Ferrari Turbo Layout Analysis
The layout of the Ferrari Turbo has been bugging me for a while, especially the intercooler positioning. Something that Scarbs said about a 'reverse compressor' jogged my memory though of a turbo I have seen before that could explain the mismatch in my head.
Some good pictures of the Intercoolers in the Marussia auction helped as well. So anyway, here goes with how
I think the Ferrari Turbo is laid out (and it is pretty neatly packaged).
First up is a picture of the intercooler from the Marussia auction showing where the compressor feeds into the intercooler, which is right in the middle of the intercooler unit:
If this is annotated onto the engine layout with my original picture of where the turbine housing is there is a clear mismatch, the compressor is definitely not feeding straight from the front into the intercooler as the intercooler is much higher:
This reminded me how Audi use a 90° bend on the exit of the Le Man car Turbo to point the compressor exit forward. Although the picture below shows a twin exit I’m sure Ferrari is using a single exit pointed forward at 90°, if this exit was on top of the compressor it would align with the intercooler entry:
How is the air entering the turbo? I have seen this side entry turbo before on a Ford double compressor wheel turbo, I have blanked out the front wheel on the picture below to show the side entry compressor.
I believe Ferrari are using the backwards facing compressor wheel with twin side air entry (for equal wheel pressure). This means that they can then put the MGUH on the back of the wheel but in front of the Turbo in the engine ‘V’ just under the intercooler:
So I could get this correct in my head and demonstrate it better I did a rough CAD model which I have broken down below (please excuse the piss-poor surface modelling but I was in a hurry)
This picture shows just the compressor housing looking from the rear of the car, the twin entries feed air onto the front of the backwards facing wheel and the volute exit bends 90° to point forwards;
This image shows the compressor from the top, downwards is rearwards:
The next picture show how the intercooler is mated to the compressor:
And this picture shows the twin entry ducts that mate to the twin exit airbox seen in the Ferrar F14T Thread:
Also in the above picture is the MGUH which is on the back of the compressor wheel but on the front of the turbo unit below the intercooler exit, this picture shows the layout in side view (right equals back of car):
Lastly are two pictures of the complete layout with the turbine housing in place connected via a short shaft to the front of the compressor wheel with its twin entries:
From the available pictures and my own knowledge of these Turbocharger I have tried to get the sizes about right and proportional but these models are very simple and so not accurate.
I may be wrong on the layout but to me this explains most of the positioning and parts we can see.
For those of us who know, of all the common types of valves, it is very difficult to control transient flow with a butterfly valve. If the valve was a regular seat valve, you can profile the plunger to give proportional flow with travel and save yourself a tonne of control system headaches, but for a butterfly valve you have to use a "feed forward" control technique, meaning you do an actual test on the valve at different positions first then record the resulting flows and pressure drops Vs valve position, then put that resulting table in your control system. It is like Ferrari just said, screw controlling boost with the waste-gate altogethe! 
