lubo69GTR (Mar 4, 2010)

BOV's are alright but I don't see the need for them on an auto (R35) as you don't lift off the throttle while going up the gears.


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## DWC (May 18, 2009)

Trust me. You want them. That sound is just worth it.


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## MiKy-HuT (Mar 7, 2012)

DWC said:


> It does'nt click it just winds like a bolt. I spent ages setting mine up but in the end found that a strong spring rate ie wound right in works best as i was getting some funny very low speed strange stuff when coming of the gas. I do get quite a bit of flutter some times but at least the car is running well now. You'll find yourself Dumping on purpose for a while then the shine wears off & you start driving it normally again ! The valves sound great when your not expecting it. As in flying up slip roads and stuff. Frightens the life out of padestrians too.
> 
> Let us know how you get on
> 
> Enjoy


thanks for your reply, they dont click as you say, they just have a little bump every half turn or so. i have mine wound pretty far out just now, its hard to test if they are holding full boost as the roads are a sheet of ice..... but i suppose the adjustment can be made when the roads clear up.

this flutter you guys go on about. do you not like it? thats the best part isnt it? i made a little video last night of mine, albeit they could be adjusted completely wrong but the sound it makes is epic! will attempt to post up this morning! :thumbsup:


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## MiKy-HuT (Mar 7, 2012)

not the best video i admit, and it may not be adjusted properly, but here goes


http://youtu.be/PytqRkmWpCk


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## DWC (May 18, 2009)

So you've got the Forge ones. Mine are the GFB ones & are quit a bit louder. It sounds like you've got the spring rate too tight as its fluttering alot. Should be more of a tish or similar with the odd flutter at certain speeds.


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## DWC (May 18, 2009)

Are you going to the Magic meet on Sunday or are you up North. We could go Dumping to compare. Lol


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## Sinth (Sep 26, 2010)

I've got the gfb and have no complaints


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## enshiu (Aug 20, 2010)

Sinth said:


> I've got the gfb and have no complaints


Nope GFB are good. 

I am going to setup a Greddy RZ twin VTA setup and will be closing the turbo inlet pipe recirculation with a rubber that comes with the set.

VTA sounds better than closed circulation which is nothing and also bad for the turbo as the excessive air is pushed back into the inlet and causes the turbo suddenly spin faster than needed.


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## j9mfu (Nov 15, 2012)

Where can I get GFB BOV's from, apart from SVM
anyone imported direct from Aus?


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## Sinth (Sep 26, 2010)

Enshiu

You mean "Yes GFB are good" right?


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## Sinth (Sep 26, 2010)

j9mfu said:


> Where can I get GFB BOV's from, apart from SVM
> anyone imported direct from Aus?


I imported mine from the US. Worked out slightly cheaper 

But I did buy gotboost air intakes , h&r springs and 1000cc injectors with it too.


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## MiKy-HuT (Mar 7, 2012)

DWC said:


> Are you going to the Magic meet on Sunday or are you up North. We could go Dumping to compare. Lol


sadly not, im in scotland. would love to travel down there for it... but if i was going to, id have to have the car booked in somewhere to get something done to make the trip worth while!


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## MiKy-HuT (Mar 7, 2012)

DWC said:


> So you've got the Forge ones. Mine are the GFB ones & are quit a bit louder. It sounds like you've got the spring rate too tight as its fluttering alot. Should be more of a tish or similar with the odd flutter at certain speeds.


yes, the forge ones. yours are louder? *insert sweary word of dismay here* 

i like the flutter too much to change it now though  its wound out pretty far if i recall though. 

the flutter wont cause any damage will it? the car is running as normal with it set up like this


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## Lofvis (Nov 19, 2010)

I had the GFB BOV's on my car sounded like I was gonna blow off the bonnet :chuckle:

To much for my taste so I sold them.


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