Why do blowers tend to make so much less power than turbos
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From: NYC, NY
Why do blowers tend to make so much less power than turbos
I see the turbo guys routinely, without much effort make 600 -700 hp, guys with the D1 don't even come close and the D1 is suppose to be good up into the 7-800 range, I have a hard time believing that it's all parasitic loss. What is going on, why do blower cars just tend to not do so hot?
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Joined: Mar 2002
Posts: 331
From: New Jersey
Re: Why do blowers tend to make so much less power than turbos
I wouldn't say it's without much effort....
I dunno what size turbo's people are using but a 5.7 Liter or bigger engine moves a dumpload of air, and turbos don't have a ceiling on them like superchargers do (i.e you make as much boost as the pulley/ blower setup will allow). If you have big enough turbo(s) all you gotta do to make more power is throw in some more fuel, and turn the boost controller ****
I dunno what size turbo's people are using but a 5.7 Liter or bigger engine moves a dumpload of air, and turbos don't have a ceiling on them like superchargers do (i.e you make as much boost as the pulley/ blower setup will allow). If you have big enough turbo(s) all you gotta do to make more power is throw in some more fuel, and turn the boost controller ****
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Joined: Jul 2004
Posts: 337
From: GERMANTOWN, MARYLAND
Re: Why do blowers tend to make so much less power than turbos
with a 12 rib belt i'm making upward of 650rwhp, with 16psi, and yes you do loose as much as 100rwhp through a belt especially 12 rib. thats why you have to go over kill with fuel set ups on blown cars, cuz the blower throuws a lot at the motor but it looses power through belt/drivetrain. so if i make 650 lets say 10% conserviteve loss through drivetrain puts me at 715 and another 110 is 825fwhp. yeah i hear you i'm going turbo my self next year
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Joined: Mar 2002
Posts: 2,743
From: Baton Rouge, LA, USA
Re: Why do blowers tend to make so much less power than turbos
Turbo's have less (but not zero) parasitic loss, but also make more boost at peak hp, whereas a centrifugal doesn't reach peak boost until redline. Also, a good turbo can be designed to run with aroudn 74-75% efficiency versus 69-70% for a supercharger. Not talking about peak efficiency of the compressor, but actual operating efficiency. This translates into cooler intake charge.
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Joined: Mar 2002
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From: Baton Rouge, LA, USA
Re: Why do blowers tend to make so much less power than turbos
Originally Posted by krispy
I wonder how much better a roots style setup would be
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Joined: Nov 2002
Posts: 272
From: GPW, MI
Re: Why do blowers tend to make so much less power than turbos
Originally Posted by engineermike
Better?!?! Try way, way worse. Efficiencies on the order of 40%.
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Joined: Feb 2000
Posts: 509
Re: Why do blowers tend to make so much less power than turbos
Your original premise is wholly flawed.
If you take identical boost (i.e. 10 psi), then the power at the cylinders should be identical, then you have to subtract the power to drive the supercharger. If you have a turbo, then you have to subtract the potential loss of a highly tuned exhaust system, and then at what RPM is the loss occuring, etc., etc.
Also, superchargers tend to bring boost on at lower RPMs, thereby providing mid-RPM torque that turbos don't...as such, the cams may be different, resulting in different power distributions across bands. Looking at total peak HP maybe exactly what you are trying to achieve and maybe a turbo is what would be your best fit. If you need street manners, and you enjoy third-gear pulls from 30 MPH, then an SC maybe more responsive.
Too many variables to simply label Turbo vs Supercharging as better/lesser power adders.
I personally use a supercharger on a 383 that has gobs of torque in the low/mid ranges and when I hit the upper RPMs, the blower meets my modest requirements for upper RPM scorching. As such, I really don't take it beyond about 5500 RPM before shifting because the torque available in the next gear will propel me quicker than holding the RPM until 6500, then shifting.
I recall reviewing a Z06 torque curve and how it peaks at about 4000 RPM. It is that way is for good reason, and their performance numbers are reflective of that design. Designing an engine with a different torque curve will put peak HP at a different RPM. Most of that is in the cam's design. If you want 400 HP at 6000 RPM, that's fine, but if your torque is only 350# at 5252 RPM, your HP will only be 350. It's all about what HP/Tq do you want at any specific RPM range...2000 to 2500, 2500 to 3000, 3500 to 3500, etc. IF you hold your RPM to 6000 before shifting, then when you hit your next gear, what RPM you fall back to will reflect you new power curve. Again, in my case, if I shift at 5500, my next gear will be about 4000...right smack in the middle of my torque curve with lots of boost ready to go. For a turbo, you probably want your RPMs a lot higher for max HP, and subsequent gears will reflect that power band.
Sorry for the long wind. But your question is too simple for this complex issue.
If you take identical boost (i.e. 10 psi), then the power at the cylinders should be identical, then you have to subtract the power to drive the supercharger. If you have a turbo, then you have to subtract the potential loss of a highly tuned exhaust system, and then at what RPM is the loss occuring, etc., etc.
Also, superchargers tend to bring boost on at lower RPMs, thereby providing mid-RPM torque that turbos don't...as such, the cams may be different, resulting in different power distributions across bands. Looking at total peak HP maybe exactly what you are trying to achieve and maybe a turbo is what would be your best fit. If you need street manners, and you enjoy third-gear pulls from 30 MPH, then an SC maybe more responsive.
Too many variables to simply label Turbo vs Supercharging as better/lesser power adders.
I personally use a supercharger on a 383 that has gobs of torque in the low/mid ranges and when I hit the upper RPMs, the blower meets my modest requirements for upper RPM scorching. As such, I really don't take it beyond about 5500 RPM before shifting because the torque available in the next gear will propel me quicker than holding the RPM until 6500, then shifting.
I recall reviewing a Z06 torque curve and how it peaks at about 4000 RPM. It is that way is for good reason, and their performance numbers are reflective of that design. Designing an engine with a different torque curve will put peak HP at a different RPM. Most of that is in the cam's design. If you want 400 HP at 6000 RPM, that's fine, but if your torque is only 350# at 5252 RPM, your HP will only be 350. It's all about what HP/Tq do you want at any specific RPM range...2000 to 2500, 2500 to 3000, 3500 to 3500, etc. IF you hold your RPM to 6000 before shifting, then when you hit your next gear, what RPM you fall back to will reflect you new power curve. Again, in my case, if I shift at 5500, my next gear will be about 4000...right smack in the middle of my torque curve with lots of boost ready to go. For a turbo, you probably want your RPMs a lot higher for max HP, and subsequent gears will reflect that power band.
Sorry for the long wind. But your question is too simple for this complex issue.
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Joined: Dec 2001
Posts: 180
From: Texas
Re: Why do blowers tend to make so much less power than turbos
Originally Posted by Ultra_Dog
Your original premise is wholly flawed.
If you take identical boost (i.e. 10 psi), then the power at the cylinders should be identical, then you have to subtract the power to drive the supercharger. If you have a turbo, then you have to subtract the potential loss of a highly tuned exhaust system, and then at what RPM is the loss occuring, etc., etc.
Also, superchargers tend to bring boost on at lower RPMs, thereby providing mid-RPM torque that turbos don't...as such, the cams may be different, resulting in different power distributions across bands. Looking at total peak HP maybe exactly what you are trying to achieve and maybe a turbo is what would be your best fit. If you need street manners, and you enjoy third-gear pulls from 30 MPH, then an SC maybe more responsive.
Too many variables to simply label Turbo vs Supercharging as better/lesser power adders.
I personally use a supercharger on a 383 that has gobs of torque in the low/mid ranges and when I hit the upper RPMs, the blower meets my modest requirements for upper RPM scorching. As such, I really don't take it beyond about 5500 RPM before shifting because the torque available in the next gear will propel me quicker than holding the RPM until 6500, then shifting.
I recall reviewing a Z06 torque curve and how it peaks at about 4000 RPM. It is that way is for good reason, and their performance numbers are reflective of that design. Designing an engine with a different torque curve will put peak HP at a different RPM. Most of that is in the cam's design. If you want 400 HP at 6000 RPM, that's fine, but if your torque is only 350# at 5252 RPM, your HP will only be 350. It's all about what HP/Tq do you want at any specific RPM range...2000 to 2500, 2500 to 3000, 3500 to 3500, etc. IF you hold your RPM to 6000 before shifting, then when you hit your next gear, what RPM you fall back to will reflect you new power curve. Again, in my case, if I shift at 5500, my next gear will be about 4000...right smack in the middle of my torque curve with lots of boost ready to go. For a turbo, you probably want your RPMs a lot higher for max HP, and subsequent gears will reflect that power band.
Sorry for the long wind. But your question is too simple for this complex issue.
If you take identical boost (i.e. 10 psi), then the power at the cylinders should be identical, then you have to subtract the power to drive the supercharger. If you have a turbo, then you have to subtract the potential loss of a highly tuned exhaust system, and then at what RPM is the loss occuring, etc., etc.
Also, superchargers tend to bring boost on at lower RPMs, thereby providing mid-RPM torque that turbos don't...as such, the cams may be different, resulting in different power distributions across bands. Looking at total peak HP maybe exactly what you are trying to achieve and maybe a turbo is what would be your best fit. If you need street manners, and you enjoy third-gear pulls from 30 MPH, then an SC maybe more responsive.
Too many variables to simply label Turbo vs Supercharging as better/lesser power adders.
I personally use a supercharger on a 383 that has gobs of torque in the low/mid ranges and when I hit the upper RPMs, the blower meets my modest requirements for upper RPM scorching. As such, I really don't take it beyond about 5500 RPM before shifting because the torque available in the next gear will propel me quicker than holding the RPM until 6500, then shifting.
I recall reviewing a Z06 torque curve and how it peaks at about 4000 RPM. It is that way is for good reason, and their performance numbers are reflective of that design. Designing an engine with a different torque curve will put peak HP at a different RPM. Most of that is in the cam's design. If you want 400 HP at 6000 RPM, that's fine, but if your torque is only 350# at 5252 RPM, your HP will only be 350. It's all about what HP/Tq do you want at any specific RPM range...2000 to 2500, 2500 to 3000, 3500 to 3500, etc. IF you hold your RPM to 6000 before shifting, then when you hit your next gear, what RPM you fall back to will reflect you new power curve. Again, in my case, if I shift at 5500, my next gear will be about 4000...right smack in the middle of my torque curve with lots of boost ready to go. For a turbo, you probably want your RPMs a lot higher for max HP, and subsequent gears will reflect that power band.
Sorry for the long wind. But your question is too simple for this complex issue.
I think some will respond to your post in the same way "whooly flawed" as you did the above person. Starting with....... "Also, superchargers tend to bring boost on at lower RPMs, thereby providing mid-RPM torque that turbos don't".
Last edited by Rpm280; Apr 22, 2005 at 03:28 PM.
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Joined: Feb 2000
Posts: 509
Re: Why do blowers tend to make so much less power than turbos
I think some will respond to your post in the same way "whooly flawed" as you did the above person. Starting with....... "Also, superchargers tend to bring boost on at lower RPMs, thereby providing mid-RPM torque that turbos don't".
...And your point is?
If you disagree, provide alternate information for us to evaluate. Yes, I am making opinion based upon limited info, as all of us do. If you can assert that mid-RPM in turbos is equal or better, go for it. If you think all things are equal and cam selection has no bearing, state your reasoning. I gave mine and stand by it. But the opening question is why do turbos make more power than SCs is like saying why are Bears stronger than Lions. It is an unqualified, and flawed, request for fact. John Force runs a supercharge on his Mustang, not a turbocharger. You would ask the same dumb question: "Why aren't turbochargers winning Top-Fuel dragster races?"
Also, my statement is not whooly flawed, but partially flawed. Whooly is a warm fuzzy product of lambs or Lhambs?
...And your point is?
If you disagree, provide alternate information for us to evaluate. Yes, I am making opinion based upon limited info, as all of us do. If you can assert that mid-RPM in turbos is equal or better, go for it. If you think all things are equal and cam selection has no bearing, state your reasoning. I gave mine and stand by it. But the opening question is why do turbos make more power than SCs is like saying why are Bears stronger than Lions. It is an unqualified, and flawed, request for fact. John Force runs a supercharge on his Mustang, not a turbocharger. You would ask the same dumb question: "Why aren't turbochargers winning Top-Fuel dragster races?"
Also, my statement is not whooly flawed, but partially flawed. Whooly is a warm fuzzy product of lambs or Lhambs?
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Joined: Aug 1998
Posts: 520
From: Perryopolis, Pa
Re: Why do blowers tend to make so much less power than turbos
Turbo's are not allowed in top fuel....
Turbo's can & usually do make more low-mid boost than a centrifugal charger if sized properly. They can make full boost at very low RPM if sized correctly. A too large sized turbo will not come up to boost at low RPM. This is what turbo lag is all about.
A roots charger can make full & linear boost through most of the RPM range.
Superchargers will not pick up exhaust heat through the housing like a turbo, but this is minimal.
Chargers are harder on the crank/balancers from the belt drive.
Turbos are harder on exhaust valves & seats due to the back pressure & resultant heat.
Just a few quick facts. Hope this helps.
Turbo's can & usually do make more low-mid boost than a centrifugal charger if sized properly. They can make full boost at very low RPM if sized correctly. A too large sized turbo will not come up to boost at low RPM. This is what turbo lag is all about.
A roots charger can make full & linear boost through most of the RPM range.
Superchargers will not pick up exhaust heat through the housing like a turbo, but this is minimal.
Chargers are harder on the crank/balancers from the belt drive.
Turbos are harder on exhaust valves & seats due to the back pressure & resultant heat.
Just a few quick facts. Hope this helps.
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Joined: Jul 1999
Posts: 34
From: Orlando, FL, USA
Re: Why do blowers tend to make so much less power than turbos
Originally Posted by Ultra_Dog
I think some will respond to your post in the same way "whooly flawed" as you did the above person. Starting with....... "Also, superchargers tend to bring boost on at lower RPMs, thereby providing mid-RPM torque that turbos don't".
...And your point is??
...And your point is??
That's funny...my old stock Syclone would leave the tree at 15psi of boost. I only ran 17psi, and that was all in by 3500rpms in 1st gear
I don't know what you're talkin' about, but you haven't been in a properly tuned and sized turbo vehicle... makin' big bold statements like that.
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Joined: Aug 2004
Posts: 93
From: SE PA
Re: Why do blowers tend to make so much less power than turbos
I don't think a turbo will make more power if both compressors supply the same cfm and boost. Unfortunately we cannot make a accurate comparison as we would have to maximize both combos which would take different camshafts and fueling. The question you need to ask is, has anybody ever run the same size compressor with both? I have seen many people take their blower off only to slap on a larger turbo and then claim the turbo makes more power.
Like other have stated one draws off the crank BUT has a maximized exhaust. While the other leaves the crank alone but bottles up the exhaust. I believe they both have their uses and its up to you to find the one that suits your needs better.
I own both and like the blower on my 442. As a matter of fact if my Syclone and Typhoon were 2 wheel drive instead of all wheel they would really suck to own the way the turbo power comes in on them. JMO
Like other have stated one draws off the crank BUT has a maximized exhaust. While the other leaves the crank alone but bottles up the exhaust. I believe they both have their uses and its up to you to find the one that suits your needs better.
I own both and like the blower on my 442. As a matter of fact if my Syclone and Typhoon were 2 wheel drive instead of all wheel they would really suck to own the way the turbo power comes in on them. JMO
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