# To dump valve or not to dump valve??



## leeroy_25 (Dec 19, 2006)

Just curious here as I currently do not have dump valves on my car. Partly as I have not yet got around to fabricating some pipework to fit one! I understand the function of a dump valve and it should in theroy make your turbo's life less stressful and therfore last longer. But that said they sound great without! 

So I was wondering what the ratio on here was for people with dump valves and people without?

ot sure if I can get the poll function working so if not can someone please set it up.

Dump valves
No dump valves

Cheers
Lee


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## LiamGTR (Nov 26, 2006)

That poll isn't biased at all, lol


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## leeroy_25 (Dec 19, 2006)

You think? Maybe we will be surprised! I am figuring most people will have dump valves but curious to know how many have not none the less!


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## freakazoid3 (Jan 19, 2008)

I ran without for a while but figured out the OEM AFM's didn't like me running without as the air was pushed back through the AFM's when shifting and thus I got overfueling and the car took a while longer to get on boost again after shifting...

So I fitted my HKS BOV's again


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## mattysupra (Oct 31, 2008)

dont skylines have stock dump valves fitted as standard but they recirc into the inlet? Hense no psssssttt noise?


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## mrjolly (Aug 1, 2009)

all modern petrol turbo cars have some sort of dump valve system!!! 
including all skylines. what do you think stops all of your boost hoses blowing up when you shut the throttle with all that compressed air in the system from the turbo! 
all aftermarket dump valves do if make a noise! and in some cases mess the air fuel metering up. 
max power readers will probably tell you they make your car faster but i think they will be the only people with that opinion. 
so the question to dump valve or not is a bit silly as all skyline turbo owners allready have them.
i was nearly ranting there!!!


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## D-Ranged (Aug 16, 2007)

I prefer the stock recirc noise although the twin R2D2 setup my mate has on his 32 sounds insane.


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## SklyaFett (Oct 18, 2005)

Stock nosie is best with some nice filters


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## Initial P! (Oct 27, 2009)

SklyaFett said:


> Stock nosie is best with some nice filters


Agreed. Have heard some nice sounding valves on old youtube touge/battle type vids, but the ones I hear now on other cars sound a bit naff to me. Sound like a budgie got trapped under the bonnet:chuckle:


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## DazGTR (Dec 5, 2007)

Initial P! said:


> . Sound like a budgie got trapped under the bonnet:chuckle:


that would be the HKS SSQV ones then:nervous: angry chicken:runaway: let the arguments beginlol


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## leeroy_25 (Dec 19, 2006)

Can you dump stock recirc valves to atmos?

I thought the HKS SQV sounded okay on my old car?!


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## Initial P! (Oct 27, 2009)

DazGTR said:


> that would be the HKS SSQV ones then:nervous: angry chicken:runaway: let the arguments beginlol


Tweet tweet!

Just kidding. Each to their own and all. Like the sound of the recircs with Apexi induction kit. 
Those other valves sound too lightweight for such a brutal sounding car imho, but it's not something that really bugs me. Not where I would spend my money but others will say the same about other things i've done to my motor.


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## Barros777 (Dec 8, 2007)

leeroy_25 said:


> Can you dump stock recirc valves to atmos?
> 
> I thought the HKS SQV sounded okay on my old car?!



no.


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## KM BlackGTR (Mar 17, 2009)

Stock re-circ bov's are best.
Aftermarket ppssstting dumpvalves are so Chavvy !


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## R32 Combat (Jan 29, 2004)

I ran a pair of overboost valves instead of dump valves.


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## Lubo69GTR (Mar 4, 2010)

Stock re-circ valves on mine and sounds ok to me, especially the pan pipes at half boost on a motorway


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## mattysupra (Oct 31, 2008)

R32 Combat said:


> I ran a pair of overboost valves instead of dump valves.


what are they?


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## R32 Combat (Jan 29, 2004)

They are valves that required a certain pressure to open, like a pressure relief valve.

2 of these to be exact

SAVE on GReddy Relief Valve - RacingWorks.com - Turbo Overboost GReddy Releif Valve List


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## bazza1 (Aug 18, 2007)

*Dump Valves*

I've been thinking of taking my HKS dump valves off as I'm getting a bit fed up with the noise.


Baz


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## Piggaz (Sep 5, 2002)

KM BlackGTR said:


> Stock re-circ bov's are best.
> Aftermarket ppssstting dumpvalves are so Chavvy !


Couldn't agree more. Stock works. Leave them alone and spend the money on something that will actually improve the car.


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## leeroy_25 (Dec 19, 2006)

R32 Combat said:


> They are valves that required a certain pressure to open, like a pressure relief valve.
> 
> 2 of these to be exact
> 
> SAVE on GReddy Relief Valve - RacingWorks.com - Turbo Overboost GReddy Releif Valve List


Okay. So it's kind of like a wastegate on the pressure side then? Can you use it to control boost instead of a boost controller? That would make it a bleed valve I guess? Does it sound like a dump valve or what?


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## R32 Combat (Jan 29, 2004)

I don't know what they sound like, but I know they work. You still need a wastegate control system/boost control. These stop the entire intake system venting. It sustains the pressure set on the valves. I set mine to 1.2 bar, same as wastegate.


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## leeroy_25 (Dec 19, 2006)

Interesting. So I assume when you lift off it opens when the pressure in the intake builds to much? So really it is just designed as a safety valve to prevent small boost spikes? How do you set the pressure on it in the first place? Trial and error? or it has a dial on it?

I might look into this as an option.

Cheers
Lee


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## R32 Combat (Jan 29, 2004)

Trial and error a bit. Bit when you buy them they are set to 1 bar I think.


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## Brains (Jul 6, 2010)

R32 Combat said:


> I ran a pair of overboost valves instead of dump valves.


But why would they open when you release the throttle?


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## leeroy_25 (Dec 19, 2006)

Pressure build up in pre-throttle in the plenum where the turbo is still spinning?


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## R32 Combat (Jan 29, 2004)

Leeroy is correct.


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## Rookemonster (Dec 29, 2010)

*Re Dump Valves*

I purchased my first Skyline (R33 GTR) 3 days ago so that kinda makes me a newbie, however, I also have a 94 Impreza WRX and fitted a dump valve, full decat, wide mouth down pipe etc, the difference was amazing, rapid pull away in any gear from 3000 RPM onwards with faster spool up, plus the sound PPPPssssttttt was worth it just for the grin factor. BTW the Impreza is going to be sold seeing as I have now finally got the car of my dreams.
I would like to fit a dump valve to the GTR, as I haven't had the car long and its been poor weather I just aint got round to having a good butchers under the bonnet, any advice on best BOV to have and how complex to fit would be appreciated....... On a separate note, HAPPY NEW YEAR to all, Roll on 2011 and some good weather. :smokin:


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## bazza1 (Aug 18, 2007)

*Dump valves*

Hello mate,

Welcome to the club !

Glad you're happy with the GTR. I did exactly the same, I had a 1995 scooby type ra that was pushing out 350bhp before then changed to my GTR, completely different cars !

BTW, I've got a set of twin HKS Dump valves for sale if you're interested ?

Happy New Year ! ! !


Baz.


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## Rookemonster (Dec 29, 2010)

Cheers Baz, thanks for the welcome. Fitting the BOV to the Scoob was a 10 minute jobby, very easy to do and made a positive difference. I'm not so sure about the GTR though, I don't want to trade performance & reliability for the PPPsssttttt even though I know the noise would make me grin like a cheshire cat. I'm gonna do a bit more research and get me nut under the bonnet before taking the plunge. BTW, today I removed the Jap fitted Sanyo minidisc CD Tuner, what a piece of junk, replaced with Alpine CD Tuner with Nissan ISO adapter, easy to do, just a bit fiddly with half the dash hanging out, still......JOB DONE. Sounds Very Good even with stock speakers. Just makes me enjoy the car even more.
Thanks again for the welcome, appreciate it. Rookie.


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## skylinegts2gtr (Jan 24, 2007)

ive got the standard recirc and love the suttle sound, in not a fan of dump valves but i think the question that needs answering is what is more efficient? whats better?


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## Azim (Aug 2, 2011)

dump valve all day long!!


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## Talski (Apr 7, 2010)

GReddy BOV going on the car next week, missed the pssssssssssst


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