lordagrabah

iTrader: (1)

Yeah I know this is a newb question but what causes certain turbo's to make a whistling noise while spooling. Some turbo's make the noise and other's don't. Here's an example. Excuse the vid.
http://www.youtube.com/watch?v=UPSG8hyrjoU

stinksause

iTrader: (5)

It's a Kuhneutson Valve that's worn out ....

Mazurfer

But wait......................you didn't give him the link! http://kalecoauto.com/index.php?main...db950c384b8b64

They got all kinds of stuff one might need!

jasonrxeight

OP's sig answered his question
"Never argue with a dummy because the dummy always wins."

stinksause

iTrader: (5)

I wanted him to find it on his own .... KaleCoAuto never gets old!


OP, this video has a clue ...

http://www.youtube.com/watch?v=Erjhkv9AzKY

9kBeep

OMG!!! i have never seen that website before! i may have just **** myself laughing so hard! my favorite was the looping exhaust! "now get 100% back pressure"

lordagrabah

iTrader: (1)

Yeah I knew I would get flamed for being ignorant lol. But really is it the size of the turbo that changes the characteristics of the sound or is it the components such as ball bearings? I have no clue.

jasonrxeight

its called a wastegate letting air out so the extra pressure wont blow up the engine.
if you can gear the turbo that far away at that speed, its shot.
you can get different sound by using different wastegate.

nycgps

iTrader: (1)

u forgot about the blowoff valve.

jasonrxeight

yea, that too but it only makes noise when you let off the gas.

SayNoToPistons

iTrader: (8)

The wastegate does not make whistling sounds. Have you ever heard a wastegate dump?

OP: Fast moving and compressed air. End of story.

NgoRX8

iTrader: (1)

Turbo.

stinksause

iTrader: (5)

that's what I was trying to get at.... OP has a fundamental misunderstanding of turbo systems tho ... and boost controllers ... I was trying to edumacate

lordagrabah

iTrader: (1)

So in a nutshell, different turbos make different noises? If so, is it the larger the turbo, the higher the pitch during spool up? This may be a better example of what I'm talking about.
http://www.youtube.com/watch?v=cslnCWlB9vE
or
http://www.youtube.com/watch?v=2HWuEjcNisM

stinksause

iTrader: (5)

In a nutshell, you want the turbo for your application.

Big Turbos will flow a lot of air efficiently .. putting out big power number, BUT take long to start flowing that air, so your power is narrow and not easily accessible (all up high)

Smaller to Medium Turbos (and 99% of factory turbos) have great response (little boost lag), however, they can't flow as much air so your maximum power is lower, but you have more power earlier on and you have a wider power range.....

A boost controller "controls boost"

Boost is not exactly the pressure of the intaked air, but rather the amount of air flowing into your engine --- most people confuse this...

However, the more air the turbo is pushing into your engine, the harder your engine is working, more wear etc ... this is why people have a high and low boost setting for example...

Nonetheless, your turbo is producing a fixed amount of air flow ... to lower, the airflow, you need a BOV to bleed off some of this air in precise amounts that are controlled by the boost controller

What you hear in the first video is the BOV bleeding off this air.

When one gets off the gas, the pshhh you hear is the BOV and wastegate bleeding off the extra pressure...

wastegate: exhaust(hot side, between engine and turbo)

Blow Off Valve : intake(cold side, between turbo and engine)

wastegate no BOV in this diagram:


3000gt turbo system (much more complicated, but you can see the BOV):

lordagrabah

iTrader: (1)

I apologize for the mix up. I have a basic understanding of how a turbo system works and I know what a b.o.v. sounds like. What I'm asking is why do some turbo's have that jet engine whine like diesel trucks while others just having a "whooshing" noise.

nycgps

iTrader: (1)

because every car/owner's setup is different. some like it quiet, some like as loud "wizzZzzZZZ" as possible.

some manufactures of BOV have their sound clips up.

as for waste gate, like above said , its used to vent excessive Exhaust pressure which might damage turbo.

BOV on the other hand, its used to vent excessive pressure on the intake side so it will not kill the cool side of the turbo and other intake components .

SayNoToPistons

iTrader: (8)

^ The wastegate isn't exactly there to protect the turbo from damage...

http://www.streetracersonline.com/ar.../wastegate.php

mysql101

How do you figure? If your WG isn't there, the turbo will overspin.

stinksause

iTrader: (5)

waste gate has two purposes:

1. Protect Turbo from over spinning to prevent damage to bearings and lengthen turbo life ... Is this referred to surging? I believe one the Greddy fixes refer to this issue.

2. Protect Engine from excessive back-pressure ... some say (Pettit) this is VERY relevant to the Renesis......

nycgps

iTrader: (1)

Lemme explain this a little more.

1. Even a Turbo can rev 10K+ some can go 100K range ~ BUT, everything has a limit, when it goes over that limit, it just breaks. when the waste gate's pre-set limit has reach, it opens the door, to let excessive pressure back to the exhaust stream. it also slows the turbo down.

2. before the waste gate opens, there is a lot of pressure inside the turbo exhaust manifold. because turbo itself is a exhaust restriction. when the pressure is too high, it might effect the pressure coming out from the engine. that's because air will always "flows" to areas with lower pressure. if the pressure inside the combustion chamber is about the same as the pressure inside the turbo manifold. boom.

Our engine's side exhaust port is already a pretty "poor" flowing design, so if the exhaust does not go away, boom.

3. If the turbo revs too high, it might create too much boost which gives the engine even more stress. if it goes over the limit. Boom.

this is why tuning is very important for all FI cars.


*forgot one thing* there is external waste gate & internal waste gate, both does the same thing, just different way to vent.

lordagrabah

iTrader: (1)

I gave up on getting my question answered. It's probably my fault, anyway thanks for the input everyone.

nycgps

iTrader: (1)

u still don't get why? wow.

stinksause

iTrader: (5)

External is better for venting since it is usually bigger right?


My turn, What is surging for a turbo?

wcs

iTrader: (2)

I know I'm not going to get the terminology right here ... but I think I understand the situation.... I'll take a crack at it

The surge line is relevant only at idle, I believe.

If the volumetric efficiency of the engine at idle is less than the amount of air being move by the turbo it will produce to much back pressure and the cause surging.

Something like that I think .....


And it is also my understanding that it is the particular characteristics of the turbo that should be considered in order to prevent surging.
Thus the turbo flow map.