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In the 11th century, it was a fact that the
world was flat. Any medieval scholar,
astronomer or captain could affirm the
self-evident truth that the Earth was the
center of the universe and that anyone who
ventured too close to the edge would fall
off into the abyss. It wasn’t until
centuries later that skeptics like
Copernicus, Galileo and Columbus reasoned
that our world was actually a tiny globe
orbiting a distant star. Reality hadn't
changed, but people's perceptions did.
Racing has its share of flat earth "facts"
that are later revealed as fictions. For
example, when I started racing, it was an
unassailable fact that the small-block
Chevy's stud-mounted rocker arms were the
ultimate high-rpm valvetrain; now, of
course, shaft-mounted rockers are nearly
universal. It was an indisputable fact that
cylinder head ports should be polished like
a mirror; today we prize the machining marks
left by CNC cutters as aids to atomizing
fuel. We once knew that lightweight pushrods
and flyweight lifters were essential for a
high-speed engine; now these components are
as stout and as stiff as Roman columns. The
physics of racing engines haven't changed,
but collectively we have revised the "facts"
to fit our new view of reality.
History teaches us that technology is
constantly in a state of flux. Some of the
mistaken beliefs that we regarded as gospel
20 years ago weren't foolish – they simply
fit with what we knew at the time. Our
flexible pushrods worked fine because we
didn't have the stiff valve springs that are
available today. They helped to suppress
some of the nastier valvetrain dynamics that
harsh cam profiles produced. They were
cheap, readily available, and offered plenty
of clearance for port walls. Consequently it
was obvious that lightweight pushrods made a
race car run faster.
I'm sure that many of the facts about racing
engines that we ardently believe today will
eventually be proven to be as wrong-headed
as the notion that the world was flat. The
people who are willing to question
conventional wisdom often become the
innovators who expand the performance
envelope. After all, if drag racers had
believed the pundits who proclaimed that the
maximum achievable speed in a quarter-mile
was 160 mph, we wouldn't have 330 mph Top
Fuel dragsters and 208 mph Pro Stocks. If
engine builders had subscribed to the rule
that an engine couldn’t survive with an
average piston speed over 4000 feet per
second, we wouldn't have 500 cubic inch
engines that are capable of running at
nearly 10,000 rpm.
The past is a mirror that reflects the
future – if you want to move forward, you
often need to look where you've been. Ten
years ago, if you had asked me where we
would find gains in engine performance, I'd
probably have answered that we'd just about
reached the end of the road in development.
And yet in the last decade, engine builders
have made tremendous strides in performance,
efficiency and reliability.
Using Pro Stock as an example, the national
speed record has climbed from 199 to 208 mph
in 10 years. Given that Pro Stock engines
are among the most refined powerplants in
racing, a nine-mph increase is an incredible
achievement. Neither the rules nor the basic
hardware has changed, so that improvement is
the result of hundreds of small, incremental
steps.
Consider the advances in valvetrain
technology, which is just one area of
development. The valve springs that were the
hot setup a decade ago wouldn't survive a
minute with today's high-lift camshaft
profiles. Similarly, we couldn't lift the
valves an inch off their seats without the
high-tech springs that are now available.
It's a continuous, self-propelled cycle:
Better springs enable more aggressive cams,
which in turn spur the development of better
springs . . .
Technology is the fuel that drives
development. The advent of coatings such as
DLC (diamond-like carbon) and Casidium has
permitted engine builders to do things that
were once thought to be impossible. The wear
resistance of these coatings has allowed
valve seat angles in high-end cylinder heads
to become steeper without sticking the
valves and reduced wrist pin galling with
ultra-efficient dry-sump and crankcase
vacuum systems.
What's the next step in engine development?
I wish I could tell you. But I'm certain
that 10 years from now, we'll look back at
the state of the art in 2006 and ask, "What
were we thinking? |