FAO techy types- Is this explanation etc right? DPV
#41
Originally Posted by Stavros
Originally Posted by GARETH T
Originally Posted by Stavros
Im confused about what happened and what people thought happened.
Anyone wanna explain?
I thought (correct me if im wrong) ported shrouds reduced compressor surge by leaking some air out after the inducer, slightly lowering wheel efficiency all round (so everything, spool and max power) but decreasing surge by a much more useable amount.
So unless you have a comp wheel that will suirge without one, it wont do you any good.
Sounds nicer tho
Anyone wanna explain?
I thought (correct me if im wrong) ported shrouds reduced compressor surge by leaking some air out after the inducer, slightly lowering wheel efficiency all round (so everything, spool and max power) but decreasing surge by a much more useable amount.
So unless you have a comp wheel that will suirge without one, it wont do you any good.
Sounds nicer tho
#42
Originally Posted by Stavros
that means nothing to me
explain what it does, and how it does it, in a simple way for thickos like me please
explain what it does, and how it does it, in a simple way for thickos like me please
#44
Originally Posted by GARETH T
Originally Posted by Stavros
that means nothing to me
explain what it does, and how it does it, in a simple way for thickos like me please
explain what it does, and how it does it, in a simple way for thickos like me please
#46
Originally Posted by Stavros
Originally Posted by GARETH T
Originally Posted by Stavros
that means nothing to me
explain what it does, and how it does it, in a simple way for thickos like me please
explain what it does, and how it does it, in a simple way for thickos like me please
now think about a turbo?
#47
Originally Posted by Flux Capacitor
Ok I will shut up then
confused me even more tho, you saying these production cars (porsches?) have variable restrictors/throttles on the turbo inlets?
#48
Originally Posted by Flux Capacitor
Ok I will shut up then
you are right aswell. the new 997 turbo has one fitted
#49
Originally Posted by GARETH T
Originally Posted by Stavros
Originally Posted by GARETH T
Originally Posted by Stavros
that means nothing to me
explain what it does, and how it does it, in a simple way for thickos like me please
explain what it does, and how it does it, in a simple way for thickos like me please
now think about a turbo?
In that same vein tho, wouldnt that mean a WRC restrictor etc mean the turbo would spool up quicker? or would that be only such a small amount its not noticable?
#51
Originally Posted by Stavros
Originally Posted by GARETH T
Originally Posted by Stavros
Originally Posted by GARETH T
Originally Posted by Stavros
that means nothing to me
explain what it does, and how it does it, in a simple way for thickos like me please
explain what it does, and how it does it, in a simple way for thickos like me please
now think about a turbo?
In that same vein tho, wouldnt that mean a WRC restrictor etc mean the turbo would spool up quicker? or would that be only such a small amount its not noticable?
#52
true. cant see it being a huge amount tho, not totally blocking it like a DPV setup seems to (well, as much as a conventional throttle does).
so basically, if you had 2 throttles, one in conventional place, one pre-turbo, with the pre-turbo one closing a lot faster (ie if the conventional one is 50% shut, pre-turbo one is maybe 75% shut, or whatever is needed) than the convenional one, then you will have much less lag etc?
If thats right, the second question has to be is that that easy to do? Im no engineer.
so basically, if you had 2 throttles, one in conventional place, one pre-turbo, with the pre-turbo one closing a lot faster (ie if the conventional one is 50% shut, pre-turbo one is maybe 75% shut, or whatever is needed) than the convenional one, then you will have much less lag etc?
If thats right, the second question has to be is that that easy to do? Im no engineer.
#53
Stavros,
I think it was porches.
My experience is with electrical power generators (big ones )
These have a 15 to 45 litre engine runnnig on diesel/gas/sewage gas etc...
They have to maintain 1500 rpm to produce the exact voltage and mains frequency.
As electrical load is applied, the generator will want to slow down so more
throttle is applied under control of a computer.
Consequently, the engine will want to speed up as load is reduced.
Most genrators cant respond quick enough and as things are turned on or off
the engine speed will wander up/down momentarily which isnt good but
is tolerated for a short time.
Diesel powered sets arent as suseptable due to their low end torque but on
gas powered sets, you need instant throttle response.
The company I am contacted to, has a system that has this exact
technology on turbos that you can fit you head into the inlet !!!
The throttle is designed like an iris of an eye to keep the air charge as a
riffle barrel effect into the turbo inlet vanes.
I will see if I can get some piccies but alot of this is company confidential
and I dont want the sack just yet
I think it was porches.
My experience is with electrical power generators (big ones )
These have a 15 to 45 litre engine runnnig on diesel/gas/sewage gas etc...
They have to maintain 1500 rpm to produce the exact voltage and mains frequency.
As electrical load is applied, the generator will want to slow down so more
throttle is applied under control of a computer.
Consequently, the engine will want to speed up as load is reduced.
Most genrators cant respond quick enough and as things are turned on or off
the engine speed will wander up/down momentarily which isnt good but
is tolerated for a short time.
Diesel powered sets arent as suseptable due to their low end torque but on
gas powered sets, you need instant throttle response.
The company I am contacted to, has a system that has this exact
technology on turbos that you can fit you head into the inlet !!!
The throttle is designed like an iris of an eye to keep the air charge as a
riffle barrel effect into the turbo inlet vanes.
I will see if I can get some piccies but alot of this is company confidential
and I dont want the sack just yet
#54
Aaah! Like an Iris on the turbo inlet. An Iris has got to be a great way, though how much better that is than a conventional throttle i dunno, but sure sounds in my head like a good plan.
#55
Originally Posted by Stavros
true. cant see it being a huge amount tho, not totally blocking it like a DPV setup seems to (well, as much as a conventional throttle does).
so basically, if you had 2 throttles, one in conventional place, one pre-turbo, with the pre-turbo one closing a lot faster (ie if the conventional one is 50% shut, pre-turbo one is maybe 75% shut, or whatever is needed) than the convenional one, then you will have much less lag etc?
If thats right, the second question has to be is that that easy to do? Im no engineer.
so basically, if you had 2 throttles, one in conventional place, one pre-turbo, with the pre-turbo one closing a lot faster (ie if the conventional one is 50% shut, pre-turbo one is maybe 75% shut, or whatever is needed) than the convenional one, then you will have much less lag etc?
If thats right, the second question has to be is that that easy to do? Im no engineer.
blag me a dyno for my workshop,, and ill do your some tests
#58
Originally Posted by GARETH T
i dont know what it would do to turbo life aswell,, im sure it could send the shaft speed very high
Was thinking of it as safer than normal ALS, but maybe not.
Due to the way it works you couldnt use em both at same time either.
Tho if your confident it will send shaft speed sky high, its safe to say your confident it works well then
#60
Im guessing its less effective and/or (prob and) more turbo killing than a well designed "conventional" ALS setup, otherwise theyd be commonly used today.
Sure would be cheaper to make tho (unless, like a escort cossie, the ALS bits are staring you in the face even as standard) by sounds of it.
Sure would be cheaper to make tho (unless, like a escort cossie, the ALS bits are staring you in the face even as standard) by sounds of it.
#61
Ported shroud is a way of reducing surge but side effect is you will no longer make as much power at the top end, it effectively shits the compressor map left (although it moves the surge line more than it moves the right handside if done properly)
Cant see what all the confusion is about
Cant see what all the confusion is about
#62
TBH chip, i dont even know why ported shrouds got mentioned, it had fook all to do with what i was on about
Thankfully what I was asking about got answered in the end, good work peeps
Thankfully what I was asking about got answered in the end, good work peeps
#63
Originally Posted by glancy2081
Originally Posted by rapidcossie
what do you think happens in a ported shroud Gareth?
#64
The DPV has nothing to do with the turbine side or ported shrouds, it is exactly what you have described a throttle pre turbo. It was used on most of the F1 turbo engines, but with ball bearing turbo's coming towards the end of the F1 turbo days and the eventual banning of turbos in F1 the idea appears to have been lost to a lot of people . I would imagine the improvements to anti-lag meat it isn't really needed in rallying but for a road car I can't understand why it never became the norm.
You can easily replicate a good portion of its effect just by moving your throttle body from the plenum to be infront of the turbo, however for it to work you'll need a turbo with a carbon seal. To save me the effort of explaining how it all works here is a link to the original patent that goes into plenty of detail of how it works http://patft.uspto.gov/netacgi/nph-P...6&RS=4,471,616 click the images link and you'll be able to see a couple of pictures that should make it all pretty obvious .
The bmw and zakspeed f1 engines just used a standard throttle body infront of the turbo no fancy multi blade unit like the one in the patent.
You can easily replicate a good portion of its effect just by moving your throttle body from the plenum to be infront of the turbo, however for it to work you'll need a turbo with a carbon seal. To save me the effort of explaining how it all works here is a link to the original patent that goes into plenty of detail of how it works http://patft.uspto.gov/netacgi/nph-P...6&RS=4,471,616 click the images link and you'll be able to see a couple of pictures that should make it all pretty obvious .
The bmw and zakspeed f1 engines just used a standard throttle body infront of the turbo no fancy multi blade unit like the one in the patent.
#65
Originally Posted by Chip-3Door
Ported shroud is a way of reducing surge but side effect is you will no longer make as much power at the top end, it effectively shits the compressor map left (although it moves the surge line more than it moves the right handside if done properly)
Cant see what all the confusion is about
Cant see what all the confusion is about
its a restrictor in the inlet of the comrpessor!
the subject is about throttles mounted on the inlet of compressors (restricting flow)
they do one and the same job, just at far diffrerent flow ratess it just dont look very obvious when you first think about it
#66
buzznwood
so on some of the norwegian cars (the silver escos?) that say they are using F1 turbo's, do they have this device fitted in the compressor housing? because they seem very responsive for the size of turbo
so on some of the norwegian cars (the silver escos?) that say they are using F1 turbo's, do they have this device fitted in the compressor housing? because they seem very responsive for the size of turbo
#67
why would you need a carbon seal mate? i thought that was just for cars with pre-compressor carbs, or am I getting mixed up.
aside from when it went off an a tangent with the totally unrelated proted shroud crap, and the VNT bullshit, this is an awesome thread, best one in a long time
aside from when it went off an a tangent with the totally unrelated proted shroud crap, and the VNT bullshit, this is an awesome thread, best one in a long time
#69
aah, poo.
i wonder how serious (how much) that happens.
sounds like some expererments are needed.
i love this, one of the least known things about turbos, something ive always wanted to know about, and i do now, mint
i wonder how serious (how much) that happens.
sounds like some expererments are needed.
i love this, one of the least known things about turbos, something ive always wanted to know about, and i do now, mint
#71
the original quote was just from some website about renault5 maxi turbo grpB cars, but thats not where i first heard about it, thats just something i dug up yesterday.
1st heard about it from the book i mention the name of to gareth on an earlier post in this thread.
1st heard about it from the book i mention the name of to gareth on an earlier post in this thread.
#72
Originally Posted by Stavros
aah, poo.
i wonder how serious (how much) that happens.
sounds like some expererments are needed.
i love this, one of the least known things about turbos, something ive always wanted to know about, and i do now, mint
i wonder how serious (how much) that happens.
sounds like some expererments are needed.
i love this, one of the least known things about turbos, something ive always wanted to know about, and i do now, mint
definately sounds like some experimentation is needed
#74
Originally Posted by GARETH T
steve you have described how it works in your first post
because it is arranged so that the turbine will idle at a higher speed than it would given a fixed intake air direction and area. And of course, the higher the compressor idle speed, the shorter the time it will take to reach its important operating RPM. Result: less lag
the only time you would need it would be in a slow corner but how would this work on a road car?
and isn't it the same with every turbo'd application?
get it to spin up to within the range it needs to be in for the best response and you've got power etc and if you are outside that range you won't
with the motorsport application in mind you wouldn't be outside of the range
secondly
what happens when you put yuor knob in a vacuum cleaner?
if you are restricting the flow then the motor will pull more to get to the same airflow it requires
but it's the oposite of a turbo where you are sucking air in rather than pushing air through
or is this linked to the other side of things and, in that case, disregard this post
#75
Originally Posted by dojj
what happens when you put yuor knob in a vacuum cleaner?
if you are restricting the flow then the motor will pull more to get to the same airflow it requires
but it's the oposite of a turbo where you are sucking air in rather than pushing air through
or is this linked to the other side of things and, in that case, disregard this post
if you are restricting the flow then the motor will pull more to get to the same airflow it requires
but it's the oposite of a turbo where you are sucking air in rather than pushing air through
or is this linked to the other side of things and, in that case, disregard this post
#76
so why does it seem to be struggling then?
is it because it's got nothin to suck on so to speak and can freewheel to it's max rpms or have i got the wrong end of the stick again?
is it because it's got nothin to suck on so to speak and can freewheel to it's max rpms or have i got the wrong end of the stick again?
#78
Nick is doing classic fan theory....if you block or restrict any flow you acheive lessen work effort so the power is reduced.....
If you had a vacuum cleaner running at say 3 amps....block the inlet off and it will reduce the consumed power...to say 2.5 2.6 amps....
If you had a vacuum cleaner running at say 3 amps....block the inlet off and it will reduce the consumed power...to say 2.5 2.6 amps....
#79
Originally Posted by foreigneRS
i guess you need a carbon seal as there will be a depression in the compressor housing if you have a throttle on the inlet to it, so oil would be sucked out of the bearing?
Dojj, the basic idea behind the system is that you keep the compressor spinning at a high speed at all times it won't give you huge amounts of boost at idle which is no doubt why anti-lag systems have replaced it in the world of motorsport, but it does help improve the transient response. If your just going down the road on part throttle there is no point having the compressor work more than it needs to.