chickendreamer
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Supercharger vs Turbo
The same question arises over and over, what’s better Supercharger or Turbo? Comparatively both have their advantage & disadvantage and both will have fans telling one is better than the other but bottom line a turbocharger will produce more horsepower per psi than a supercharger. This of course has to be under the assumption that both the supercharger and turbocharger produce the same amount of flow.
For superchargers there are 3 different kinds, there is a roots style, twin-screw and centrifugal supercharger. The main difference between each of these superchargers is how they push air into the engine. Roots and twin-screw superchargers use meshing lobes of differing design where a centrifugal supercharger uses an impeller to draw air into the engine. Although all of these designs provide a boost, they efficiency of them varies considerably. Each type of supercharger is available in different sizes depending on the amount of flow desired.
The Roots supercharger is the oldest design. The Roots supercharger is the oldest designed patented in 1860 by Philander and Francis hence the term “roots†supercharger. As the meshing lobes spin via a belt driven by the engine crankshaft, air trapped in the pockets between the lobes is carried between the fill side and the discharge side. Large quantities of air move into the intake manifold and "stack up" to create positive pressure. For this reason, Roots superchargers are really nothing more than air blowers, and the term "blower" is still often used to describe all superchargers. Roots superchargers are usually large and sit on top of the engine. They are popular in muscle cars and hot rods because they stick out of the hood of the car. However, they are the least efficient supercharger for a few reasons: They add more weight to the vehicle, they move air in discrete bursts instead of in a smooth and continuous flow and also they are limited to a relatively small maximum amount of flow. However, these superchargers typically have the quickest response in power and produce enormous amounts of low end torque which allow the driver to smoke the tires under 3000rpm. They give the best low end power but top end power is restricted because the blower can only flow so much.
A twin-screw supercharger operates by pulling air through a pair of meshing lobes that resemble a set of worm gears. Like the Roots supercharger, the air inside a twin-screw supercharger is trapped in pockets created by the rotor lobes. But a twin-screw supercharger compresses the air inside the rotor housing. That's because the rotors have a conical taper, which means the air pockets decrease in size as air moves from the fill side to the discharge side. As the air pockets shrink, the air is squeezed into a smaller space. This makes twin-screw superchargers more efficient, but they cost more because the screw-type rotors require more precision in the manufacturing process. Some types of twin-screw superchargers sit above the engine like the Roots supercharger. They also make a lot of noise. The compressed air exiting the discharge outlet creates a whine or whistle that must be subdued with noise suppression techniques. Similar to roots style, the twin-screw produces enormous amounts of low end power to the engine. Kenne-bell superchargers use the twin screw type of arrangement. Twin screws also give excellent low end response but are limited to top end rpm power.
The final type of supercharger is the centrifugal which is Vortech, Paxton or Procharger. More of each of these brands I will discuss later but for now I will stick with how they work. A centrifugal supercharger powers an impeller, a device similar to a rotor, at very high speeds to quickly draw air into a small compressor housing. An impeller is similar to a rotor. Impeller speeds can reach 50,000 to 60,000 RPM. As the air is drawn in at the hub of the impeller, centrifugal force causes it to radiate outward. The air leaves the impeller at high speed, but low pressure. A diffuser, a set of stationary vanes that surround the impeller, converts the high-speed, low-pressure air to low-speed, high-pressure air. Air molecules slow down when they hit the vanes, which reduces the velocity of the airflow and increases pressure. Centrifugal superchargers are the most efficient and the most common of all forced induction systems. They are small, lightweight and attach to the front of the engine instead of the top. They also make a distinctive whine as the engine idles.
Turbochargers like superchargers compress the intake air and push it into the engine. In order to achieve this boost, the turbocharger uses the exhaust gases from the engine to spin a turbine, which in turn spins an air pump. The turbine in the turbocharger spins at speeds of up to 150,000 rotations per minute (rpm) which is the reason you here a whine as turbo’s spool up. And since it is hooked up to the exhaust, the temperatures in the turbine are also very high which is why typically turbocharger systems are intercooled.
Both superchargers and turbochargers drain power from the engine in order to produce the power. Superchargers require the engine itself to turn over the lobes or impeller. To test the efficiency of a supercharger Campbell Automotive did an interesting test using a centrifugal supercharger.
“We did a test with a 8.5:1 compression 510" BBC with a D1 procharger. We ran it N/A with no belt and the engine make 595 HP. With the belt hooked up but not pushing air into the engine it make 425HP and wouldn't pull a stiff cock out of a pail of grease in July. The blower took 170HP to turn at 6500rpm, Now granted the engine makes 1000hp with the blower all hooked up is cool, but imagine if it was a turbo.â€Â
As tested, it is clear to understand that a turbocharger will produce more power per psi than a supercharger because of the above test. However, turbochargers are not 100% efficient like some people make it out to be. One cause of inefficiency of a turbo comes from the fact that the power to spin the turbine is not free. Having a turbine in the exhaust flow increases the restriction in the exhaust. This means that on the exhaust stroke, the engine has to push against a higher back-pressure. However, turbochargers still have less inefficiency than a supercharger. Another loss of the efficency is turbo chargers significantly increase the intake air since the exhaust flow heats up the turbocharger so much. However, this is easily remedied by adding an intercooler to a turbocharger system which is very common.
Often times the costs of a supercharger are usually lower than turbocharger system… well, that’s what people think on first look. If we were to compare all of the supporting mods we need with both a supercharger and turbocharger it becomes clear the price usually adds up to be close in the end. Let’s do a comparison with a Paxton novi 2000 for a 94-95 mustang and a HP Performance turbocharger kit with supporting mods.
Novi 2000 - $3,420.00
Injectors - $300.00
Maf - $250
Headers (short) - $200
Total - $4170
(includes fuel pump)
HP Performance Turbocharger kit w/ T60 - $4500
(includes maf, injectors, fuel pump, also includes intercooler)
So after adding up the numbers you can see the turbocharger system isn’t much more money, also if you ended up getting an intercooler for the supercharger kit, the supercharger system will cost you more.
Performance wise, a supercharger on a 94-95 mustang with H/C/I around10psi will give you rougly 400rwhp/400rwtq on a mustang dyno. Where for a turbocharger system, like my car I produced 467rwhp/506rwtq at 9.5psi.
However, installation of a supercharger is usually much easier than a turbocharger. Of course if we do install the supporting mods of headers and an intercooler with a supercharger then the difficulty of the installation isn’t much different.
Finally, a turbocharger puts less strain on the engine block since the engine crank isn’t turning over an extra accessory like the supercharger needs too. And for the 302 guys anything over 400rwhp is block splitting territory.
If you want any additional information regarding turbo mustangs check here: http://www.turbomustangs.com/turbofaq.php
The same question arises over and over, what’s better Supercharger or Turbo? Comparatively both have their advantage & disadvantage and both will have fans telling one is better than the other but bottom line a turbocharger will produce more horsepower per psi than a supercharger. This of course has to be under the assumption that both the supercharger and turbocharger produce the same amount of flow.
For superchargers there are 3 different kinds, there is a roots style, twin-screw and centrifugal supercharger. The main difference between each of these superchargers is how they push air into the engine. Roots and twin-screw superchargers use meshing lobes of differing design where a centrifugal supercharger uses an impeller to draw air into the engine. Although all of these designs provide a boost, they efficiency of them varies considerably. Each type of supercharger is available in different sizes depending on the amount of flow desired.
The Roots supercharger is the oldest design. The Roots supercharger is the oldest designed patented in 1860 by Philander and Francis hence the term “roots†supercharger. As the meshing lobes spin via a belt driven by the engine crankshaft, air trapped in the pockets between the lobes is carried between the fill side and the discharge side. Large quantities of air move into the intake manifold and "stack up" to create positive pressure. For this reason, Roots superchargers are really nothing more than air blowers, and the term "blower" is still often used to describe all superchargers. Roots superchargers are usually large and sit on top of the engine. They are popular in muscle cars and hot rods because they stick out of the hood of the car. However, they are the least efficient supercharger for a few reasons: They add more weight to the vehicle, they move air in discrete bursts instead of in a smooth and continuous flow and also they are limited to a relatively small maximum amount of flow. However, these superchargers typically have the quickest response in power and produce enormous amounts of low end torque which allow the driver to smoke the tires under 3000rpm. They give the best low end power but top end power is restricted because the blower can only flow so much.
A twin-screw supercharger operates by pulling air through a pair of meshing lobes that resemble a set of worm gears. Like the Roots supercharger, the air inside a twin-screw supercharger is trapped in pockets created by the rotor lobes. But a twin-screw supercharger compresses the air inside the rotor housing. That's because the rotors have a conical taper, which means the air pockets decrease in size as air moves from the fill side to the discharge side. As the air pockets shrink, the air is squeezed into a smaller space. This makes twin-screw superchargers more efficient, but they cost more because the screw-type rotors require more precision in the manufacturing process. Some types of twin-screw superchargers sit above the engine like the Roots supercharger. They also make a lot of noise. The compressed air exiting the discharge outlet creates a whine or whistle that must be subdued with noise suppression techniques. Similar to roots style, the twin-screw produces enormous amounts of low end power to the engine. Kenne-bell superchargers use the twin screw type of arrangement. Twin screws also give excellent low end response but are limited to top end rpm power.
The final type of supercharger is the centrifugal which is Vortech, Paxton or Procharger. More of each of these brands I will discuss later but for now I will stick with how they work. A centrifugal supercharger powers an impeller, a device similar to a rotor, at very high speeds to quickly draw air into a small compressor housing. An impeller is similar to a rotor. Impeller speeds can reach 50,000 to 60,000 RPM. As the air is drawn in at the hub of the impeller, centrifugal force causes it to radiate outward. The air leaves the impeller at high speed, but low pressure. A diffuser, a set of stationary vanes that surround the impeller, converts the high-speed, low-pressure air to low-speed, high-pressure air. Air molecules slow down when they hit the vanes, which reduces the velocity of the airflow and increases pressure. Centrifugal superchargers are the most efficient and the most common of all forced induction systems. They are small, lightweight and attach to the front of the engine instead of the top. They also make a distinctive whine as the engine idles.
Turbochargers like superchargers compress the intake air and push it into the engine. In order to achieve this boost, the turbocharger uses the exhaust gases from the engine to spin a turbine, which in turn spins an air pump. The turbine in the turbocharger spins at speeds of up to 150,000 rotations per minute (rpm) which is the reason you here a whine as turbo’s spool up. And since it is hooked up to the exhaust, the temperatures in the turbine are also very high which is why typically turbocharger systems are intercooled.
Both superchargers and turbochargers drain power from the engine in order to produce the power. Superchargers require the engine itself to turn over the lobes or impeller. To test the efficiency of a supercharger Campbell Automotive did an interesting test using a centrifugal supercharger.
“We did a test with a 8.5:1 compression 510" BBC with a D1 procharger. We ran it N/A with no belt and the engine make 595 HP. With the belt hooked up but not pushing air into the engine it make 425HP and wouldn't pull a stiff cock out of a pail of grease in July. The blower took 170HP to turn at 6500rpm, Now granted the engine makes 1000hp with the blower all hooked up is cool, but imagine if it was a turbo.â€Â
As tested, it is clear to understand that a turbocharger will produce more power per psi than a supercharger because of the above test. However, turbochargers are not 100% efficient like some people make it out to be. One cause of inefficiency of a turbo comes from the fact that the power to spin the turbine is not free. Having a turbine in the exhaust flow increases the restriction in the exhaust. This means that on the exhaust stroke, the engine has to push against a higher back-pressure. However, turbochargers still have less inefficiency than a supercharger. Another loss of the efficency is turbo chargers significantly increase the intake air since the exhaust flow heats up the turbocharger so much. However, this is easily remedied by adding an intercooler to a turbocharger system which is very common.
Often times the costs of a supercharger are usually lower than turbocharger system… well, that’s what people think on first look. If we were to compare all of the supporting mods we need with both a supercharger and turbocharger it becomes clear the price usually adds up to be close in the end. Let’s do a comparison with a Paxton novi 2000 for a 94-95 mustang and a HP Performance turbocharger kit with supporting mods.
Novi 2000 - $3,420.00
Injectors - $300.00
Maf - $250
Headers (short) - $200
Total - $4170
(includes fuel pump)
HP Performance Turbocharger kit w/ T60 - $4500
(includes maf, injectors, fuel pump, also includes intercooler)
So after adding up the numbers you can see the turbocharger system isn’t much more money, also if you ended up getting an intercooler for the supercharger kit, the supercharger system will cost you more.
Performance wise, a supercharger on a 94-95 mustang with H/C/I around10psi will give you rougly 400rwhp/400rwtq on a mustang dyno. Where for a turbocharger system, like my car I produced 467rwhp/506rwtq at 9.5psi.
However, installation of a supercharger is usually much easier than a turbocharger. Of course if we do install the supporting mods of headers and an intercooler with a supercharger then the difficulty of the installation isn’t much different.
Finally, a turbocharger puts less strain on the engine block since the engine crank isn’t turning over an extra accessory like the supercharger needs too. And for the 302 guys anything over 400rwhp is block splitting territory.
If you want any additional information regarding turbo mustangs check here: http://www.turbomustangs.com/turbofaq.php