Frozen Butts & Boost

(e.d. This is a well-considered weigh-in on the beauty of boost. I experienced this in heavy doses last night. Kurt Nelson is a top-notch ski-racing coach who knows more than me about horizontal and vertical speed. Pictured: The terror of all turbos—the Porsche 935.)

“There is no replacement for displacement” — that hackneyed
old saying that those who love the big Detroit iron like to chant when the
subject of turbocharging comes into the conversation. Sure — as Chris spoke about a while back with
regard to thrust — a tuned V8 will give you prodigious thrust, but what really gives
you a kick in the ass is boost. Mash the
throttle in the mid RPM range, wait just a second for the turbo to spool, and
hold on. Now, that is driving. Power is
not linear, like in a normally aspirated engine; it spikes with a kick that leaves
most cars in the dust, wondering how that sedan just did what it did.

Above: Pike’s Peak SAAB Turbo. K’s ride shares the same genes.

With the dense cold air that has invaded us during the past couple
of days, the turbo really shines. More
air in means more air out, and that is what boost is all about: air flow. Cold air is much more dense than warm, which
is why getting on the go peddle in the cold is so much more fun in winter — if
only my snow tires would grip more. Open
the air intake, increase the size of the exhaust, and you have an immediate
increase in drivability. The turbo
spools much more quickly, and the intercooler does not soak as much heat with
repeated bursts of boost. Just today,
for example, with the ambient temperature of about 0, I was able to get the
tires to break loose in four gears, spinning madly in the first two, and chirping
with three and four. Full boost in three and four is
about 21 lbs, at 4000 rpm, tapering to a sustained 17 lbs up to redline, and
that translates to about 120 mph. Try as
I may, I just do not have the oomph to get them loose in fifth, but
the Saab pulls hard until 150 mph, so that’s cool.

So, next time you are thinking that you need a bunch of
cylinders to give you the power you think you need, guess again. My little 2.3l gives me 130hp per liter. Try to find a normally aspirated engine that
gives that type of output. As Chris can
attest, from a little test drive last night, turbo charging rocks.