Hi,

If you havn't notcied by now im quite ignorant when it comes to engines escially turbos... i understand that boost is the 'power' in the turbo measured in ftlb...(correct me if i go asstray) and this pressure can be measured on a dial and incressed to create more BHP as a reuslt a quicer car.. im right in thinking a turbo assists the engine to get rid of the waste gasses helping the engine run...thats why turbo cars genrally out performe no turbo cars..

whats the standard ftlb of a standad turbo on the octy VRS's?

Joel

Slightly rippled with a smooth underside.

(sorry couldn't resist)

Slightly rippled with a smooth underside.

(sorry couldn't resist)

And the winner is spindrift for the quickest most annoying answer EVER !!

Joel

I'm an engine numpty too with regards to turbos.

Have a look here http://auto.howstuffworks.com/turbo.htm

Sorry, Joel, you're a few feet off the mark.

The turbo (or turbocharger) is a compressor which sits on the intake side of the engine. This compressor is (rather cleverly) driven from the pressure produced by the exhaust gasses leaving the engine. The "boost" referred to is the barometric pressure created in the intake when the turbo is spinning.

A similar arrangement, which is driven by a belt, is called a "supercharger"

Hope this clears things up. An expert may be along shortly to give a more detailed explanation of how the 1.8t engine works......

Phil

This this will explain far better than no end of words on here:

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

As for Boost being "Slightly rippled with a smooth underside" good reply

This this will explain far better than no end of words on here:

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

As for Boost being "Slightly rippled with a smooth underside" good reply

I have a wierd feeling of deja vu

Isn't a boost a chocolate bar rich in glucose?

Philc was spot on, The more air you can get into an engine the more fuel you can get into the cylinder as well... Result.... more power. Now an intercooler helps to cool the air coming into the turbo, the cooler the air the more dense the air is... the more dense the air is the more you can get into the cylinder...

ahhh yes that web site is a good read...only thing i didnt mention was the DV now my again basic understanding is this release 'back pressure' between gears or when ever you take your foot off the gas.. so the turbo keep spinning the direction it should be..next time you apply the gas it still has a good spool rpm.. :confused:

Joel

Right IIRC the dump valve sits between the throttle plate and the inlet for the turbo. It releases pressure behind the turbo when you take your foot of the throttle and the throttle plate shuts, the dump valve stops the turbo stalling IIRC thus making it more efficent for when you throttle up again as the turbo is already spinning.

The Accuator which is after the turbo regulates the pressure the turbo runs at and when the pressure is high enough it dumps the excess pressure out of the exhaust past the turbo to regulate the boost pressure to whatever it is set at. This is what you adjust when you wanna run higher boost pressures but run to much boost pressure and it's bang !

Think of a turbo as a hairdryer. You turn the hairdryer on and it sucks air in one end and chucks it out t'other. The air that dries your hair is 'charge air' and the pressure the hairdryer generates is 'boost pressure'

The 'dump valve' is like a spring activated safety relief valve for the turbo. When accelerating the engine demands charge air so all is tickety boo. But once the demand for charge air reduces (during a gear change for example) the charge air has to be got rid of or it could stall the turbine and damage the blades. This is where the 'safety valve' comes in and releases charge air to atmosphere or in the case of the 1.8T motor back to the airbox. The tension in the spring is set such that the valve will lift when it sees a certain pressure.....

There is lots more useful information on DVs in the link below:

http://dv.mistertam.com/

This is where the 'safety valve' comes in and releases charge air to atmosphere or in the case of the 1.8T motor back to the airbox. .

or in my case the atmosphere PPPPPSSHHHHTTTT

i see so even tho my DV is in the line pipe that goes into the intercooler it still releases the unwanted air.. in the turbo's pipe system

joel

I suppose any location between the inlet manifold and the outlet of the turbo is ok as long as pressure drop isn't a problem. The usual location is as close to the pressure source as possible...

Also helps prolong the life of your turbo as the stress of it stalling causes premature death.

Turbos are basically jet engines without the combustion chamber of a jet engine in the middle, and instead the whole assembly of your engine block.

A picture is worth a thousand words, so they say. (It's a block diagram of a Diamond Star - joint Mitsubishi/Chrysler - 1.8 turbo engine; almost identical to the VAG 1.8T.)

Turbos are basically jet engines without the combustion chamber of a jet engine in the middle, and instead the whole assembly of your engine block.

Indeed, and some people have made jet-engined beer coolers from them :cheers:

That is brilliant!!! hats off to the guy. Ever since (about 2 years ago) i found out a turbo was a jet engine - always wanted to make one....

P.S you can also see from reading that a turbo charger will happily run at 100000rpm - and some can even hit 150000rpm, so they have to be built well and especially with the problem of stalling from a speed like that, can cause a LOT of stress on components, which is where a BoV helps.

Can anyone explain the wastegate and actuator pls?

i found out a turbo was a jet engine

a friend of mine made one from an old T3 turbo, and some Gas.

Can anyone explain the wastegate and actuator pls?

The wastegate regulates the exhaust gas pressure available to the turbo. If the exhaust gas pressure is too high the wastegate opens to divert exhaust gases away from the turbine. The 'diverter' is a type of flap operated by an actuator - an electro / mechanical linear positioner.

The wastegate regulates the exhaust gas pressure available to the turbo. If the exhaust gas pressure is too high the wastegate opens to divert exhaust gases away from the turbine. The 'diverter' is a type of flap operated by an actuator - an electro / mechanical linear positioner.

On non "low pressure" turbo systems, the wastegate would simply act to limit the boost pressure. Exhaust gas (EG) pressure forces it open against a fixed spring pressure, resulting in an upper limit to gas flow through the turbine (and hence boost pressure).

It's a bit more sophisticated with a low pressure system such as the VAG 1.8T. The wategate has a fairly weak spring, and if uncontrolled woud open at low EG pressures, limiting boost to very low levels. The regulator valve - commonly known as the N75 valve on VAG 1.8T engines - is under ECU control; and regulates the exhaust gas pressure working on the wastegate, allowing it to stay closed longer, resulting in more boost.

It's the ECU control of the N75 valve which determines boost (and hence power/torque), and explains why the 1.8T is so amenable to tweaking.

Philc was spot on, The more air you can get into an engine the more fuel you can get into the cylinder as well... Result.... more power. Now an intercooler helps to cool the air coming into the turbo, the cooler the air the more dense the air is... the more dense the air is the more you can get into the cylinder...

all perfect just, the more dense the air- the higher the oxygen content. the higher the oxygen content the more burning the air can support:thumbup:

all perfect just, the more dense the air- the higher the oxygen content. the higher the oxygen content the more burning the air can support:thumbup:

Your 3.5 years late mate:)