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According to the informal David
Reher telephone poll, interest in fast Sportsman classes
is skyrocketing. If the sample of racers I talk to is
representative of the sport as a whole, then Top
Sportsman racing has a bright future. Interest in this
particular style of fast doorslammer racing is spreading
as quickly as a rumor on the Internet. The fact that Top
Sportsman has been adopted by several NHRA divisions is
a leading indicator of the class' future growth.
As participation in fast
classes such as Top Sportsman, Top Dragster and Quick 32
shows accelerates, a powerful, big-inch engine is no
longer a luxury - it's a necessity. When racers upgrade
their engines with eight-barrel induction systems and
run higher rpm to meet the need for quicker elapsed
times, I find myself talking more frequently about the
advantages of dry-sump lubrication systems for drag
racing.
Dry-sump systems aren't just
for Pro Stocks anymore. Just as induction and camshaft
technology has migrated from the Pro pits to the
Sportsman staging lanes, Pro-style lubrication systems
science has also made the leap to Sportsman engines. I
certainly don't suggest that every Sportsman racer with
a 509 or 522-cubic-inch big-block immediately invest in
a dry-sump pump and hardware - but if you are building a
565 or larger engine and turning it 8,000 rpm or higher,
I strongly recommend that you consider a dry-sump
system. In my view, a dry-sump system has four
advantages over a wet-sump system: safety, reliability,
horsepower and cooling.
Safety is the No. 1 reason
to run a dry-sump system in a fast race car. With an
external oil tank and an efficient scavenging system,
there is very little oil inside the engine that can end
up on the track in the aftermath of a catastrophic
engine failure. Dry-sump oil pans are typically so big
and the pan walls are so far away from the rotating
assembly that a broken rod seldom penetrates the pan.
When you're running close to 200 mph, the last thing you
want is oil under the rear tires.
The dry-sump system I
recommend for most Sportsman big-block engines uses a
five-stage pump with four sections scavenging the oil
pan and one pressure stage. With four oil pan pickups,
you can evacuate the pan very efficiently. Reliability
has long been recognized as an advantage of dry-sump
oiling. A dry-sump system ensures that an uninterrupted
supply of non-aerated oil reaches the bearings. That's
vitally important when you are running a long-stroke
engine at high rpm. Even with elaborate windage trays
and baffles, a wet-sump system just can't achieve the
same level of effectiveness in supplying a constant oil
supply as a basic dry-sump system.
A typical Top Sportsman car
has a Pro Stock chassis and weighs a minimum of 2,350
pounds. With no limit on engine displacement, these cars
accelerate at well over 2 g's on the starting line and
approach 200 mph on the top end. Top Sportsman cars use
a parachute for braking, and when the 'chute opens, the
negative g's are high enough to uncover the oil pump
pickup in any wet-sump system. Most Top Sportsman cars
use automatic transmissions, so the engine gears down
during deceleration. It's essential to maintain constant
oil pressure under this condition.
Some racers cite the cost of
a dry-sump system as a reason to use a wet-sump, but I
don't think the real price difference is significant.
Most high-end wet-sump systems require a belt-driven
vacuum pump and an external oil pump; that's money that
could be allocated for a dry-sump pump, brackets and
pulleys. A dry-sump system is an investment that won't
become obsolete if you build a bigger engine next
season, and it can save you money in the long run by
improving reliability. When you compare the cost of a
dry-sump system to the expense of repairing a spun
bearing or a broken rod, it's a bargain.
Installing a dry-sump system
reduces the odds of an oil-related failure virtually to
zero. About the only possible pitfall is losing a pump
belt, and that rarely happens. After all, every NASCAR
Winston Cup car in the world runs in circles with a
belt-driven oil pump.
A dry-sump system is one of
the few racing products you can buy with confidence that
it will actually improve performance. If you buy a new
carburetor, a new set of headers or a new camshaft, your
car's performance may or may not improve. But if you
replace a wet-sump pan with a dry-sump system, you can
be confident that horsepower will increase.
An often-overlooked
advantage of a dry-sump system is its cooling capacity.
The aluminum oil pan and oil tank work like radiators to
keep the lubricant cool. That's important when you're
running with only minutes between rounds in final
eliminations.
I wouldn't race a fast car
without a dry-sump oil system, and I urge Sportsman
racers to consider the advantages of dry-sump
lubrication for drag racing.
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