Turbo operation question

[fender22]

Hi. Have a 93 Deefer, 200TDI, 140000k's. Took it to the mechanics today and he mentioned there was a bit of a whine at a certain rev range. At first I told him I'd never noticed it but then I remembered.
When you get to about 2500 rpm, or put your foot down hard you can hear ....not what I'd call a whine or a squeal, more like a fan whir I guess. Not loud, just noticeable to hear over the engine... something spinning a lot faster than the poor old donk is going.

When I first bought the vehicle and heard it, I nearly thought it was the clutch slipping because whatever it was was whirring faster than then engine was going and would notice it when I put my foot down to power up a hill or something. Anyway, I guess that's the turbo eh?

Was wondering how they operate...do they cut in at a certain rev range? Does that sort of noise sound normal?

[stig0000]

you tube is your frend here, its the best way to see how a turbo works, but bascly when it gets 'on boost' you will hear that ausum turbo sound,, some are louder then others, like mine is very loud,, only as i have my boost wound right up,

shoudl sound like a light wissle on a tdi,

[fender22]

That sounds about right, a light whistle...just enough to notice

[fender22]

Is the turbo meant to "cut in" at a certain rev range?

What happens if it craps itself or a bearing goes? Will the vehicle still drive?

[stig0000]

it will, but if the turbo goses and pumps oil into the intake,, the turbo will be forcing alot of oil into the motor, witch can mean it could run on,, thats very worse case tho,,

the noise may become very grindy sorta noise and thats the impela hitting the housing,, prity rare tho,

[slug_burner]

Is the turbo meant to "cut in" at a certain rev range?

What happens if it craps itself or a bearing goes? Will the vehicle still drive?

Not sure if your pulling our leg here.

The turbo is not a switch where it is either on or off, it has some momentum so takes a brief period to build up revs on the turbine/compressor and it also needs to use the heat and pressure coming out of the exhaust ports in the engine and that also builds up as the engine is fed more fuel.

Yes the vehicle will still drive as long as the turbo failure does not cause another problem. The vehicle will just be very gutless.

[tazd]

basic but it shows how the turbo works

YouTube - How a turbo works

[fender22]

Not pulling anyones leg, just don't have a clue



Not sure if your pulling our leg here.

The turbo is not a switch where it is either on or off, it has some momentum so takes a brief period to build up revs on the turbine/compressor and it also needs to use the heat and pressure coming out of the exhaust ports in the engine and that also builds up as the engine is fed more fuel.

Yes the vehicle will still drive as long as the turbo failure does not cause another problem. The vehicle will just be very gutless.

[Lucus]

The turbo "cuts in" or as its more commonly refferd too "spools up" at a certain RPM as the turbo is nothing more than an air pump.

Think of a wind mill, it needs a certain amount of wind (exhaust gas) too pump a certain amount water (charge air) so that gives the feeling that the turbo is cutting in as it moves up into its operating range.


Boost pressure refers too the amount of positive pressure in the intake system of the car. Boost doesnt = power. Boost and Air mass arent related.IE a BIG low boost turbo will move a larger mass of air at a lower boost pressure and Charge air temp than a smaller turbo that has too work flat our too produce the same MASS of ait at a higher pressure. Normally at the expense of response. You need extra airmass too add extra fuel too create extra torque and power.

have a read of the turbo's 101 section on the garret website. Lots of good info there!:)

TurboByGarrett.com - Turbo Tech101 (http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech101.html)

Luke:cool:

[xuma]

Hi Guys, I had a similar problem with a 300 tdi with all the loud bad noises and the fix was replace the perished hose from the charge air to the waste gate actuator,
Seems the noise was a result of the waste gate not opening when necessary.
Just my 2 cents worth.
Xuma

[Loubrey]

Xuma,

Standard problem on the 300Tdi (one of the very few!) is that hose!

I was out in the sticks when I blew one and no spare left. I ended up putting a similar looking one from a Massey Ferguson tractor in and that lasted about a 100 000km!

Unfortunately 300Tdi's like a bit of cool-down time after a long hot stretch and 2 to 3 minutes of idling feels like an age...

[slug_burner]

Not pulling anyones leg, just don't have a clue

Here is another for you

YouTube - Forced Induction - Supercharger vs. Turbo Charger