??

Inlet pressure is not effected by fitting an intercooler, only the turbo to cylinder head side of the inlet manifold is pressurized so this extra volume, as you put, it is not pressurized.

An intercooler only serves to lower air temperature.

Lower air temperature equals denser air equals a greater volume of air which means more oxygen per combustion cycle, this combined with the turbo which takes that air and compresses it up to 1 bar above atmospheric pressure, means even more oxygen per induction cycle.

For any combustion to take place you need three things:

Fuel..............oxygen.................and ignition

If you can increase the volume of air OR the amount of oxygen within that air you can create a more powerful explosion/power stroke.

NOS is a prime example of this, inject a gas into the manifold which has a high oxygen content and you will expedentially increase the power per combustion stroke.

Turbo's increase the oxygen content by compressing the air in each induction cycle.

Afterall "air" does not contain that much oxygen, approximately 78% is Nitrogen, only 21% is Oxygen and the other percent in carbon dioxide and other gasses.

Using the otherwise wasted energy (moving exhaust gasses) to propel a turbine that compresses the inlet manifold air, not only makes the engine more powerful but it makes it more thermally efficient, that is to say, more of the fuel is turned into kinetic (moving) energy, so a turbo is often used to increase fuel economy ie on heavy goods vehicle engines etc which all have turbo's (more power from a smaller engine unit.

Martin

The purpose of a turbo is to compress intake air, so you can get more air into the cylinders per charge - more air, more bang effectively.  When air is compressed though (by the compressor in the turbo) is also gets hotter and expands (this is bad!).  The object of an intercooler is to cool the compressed air, therefore allowing a 'bigger' charge into the cylinders.

fitting an air cooling system of some kind charge cooler or intercooler if effective makes the system more use its air better...

by fitting a cooling system you just giving the engine better quality air.. to a degree there will always be an improvement in combustion even without more fuel.

if the cooler is very effective and ALL Fuel going in is used then upping the fuel rate is needed.. but this is more the case when "MORE" air (ie higher pressure from the turbo) rather than more dence air s being fed to the engine..

Lets put it another way:

On a cold damp day your engine will be more powerful than on a hot summers day. So does that mean you have to turn the fuel up on a cold day? Nope!

In general the engine has many sensors that detect temperatures/oxygen content in the exhaust/manifold air pressure and air mass as well as crank position, so the ECU knows where it is in the combustion cycle and based on all the information from the sensors it adjust fuel delivery accordingly.

A manifold absolute pressure sensor (MAP) is one of the sensors used in an internal combustion engine's electronic control system.The manifold absolute pressure sensor provides instantaneous manifold pressure information to the engine's electronic control unit (ECU). This is necessary to calculate air density and determine the engine's air mass flow rate, which in turn is used to calculate the appropriate fuel flow. (stoichiometry.)

An engine control system that uses manifold absolute pressure to calculate air mass, is using the speed-density method. Engine speed (RPM) and air temperature are also necessary to complete the speed-density calculation. Not all fuel injected engines use a MAP sensor to infer mass air flow, some use a MAF sensor (mass air flow).

Or how to rewire my flux capacitor? Tho gettin one of these babies up to 88.8 mph is hard anyway so not much shit'll happen anyway...

Thanx for the information tho chaps i have an intercooler fitted (badly) and am in the process of shifting it and getting ducting to it and wondered what the heck it did anyway! I reckon the oil cooler going on nex week will be more useful tho!  

Brain fodder, chomp away.

"Inlet pressure is not effected by fitting an intercooler, only the turbo to cylinder head side of the inlet manifold is pressurized so this extra volume, as you put, it is not pressurized"

Erm...thats odd, coz my intercooler is on the pressurised side of the turbo.........in other words the air route is

Airfilter to Turbo to Intercooler to Cylinder and out via turbo to exhaust....

GaV

An intercooler is, by definition fitted between the turbo and the manifold.
Manifold pressure will be affected by fitting one.  The air system is not static, it flows and the additional restriction of the intercooler and pipework to it will lower the pressure after it.
I don't know if the T3 turbo is wastegated, or where the wastegate sees it's pressure from (usually compressor housing, but sometimes direct from the manifold).

In summary you could up wastegate setting a bit, but to see real benefit you need to up fuelling, or you could just enjoy the engine running sweeter on more days....
You may also see better fuel economy as the engine will run leaner... however if you overcool the air you might get white smoke.

Let us know how you get on.