boost bleed
boost bleed
does anyone know of a way of bleeding boost at a set pressure?
the reason for wanting to do this is so that on a turbo application, rather then dumping all boost and then building it up again, it could be maintained at a set level while off the throttle
you would get a bit of chatter yes but you would maintain boost!
the best I can think is to find a vacuum pump and try to retrofit it to deliver vacuum at a certain boost level.
at this level of boost the pump would provide vacuum which would open the blow-off valve, and then shut it when boost drops to the desired level, thus maintaining boost levels!
I realise turbo stall is a problem that would need addressing, but this is a hypothetical question about the bleed type valve and control itself.
has anyone got any better ideas for achieving this task, or even know of a similar system, or a reason why it wouldn't work. I can't work out why people don't do it already!
Cheers peeps! :thumbup:
ok, weird one this?!? as per from me :whistling:
does anyone know of a way of bleeding boost at a set pressure?
the reason for wanting to do this is so that on a turbo application, rather then dumping all boost and then building it up again, it could be maintained at a set level while off the throttle
you would get a bit of chatter yes but you would maintain boost!
the best I can think is to find a vacuum pump and try to retrofit it to deliver vacuum at a certain boost level.
at this level of boost the pump would provide vacuum which would open the blow-off valve, and then shut it when boost drops to the desired level, thus maintaining boost levels!
I realise turbo stall is a problem that would need addressing, but this is a hypothetical question about the bleed type valve and control itself.
has anyone got any better ideas for achieving this task, or even know of a similar system, or a reason why it wouldn't work. I can't work out why people don't do it already!
Cheers peeps! :thumbup:
Or drive in such situations where you don't want to loose boost properly (heal & toe method)
I very much doubt a vacuum pump will be able to keep up with the demands an engine would put on it.
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
FirebirdPhil
17-07-2018, 10:55 AM #2Would it be easier just to use the correct size turbo for the application, therefore removing the need for anti lag system - especially one so off the wall!!
Or drive in such situations where you don't want to loose boost properly (heal & toe method)
I very much doubt a vacuum pump will be able to keep up with the demands an engine would put on it.
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
http://www.rallycars.com/Cars/bangbang.html
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
FirebirdPhil
17-07-2018, 10:56 AM #3Oh have a look at this link for Anti Lag:
http://www.rallycars.com/Cars/bangbang.html
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
what about big power from small engines on a budget? and what do we learn by copying others?!?i'm familier with 'bang bang' (lol) system, as the method is used in the launch control system I have been eyeing up. it works well but is hard to set-up on a budget, and i'm all about the back garage budget!
interesting greeny, i'm going to have a look into that now, I have no experience in recirc as my first and current turbo car came with a dump valve, it also has a maf, so i had immediate problems (motobitz tuners:thumbdown
the thing is, if i'm hearing you rite, your suggesting that the boost being redirected to the inlet before the turbo air inlet, will help to maintain boost levels within the compressor side of the system.
however I believe (please tell me if i'm wrong ppl, as this is hypothesis only) that as the expelled boost is introduced into an open envioronment, as in; the inlet before the turbo, and its under no restrictions to enable it to maintain 'above atmospheric pressure', then it will 'de-compress', so your not actually delivering compressed air to the inlet (delivering compressed air would really be compounding, and can produce some strange and harsh effects).
end result (I believe, with a recirc) wouldn't be an increase in boost levels, or even the steady maintenance of boost levels, but actually in a manic swirl of decompressing air affecting the smoothness of the air to the turbo air inlet! maybe even restricting it!
either way, i'm going to do some research into recircs now, if they do have a pressure regulated/boost release control system then you would have made my day....
an cheers for the help peeps,
I'v decided to become a paid up member of outlaw tonight, all the feed back an nice peeps giving it is well worth the £ contribution to keep it growing! .......................:thumbup::thumbup::thumbup:
thanks 2tongues, as for using a better sized turbo, yes, a faster spooling smaller turbo would reduce the lag in a smaller engine, with a reduced power output but smoother response and pick-up, but where's the fun in that hypothetical discussion? what about big power from small engines on a budget? and what do we learn by copying others?!?
i'm familier with 'bang bang' (lol) system, as the method is used in the launch control system I have been eyeing up. it works well but is hard to set-up on a budget, and i'm all about the back garage budget!
interesting greeny, i'm going to have a look into that now, I have no experience in recirc as my first and current turbo car came with a dump valve, it also has a maf, so i had immediate problems (motobitz tuners:thumbdown
the thing is, if i'm hearing you rite, your suggesting that the boost being redirected to the inlet before the turbo air inlet, will help to maintain boost levels within the compressor side of the system.
however I believe (please tell me if i'm wrong ppl, as this is hypothesis only) that as the expelled boost is introduced into an open envioronment, as in; the inlet before the turbo, and its under no restrictions to enable it to maintain 'above atmospheric pressure', then it will 'de-compress', so your not actually delivering compressed air to the inlet (delivering compressed air would really be compounding, and can produce some strange and harsh effects).
end result (I believe, with a recirc) wouldn't be an increase in boost levels, or even the steady maintenance of boost levels, but actually in a manic swirl of decompressing air affecting the smoothness of the air to the turbo air inlet! maybe even restricting it!
either way, i'm going to do some research into recircs now, if they do have a pressure regulated/boost release control system then you would have made my day....
an cheers for the help peeps,
I'v decided to become a paid up member of outlaw tonight, all the feed back an nice peeps giving it is well worth the £ contribution to keep it growing! .......................:thumbup::thumbup::thumbup:
Take a look at Saab turbo systems they are Recirc from factory.
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
FirebirdPhil
17-07-2018, 02:05 PM #6Well done for becoming a paid up member, mine has just expired and as soon as I have Paypal set up in the USA I will join again.
Take a look at Saab turbo systems they are Recirc from factory.
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
the point of a dump valve as im sure you know is to release the pressure behind the throttle body so that it can open again (a high differential pressure between the engine internals and the pipework will make it hard to open).
what your asking for is basically a dump valve without the opening at the top for engine pressure. a spring that lifts when the pressure gets too high and reseats again with pressure still in the system.
the problem is that with pressure in the system you risk damaging the throttle body, what you really need is something like a tank that the recirc dump valve dumps all the pressure in that dumps it all back once the throttle is open.
Problem is that it will have to be in similar volume to all the pipework between the turbo and inlet plus a bit.
![[Image: LexuS-Copy.jpg]](http://i65.photobucket.com/albums/h204/Sparkystav/LexuS-Copy.jpg)
Read my thread here: The Evolution of my Turbo Lexus from NA-Supercharged-Twin Turbo-Massive Single
Please leave your comments.
Sparkystav
17-07-2018, 02:14 PM #7what you want could struggle.
the point of a dump valve as im sure you know is to release the pressure behind the throttle body so that it can open again (a high differential pressure between the engine internals and the pipework will make it hard to open).
what your asking for is basically a dump valve without the opening at the top for engine pressure. a spring that lifts when the pressure gets too high and reseats again with pressure still in the system.
the problem is that with pressure in the system you risk damaging the throttle body, what you really need is something like a tank that the recirc dump valve dumps all the pressure in that dumps it all back once the throttle is open.
Problem is that it will have to be in similar volume to all the pipework between the turbo and inlet plus a bit.
Read my thread here: The Evolution of my Turbo Lexus from NA-Supercharged-Twin Turbo-Massive Single
Please leave your comments.
sparkystav i have thought about storing the compressed air many times, do practical systems like this, exist?
I gave up hypothetical design when i was unable to find a controllable one way valve that was fast enough for the storage tank (on a budget). and realised that any stored boost would, in effect have to contain enough excess pressure to recompress the whole inlet system, and provide continued pressure untill the turbo spooled, so more pressure is required then the turbo wastegate allowes anyway! on top of that the released pressurised air would surely push back against the turbo compressor, and reduce compression times for the turbo? also it would hit a point of nominal gain, when the pressure in the cylynder is higher then the pressure required to create a surge back at the turbo, so i could only store a little and it would be hard to account for as i would still get compressor leak! this would happen each time! not really the retrofit solution I was looking for! cheers thou,
dude, i'm sorry, i jus re-read your post and clearly missed you saying pretty much the same thing! so you can see the potential then?
yes, i want a sprung seat on a valve that opens at a certain pressure, exactly! and i wouldn't be risking my throttle body, it operates at higher boosts, opening and shutting then i can run, and will always out perform a turbo when it comes to sealing the intake, its chatter i'll get, bare in mind, if i'm running 18psi, and i have the bleed valve (prob what i would call it) set at 18psi, then i am not exceeding its normal running peramiters anyway! the throttle will be fine, the turbo shaft will ache, and the compressor will be strained. but no more then a 10yr old turbo would anyway!
can you have any ideas how we could fabricate or retro-design a valve of that type?
sory ppl, its late and i couldn't be bumphed to spell check, and what not. u work out what i meant lol!
oh and research done, recircs dont seem to work on a different system as far as i have found, they all just open at vacuum and shut on pressure, good thinkin thou, an please let me know if you manage to find a system different to that............nite peeps :thumbup::thumbup::thumbup:
cheer again 2tounges, power requrments from a vacume pump are way to much for my liking! :thumbup: waste of an idea, how about other ways of controlling vacuum?
sparkystav i have thought about storing the compressed air many times, do practical systems like this, exist?
I gave up hypothetical design when i was unable to find a controllable one way valve that was fast enough for the storage tank (on a budget). and realised that any stored boost would, in effect have to contain enough excess pressure to recompress the whole inlet system, and provide continued pressure untill the turbo spooled, so more pressure is required then the turbo wastegate allowes anyway! on top of that the released pressurised air would surely push back against the turbo compressor, and reduce compression times for the turbo? also it would hit a point of nominal gain, when the pressure in the cylynder is higher then the pressure required to create a surge back at the turbo, so i could only store a little and it would be hard to account for as i would still get compressor leak! this would happen each time! not really the retrofit solution I was looking for! cheers thou,
dude, i'm sorry, i jus re-read your post and clearly missed you saying pretty much the same thing! so you can see the potential then?
yes, i want a sprung seat on a valve that opens at a certain pressure, exactly! and i wouldn't be risking my throttle body, it operates at higher boosts, opening and shutting then i can run, and will always out perform a turbo when it comes to sealing the intake, its chatter i'll get, bare in mind, if i'm running 18psi, and i have the bleed valve (prob what i would call it) set at 18psi, then i am not exceeding its normal running peramiters anyway! the throttle will be fine, the turbo shaft will ache, and the compressor will be strained. but no more then a 10yr old turbo would anyway!
can you have any ideas how we could fabricate or retro-design a valve of that type?
sory ppl, its late and i couldn't be bumphed to spell check, and what not. u work out what i meant lol!
oh and research done, recircs dont seem to work on a different system as far as i have found, they all just open at vacuum and shut on pressure, good thinkin thou, an please let me know if you manage to find a system different to that............nite peeps :thumbup::thumbup::thumbup:
Read my thread here: The Evolution of my Turbo Lexus from NA-Supercharged-Twin Turbo-Massive Single
Please leave your comments.
Sparkystav
17-07-2018, 03:53 PM #9You could do it by blocking the little connection on top of something like a Bailey dump valve. Then adjust the spring to one for the pressure you want. Bit like an external wastegate.
Read my thread here: The Evolution of my Turbo Lexus from NA-Supercharged-Twin Turbo-Massive Single
Please leave your comments.
the thing is finding a spring that precise, finding one that wouldn't creep untill the desired limit would be near impossible, the assist from the vacuum in a dump valve allows the spring to lift below its limit, as the pressure rises at one and and vacuum at the other it will open, to have it just controlled by the pressure would be to hard to seal on the limits!
actuators do seem to have alot of control over the wastegate thou, even under heavy load, which i do find interesting, its just how to convert that force into an appropiate valve on the compressor side intake?!?
I have a bailey piston already and that what what I was hoping to be able to do, a self contained valve would be ideal! it was thinkin bout that units spring that that got me thinking bout this, i had no luck finding any different springs for mine, or even a unit with variable springs (but i did found one in america with three spring choices for a couple of ton)
the thing is finding a spring that precise, finding one that wouldn't creep untill the desired limit would be near impossible, the assist from the vacuum in a dump valve allows the spring to lift below its limit, as the pressure rises at one and and vacuum at the other it will open, to have it just controlled by the pressure would be to hard to seal on the limits!
actuators do seem to have alot of control over the wastegate thou, even under heavy load, which i do find interesting, its just how to convert that force into an appropiate valve on the compressor side intake?!?
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