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re: intercooler ramblings
As I understand it, a recommended upgrade for chipped 10v turbo 5000/200's is
a better (more efficient) intercooler than the stock 2-pass unit. The
factory upgrade is the single pass slightly longer length '91 200q20v
intercooler, which requires a new cross-pipe and some metal work to fit into
the 10vt cars (as I understand it).
Another recommendation is to rework the factory 2-pass intercooler into a
single pass intercooler, using new end tanks and some custom plumbing. Any
idea on why the factory used the 2-pass? As I recall, it was used on the 10v
turbo cars in USA/Canada through '91; the 10vt cars in europe got a single
pass intercooler at some (earlier) point.
Third option is to have a custom unit fabricated (Spearco etc.); however,
there's not much room for a bigger system. Listers have done this and
reportedly got a larger more efficient system to fit in the stock location.
Anyone considered adding a second intercooler into the system, rather than
adding a larger unit? Seems that the intercooler off an A4 1.8t or other
small car, or an urS4/S6 unit could be plumbed in place prior to the stock
10vt intercooler, perhaps placed down low like on the urS4/S6. Or, if you're
fabricating a custom cross-pipe from the turbo across the front of the car to
the intercooler, perhaps that cross-pipe could be "finned" or designed to aid
in cooling (might require slotting the bumper cover?). Or placed down low
where the auxiliary radiator is on the 200q20v. Or perhaps a good place to
add that air-to-water intercooling from a small radiator placed elsewhere...
I would expect that the drawbacks would be: more drag from internal friction,
and a higher volume of (pressurized) air in the system, leading to more
perceived lag. Isn't that why they moved the intake on the later 20vt cars
to the front, to reduce the pipe lengths? I would have swapped the radiator
and air cleaner positions as well to isolate hot and cold sides of the engine.
A second intercooler (i.e., larger system) should have the capacity to cool
more air before heat soaking and reducing efficiency; a tradeoff against lag
and pressure loss through friction. On a track car, where the turbo is kept
spooled up, this might be acceptable.
chris miller, windham nh, email@example.com
'91 200q20v ==> http://members.aol.com/c1j1miller/index.html