Dry Sump Oil System

A dry sump is a lubricating oil management method for four-stroke and large two-stroke piston internal combustion engines that uses a secondary reservoir for oil, as compared to a conventional wet sump system.

Four-stroke engines are lubricated by oil which is pumped into various bearings and thereafter allowed to drain to the base of the engine. In most production cars, which use a wet sump system, this oil is simply collected in a three to seven liter capacity pan at the base of the engine, known as the oil pan where it is pumped back up to the bearings by the oil pump, internal to the engine. In a dry sump, the oil still falls to the base of the engine, but rather than being collected into an oil pan, it is pumped into another reservoir by one or more scavenger pumps, run by belts from the front of the crankshaft. Oil is then pumped from this reservoir to the bearings of the engine by the pressure pump. Typical dry sump systems have the pressure pump and scavenger pumps "stacked up", so that one pulley at the front of the system can run as many pumps as desired, just by adding another to the back of the stack.

A dry sump affords many advantages, namely increased oil capacity, and decreased parasitic loss and a lower center of gravity for the engine. Because the reservoir is external, the oil pan can be much smaller in a dry sump system, allowing the engine to be placed lower in the vehicle; in addition, the external reservoir can be as large as desired, whereas a larger oil pan raises the engine even further. Increased oil capacity by using a larger external reservoir leads to cooler oil. Furthermore, dry sump designs are not susceptible to the oil starvation problems wet sump systems suffer from if the oil sloshes in the oil pan, temporarily uncovering the oil pump pickup tube. Having the pump(s) external to the engine allows them to be maintained or replaced more easily, as well.

DC

The Lowdown on Hypereutectic Pistons

Hypereutectic (hy·per·eu·tec·tic) pistons are cast pistons made from aluminum with over 16% silicon content for strength and durability. The term “hypereutectic” comes from “eutectic.” By definition, “eutectic” is a mixture of two or more elements which have a lower melting point than any of its constituents. The term “eutectic” comes from the Greek word “eutektos,” meaning “easily melted.” The term “metallic eutectics” is often used in metallurgy to describe the alloy of two or more component materials having relative concentrations specified at the “eutectic point.”  When a non-eutectic alloy freezes, one component of the alloy crystallizes at one temperature and the other at a different temperature. With a eutectic alloy, the mixture freezes as one at a single temperature. A eutectic alloy therefore has a sharp melting point, and a non-eutectic alloy exhibits a plastic melting range. A few examples of “metallic eutectics” include, casting alloys, such as aluminum-silicon and cast iron (an iron-carbon eutectic).

Special melting processes are necessary to “super-saturate” the aluminum with additional silicon content. Special molds, casting and cooling techniques are required to obtain finely and uniformly dispersed silicon particles throughout the material.

These newer pistons are very hard, thus brittle. They have proven to be unforgiving with engine knocking. For this reason they are great in naturally aspirated engines, but should never be used when building a nitrous, supercharged or turbocharged engine. Generally speaking, forged pistons are a much better choice for high boost engines.

Hypereutectic pistons are used in some original equipment engines. They are favored because of reduced scuffing, improved power, fuel economy and emissions. The reduced thermal expansion rate allows the piston to be run with reduced clearance.

DC

The Wonderful Muscle Cars

Muscle cars are high-performance automobiles made primarily in Detroit from 1964 to 1974. Car manufacturers placed large V8 engines in mid-sized cars, giving them quite startling performance and setting off intense competition between manufacturers to produce the most powerful and extreme machine. The 1973 OPEC oil embargo, stricter air pollution laws and insurance premiums killed most muscle car models, though they are actively collected and restored.

Although auto makers such as Chrysler had occasionally experimented with placing a high performance V-8 in a lighter mid-size platform, and full-size cars such as the Ford Galaxy and Chevrolet Impala had high-performance models, Pontiac usually gets credit for starting the muscle car trend with its Pontiac GTO, based on the rather more pedestrian Pontiac Tempest. Spearheaded by Pontiac division president John De Lorean, the GTO proved far more popular than expected, and inspired a host of imitations and a general trend towards performance, both in the true 'muscle car' class of intermediate vehicles, and also the smaller pony cars like the Ford Mustang, Plymouth Barracuda and AMC AMX, and more luxurious and expensive vehicles such as the Buick Riviera.

However, a large part of the appeal behind muscle cars was that they were mostly inexpensive models young drivers could afford. For instance, Chevrolet placed an extremely large 396 cubic inch (6.5 Liter) engine in its compact Nova. In today's terms this would be equivalent to attempting to make a Chevy Prizm with a Corvette motor. Mopar also had several low-cost models, such as the Dodge Super Bee and Plymouth Road Runner.

Between 1964 and 1970, Detroit auto makers were in competition for the bragging rights to the most powerful motor. Power numbers generally hit their peak in 1970; the Chevelle SS 454 from that year is generally considered to have had the highest advertised output, producing 450 horsepower (336 kW) from a 454 cubic inch (7.4-Liter) engine. By 1971, muscle cars began to fall out of favor and disappear, with Pontiac's Trans Am model being the last holdout by 1975. Actually the Trans Am continued until 2002.

The National Electric Drag Racing Association is a North American-based racing league for competing electric vehicles against each other and against current high performance or classic muscle cars. Their goal is to show that electric cars aren't just golf carts or milk floats, but instead high performance machines capable of out-accelerating most current production cars today. Examples of this are the Maniac Mazda; a Mazda RX-7 converted to run on electricity. It can achieve 1/4 mile times in less than 12 seconds. Another example is the White Zombie, a converted Datsun 300 Sedan that can win against a Dodge Viper.

DC

What Do Some NHRA Pro Stock Teams Have That Other Teams Don’t?

You may have asked yourself this simple question, what do some NHRA Pro Stock teams have in terms of performance advantages over other teams? Here are a few thoughts, rumors or possible facts, take this article with a grain of salt, or whatever, but it will invoke your brain a bit.

One main factor in Pro Stock performance is diffenently the engine, what magical engine secret do some professional teams have? Well, here are a few thoughts on this crazy subject. Lets start with the basic engine block. As you know, a standard V8 engine block has a 90-degree angle between the two banks of cylinders. OK, here is one possible scenario, lets say the 90-degree angle was reduced to 87-degrees by means of a custom designed & manufactured engine block. NHRA Pro Stock rule book states, that a “90-degree V-8 automotive-type engine must be used.” This rule could be interpreted a few different ways, such as, less than 90-degrees may fall within the rules, or there might be a +/- factor of 3-degrees. Who knows? Again this idea about an 87-degree V8 engine block was indicated to me by a former pro stock drag racer, this could be B.S. or fact, we may never know.

All race teams must play by the rules, but there are certain performance tricks that may seem illegal, but somehow fall within the rules, thus finding a slight performance advantage of some sort. If a team is using a tricked out engine block, it is hard to say. Certain Pro Stock team performance advantages could be in the heads, intake manifold or a super-slick car wax, anything is possible in the world of professional drag racing.

In the world of auto racing there will always be huge performance gains via new technologies, tuning, or maybe a hidden wizard somewhere. Performance gains can be found in strange ways. This is all food for thought or conversation, or maybe a bad argument.

DC

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