How they work?

I know they help prevent surge, but how?

 

do they only work if you use red bull as octane booster?

 

On the car that I have seen this type of inlet on, it suffers from very bad surge. Obviously not sure if this is related? Doesn't this help spool up (so I was told by the owner)?

 

I would imagine it works on same principle as an aircraft engine inlet duct , which on fighters etc (and on some f1 cars- barge boards etc) is positioned slightly away from the main body, as it removes the turbulent boundry layer of air by effectivly "peeling" it away from the smooth airflow. turbulent air is inherent in any intake system,by keeping the airflow laminar into the compressor as much as possible it is far easier to conrol surge/stall etc

 

Will- WAs that a cut n paste from a website that you added "I would imagine" at the start of, or are you very clever?

Either way- Good reply!

 

Its just a restricter (spelling)

 

Restrictor in what way? How can a restrictor reduce surge (which is the point of a Ported Shroud inlet)

 

I'm an aircraft engineer Itsmeagain , but I added I would imagine as I might be talking complete bollox

 

I think your right will, but then again ive no fucking clue

 

I had it done on my MD240... still surged like my balls do if I haven't wanked for 2 days... (thats ALOT )

I'll see if I can find a picture of it. Hold on (The Turbo, NOT my full balls)

 

Some air is meant to enter the 4 sausage shaped areas in the shroud (which also has a slit in the housing) and passes through the slits and onto the compressor wheel and in theory, speed the compressor wheel up.......doesn't work on an MD240R....

 

AROFL

 

It works by providing fast moving low volume air to the sides and rear of the
compressor wheel which experience high vacuum under boost which adds
drag to the wheel.
This ducted air reduces drag/vacuum and heat build up in the air charge.

 

SECS, sounds good too me

 

steve who's engine is that?

 

Ade- NOT Lees (the copying bastard ) tho he is using the same turbo as that.

Thas a R32GTR from America, 925bhp@wheels if i remember right

 

LOL @ the above descriptions.

The answer is in what are you trying to achieve?

Think about surge and what causes it and the answer is logical.

Everyone keep guessing it makes for fun reading!

 

I was just reading through this and thinking similar!

Think along the lines of alleviating pressure build between the inducer and exducer and have a few more guesses folks...

 

Just to help people guess again, I'll let you know that surge is caused by the compressor stage processing more air than the engine can consume. With that in mind, for a given turbo shaft speed how can we make the compressor stage process less air in order to reduce surge, but keep a large compressor wheel?

Answers on a postcard??

 

roflol.. thats enough tips

 

Stu, pls PM the answer so I can look really cool and impress Karl... cheers mate

 

Final tip for ya:



Porkie... i reckon with your level of intelligence you can now work it out yourself pal

 

Isn't the whole point of fighter air inlet systems to control the inlet air speed and density. This is for keeping the air intake velocity sub sonic in all situations no matter how many machs the aircraft may be doing. This is the whole point of the most popular moving cone (MIG 21, Mirage,...) and deflector plate designs (F14, Mig 25, Mig 29,...).

 

BTW im not trying to achive shit as my turbo hasnt got a ported shroud Just wondered

 

is it because the air will take longer to get into the turbo (as there can be more air on the front of the compressor housing and the pressure will be lower at that certain moment then when u havent got it done?

 

restrict the amount of air that can get it, hence less surge?

 

Am i right in saying ported shroud turbos sound like a fookin Jet engine? Heard a few cars with them on (mainly GT42s/T51s) and they dead high pitched sounding crazy noise...

 

Shroud

 

this is interesting. i want to have a guess at what is happening here.

turbo surge happens when the compressor is making more air than the engine can consume. i don't know why we can't open the wastegate to slow down the turbine, and hence the compressor, at this point which should be possible if we have mappable boost and a suitable sized wastegate shouldn't it?

anyway, assuming we cannot slow the compressor down in this way we need another way. how about if the compressor gets up to a certain speed the air entering it will go mental and form a sort of a barrier in front of the inlet to prevent too much air being sucked in. that means that the engine will not be being force fed more air than it can handle which will keep the turbine speed down and reduce surge.

somehow the ported shroud makes the air go mental and not get sucked in

is that something like it?

 

 

Matt... Cant you see a ported shroud in that pic? I cant

Think that was before it had the ported shroud....

 

did i say there was

 

its a bit quick then ...

 

Yes, yes you did

 

I wrote this to explain the ported shroud NOT why it prevents surge.

 

foreigneRS,
nail and head,,, well the way i understand it


what if you havent got enough actuator pressure to overcome the preload, this is whats normally happening,

 

Has this riddle been solved then lads??

I might have a stab(probably in the dark......)

Is it to do with the speed/amount of air hitting the exducer of the compressor wheel? Either blocking the amount that hits the outer tip as this will turn the wheel harder/quicker kinda like the larger the gear on your pushbike? Or is it somehow increasing the speed of the air that will hit the outer tips by increasing the pressure using the shroud to "tune" the air?

Thats probably bollox but I wanna, like Steve, know the anwer from both Karl and Stu and they wont post the answer till we try to guess!!!


P.


I have heard a few really cool sounding Jap motors and have never known what made them sound so mint....maybe this is the reason?? Has anyone seen the viddy of the 200SX S13 with 513BHP doing donuts this sounded really highpitch when spooled up??

 

oh god, we're getting all techy