- 3,133
What's the difference in these two systems? i know they both increase hp...... anyone wanna help?
Superchargers and Turbochargers
- Thread starter halfracedrift
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- South Carolina
Let's start with the similarities. Both turbochargers and superchargers are called forced induction systems. They compress the air flowing into the engine. The advantage of compressing the air is that it lets the engine stuff more air into a cylinder. More air means that more fuel can be stuffed in, too, so you get more power from each explosion in each cylinder. A turbo/supercharged engine produces more power overall than the same engine without the charging.
The typical boost provided by either a turbocharger or a supercharger is 6 to 8 pounds per square inch (psi). Since normal atmospheric pressure is 14.7 psi at sea level, you can see that you are getting about 50-percent more air into the engine. Therefore, you would expect to get 50-percent more power. It's not perfectly efficient, though, so you might get a 30-percent to 40-percent improvement instead.
The key difference between a turbocharger and a supercharger is its power supply. Something has to supply the power to run the air compressor. In a supercharger, there is a belt that connects directly to the engine. It gets its power the same way that the water pump or alternator does. A turbocharger, on the other hand, gets its power from the exhaust stream. The exhaust runs through a turbine, which in turn spins the compressor.
There are tradeoffs in both systems. In theory, a turbocharger is more efficient because it is using the "wasted" energy in the exhaust stream for its power source. On the other hand, a turbocharger causes some amount of back pressure in the exhaust system and tends to provide less boost until the engine is running at higher RPMs. Superchargers are easier to install but tend to be more expensive.
I just found that online.
The typical boost provided by either a turbocharger or a supercharger is 6 to 8 pounds per square inch (psi). Since normal atmospheric pressure is 14.7 psi at sea level, you can see that you are getting about 50-percent more air into the engine. Therefore, you would expect to get 50-percent more power. It's not perfectly efficient, though, so you might get a 30-percent to 40-percent improvement instead.
The key difference between a turbocharger and a supercharger is its power supply. Something has to supply the power to run the air compressor. In a supercharger, there is a belt that connects directly to the engine. It gets its power the same way that the water pump or alternator does. A turbocharger, on the other hand, gets its power from the exhaust stream. The exhaust runs through a turbine, which in turn spins the compressor.
There are tradeoffs in both systems. In theory, a turbocharger is more efficient because it is using the "wasted" energy in the exhaust stream for its power source. On the other hand, a turbocharger causes some amount of back pressure in the exhaust system and tends to provide less boost until the engine is running at higher RPMs. Superchargers are easier to install but tend to be more expensive.
I just found that online.
- 3,133
ohhhh alrite, thanks josh
Also, the big argument between the two is that in general, BLOWERS(superchargers) tend to give you basically FULL boost from right off idle on, But drop off towards the top end.
On the other hand, TURBOS (most of them) have a BIG trade-off...the dreaded TURBO LAG!!
That's when a turbo has to spool up (start spinning faster) in order to make BOOST pressure. The disadvantage is that you have to wait a second or two(not on all turbos) until it starts making serious power. on some turbos, they make fairly smooth power that's a constant increase of power. On others, you wait & then get an almost sudden surge of amazing acceleration that just does'nt fall of until either the rev limiter kicks in OR the wastegate takes over(letting pressure out of your turbo).
Well I hope that gives you a little info on the subject, BTW can you tell I've had some experience with them??
On the other hand, TURBOS (most of them) have a BIG trade-off...the dreaded TURBO LAG!!
That's when a turbo has to spool up (start spinning faster) in order to make BOOST pressure. The disadvantage is that you have to wait a second or two(not on all turbos) until it starts making serious power. on some turbos, they make fairly smooth power that's a constant increase of power. On others, you wait & then get an almost sudden surge of amazing acceleration that just does'nt fall of until either the rev limiter kicks in OR the wastegate takes over(letting pressure out of your turbo).
Well I hope that gives you a little info on the subject, BTW can you tell I've had some experience with them??
- 66
wow. turbo2 sure confused me.
but i figure he's trying to explain Turbo V.S twin Turbo.
but i figure he's trying to explain Turbo V.S twin Turbo.
- 24,344
- Midlantic Area
- GTP_Duke
No, he's actually explaining the difference between turbocharging and supercharging.
Superchargers are mechanically driven and therefore make power that increases evenly from idle until high rpm, where they tend to drop off.
Turbochargers are not mechanically driven and have no hard connection between the power source (exhaust stream) and the impeller. So they tend to make less power at lower rpms, but come on more steeply once the revs come up, and do not fall off as much at high rpms.
Rather like jet engines don't make much power from idle, but come on strong as they wind up.
Superchargers are mechanically driven and therefore make power that increases evenly from idle until high rpm, where they tend to drop off.
Turbochargers are not mechanically driven and have no hard connection between the power source (exhaust stream) and the impeller. So they tend to make less power at lower rpms, but come on more steeply once the revs come up, and do not fall off as much at high rpms.
Rather like jet engines don't make much power from idle, but come on strong as they wind up.
Yeah, what he said ! I was trying to explain things in simple terms, not everybody understands the difference between the two. And YES I've worked on BOTH, I was just being goofy about the experience thing.
I'm currently starting on yet another project car- a turbo SHELBY CHARGER. My last MOPAR turbo was an '84 Daytona turbo with around 230-250HP TO THE WHEELS! (may it rest in peace).
I'm currently starting on yet another project car- a turbo SHELBY CHARGER. My last MOPAR turbo was an '84 Daytona turbo with around 230-250HP TO THE WHEELS! (may it rest in peace).
- 4,473
Well they are pretty much an even trade off. Some cars do better with Superchargers while some do better with Turbo's. There is an experimental turbo combined supercharger. Still in testing stages. If it was released now it would be as expensive as a car lol 
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- 4,473
Hey they are all good 
. POWER POWER POWER 
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. POWER POWER POWER ...
advanR
(Banned)
- 1,389
I feel I should bring up the fact that cars have been made using both before. Im not sure if others have, probably...., but rally cars have used that setup before. Maybe the Delta integral HF, Im sure someone else will know.
This combo was designed to eliminate the weaknesses of both. Im not sure how it worked, and what the disadvantages were. It would be nice to know why the engineering of such a simple combination of them both has been such a slow process. I mean, why not sooner?
These things interest me I guess. Another cool innovation being developed by Audi is the variable ratio transmission. Thats right, only one gear, but it covers the whole band of ratios needed. I imagine a car would be able to rev up to where an engine makes peak torque, and stay there while it accelerates. Maximizing acceleration. I havent read too much into it, only saw an article in a magazine some time ago, but the reason why the development and implementation of this has been slow is because it has been difficult to design a transmission like this that could handle a lot of power.
It was odd because one day I was just sitting down thinking of things like this that should be invented and I came up with that exact concept. Then I saw someone had beaten me to it. It was too general an idea I guess.
This combo was designed to eliminate the weaknesses of both. Im not sure how it worked, and what the disadvantages were. It would be nice to know why the engineering of such a simple combination of them both has been such a slow process. I mean, why not sooner?
These things interest me I guess. Another cool innovation being developed by Audi is the variable ratio transmission. Thats right, only one gear, but it covers the whole band of ratios needed. I imagine a car would be able to rev up to where an engine makes peak torque, and stay there while it accelerates. Maximizing acceleration. I havent read too much into it, only saw an article in a magazine some time ago, but the reason why the development and implementation of this has been slow is because it has been difficult to design a transmission like this that could handle a lot of power.
It was odd because one day I was just sitting down thinking of things like this that should be invented and I came up with that exact concept. Then I saw someone had beaten me to it. It was too general an idea I guess.
Sage
Staff Emeritus
- 12,533
- United States
- GTP_Sage
advanR, would you be referring to their CVT (continuously Varitable Transmission), or something totally different? If it's the former, then I think it's fair to say that Audi's not the only one... Nissan currently is hailed as having one of the best, which is installed on it's 4WD Murano (the Audi CVT can't quite take the same amount of torque, yet). If it's the latter that you're talking about, then I'll shut up. 
- 5,198
- Montana
- DethMOPAR340
Heres My drawing to explain how the blower works....
The blower uses the crankshaft to turn the turbines in the blowers case,while you may think it forces air down the middle,it actually forces it down the sides.
my opinion-the blower is the best way to go....,by the way,anyone know where i can get a dodge small block blower??
The blower uses the crankshaft to turn the turbines in the blowers case,while you may think it forces air down the middle,it actually forces it down the sides.
my opinion-the blower is the best way to go....,by the way,anyone know where i can get a dodge small block blower??
Attachments
Sage
Staff Emeritus
- 12,533
- United States
- GTP_Sage
If I read correctly, the CVT is like what you are describing. Basically, there is no shifting when using one, and no "lunging".
Audi made one some time ago, and it has been available in their A4. The Nissan Murano is just he latest car, and is touted with having the best CVT, since it handles more torque than any other. I think a few other manufacturers have also made CVTs, but I can't remember them offhand.
Also, if memory serves correctly, CVTs were introduced in eco-cars in Japan several years ago, but they only recently came to the states due to the fact that Americans like torquer cars (the ones in the Japanese cars didn't have to cope with much torque, and so could be simple belt units... I think the ones used these days are interlocking chains).
Audi made one some time ago, and it has been available in their A4. The Nissan Murano is just he latest car, and is touted with having the best CVT, since it handles more torque than any other. I think a few other manufacturers have also made CVTs, but I can't remember them offhand.
Also, if memory serves correctly, CVTs were introduced in eco-cars in Japan several years ago, but they only recently came to the states due to the fact that Americans like torquer cars (the ones in the Japanese cars didn't have to cope with much torque, and so could be simple belt units... I think the ones used these days are interlocking chains).
- 24,344
- Midlantic Area
- GTP_Duke
The Subaru Justy was the first CVT car sold in America, as far as I know, in the late '80s and early '90s. There was also a CVT Civic in the mid '90s. Neither car was terribly popular here. I had no idea that the Murano was CVT.
Back on the original topic, neither supercharging nor turbocharging is definitively better. It depends a lot on the application. In general, turbocharging is better for FWD cars and sustained high speeds. This is because it comes on progressively and does not annihilate the FWD traction as badly a supercharged engine would, which makes boost right off of idle. Plus, turbocharging (like a jet engine) makes its best power at sustained high RPMs unlike a blower which falls off at the high end because it loses efficiency at high rpms.
This is why most RWD drag racers use supercharged engines and most FWD drag racers use turbocharging. It's also why most roadrace and rally cars that are "supernaturally" aspirated use turbocharging rather than supercharging.
Back on the original topic, neither supercharging nor turbocharging is definitively better. It depends a lot on the application. In general, turbocharging is better for FWD cars and sustained high speeds. This is because it comes on progressively and does not annihilate the FWD traction as badly a supercharged engine would, which makes boost right off of idle. Plus, turbocharging (like a jet engine) makes its best power at sustained high RPMs unlike a blower which falls off at the high end because it loses efficiency at high rpms.
This is why most RWD drag racers use supercharged engines and most FWD drag racers use turbocharging. It's also why most roadrace and rally cars that are "supernaturally" aspirated use turbocharging rather than supercharging.
Centrifugal blowers have good top end power AND basically NO lag, but they don't have the top end charge that turbos do. This is due to the limit of how much they can spin.
A turbo can spin to alot higher rpms than a comparably sized centrifugal type, as the crankshaft can only go so fast, your exhaust can spin the turbine MORE than Double those speeds!
A turbo can spin to alot higher rpms than a comparably sized centrifugal type, as the crankshaft can only go so fast, your exhaust can spin the turbine MORE than Double those speeds!
- 6,977
- old-guy64
Duke, you are right on as usual. Another point, you will see superchargers on motors that are ALREADY pretty powerful to begin with. In the most successful applications you will find them on V-8's which already have a torque advantage, usually doe to cubic inch displacement.
On a turbo system, the trick is to find a turbo the right SIZE for the application. If you want the power to come on at say, 5000rpm, you want a bigger turbine, The lag won't be as much of an issue.
The best of both worlds is the twin turbo set up as a two-stage system, with the smaller turbo making power off the line and the bigger (second stage) making top end power. Of course the trade off is that you will need much more complicated (computer) engine management with a turbo.
On a turbo system, the trick is to find a turbo the right SIZE for the application. If you want the power to come on at say, 5000rpm, you want a bigger turbine, The lag won't be as much of an issue.
The best of both worlds is the twin turbo set up as a two-stage system, with the smaller turbo making power off the line and the bigger (second stage) making top end power. Of course the trade off is that you will need much more complicated (computer) engine management with a turbo.
- 944
If you guys don't mind I would like to add a bit to the turbo charging. There is so much made of large lag or turbo lag. The time it takes for the turbine to spin fast enough, usually around 130,000 rpms (not a typo) before it makes boost. While that is true there will always be a bit of lag, you can minimize that by choosing the right turbo, or turbos for your particular application. Also you need to blance the flow into the turbine housing to maximize the efficentcy of the exhaust gasses.
I will use the RB26 engine for this exercise.
Single turbo setups are the easiest to work with. They also cause the most lag until you reach a certain hp range, usually around the 700hp. Due to the larger AR rating of the turbine housing reqired to blance out the larger compressor wheel you will experince much more lag. They also "come on" or spool later and once you achive boost thresh hold they hit like NOS for those that haven't been in a large single turbo'ed car. The power deliver is very sudden and massive. A .8 AR rated turbine housing will hit boost thresh hold at approx 4,800 rpms. This causes great strains on the entire drive line but really sets you back in your seat big time.
Twin Parralle turbos setups like those found on the GTR are two smaller turbos but flow the same hp as a much larger turbo. the turbos are mounted in parralle. Three cylinders feed each turbo using a split manifold that again joins after each turbo via a down pipe setup simular to a header for a V8. The fact that the AR on the turbine housing is very small say .46 as comparred to a comprable single that will have an AR of .8 . they spool very quickly. Approximately 3200 rpms and you are already at max boost pressure. Well before th peak power and torque of the engine. As you can see there is slightly less lag. Also if crusing and down shift and plant your foot they hit full boost much quicker than the single. The power deliever is much smoother and very deceptive. The only really draw back is life span. Due to they are spinning at nearly 150,000 rpms to produce boost they just don't last as long.
Twin sequencial such as what is found on the RX7, Subaru Legacy GT, 2JZ Supra, ect are a unique setup. There is a primary turbo and a secondary turbo. The primary is very small. It produces boost at very low rpms. After a certain rpm when the secondary turbo starts to become efficent, a valving system redirects 90% of the exhaust gasses to the secondary to provide mid to high rpm power. There is very little lag in this system. The least availble. A major draw back is the primary has a tendency to over boost and handgrande itself. I am not sure why they still use this system. The smaller primary turbo does not hold up very well, and they really don't like even mild boost. Most change them over to a single setup and some go to a parralle setup.
Now on the boost thresh hold thing. I am sure many of you think it is just rpm that a turbo needs to produce boost. That is incorrect. It takes three things for a turbo to produce boost.
1. RPM
2. Back pressure
3. Resistance
As an example while during a burnout in a turbo car you will produce very little effective boost. Usually around the 4-6 psi mark. You have rpm, and a small amount of resistance, but little back pressure. Unlike a supercharger or blower where rpm's dictate boost and power it is more complex than that for a turbo to achive the same.
As an example if you were to set peak boost at 1 bar or 14.6 psi with a mechanical boost controller, you will not acheive that until you are in the later gears under wot (wide open throttle). To further this in first gear you may make around 13 psi., second gear 14.1, 3rd gear 14.5, and fourth gear 14.6. The reason is rolling resistance.
Now it gets a little wierd. If you were to fit an electronic boost controller the vairence will not be as much. Neither will boost spiking, but that is another story.
I will use the RB26 engine for this exercise.
Single turbo setups are the easiest to work with. They also cause the most lag until you reach a certain hp range, usually around the 700hp. Due to the larger AR rating of the turbine housing reqired to blance out the larger compressor wheel you will experince much more lag. They also "come on" or spool later and once you achive boost thresh hold they hit like NOS for those that haven't been in a large single turbo'ed car. The power deliver is very sudden and massive. A .8 AR rated turbine housing will hit boost thresh hold at approx 4,800 rpms. This causes great strains on the entire drive line but really sets you back in your seat big time.
Twin Parralle turbos setups like those found on the GTR are two smaller turbos but flow the same hp as a much larger turbo. the turbos are mounted in parralle. Three cylinders feed each turbo using a split manifold that again joins after each turbo via a down pipe setup simular to a header for a V8. The fact that the AR on the turbine housing is very small say .46 as comparred to a comprable single that will have an AR of .8 . they spool very quickly. Approximately 3200 rpms and you are already at max boost pressure. Well before th peak power and torque of the engine. As you can see there is slightly less lag. Also if crusing and down shift and plant your foot they hit full boost much quicker than the single. The power deliever is much smoother and very deceptive. The only really draw back is life span. Due to they are spinning at nearly 150,000 rpms to produce boost they just don't last as long.
Twin sequencial such as what is found on the RX7, Subaru Legacy GT, 2JZ Supra, ect are a unique setup. There is a primary turbo and a secondary turbo. The primary is very small. It produces boost at very low rpms. After a certain rpm when the secondary turbo starts to become efficent, a valving system redirects 90% of the exhaust gasses to the secondary to provide mid to high rpm power. There is very little lag in this system. The least availble. A major draw back is the primary has a tendency to over boost and handgrande itself. I am not sure why they still use this system. The smaller primary turbo does not hold up very well, and they really don't like even mild boost. Most change them over to a single setup and some go to a parralle setup.
Now on the boost thresh hold thing. I am sure many of you think it is just rpm that a turbo needs to produce boost. That is incorrect. It takes three things for a turbo to produce boost.
1. RPM
2. Back pressure
3. Resistance
As an example while during a burnout in a turbo car you will produce very little effective boost. Usually around the 4-6 psi mark. You have rpm, and a small amount of resistance, but little back pressure. Unlike a supercharger or blower where rpm's dictate boost and power it is more complex than that for a turbo to achive the same.
As an example if you were to set peak boost at 1 bar or 14.6 psi with a mechanical boost controller, you will not acheive that until you are in the later gears under wot (wide open throttle). To further this in first gear you may make around 13 psi., second gear 14.1, 3rd gear 14.5, and fourth gear 14.6. The reason is rolling resistance.
Now it gets a little wierd. If you were to fit an electronic boost controller the vairence will not be as much. Neither will boost spiking, but that is another story.
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