Usefulness of wastegate

[BLaCkHoWLiNG]

joe: ahahhah.. u took the other 4

 

[VANILLA]

To control overboost, a pneumatic relieve valve like the ones used on CART racers in US would be more viable.QUOTE]

ya thats the one i wuz mumbling about, wiseguy:_:

 

[alvin24]

dude i already got the fluid dynamics book ...i stole it from the library while doing my degree in mechanical engineering....a few years back......i also use to design piping systems for factory in my old company....thats why everything around a turbine in an engine revolves around preasure and not flow......there is also positive preasure and negative preasure(vaccum)........

Hahaha... i surely hope u don't expect me to actually believe that now do u? oooOOOoo.... wow... degree in mechanical engineering, design piping system for factory.... yES... i 'believe' u... really... coming from a guy who doesn't know how to spell PRESSURE.

How can someone so 'educated' say things that are so 'educationally' shallow? Saying things of the obvious. "there is also positive PRESSURE and negative PRESSURE"... i think people have already learnt that in form 1 science.

Anywayz... i too lazy to argue with you la... if you REALLY have the fluid dynamics book... and you've REALLY went thru the turbomachinery topics... then you wouldn't be saying what u've just said.

Go look up the Euler equtions on turbomachinery la...

 

[Dino@Casper]

I dun see why there cannot be a negative pressure?.. why isn't that possible.. simple year 2 fluids.. Force is a Vector, area is scaler.. pressure is force over area.. so its still a vector.. Now now.. a Vector has a have direction n magnitud.. so are u telling me simple physics here is wrong??.. Everything we consider in our system is to be at atmosphere pressure.. which is actually 101KPa so if we consider something below that wouldn't it be negative ... and what about space... i mean how can u say there is not such thing as no negative.... There is a special term where the pressure is actually lower than atmosphere i can't remember the term but is there somewhere.. so what would u call that.. thats what i have learn.. No point doubting his qualification..

And about your qoute saying that the air flow has more effect on the speed of the turbine.. thats true in off cause.. it just like spinning a disc where in this case it would be a shaft.. definetely your speed of shaft will actually depend on the speed of your air flow... why cause air is driving it.. when it reaches a steady state.. where the wastegate actually open to allow the extra exhaust gas the speed of the exhaust air would roughly be the same with the angular speed of the shaft.. why cause if there is a difference it will cause acceleration to the system.. convervation of momentum.. But as mention before.. Pressure is DIRECTLY related to your Velocity.. Simple dimension analysis.. And i mean giving an example of a simple pump that pumps water inside ur house.. the higher the pressure wouldn't it be the faster the water is flowing?... so what are u saying about the speed and the relationship with the turbine is more important?? i just simply find it hard 2 understand
So I dun get what are u still arguing about.. unless i have said something wrong that u can prove.. please go ahead..

I do believe he has his points, so what if he cannot spell correctly.. that doesn't mean anything...

 

[alvin24]

Another fella trying to be smart...

Your whole 1st paragraph is rubbish... simply because nobody was arguing that fact. I never said there was no such thing as negative pressure also... DUH. I said that was OBVIOUS... and it was a shallow thing to say for someone of 'that' qualification because all of us have already learnt it probably in form 1 science... why? did u JUST learn it in your year 2 fluids ??

As for the 2nd paragraph... I'm really too lazy to explain to people who have closed minds. Go to your library, dig out a fluid dynamics book... turn to the pages on turbomachinery... and read up on Euler equations.

I can certainly understand why YOU don't find anything wrong with him spelling things incorrectly... coz' your grammar ain't that good either.
I just find it wierd for someone who supposedly GRADUATED mechanical engineering degree course... and WORKED designing PIPES for so long... and still NOT know how to spell PRESSURE correctly... kinda tells how often the word 'pressure' is used in his everyday context. I find it hard for even somebody to graduate a mechanical engineering course itself without knowing how to spell pressure!
ITs like driving a ferrari for 4 years and still spell it as FELLALI.
Best part is... that this is not a type error.. he's spelled it wrong even in his previous few postings!

Anywayz... i'm too lazy to argue bout this already lah. If you guys think u're right, then you're right loh... just assume i'm wrong loh. =Þ And neglect everything that I've said loh... *wave white flag* I surrender.

 

[imoloq]

hey hey let's not start a war in this thread ok?

both of you have good points.

Here's a good read on wastegates

 

[jeffblazed]

I dun see why there cannot be a negative pressure?.. why isn't that possible.. simple year 2 fluids.. Force is a Vector, area is scaler.. pressure is force over area.. so its still a vector.. Now now.. a Vector has a have direction n magnitud.. so are u telling me simple physics here is wrong??.. Everything we consider in our system is to be at atmosphere pressure.. which is actually 101KPa so if we consider something below that wouldn't it be negative ... and what about space... i mean how can u say there is not such thing as no negative.... There is a special term where the pressure is actually lower than atmosphere i can't remember the term but is there somewhere.. so what would u call that.. thats what i have learn.. No point doubting his qualification..

And about your qoute saying that the air flow has more effect on the speed of the turbine.. thats true in off cause.. it just like spinning a disc where in this case it would be a shaft.. definetely your speed of shaft will actually depend on the speed of your air flow... why cause air is driving it.. when it reaches a steady state.. where the wastegate actually open to allow the extra exhaust gas the speed of the exhaust air would roughly be the same with the angular speed of the shaft.. why cause if there is a difference it will cause acceleration to the system.. convervation of momentum.. But as mention before.. Pressure is DIRECTLY related to your Velocity.. Simple dimension analysis.. And i mean giving an example of a simple pump that pumps water inside ur house.. the higher the pressure wouldn't it be the faster the water is flowing?... so what are u saying about the speed and the relationship with the turbine is more important?? i just simply find it hard 2 understand
So I dun get what are u still arguing about.. unless i have said something wrong that u can prove.. please go ahead..

I do believe he has his points, so what if he cannot spell correctly.. that doesn't mean anything...

thanks la bro....my spelling really screwed up la...cause did my diploma in politeknik,then did my degree in local uni ....so every thing in malay......aiyo some dudes really know how to mix theory and fantasy .....turbo flow rate......so i think he better tell blitz,hks,greedy, to manufacture..flow meter instead of boost meter.....so funny la this due he thinking only about flow...flow this and flow that....but no pressure......somore tell us go and read fluid book......no need la...even though i dont know how to spell properly...but i still know how stuff works.......

 

[VANILLA]

hey leave him alone. its ok to disagree on laws of psychics. i do it all the time:)

 

[imoloq]

hey leave him alone. its ok to disagree on laws of psychics. i do it all the time:)

ya, defying grip when we're drifting! :regular_smile:

 

[alvin24]

thanks la bro....my spelling really screwed up la...cause did my diploma in politeknik,then did my degree in local uni ....so every thing in malay......aiyo some dudes really know how to mix theory and fantasy .....turbo flow rate......so i think he better tell blitz,hks,greedy, to manufacture..flow meter instead of boost meter.....so funny la this due he thinking only about flow...flow this and flow that....but no pressure......somore tell us go and read fluid book......no need la...even though i dont know how to spell properly...but i still know how stuff works.......

HAhaha.... don't try make up excuses la... i don't remember my older sister studying in Malay when she got her degree in a local U many many years ago also.

I dunno if u blind or lazy to read what i typed... or just plain dun understand laa.. I already explained about the flow thing... and u keep insisting to talk about boost meter... gosh... how clueless can u be? Why don't u talk about oil press and fuel press while u're at it? WAhahahahaa.... now we're arguing about exhaust flow... got nothin' to do with the intake pressures also.

I also give up lah... i guess u'll never understand... so i'll say this... YOU ARE RIGHT!! And because you are RIGHT... your "blitz,hks,greedy" (btw, its spelled GREDDY... DUH!)... should all go and produce EXHAUST PRESSURE METERS !! =)

 

[AsianBookie]

dun quarral relax

i just wanna know more abt the wastegates thingy

alvin24: relax

jeffblazed: relax

 

[Dino@Casper]

The waste gate is connected to the intake manifold through vacum right? so when the desire boost is achieve in the intake manifold.. the pressure in the intake through the vacum hose will open the valve in the wastegate so that exhaust gas is release.. that is how u maintain the boost pressure inside ur intake manifold.. so if thats not pressure i have no idea how can u say its the flow rate...

As mention earlier wikipedia and how stuff works already shows that wastegates work base on pressure... dun get what else u wanna argue about..

 

[Joeker]

The waste gate is connected to the intake manifold through vacum right?

Wastegate signal comes from compressor or i/c piping, not intake manifold.

 

[Dino@Casper]

my mistake so its still control base on vacum right? thats means pressure related i'm correct..

 

[jeffblazed]

HAhaha.... don't try make up excuses la... i don't remember my older sister studying in Malay when she got her degree in a local U many many years ago also.

I dunno if u blind or lazy to read what i typed... or just plain dun understand laa.. I already explained about the flow thing... and u keep insisting to talk about boost meter... gosh... how clueless can u be? Why don't u talk about oil press and fuel press while u're at it? WAhahahahaa.... now we're arguing about exhaust flow... got nothin' to do with the intake pressures also.

I also give up lah... i guess u'll never understand... so i'll say this... YOU ARE RIGHT!! And because you are RIGHT... your "blitz,hks,greedy" (btw, its spelled GREDDY... DUH!)... should all go and produce EXHAUST PRESSURE METERS !! =)

what ever la..............i aint blind as you...and iaint as lazy as you.......

 

[Joeker]

my mistake so its still control base on vacum right? thats means pressure related i'm correct..

No, it has nothing to do with vacumn.

 

[Dino@Casper]

Joeker.. what i mean its that if there is a hose from the IC piping to the wastegate... means the total pressure inside the intake of the car would be than related to the wastegate right.. and once the pressure increase pass the desired boost level the wastegate would open... is that wrong?

 

[chriiz18]

Hope this help you guys.

1) http://www.streetracersonline.com/articles/turbo/wastegate.php

2) http://auto.howstuffworks.com/

3) http://home.arcor.de/hildst/asBTerms.html

4) http://www.turbosmart.com.au/index.php?s=faq

5) http://www.mototuneusa.com/break_in_secrets.htm



This is some calculation you can use.

http://www.xspeed.com.au/conversion_tool.php

http://www.nightrider.com/biketech/calculations.htm

 

[Maxee]

http://www.turbosaturns.net/articles/wastegate101.htm

When you begin accelerating exhaust gas pressure builds inside the manifold and is forced through the turbo. This pressure continues to increase as the turbo spins faster (remember the positive feedback loop). When the desired boost level is reached the wastegate opens and vents pressure from inside the manifold so the turbo won't spin any faster.

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http://auto.howstuffworks.com/turbo1.htm

In order to achieve this boost, the turbocharger uses the exhaust flow from the engine to spin a turbine, which in turn spins an air pump. The turbine in the turbocharger spins at speeds of up to 150,000 rotations per minute (rpm) -- that's about 30 times faster than most car engines can go. And since it is hooked up to the exhaust, the temperatures in the turbine are also very high.

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Combined

When you begin accelerating exhaust gas pressure builds inside the manifold and the exhaust gas is forced to flow through the turbo to spin a turbine.

Both are correct, just different way to explain a thing. Peace.

 

[hattasan]

i wondering/dreaming...if the wastegate can really sound "woi"...
waahh that sure many ppl will buy.....

imagine....potong other kereta than change gear, after that ur car sound "woi..!"

wallamak...sure the other car terkejut berok nyer..!!!