centrifugal supercharger

[kappone]

For sure it is not a usual way to get more power on a 1,8t.
My thought is that ones a big turbo setup gives us a big lag in the low rpm range and high power at the high rpm , this way we could use e big supercharger and to have the power increasing the way the rpm is increasing. So we would have as high power as a big turbo but having more power from the low rpm. Also the drivability will be very good since the power is not coming sudently.the intake temperature will be lower too since the charger is like a half turbo ( the cole side).
There are companies like rotrex, paxton,vortech but I never saw a kit for a 1,8t.

What do you think about a upgrade like this?

[Jeronkie]

For sure it is not a usual way to get more power on a 1,8t.
My thought is that ones a big turbo setup gives us a big lag in the low rpm range and high power at the high rpm , this way we could use e big supercharger and to have the power increasing the way the rpm is increasing. So we would have as high power as a big turbo but having more power from the low rpm. Also the drivability will be very good since the power is not coming sudently.the intake temperature will be lower too since the charger is like a half turbo ( the cole side).
There are companies like rotrex, paxton,vortech but I never saw a kit for a 1,8t.

What do you think about a upgrade like this?

First Vw have it they call it the 1.4 tsi twin charge (engine of the year lunched in 2005 ), Super charger and turbo , and as you describe they use large Turbos with Lag on a small engine , to give it some low down grunt they use the supercharger   

Actually Old as Lancia Delta S4 rally car used twin charge in the 80’s   

The Problem with this , Where the exhaust gas goes to waist in any case why not use it , the Supercharger depending on the type use HP from the engine to work and you will struggle to find something good enough that will work very very low they still have some form of Lag even for a supercharger

Then to correct your statement , the air of a turbo get hot not because it connected to the exhaust (although some heat transfer take place) it gets hot because you pressurize it 
Turbochargers and superchargers compress the air being fed to the engine.

When air is compressed it heats up and this makes it less dense, meaning that for a set volume there will be less air available for the engine and hence less power.
The inter cooler cools the air and makes it more dense etc etc .

Lastly http://forums.vwvortex.com/zerothread?id=4170651&page=1 you will find http://inaengineering.com/ is busy with something   

[Jeronkie]

the intake temperature will be lower too since the charger is like a half turbo ( the cole side).

This sounds better

When air is compressed, it heats up, and when air heats up, it expands. So some of the pressure increase from a turbo is the result of heating the air before it goes into the engine. In order to increase the power of the engine, the goal is to get more air molecules into the engine, not necessarily more air pressure. 

An inter cooler or charge air cooler is an additional component that looks something like a radiator, except air passes through the inside as well as the outside of the inter cooler. The intake air passes through sealed passageways inside the cooler, while cooler air from outside is blown across fins by the engine cooling fan, thus cooling the charged air.   

The inter cooler further increases the power of the engine by cooling the pressurized air coming out of the compressor before it goes into the engine. This means that if the turbocharger is operating at a boost of 7 psi, the inter cooled system will put in 7 psi of cooler air, which is denser and contains more air molecules than warmer air.   

[kappone]

Hello Jeronkie,

Yes the 1,4 has a compessor for the loe rpm and a k03 for the high rpm. The compressor is a eaton which is like the ones they use for the mercedes compressor models or the mini cooper s.

I thought about to have a very big centrifugal instead of the turbo.

So with stock internals if you would run a turbo with a size of the  ihi vf34 from a subaru impreza you could have about 310 hp without having a lag and an increase of power and boost depending on the rpm.
Or to use very big compressor on a build engine where you may have very high power and a very good drivability.

Once is asdked at rotrex and they said that for 300 hp I shoiuld use the c-30 94 compressor but they have no ready kits.

[kappone]

Sorry I ment ...if you run a supercharger of the size of an ihi vf34

[Jeronkie]

Before I explain . and please the others must help me , What amount of power do you want ??? 200,300 ,,,,,500,,,,,,,,,,,1000 for every HP range you will get a turbo that can supply the HP with the minimum amount of Lag ,No need to Use a GT42  if you only want to make 300hp pick the correct turbo for the job ,,,,because saying the KO3 got lag you must try GT35 or other BT , And stock internals and I know some guys have taken it further but I would say You can see a safe 250 HP/290 WTQ on stock stuff any ting over that you are playing with fire , now the problem with Supper chargers especially for only 300hp 

It takes power to pump (compress) a large volume of air. The supercharger's power is derived directly from the crank shaft, where as a turbo's power comes from energy contained in the exhaust gasses. On a typical 8 psi supercharger, the power used can be in the neighborhood of 40-60hp! On a 1500hp engine, the power used by the supercharger can be as much as 300hp! This would leave only 1200hp to accelerate the car. 

A turbo is not entirely 'free' horsepower as some additional back pressure is created by the turbine, but a turbo derives a very large portion of its energy from heat. This is shown by the fact that exhaust gas temperature can drop by as much as 300 degrees Fahrenheit as it leaves the turbine housing. In essence the power 'robbed' by the extra back pressure is very very small (also due to other more 'complicated' factors like critical exhaust flow, but we wont get into that here). 

So what does this all mean? Basically an 8 psi turbo kit will produce more peak power due to the fact that a supercharger is using a fairly large amount of power just to get it spinning. What is more important for a street car is 'power under the curve' meaning the average horsepower produced. This is where the turbo really shines since you can have full boost at as little as 2500 rpm! This will make the turbo car feel like it has 50% more cubic inches (or more). The difference in torque at low rpm's can be as much as 100 lb ft in favor of the turbo due to the additional available boost..!