Dump Valve King Thread - A discussion

R

Red Hot

Member +
GTti said:
An effective dump valve does not operate by vaccum and would simply be a spring with a hard resistance (depending on the application). This way it can be configured (With different strength springs) to release pressure in the intake at a set level (Say 18psi if you're running 15psi).

This method will maintain pressure in the intake but also keep it under tabs by releasing pressure above 18psi (If you think high pressure is bad for your setup). A recirculation valve will work in much the same way by maintaining pressure in the intake, therefore I think it's far more efficient than the usual dump valve!

Unfortunatly most dump valves operate purely by vaccum and open fully to release all air mass. Logic and science would say this is not effective, creating a huge pressure drop by releasing intercooled(cold) air. When the throttle butterfly is opened how can response be better when all the cold compressed air has been blown into the atmosphere?
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I don't know about that. The circulating air is probably hotter then the outside temp. So when you circulate it, it will heat up. Also, without a bov, the air inside the ic pipes will heat up. A dump valve will release pressure, but will also keep it at the set level because your turbo keeps the pressure on.
So with a dump valve the air inside you piping will be fresh outside air which is cooler, if you get what I mean.
If you notice the difference is another question...:p
 
GTti

GTti

Member +
Monkfish said:
The thing is with turbo's is that they are subject to so many variables it is impossible to pin a failure on one thing, such as running with no BOV. Exhaust gas temperature, fuel mixture, vibration, oil contamination, oil starvation, foreign object (Stone, bird, small children etc), wategate/actuator failure, the list goes on.
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Thats a good answer, lets hug.
 
sx_turbo

sx_turbo

Lifer
so i think we've learnt today that it's down to personal preference whether you run with a BOV or woithout. they both have good and bad things for and against them.

i personally notice more lag when not using a BOV, although the noise of my r2d2 can become annoying at times.
 
GTti

GTti

Member +
Red Hot said:
I don't know about that. The circulating air is probably hotter then the outside temp. So when you circulate it, it will heat up. Also, without a bov, the air inside the ic pipes will heat up. A dump valve will release pressure, but will also keep it at the set level because your turbo keeps the pressure on.
So with a dump valve the air inside you piping will be fresh outside air which is cooler, if you get what I mean.
If you notice the difference is another question...:p
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Of course outside air is cooler, it always will be, compression generates heat thats why you have an intercooler.

When you re-circulate it, it will be re-cooled via the intercooler.

You think temperatures will increase in the time it takes for you to change gear? I think heat difference is so minimal in a real world (Racing) application that it can hardly be considered in regards to running a dump valve or not.
Remember compressed air has the most energy, meaning it's the compressed air that will be right at the throttle butterfly waiting to enter the engine.
 
Cooch

Cooch

Member +
Wel ive done both. Run an SSQV for a time then took it of to play about with mounting points and havent refiitted it yet. She seems fine and has never complained. When i start to run more boost though i will replace the dumpvalve cos if i push 14psi with no valve i think she might cry. 7 psi is all good though! LOL
 
G

GT*star

Fresh Recruit
i have a blitz dump valve on mine, makes more of a flutter sound rather than that "woop-tish" prefer the flutter tho, get ppl turnin around to look like WTF??!!:p;)
 
R

Red Hot

Member +
GTti said:
Red Hot said:
I don't know about that. The circulating air is probably hotter then the outside temp. So when you circulate it, it will heat up. Also, without a bov, the air inside the ic pipes will heat up. A dump valve will release pressure, but will also keep it at the set level because your turbo keeps the pressure on.
So with a dump valve the air inside you piping will be fresh outside air which is cooler, if you get what I mean.
If you notice the difference is another question...:p
Click to expand...

Of course outside air is cooler, it always will be, compression generates heat thats why you have an intercooler.

When you re-circulate it, it will be re-cooled via the intercooler.

You think temperatures will increase in the time it takes for you to change gear? I think heat difference is so minimal in a real world (Racing) application that it can hardly be considered in regards to running a dump valve or not.
Remember compressed air has the most energy, meaning it's the compressed air that will be right at the throttle butterfly waiting to enter the engine.
Click to expand...

yea, as I said. You prob. don't notice it when pushing it. But I like my smart thinking:p
 
thefalls

thefalls

Member +
I have the HKS SQV version....model before the ssqv came out....i really like the whoosh it makes [quite loud i must say]....but at times after a hard days work and when the migraine kicks in then i'd prefer the lack of the blow off.....
But i wanna try removing it for a change.....compression stall sounds nice!
 
C

CaL

Guest
either OEM valve or no valve....not needed to waste stupid money on a stupid piece of metal....my standard plastic valve Sounds great.....better than hks imo.....hks are really expensive,blitz break,and bailey are really unreliable.....spesh if your running over 15+psi(dont say'' yeah but how do you know,your 4'' as i have had 3 given to me...all off fords and a rover...running 15+psi)....the springs have snapped on 2 and the spring has sagged one one....iv tried fixing one but i couldnt find a good spring....
 
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rb69

rb69

Member +
CaL said:
i have had 3 given to me...all off fords and a rover...running 15+psi)....the springs have snapped on 2 and the spring has sagged one one....iv tried fixing one but i couldnt find a good spring....
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Maybe if you had bought them new they would have been fine?
 
C

CaL

Guest
yeah....they were given to me from friends....as they didnt know what to do with them....shame really as i could have made some money....
 
Matt_Seicentos

Matt_Seicentos

Member +
running no bov atm since I put the fmic on, however its not that loud as I've still got the stock airbox, but I did have a sard r2d2 on it for a year and a half.

prefer not having a bov now
 
turbo-fever

turbo-fever

Member +
well i have been running 15 psi with no dump valve for about 3 months now and i am beginning to think the old girl likes it plus i relocated the filter to the front bumper:p gotta love the chatter sounds better through a mushroom filter rather then a cone filter
 
Chris@CCM

Chris@CCM

Member +
look at wrc cars thay dont run a bov so i realy cant see it doing much harm . i also think it sounds better with out one
 
R

Rutger

Member +
some people like the sound,
and some people dnt :) thats obvious
im just wondering if a bov actually does as much as people think.
i jsut have my bov and i like it, sounds "orriginal". up here there arnt that many cars wif dump valves going about at the mo. so why not have one :) hehe.
i can see that it could get annoying after a while, dnt no yet tho! am enjoying it at the mo! :) hehe

Rut
 
B

buckfast

Fresh Recruit
Currently looking for a dump valve dont really know wat one yet but between the Blitz and the ssqv seen vid for blitz anyone got any vid or sound clip for ssqv?
 
gayan_GT

gayan_GT

Lifer
im currently running a Greddy Type S BOV... and it sounds great... the best part about it is you can adjust the sound and the loudness... im not allowed to adjust it on mine cos its me friends and im not allowed to :(

but honestly speaking does a BOV really increase your cars performance on a std level???
 
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