Someone posted a SAE paper by Jack Yamaguchi on
rec.autos.rotary detailing what's new in the '99 RX-7
that we don't get. :( The following paragraph is
especially interesting in light of the RX-7TT's
tendency to get pretty warm in an autocross. The
complete article appears in the September 1999 issue
of Automotive Engineering.
"The third-generation RX-7 had come off Mazda's
rigorous development test programs on the bench and on
the demanding Global Road Circuit section of the
Miyoshi Proving Ground with flying colors. Yet, there
was one arduous test left undone. When the car was
taken to a race track near Tokyo known for its tight
turns requiring short bursts of speed followed by
fierce deceleration, the pride of Mazda's rotary
rocket team quickly cooked its powerplant when pushed
to the limit. Subsequent investigation revealed that
air temperature at the entry area had risen as high as
50 C (122 F). Fresh air for the engine's consumption
was taken from the single intake that also fed to the
air-to-air intercooler. On wide-open driving, air
flow reversed its course from the intercooler and went
straight into the engine's intake. The intercooler was
acting as an inter-heater! In the updated RX-7 with a
designed fascia, fresh air is taken through a
separate, dedicated duct guided by a newly installed
air-guide. Air temperature at the engine's intake
entry area has been halved to about 25 C ( 77 F),
which adds about 7 kW (10bhp) to the output."
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