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Steve,
I hate being a nay-sayer, but I suspect you're making
too big a project out of this, trying to "tweak" a system
that has a major underlying flaw.
There is one other difference, and I think it is not
trivial. Looking at the two systems, John's radiator is
mounted at an angle to the air flow that requires
considerably less than a 90* turn of the airflow. Yours
requires considerably more than 90* - it actually forces
the air to travel slightly forward again, in order to get
through the radiator. The new scoop offers a slightly
wider radius in which to do so, but at the cost of
significant drag.
I have looked at pictures John's installation. He has basically the same
type/size of engine mount, and has the same size radiator, yet has enough
vertical space to rotate the radiator enough to be <90 degrees. I believe
that his cowling must extend down approximately 4-5 inches to achieve that.
That may be the way to do it, but I started with the stock cowling, and only
squared up the back end some to accommodate the radiator. I think that
dropping the whole engine cowling down is probably going to create more drag
than the scoop. We'll see.
Also, the gap between the oil cooler and the radiator:
how has it been sealed? - or has it? You have high velocity
air going into a plenum; it will take the path of least
resistance to get out. If there is _any_ way easier than
going through the heat exchangers, you lose cooling capacity.
There is a baffle between the oil cooler and radiator that seals the gap.
Actually the whole high pressure side is sealed up.
Finally, there has been considerable talk here, in the
past, regarding the relationship between the intake size
and the radiator area; there have been fewer about the
relationship of the outlet size. You have heated air
exiting your heat exchangers, that means it's expanding.
You need enough outlet area to keep from bottlenecking
the airflow _after_ the rad, or you'll lose pressure
differential right when you need it the most. That outlet
area has to take into account ALL the sources that are
adding heat to it - engine radiation, exhaust ...
The exit area is pretty good sized. Actually I had planned to close It up
some if cooling was OK. Hasn't been. See the attached photo.
My tupence,
Dale R.
Steve Brooks
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