Andy Metcalfe Posted July 19, 2001 Share Posted July 19, 2001 Been thinking about getting a dump valve. Which one is best and where is the best place to get one from? P.S. i`m not afraid to get my hands dirty and fit it myself-so long as it`s not rocket science!) Quote Link to comment Share on other sites More sharing options...
Paul Booth Posted July 19, 2001 Share Posted July 19, 2001 As per FSE, I'm not going to wait until the end of this thread before I ask: Although I think I have a good idea, why doesn't someone explain in technicolour, what a dump-valve does. Quote Link to comment Share on other sites More sharing options...
Guest Ash Posted July 19, 2001 Share Posted July 19, 2001 It's a device that makes a big whoooshing noise as you lift off the throttle. Great for scaring animals and young chilren. :biggrin: Yours, J Quote Link to comment Share on other sites More sharing options...
Branners Posted July 19, 2001 Share Posted July 19, 2001 Ash has given you the real answer, it is great for whoosh. The official answer is that it releases excess pressure in the turbo system which avoids 'slamming' the turbos when the throttle is closed due to all the boost still being in the system, and also ensures the turbos continue to spin due to the pressure being released. Its another one of these 'air filter' scenarios. Nobody can say for sure that it helps or hinders the engine. Numerous people have said it doesnt really help, at least one has said it is detrimental to performance, and some say it is worth having as it does help in some small way. I have one, it makes a whoosh, my car is quick, but then at 19psi it bloody well should be. As for the best one, well the HKS and Blitz are both nice units. The blitz is a little quiet, the HKS is slightly louder, and the Apexi is adjustable and on the loudest setting is just NUTS. RJ has one on his Supra so he can tell you just howloud the Apexi one is. Not cheap items, ranging from about £280 upwards, but combined with the air filter it makes the induction noises amazing. HKS price available in Shop!! is you are interested. JB Shop!! Quote Link to comment Share on other sites More sharing options...
Paul Booth Posted July 19, 2001 Share Posted July 19, 2001 Quote: from branners on 5:08 pm on July 19, 2001[br]...... RJ has one on his Supra so he can tell you just howloud the Apexi one is. JB Shop!! Is that RJ as in "I'm driving an Integra" RJ? Quote Link to comment Share on other sites More sharing options...
Phil Wall Posted July 19, 2001 Share Posted July 19, 2001 So does this mean that the stock BOV not do as good a job as a dump valve I thought that the aperture opening on a most dump valves was about the same as the stock BOV tubing.. I assumed that pressure release would be governed by the minimum opening diameter of the system. The USA guys run a mod with two BOV’s mounted together, presumably to almost double the amount of pressure that is allowed to escape. This route may not make the amazing sound of a dump valve. But might it give better protection? We need an expert opinion here. The must be one somewhere...... Ash your thoughts... Quote Link to comment Share on other sites More sharing options...
Syed Shah Posted July 25, 2001 Share Posted July 25, 2001 Apparently, u should only use a re-circulating dump valve as if u use a standard on it interferes with the cars turbo monitoring stuff. But those re-circ dump valves don't make the whoosh!!!!!!!!! Quote Link to comment Share on other sites More sharing options...
Phil Posted July 25, 2001 Share Posted July 25, 2001 It depends how the air is metered into the engine. The UK spec supras shouldn't have a dump to atmosphere valve because the air being dumped out of the system has been accounted for in the fuel/air ratio. The Jap specs don't have so much of a problem with this because they have a MAP sensor instead of a MAF sensor, but having had a Dump Valve go south on me before I just stick to the standard BOV with an induction kit to make it sound louder. Quote Link to comment Share on other sites More sharing options...
Branners Posted July 25, 2001 Share Posted July 25, 2001 aparently the UK specs do NOT react badly to dump to atmos BOVs. I think TDI have fitted quite a few and had no problems at all. JB Shop!! Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted July 25, 2001 Share Posted July 25, 2001 I don't seem to be experiencing any problems with my HKS SSQV. Whooooossssssssssshhhhhhhhhh!!!!!! Quote Link to comment Share on other sites More sharing options...
Branners Posted July 25, 2001 Share Posted July 25, 2001 conclusive proof, a man with a UK spec and Whoooooshh and no problems... JB Quote Link to comment Share on other sites More sharing options...
Phil Posted July 25, 2001 Share Posted July 25, 2001 I stand corrected. Cheers, Phil Quote Link to comment Share on other sites More sharing options...
Guest Ash Posted July 25, 2001 Share Posted July 25, 2001 I cannot really add any more than what Branners has said in his post. Except to reiterate the technical reason why they are fitted is to stop the axial compressor going into what is called a surge condition when the throttle is suddenly snapped shut. Under such conditions there is much turbulence developed within the compressor housing. This has the effect of placing a lot of drag on the compressor wheel, just at the time when exhaust flow has stopped due to the throttle having closed. The basic theory behind the BOV is the moment the throttle closes, you blow off the boost-pressure in the intake to atmosphere. This is meant to then reduce turbulence and, therefore, reduce the drag on the compressor wheel. The idea being, momentum will keep the compressor wheel spinning between gear-changes if, as I say, you cut the drag on the compressor blades to as small a degree as possible. To my mind, though, it's a case of swings and roundabouts. Okay, the compressor wheel may well continue to spin faster than if there were no BOV fitted. But what about all that pressurised air you have just blown off to atmosphere? After a quick gear-change, where there would normally be pressure remaining in the intake. Now you have to charge the whole intake from scratch. But you have the advantage the turbo is spinning faster. Without a BOV, the turbo would be spinning more slowly after a gearchange but, then again, there will be more pressure in the manifold as you quickly get back on the gas. So, as I say, it could well be a case of swings and roundabouts when looked at from the point of view of overall efficiency. I imagine that the stock BOV will technically be adequate. But there are instances, like with the air-filter, for example, where what has been fitted is *technically* adequate but lacking in other features like a great intake sound. Not that the sound is everyone's cup of tea. Same with the whooosh-type BOV's... some people like them and some people loath them. Personally, I love them. There's nothing like making a big whooosh during gear-changes. :biggrin: I fitted the HKS sequential BOV just after I got the car. I already had the stock valve fitted which was in good condition. Out of curiosity I removed it and really didn't notice any change. Though I didn't engage in any exhaustive tests: just went for a quick blast up and down a few fast A-roads. Then I fitted the HKS BOV and went for a blast and, apart from making a big whooosh during gearchanges, performance-wise the car felt the same. Yours, J Quote Link to comment Share on other sites More sharing options...
Rich J Posted July 25, 2001 Share Posted July 25, 2001 Quote: from Paul Booth on 6:26 pm on July 19, 2001[br]Quote: from branners on 5:08 pm on July 19, 2001[br]...... RJ has one on his Supra so he can tell you just howloud the Apexi one is. JB Shop!! Is that RJ as in "I'm driving an Integra" RJ? Yes and the the answer is BLOODY loud. When blipping the throttle from the engine bay, perople used to comment how my hair used to stick up straight in the air when the pressure was released, because as I lent over my head was directly above the BOV, and I cthen couldn't hear what they were saying LOL. Matt (sorry didn't catch last name) will probably be able to tell you more once he has it fitted mine to his hardpipe. Quote Link to comment Share on other sites More sharing options...
Andy Metcalfe Posted July 25, 2001 Author Share Posted July 25, 2001 Seriously thinking about an Apexi dump valve now because in my mind "If your gonna have one-have a big one!"(WWOOOOOSSSSHHHHH that is!!).Is anybody going to Billing this weekend who has one so that i can experience the king of all wooshy things first hand?? Quote Link to comment Share on other sites More sharing options...
Branners Posted July 26, 2001 Share Posted July 26, 2001 RJ was the only person I knew with one.... JB Quote Link to comment Share on other sites More sharing options...
Guest Ash Posted July 26, 2001 Share Posted July 26, 2001 Mark Ayling has a loud BOV. Not sure of the make. Yours, J Quote Link to comment Share on other sites More sharing options...
Andy Metcalfe Posted July 26, 2001 Author Share Posted July 26, 2001 Well i guess i`ll just have to wait and see who i can pester on the day then! Quote Link to comment Share on other sites More sharing options...
Branners Posted July 27, 2001 Share Posted July 27, 2001 thats probably the best way to do it, if I have time on the 'honk if your horny' meet I might try and record the BOV sounds as well. JB Quote Link to comment Share on other sites More sharing options...
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