Wanted to get your thoughts, if you can get 700HP from a centrifigul supercharger and just about the same from a twin turbo set up? Don't these two function in the same regards? I'm just researching my options right now, and after some of the ads that I have read, it looks like these two units are about the same? Am I mistaken?

Thank you boys and girls! :p

The main difference between the centrifugal supercharger and the twin turbos are when the boost comes in. Centrifugals typically need to see a little more RPM to start making boost, so it doesn't come on untill 3000-3500 RPM, where the Twin Turbos usually use 2 smaller turbos that spool up faster, so they start making boost by 2000-2500 RPM.

For a street application where you are only making 5-6 PSI of boost, the supercharged setup may be more desirable due to lower cost, and less complexity. There's also roots style superchargers that give you the early boost of a twin turbo, with the lower cost and ease of install like a centrifugal.

It's best to discuss your specific goals, and driving habits with someone who is familiar with all types of systems, then you can make a better decision on which is best for you.

Ed

The turbocharger and the centrifugal supercharger use the same style of compressor to pump the air into the engine. The main difference is the way that they drive the compressor. The supercharger uses a belt driven off of the crank shaft to turn the compressor. This has 2 main characteristics - #1 being that it takes horsepower away from the engine to drive the compressor. It will rob power any time the engine is on, just like running your AC does so fuel mileage is typically less. At WOT when the supercharger is working hard, depending on how much boost you are running, it can take anywhere from 50 to 100+ hp on street applications. Result from this is that you are putting a substantially large demand on the engine and it's components to make additional horsepower that you aren't ever going to see at the tires. #2 is going to be the way the boost acts because the compressor rpm is tied directly to engine rpm. By design, the centrifugal compressor wheel is not a positive displacement compressor. So this means that it gets more efficient as the rpms increase. This causes the compressor to make more boost as rpm's increase. The higher you rev the engine, the more boost the compressor will make. So you may not have any boost at 2000 rpm, a couple pounds by 3000, 4 psi by 4500 and then the full 6 psi (if that is your max boost) by 6500 rpm. Then when you shift the car and the rpm drops back down to 4500, the boost also drops back down to 4 psi. This is why you typically don't see a big flat hp and torque curve and the superchargers produce big peak numbers but don't perform so well in the 2-4k rpm ranges.

Because of the belt drive, any change in boost level requires a pulley/belt size change. Running higher boost many times requires that you run a 'cogged' type of belt rather than the standard ribbed belt. This increases the cost and the noise that the drive produces and is obviously something that you can't do 'on the fly'. Larger increases in boost levels also may require changing the compressor head unit which is going to be very costly. The throttle is very responsive and boost is nearly instantaneous but only to the amount that the supercharger is going to produce at that rpm (i.e. - stabbing throttle quickly produces 3 psi at 3k rpm but then you have to wait until the speed of the vehicle picks up and the engine reaches 6500 before you see the full 6 psi). Most centrifugal superchargers are quite noisey, even at idle due to the complicated gear drive/belt drive systems so make sure that you want your vehicle to produce this kind of noise before making a purchase.

The roots style superchargers are a positive displacement so they will have full boost anywhere from about 1500 rpm to redline. Like the centrifugal they are crank shaft driven so they do suck a fair amount of power off the crank, moreso than a centrifugal so you can expect less hp per pound of boost and lower fuel mileage. They are typically a less efficient method to compress air so they put a lot of heat into the aircharge. By design they are hard to build a large efficient intercooler into the system so this heat dramatically affects the power that the system makes. Heat creates more volume in the air charge which basically puts less air in the engine and the air that does go in is hot - bad on both accounts if you are trying to make power. Belt driven systems are capable of different boost levels (within fairly small limits without changing compressors) but do require a belt/pulley size change to raise or lower the boost level. These systems tend to have instant throttle response and instantly go to full boost which produces big bottom end power, moderate midrange and poor high rpm performance mainly due to the heat and parasitic loss. Great for burning the tires at a stop light but not very good for a good hard pull on the freeway.

Turbochargers are very similar to the centrifugal supercharger compressor, however they are driven from spent exhaust leaving the engine. They are not 'free' horsepower but they are way more efficient and cause much less of a parasitic loss than the belt driven alternatives. As the turbo puts more air into the engine, the engine produces more exhaust - which spins the turbo faster to put more air into the engine. This process is defined as the 'spooling up' of the turbo. You can think of the snowball effect logically in your mind as the above process continues to build more and more boost but it acually all happens in a fraction of a second. Turbos typically do not produce boost under 2k rpm but above that they can spool up and produce boost. This allows the compressor to go from zero boost to full boost in a fraction of a second and sometimes within 100 rpm, depending on what gear you are in. Due to the efficiency of the system, they typically get a very high hp per pound of boost. We've seen as high as 50 hp per psi on some systems but 35 hp per 1 psi is more typical. The torque curve of the turbocharger is what is really impressive. They typically will have a huge broad torque curve that gives you massive power and full boost in the 3-5k rpm range, which is where you spend most of your time driving.

Turbochargers typically get better fuel mileage than a stock vehicle so really are a great option with no real downsides. This 'lag' in the system also brings the power in just a little smoother than the superchargers do. This small cushion makes the turbocharger much easier on drivetrain components and typically keeps the tires hooked up rather than causing them to break loose. Out of all the power adders, the turbocharger produces the most power with the least abuse to the engine and drivetrain and can typically put more hp at the tires with all other conditions being equal. The turbo system can also produce different levels of boost which can be switched 'on the fly' and typically are capable of turning the boost and hp way up without any major component changes or additional financial investment in the system. You basically get your cake and get to eat it too. Win-Win in my book. If anyone has questions about the differences between front mount and remote mount turbos I would be glad to into that but this response is getting a little long. Hot Rod Magazine did an interesting comparison between these 3 power adders. For more info on this article you can click HERE (http://www.ststurbo.com/sts_technology). You can also click HERE (http://www.ststurbo.com/turbo_vs__supercharger) to see some additional information comparing superchargers and turbochargers.

So depending on what you are looking for, each system is capable of producing lots of added power to your vehicle. Understanding the differences allows you to pick the right system for your needs and for your changing needs down the road.

Rick@STS
www.STSTurbo.com

if i had to choose from either one ill choose the TT i used to have to P1SC but if i had the money ill go for the TT

Go with the TT, that just sounds cool!:cheers: OR go with the SC, that sounds cool also!! Either way I think you will have a ton of fun!:burnout:

The turbocharger and the centrifugal supercharger use the same style of compressor to pump the air into the engine. The main difference is the way that they drive the compressor. The supercharger uses a belt driven off of the crank shaft to turn the compressor. This has 2 main characteristics - #1 being that it takes horsepower away from the engine to drive the compressor. It will rob power any time the engine is on, just like running your AC does so fuel mileage is typically less. At WOT when the supercharger is working hard, depending on how much boost you are running, it can take anywhere from 50 to 100+ hp on street applications. Result from this is that you are putting a substantially large demand on the engine and it's components to make additional horsepower that you aren't ever going to see at the tires. #2 is going to be the way the boost acts because the compressor rpm is tied directly to engine rpm. By design, the centrifugal compressor wheel is not a positive displacement compressor. So this means that it gets more efficient as the rpms increase. This causes the compressor to make more boost as rpm's increase. The higher you rev the engine, the more boost the compressor will make. So you may not have any boost at 2000 rpm, a couple pounds by 3000, 4 psi by 4500 and then the full 6 psi (if that is your max boost) by 6500 rpm. Then when you shift the car and the rpm drops back down to 4500, the boost also drops back down to 4 psi. This is why you typically don't see a big flat hp and torque curve and the superchargers produce big peak numbers but don't perform so well in the 2-4k rpm ranges.

Because of the belt drive, any change in boost level requires a pulley/belt size change. Running higher boost many times requires that you run a 'cogged' type of belt rather than the standard ribbed belt. This increases the cost and the noise that the drive produces and is obviously something that you can't do 'on the fly'. Larger increases in boost levels also may require changing the compressor head unit which is going to be very costly. The throttle is very responsive and boost is nearly instantaneous but only to the amount that the supercharger is going to produce at that rpm (i.e. - stabbing throttle quickly produces 3 psi at 3k rpm but then you have to wait until the speed of the vehicle picks up and the engine reaches 6500 before you see the full 6 psi). Most centrifugal superchargers are quite noisey, even at idle due to the complicated gear drive/belt drive systems so make sure that you want your vehicle to produce this kind of noise before making a purchase.

The roots style superchargers are a positive displacement so they will have full boost anywhere from about 1500 rpm to redline. Like the centrifugal they are crank shaft driven so they do suck a fair amount of power off the crank, moreso than a centrifugal so you can expect less hp per pound of boost and lower fuel mileage. They are typically a less efficient method to compress air so they put a lot of heat into the aircharge. By design they are hard to build a large efficient intercooler into the system so this heat dramatically affects the power that the system makes. Heat creates more volume in the air charge which basically puts less air in the engine and the air that does go in is hot - bad on both accounts if you are trying to make power. Belt driven systems are capable of different boost levels (within fairly small limits without changing compressors) but do require a belt/pulley size change to raise or lower the boost level. These systems tend to have instant throttle response and instantly go to full boost which produces big bottom end power, moderate midrange and poor high rpm performance mainly due to the heat and parasitic loss. Great for burning the tires at a stop light but not very good for a good hard pull on the freeway.

Turbochargers are very similar to the centrifugal supercharger compressor, however they are driven from spent exhaust leaving the engine. They are not 'free' horsepower but they are way more efficient and cause much less of a parasitic loss than the belt driven alternatives. As the turbo puts more air into the engine, the engine produces more exhaust - which spins the turbo faster to put more air into the engine. This process is defined as the 'spooling up' of the turbo. You can think of the snowball effect logically in your mind as the above process continues to build more and more boost but it acually all happens in a fraction of a second. Turbos typically do not produce boost under 2k rpm but above that they can spool up and produce boost. This allows the compressor to go from zero boost to full boost in a fraction of a second and sometimes within 100 rpm, depending on what gear you are in. Due to the efficiency of the system, they typically get a very high hp per pound of boost. We've seen as high as 50 hp per psi on some systems but 35 hp per 1 psi is more typical. The torque curve of the turbocharger is what is really impressive. They typically will have a huge broad torque curve that gives you massive power and full boost in the 3-5k rpm range, which is where you spend most of your time driving.

Turbochargers typically get better fuel mileage than a stock vehicle so really are a great option with no real downsides. This 'lag' in the system also brings the power in just a little smoother than the superchargers do. This small cushion makes the turbocharger much easier on drivetrain components and typically keeps the tires hooked up rather than causing them to break loose. Out of all the power adders, the turbocharger produces the most power with the least abuse to the engine and drivetrain and can typically put more hp at the tires with all other conditions being equal. The turbo system can also produce different levels of boost which can be switched 'on the fly' and typically are capable of turning the boost and hp way up without any major component changes or additional financial investment in the system. You basically get your cake and get to eat it too. Win-Win in my book. If anyone has questions about the differences between front mount and remote mount turbos I would be glad to into that but this response is getting a little long. Hot Rod Magazine did an interesting comparison between these 3 power adders. For more info on this article you can click HERE (http://www.ststurbo.com/sts_technology). You can also click HERE (http://www.ststurbo.com/turbo_vs__supercharger) to see some additional information comparing superchargers and turbochargers.

So depending on what you are looking for, each system is capable of producing lots of added power to your vehicle. Understanding the differences allows you to pick the right system for your needs and for your changing needs down the road.

Rick@STS
www.STSTurbo.comWow, great response Rick.
Nice read, and well thought out...wish more people could get straight answers like that on more forums....:cheers:

Thanks
Mike

Wow, great response Rick.
Nice read, and well thought out...wish more people could get straight answers like that on more forums....:cheers:

Thanks
Mike

:iagree: This is awsome, thanks everyone, especially Rick! Going to read this over a few times!