research paper turbos vs. superchager
10-25-2005, 01:21 PM
#1
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research paper turbos vs. superchager
hey,
in english we are starting our research papers for senior year and im doing why turbo chargers are beter than super chargers. so if any of you have good websites that have amazing info and like even diagrams on how each work the pluses and the drawbacks of each ...or even a site that already argues turbos are better post them cause i need sources.
in english we are starting our research papers for senior year and im doing why turbo chargers are beter than super chargers. so if any of you have good websites that have amazing info and like even diagrams on how each work the pluses and the drawbacks of each ...or even a site that already argues turbos are better post them cause i need sources.
10-25-2005, 01:35 PM
#2
Hopefully you know how to use the internet as a library 
It took me 3 seconds to find this page:
http://www.turbocalculator.com/turbo...ercharger.html
Turbochargers and superchargers have both been around for many decades - cramming air into engines to squeeze out as much power as possible. The turbocharger vs supercharger debate has raged for just as long as they have existed. There are those who swear by one or the other, but in reality, both turbochargers and superchargers have their own strengths and weaknesses.
The Supercharger
Superchargers are compressors which use power from the engine to compress the intake air. In reality, turbochargers are superchargers which are driven by engine exhaust. Typically, however, when one refers to a supercharger, they mean all superchargers except turbochargers. There are three types of superchargers which are commonly used: the roots blower, centrifugal superchargers, and screw-type superchargers. Each of these superchargers are driven by a pulley system by the engine crankshaft, so the faster the engine speed, the faster the supercharger speed. The roots blower and screw-type superchargers typically operate up to 15,000 RPMS. The centrifugal supercharger can reach speeds exceeding 40,000 RPMS.
The Turbocharger
Turbochargers, however, are driven by the engine's exhaust gases. A turbocharger operates at maximum speeds often reaching 150,000 RPMS.
The Comparison: Turbocharger vs Supercharger
Response. Superchargers afford the engine immediate response since the supercharger is always compressing intake air, provided that the engine is rotating. Although this initial boost is very small, it's growth is gradual with increased engine speed, resulting in a smooth increase in power. Turbochargers, on the other hand, suffer from what is refered to as turbo lag. Becuase of the inertia of the turbocharger rotating assembly, the turbo must "spool up" before it is able to compress air, so there is no power increase at low engine speeds, as the turbo impeller starts rotating. At WOT (wide-open throttle), there is usually a very sudden increase in turbo boost at a certain RPM range (typically near 3000 RPM). If you've ever driven a turbocharged vehicle, you probably know what this kick in the pants feels like. Turbochargers can also be sized so that faster response is acheived. For example, diesel engines use turbochargers which are small enough to spool by 1700-2000 RPMS. The trade-off is that maximum power can't be reached with such a small turbocharger.
Parasitic Power Loss. Becuase superchargers are driven by the crankshaft, they draw some of the power which the crankshaft would be producing to compress the intake air. This parasitic power loss can exceed 50 hp. Of course, the supercharger is more than making up for the power it uses by introducing additional air. Turbochargers, however, do not use any of the crankshaft's power in order to operate. Turbos are often described as exhaust restrictions, though. The argument is that the increased exhaust backpressure presented by the turbo also robs power from the crankshaft (since it is now harder to push the piston up to expell the exhaust gases. This argument, however, is overstated. Because the intake air is also under pressure (typically greater pressure until the maximum horsepower engine speed), it pushes the piston down. For the majority of the power band, these two forces cancel on another out. Because turbochargers do not use much of the power output of an engine, the highest power levels are possible when using a turbocharger rather than a suprecharger.
Heat Production. Cooler intake air is denser - which means more oxygen per unit volume. More oxygen means more power. Roots blowers are notorious for their heat production. This heat production is a result of inefficient compression of the intake charge. Turbochargers tend to operate at a much better efficiency than thest upes of superchargers. Centrifugal superchargers can be just as efficient as turbochargers, and offer the advantage of flexibility in placement. Turbochargers must be placed so that the exhaust flows through the turbo's turbine. This brings the hot exhuast pipes closer to the intake pipes - resulting in higher intake temperatures. A well designed centrifugal supercharger installation can reduce this heating, resulting in a cooler intake charge.
Reliability. People often say that superchargers are more reliable than turbochargers. Because turbochargers operate at such high temperatures and are oil lubricated, if they are not allowed to cool down before the engine is turned off, the oil can bake inside the turbocharger. This can result in shorter turbocharger life. However, with proper care and cool down, a turbocharger can last as long as an engine.
Boost Levels. For absolute maximum power applications on stout engines, turbochargers allow much higher boost levels than superchargers. In tractor pulling, to take the example to the extreme, up to three turbochargers are used in series to produce boost levels of up to nearly 200 psi!
It took me 3 seconds to find this page:http://www.turbocalculator.com/turbo...ercharger.html
Turbochargers and superchargers have both been around for many decades - cramming air into engines to squeeze out as much power as possible. The turbocharger vs supercharger debate has raged for just as long as they have existed. There are those who swear by one or the other, but in reality, both turbochargers and superchargers have their own strengths and weaknesses.
The Supercharger
Superchargers are compressors which use power from the engine to compress the intake air. In reality, turbochargers are superchargers which are driven by engine exhaust. Typically, however, when one refers to a supercharger, they mean all superchargers except turbochargers. There are three types of superchargers which are commonly used: the roots blower, centrifugal superchargers, and screw-type superchargers. Each of these superchargers are driven by a pulley system by the engine crankshaft, so the faster the engine speed, the faster the supercharger speed. The roots blower and screw-type superchargers typically operate up to 15,000 RPMS. The centrifugal supercharger can reach speeds exceeding 40,000 RPMS.
The Turbocharger
Turbochargers, however, are driven by the engine's exhaust gases. A turbocharger operates at maximum speeds often reaching 150,000 RPMS.
The Comparison: Turbocharger vs Supercharger
Response. Superchargers afford the engine immediate response since the supercharger is always compressing intake air, provided that the engine is rotating. Although this initial boost is very small, it's growth is gradual with increased engine speed, resulting in a smooth increase in power. Turbochargers, on the other hand, suffer from what is refered to as turbo lag. Becuase of the inertia of the turbocharger rotating assembly, the turbo must "spool up" before it is able to compress air, so there is no power increase at low engine speeds, as the turbo impeller starts rotating. At WOT (wide-open throttle), there is usually a very sudden increase in turbo boost at a certain RPM range (typically near 3000 RPM). If you've ever driven a turbocharged vehicle, you probably know what this kick in the pants feels like. Turbochargers can also be sized so that faster response is acheived. For example, diesel engines use turbochargers which are small enough to spool by 1700-2000 RPMS. The trade-off is that maximum power can't be reached with such a small turbocharger.
Parasitic Power Loss. Becuase superchargers are driven by the crankshaft, they draw some of the power which the crankshaft would be producing to compress the intake air. This parasitic power loss can exceed 50 hp. Of course, the supercharger is more than making up for the power it uses by introducing additional air. Turbochargers, however, do not use any of the crankshaft's power in order to operate. Turbos are often described as exhaust restrictions, though. The argument is that the increased exhaust backpressure presented by the turbo also robs power from the crankshaft (since it is now harder to push the piston up to expell the exhaust gases. This argument, however, is overstated. Because the intake air is also under pressure (typically greater pressure until the maximum horsepower engine speed), it pushes the piston down. For the majority of the power band, these two forces cancel on another out. Because turbochargers do not use much of the power output of an engine, the highest power levels are possible when using a turbocharger rather than a suprecharger.
Heat Production. Cooler intake air is denser - which means more oxygen per unit volume. More oxygen means more power. Roots blowers are notorious for their heat production. This heat production is a result of inefficient compression of the intake charge. Turbochargers tend to operate at a much better efficiency than thest upes of superchargers. Centrifugal superchargers can be just as efficient as turbochargers, and offer the advantage of flexibility in placement. Turbochargers must be placed so that the exhaust flows through the turbo's turbine. This brings the hot exhuast pipes closer to the intake pipes - resulting in higher intake temperatures. A well designed centrifugal supercharger installation can reduce this heating, resulting in a cooler intake charge.
Reliability. People often say that superchargers are more reliable than turbochargers. Because turbochargers operate at such high temperatures and are oil lubricated, if they are not allowed to cool down before the engine is turned off, the oil can bake inside the turbocharger. This can result in shorter turbocharger life. However, with proper care and cool down, a turbocharger can last as long as an engine.
Boost Levels. For absolute maximum power applications on stout engines, turbochargers allow much higher boost levels than superchargers. In tractor pulling, to take the example to the extreme, up to three turbochargers are used in series to produce boost levels of up to nearly 200 psi!
10-25-2005, 08:32 PM
#3
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Join Date: Oct 2001
Location: San Diego
Posts: 1,220
If you can find the old "Suck, Squish, Bang, Blow" articles by Mike Kojima, he highlights why turbos tend to be better than superchargers. I believe his articles were published in Sport Compact Car about 2 years ago or so. Also on a side note, turbos are banned from most forms of racing, including top fuel drag racing where only superchargers are allowed to run. The turbos made too much power and before anyone could develop the technology to hold the power without blowing up, they were banned from competition.
10-26-2005, 08:57 AM
#6
The Evil Twin
Join Date: Mar 2001
Location: Seattle, WA
Posts: 9,294
Originally Posted by emo236
turbos are free hp in the sense that they don't directly put any extra strain on your motor like a supercharger does. That's the biggest pro to it.
10-26-2005, 09:38 AM
#7
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Join Date: Jul 2003
Location: Salinas, CA
Posts: 3,074
I meant the type of strain a blower puts on your engine. Since the blower itself is driven by the engine, it's like another big accessory that drains power (like AC, PS, etc), but then more than makes up for it. there is a direct strain put on the motor. Turbos will put little minimal strains, but nothing like a blower. The amount of backpressure is also relative to what kind of turbo(s) you're running, some are more flowing than others and will have less, but will usually take longer to spool. It also depends on the rest of your exhaust.
10-26-2005, 05:53 PM
#8
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Originally Posted by lifegrddude
If you can find the old "Suck, Squish, Bang, Blow" articles by Mike Kojima, he highlights why turbos tend to be better than superchargers. I believe his articles were published in Sport Compact Car about 2 years ago or so. Also on a side note, turbos are banned from most forms of racing, including top fuel drag racing where only superchargers are allowed to run. The turbos made too much power and before anyone could develop the technology to hold the power without blowing up, they were banned from competition.
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