Question for the Turbo Guys...

[ProTouring442]

I am not familiar with your stock turbos effeciency range or the bottom end strength of the ford 2.3 so my comments are based on my experience building and tuning other 4 cylinder turbo combos.
first off an increase in cr from 8.0 to 9.5 is drastic. typical cr bumps on a well prepared block and rotating assembly for street use is less then 1.0.
second, by adding a 'bigger cam' I assume you are planning to drop cylinder pressure through increased overlap. one aspect is that overlap in a turbo application has a much more dynamic effect as boost increases. in my experience aftermarket turbo cam for the street do not produce returns similar to na applicaitons. the major considerations here is boost lag and low end power loss. ultimately your plan also works against itself. your adding compression only to leak it away. this combination would really hurt fuel economy too.
again I'm not versed on the stock t-bird turbo but in general stock turbo are only good to maybe 12psi. after that their effeciency drops and the heat introduced is counter productive. consider getting the head to flow, open the exhaust, bump the turbo size and increase compression only moderately like 0.5.

thinking more, I don't think I would go for too much more overlap, but rather just a good turbo cam...

Many new turbo motors are running 9.5 or higher, and I can't help but think that a lot of that is because they are looking to increase mileage. As an example, the BMW 7 series twin turbo runs 10.0:1

The IHI, as far as I know, remains reasonably efficient up to 18psi.



Shiny Side Up!
Bill