All turbos have a sweet spot, measured in % that represents the adiabatic effiency of the turbo - a small turbo with high boost will thrash the air and heat it up far more than a larger turbo that will shift more air at a lower boost pressure - trade off if a higher moment of intertia to reach the same air volume. Read that as 'lag'. Much generalisation in there but you get the point.Lucky wrote:Are the turbos so small due to the problems of cooling the charge? Obviously you can't have a carburetted application blowing through an intercooler cos then that makes basically a bomb out of the 'cooler. Maybe the turbo is kept small to avoid shoving too much air in too hot?
The aim of the game isnt how much boost or air mass enters the engine, its the oxygen content of the air - cooler air is more dense (more O2 %) so a lower boost, cooler charge makes more power that a hotter higher pressure charge. Intercoolers reclaim some lost efficiency, but as they are also a restriction to flow they will reduce pressure before and after the turbo - at least 1psi, but could be 3-4psi. Lucky - where do you take your boost reference from? The inlet manifold is a more accurate source of pressure for both a boost guage and the ECU, but the turbo outlet will exhibit a higher pressure ratio than this.
If you have the spare time, connect you boost guage to your turbo outlet and check the boost - compare to what you expect and see how many PSIs are being lost through your cooler. In the case of an intercooler upgrade, trhe benefit can be 2 fold, cooler air becuase it has more cooling capacity, and lower turbo pressure for any given manifold pressure which further reduces the temp and increases density.
and it would explain the different rims and why i have a washer bottle for the headlights 
Altough i haven´t got any nozzles on the bumper 
Now I just kick the doors in every time I drive it and live in blissful ignorance 
