Mio Engineering and I have also been making some Roller Barrel Throttle bodies for the Zetec engine.
As the name suggests they are not with a conventional throttle butterfly but with a roller barrel instead.
This means that there is no "butterfly" to intervene in the airflow witch results in better airflow and there for higher power output. It also makes less noise witch is both nice and useful at track days with noise regulations.
The throttle bodies are also mounted directly to the cylinder head; this puts the throttle close to the valves witch results in a very quick throttle response. It also means that we don't use an intake manifold, and that gives us a nice compact design with small build-in dimensions, and room for longer trumpets witch improves the midrange torque.
Michael has mounted the throttle bodies on several cars where we have seen outputs of 180HP at 6.500 and 200Nm at 2.000 rpm. from a stock 2.0L Zetec with only these throttle bodies and an exhaust. But the best thing is the driveability and the way the engine pick-ups the rews without any hiccups.
All the parts are made from billet 6082 aluminium and black anodized, so they have a very nice finish to them.
Here is a link to a YouTube clip from when they were on the rollers with a lotus Seven:
http://www.youtube.com/watch?v=G2z97WRavUo&feature=relmfu... yes it is the valve stems that you can see
I have some pictures that I will add when I get home.
We have also made a set for the Opel GSI or Vauxhall C20XE engine.
Here are some CAD renderings.
