Hard on for turbochargers?
12-05-2007, 09:44 PM
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Hard on for turbochargers?
I'm curious if somene in here could tell me why everyone seems to have a big hard on for turbo chargers over superchargers? Yes I understand that turbochargers "apparently" tend to require less drain/pull from the engine to make their boost by using exhaust flow to turn the turbine. But the HP superhcargers use off the pulley to turn their impellers couldn't be *that* much more to offset the advantages that superchargers offer, namely no issues with turob lag, way less installation issues, much easier to install and uninstall, cleaner looking engine bays, etc. Is there something I am missing here?
12-05-2007, 09:50 PM
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Personaly from what ive seen on YT the oppinions are rather split. Turbo's offer less resistance and take less power, and can produce WAY more boost and hp then a SC can, though on the flipside SC's have power on demand and produce much more low end torque. As well SC's are far more durable offroad as long as you are sure to bring spair belts. Though people will argue either way on the durability.
Im sure youve opened up a can of worms with this thread as it will probably just start the whole argument over again...
Im sure youve opened up a can of worms with this thread as it will probably just start the whole argument over again...
12-05-2007, 10:04 PM
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Well I can see the can of worms coming around. But I'd be interested if this can is opened, if there are any other details or points that I may have missed that may help me understand the turbocharger crowd a bit better.
EDIT: Here's a question for you - why don't you ever hear of Supercharged Diesel engines? It appears as though all they ever come out with are Turbo Diesels - why no supercharged diesels?
EDIT: Here's a question for you - why don't you ever hear of Supercharged Diesel engines? It appears as though all they ever come out with are Turbo Diesels - why no supercharged diesels?
Last edited by CoedNaked; 12-05-2007 at 10:07 PM.
12-05-2007, 10:26 PM
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Diesles have great low end power, top end is where they drop off, and thats where turbos work best. At least thats what I made of it...
supercharger wine > turbo blow off valve
supercharger wine > turbo blow off valve
12-05-2007, 11:01 PM
#5
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At the top of the cylinder are typically two or four exhaust valves that all open at the same time. There is also the diesel fuel injector (shown above in yellow). The piston is elongated, as in a gasoline two-stroke engine, so that it can act as the intake valve. At the bottom of the piston's travel, the piston uncovers the ports for air intake. The intake air is pressurized by a turbocharger or a supercharger (light blue). The crankcase is sealed and contains oil as in a four-stroke engine.
The two-stroke diesel cycle goes like this:
When the piston is at the top of its travel, the cylinder contains a charge of highly compressed air. Diesel fuel is sprayed into the cylinder by the injector and immediately ignites because of the heat and pressure inside the cylinder. This is the same process described in How Diesel Engines Work.
The pressure created by the combustion of the fuel drives the piston downward. This is the power stroke.
As the piston nears the bottom of its stroke, all of the exhaust valves open. Exhaust gases rush out of the cylinder, relieving the pressure.
As the piston bottoms out, it uncovers the air intake ports. Pressurized air fills the cylinder, forcing out the remainder of the exhaust gases.
The exhaust valves close and the piston starts traveling back upward, re-covering the intake ports and compressing the fresh charge of air. This is the compression stroke.
As the piston nears the top of the cylinder, the cycle repeats with step 1.
From this description, you can see the big difference between a diesel two-stroke engine and a gasoline two-stroke engine: In the diesel version, only air fills the cylinder, rather than gas and air mixed together. This means that a diesel two-stroke engine suffers from none of the environmental problems that plague a gasoline two-stroke engine. On the other hand, a diesel two-stroke engine must have a turbocharger or a supercharger, and this means that you will never find a diesel two-stroke on a chain saw -- it would simply be too expensive.
The two-stroke diesel cycle goes like this:
When the piston is at the top of its travel, the cylinder contains a charge of highly compressed air. Diesel fuel is sprayed into the cylinder by the injector and immediately ignites because of the heat and pressure inside the cylinder. This is the same process described in How Diesel Engines Work.
The pressure created by the combustion of the fuel drives the piston downward. This is the power stroke.
As the piston nears the bottom of its stroke, all of the exhaust valves open. Exhaust gases rush out of the cylinder, relieving the pressure.
As the piston bottoms out, it uncovers the air intake ports. Pressurized air fills the cylinder, forcing out the remainder of the exhaust gases.
The exhaust valves close and the piston starts traveling back upward, re-covering the intake ports and compressing the fresh charge of air. This is the compression stroke.
As the piston nears the top of the cylinder, the cycle repeats with step 1.
From this description, you can see the big difference between a diesel two-stroke engine and a gasoline two-stroke engine: In the diesel version, only air fills the cylinder, rather than gas and air mixed together. This means that a diesel two-stroke engine suffers from none of the environmental problems that plague a gasoline two-stroke engine. On the other hand, a diesel two-stroke engine must have a turbocharger or a supercharger, and this means that you will never find a diesel two-stroke on a chain saw -- it would simply be too expensive.
Last edited by superjoe83; 12-05-2007 at 11:11 PM.
12-05-2007, 11:06 PM
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yeah superchargers are awesome with that classic blower "whine", but IMO, a turbo just can't be beat...i mean, it gives the engine more power from the engines exhaust (so it's not "using" any of the motor's power to make more power), it can be tweaked to make more boost, which = even more power, and i guess b/c i'm such a big diesel fan, the spool-up and blow-off valve sounds are cooler to me, but that's just IMO...
12-05-2007, 11:13 PM
#7
I prefer a turbo charger because it is power when you need it. Say it doesn't spool until 3500RPMs, until then it's like you have a normal naturally aspirated engine. Thus saving gas yet having the power when you need it.
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12-06-2007, 12:13 AM
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With newer turbo designs and proper tuning there is very little lag, you won't notice at all.
Original supercharger designs, "gmc" roots-style blowers used by early drag-racers are actually revamped industrial or diesel blowers.
Also, instant power from a supercharger is a myth as their rated psi is on the top end, therefore just like a turbo the faster it spins the more air it pushes.
You can put together a homemade cheap turbo set-up quite easily with a farm equipment turbo that would make tons of power for less than $1000, the cheapest supercharger, be it roots-style or centrifugal will cost $2500 or more.....ouch!
Original supercharger designs, "gmc" roots-style blowers used by early drag-racers are actually revamped industrial or diesel blowers.
Also, instant power from a supercharger is a myth as their rated psi is on the top end, therefore just like a turbo the faster it spins the more air it pushes.
You can put together a homemade cheap turbo set-up quite easily with a farm equipment turbo that would make tons of power for less than $1000, the cheapest supercharger, be it roots-style or centrifugal will cost $2500 or more.....ouch!
12-06-2007, 12:38 AM
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For me, It would really depend on what I was using my car for, and what kind of car it is. For example, I'd much rather have a supercharged SUV than a Turbo, esp for low speeds(and low RPM, too). I'd like to have a turbo on a diesel, or a BMW sports car. I'd want a supercharger on a muscle car, or on a large gasoline engine (IE, the 4.3 chevy, the 5.7 chevy, and pretty much anything over 350CI). On a Z06 Corvette, which is fast enough as it is, I'd like a Supercharger. I guess all in all, I like superchargers better. I'm not sure why, but I think the whole ricer scene kind of ruined turbos for me a little bit.
12-06-2007, 12:48 AM
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yeah superchargers are awesome with that classic blower "whine", but IMO, a turbo just can't be beat...i mean, it gives the engine more power from the engines exhaust (so it's not "using" any of the motor's power to make more power), it can be tweaked to make more boost, which = even more power, and i guess b/c i'm such a big diesel fan, the spool-up and blow-off valve sounds are cooler to me, but that's just IMO...
Most turbochargers just cant live up to the simplistic, enclosed, bolt on design of an SC, as well as they are not positioned as high up on the block which makes them even more succeptible to water damage. Im not saying that there arent some incredibly durrable and efficient turbo's out there that can be used for offroad, but i am saying that for the price the general consumer is going to get better end results from a supercharger.
12-06-2007, 01:05 AM
#13
The fuel economy turns me off superchargers. I'd like to put a bi-turbo setup in my 22RE. A little turbo to spool up fast for power on tap and the a bigger turbo for higher revs. In the perfect word, I'd just have a turbo diesel 4Runner.
12-06-2007, 06:34 AM
#14
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First, let's have a little lesson.
A turbocharger IS a supercharger. A supercharger compresses the intake air to provide more oxygen so you can burn more fuel. As simple as that.
The difference in the two is the way the compressor is driven. A turbocharger is a special kind of supercharger that uses the exhaust gas to drive a radial turbine compressor.
What people are talking about above are their experiences in the execution of the idea. There are many poorly executed designs out there. You can make a supercharger that has the high end boost like a turbo and you can make a turbo with NO lag like a supercharger - and there are plenty of both out there.
Since a turbo is ALWAYS remote mounted, it is easier to intercool it to boost that oxygen density even further. As mentioned above, though, that comes at the expense of complex exhaust routing.
Typically, a supercharger is easier to install, but does have some parasitic drag and, for the intake mounted versions especially, they are harder to intercool.
Because of the high compression ratios diesel engines operate at, they have a lot of energy in their exhaust streams which are "ripe pickings" for a turbo. From a factory standpoint, turbos have the advantage of quieting the exhaust and reducing the exhaust temp which helps them meet EPA requirements.
http://auto.howstuffworks.com/supercharger.htm
A turbocharger IS a supercharger. A supercharger compresses the intake air to provide more oxygen so you can burn more fuel. As simple as that.
The difference in the two is the way the compressor is driven. A turbocharger is a special kind of supercharger that uses the exhaust gas to drive a radial turbine compressor.
What people are talking about above are their experiences in the execution of the idea. There are many poorly executed designs out there. You can make a supercharger that has the high end boost like a turbo and you can make a turbo with NO lag like a supercharger - and there are plenty of both out there.
Since a turbo is ALWAYS remote mounted, it is easier to intercool it to boost that oxygen density even further. As mentioned above, though, that comes at the expense of complex exhaust routing.
Typically, a supercharger is easier to install, but does have some parasitic drag and, for the intake mounted versions especially, they are harder to intercool.
Because of the high compression ratios diesel engines operate at, they have a lot of energy in their exhaust streams which are "ripe pickings" for a turbo. From a factory standpoint, turbos have the advantage of quieting the exhaust and reducing the exhaust temp which helps them meet EPA requirements.
http://auto.howstuffworks.com/supercharger.htm
12-06-2007, 09:27 AM
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For me, It would really depend on what I was using my car for, and what kind of car it is. For example, I'd much rather have a supercharged SUV than a Turbo, esp for low speeds(and low RPM, too). I'd like to have a turbo on a diesel, or a BMW sports car. I'd want a supercharger on a muscle car, or on a large gasoline engine (IE, the 4.3 chevy, the 5.7 chevy, and pretty much anything over 350CI). On a Z06 Corvette, which is fast enough as it is, I'd like a Supercharger. I guess all in all, I like superchargers better. I'm not sure why, but I think the whole ricer scene kind of ruined turbos for me a little bit.
i bet this kit for a Z06 would make you change your mind about a supercharger...and they even had a corvette for a car & driver test that was making more HP than this kit...1000+ HP!
Last edited by mikes19984x4; 12-06-2007 at 09:31 AM.
12-06-2007, 02:59 PM
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Of course it comes down to design of the system and what you want out it. Turbo systems designed correctly for your goals, are superior to SC, with the appropriate maintenance.
Again, begging the question i had earlier, T25-42AR turbine, 48AR compressor, 2.7L 3RZ; any takers on full boost before say 2k?
12-06-2007, 03:55 PM
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Tc is on time. Take a look at a top fuel car sometime blowers rule no mater what drives em. They are all usually built to pull after they start to spool up some. Rock crawlers need the low end umph. Turbo's need a lot of engineering to get that. But check this out.
http://www.nelsonracingengines.com/video_drive.html
Ya gotta like that
Jim
http://www.nelsonracingengines.com/video_drive.html
Ya gotta like that
Jim
12-06-2007, 10:22 PM
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http://www.lingenfelter.com/Lingenfe...boCorvette.htm
i bet this kit for a Z06 would make you change your mind about a supercharger...and they even had a corvette for a car & driver test that was making more HP than this kit...1000+ HP!
i bet this kit for a Z06 would make you change your mind about a supercharger...and they even had a corvette for a car & driver test that was making more HP than this kit...1000+ HP!
12-07-2007, 03:42 PM
#20
there are 2 types of forced induction systems: one type is the turbocharger (powered by engine exhaust) and the other is the supercharger (powered by the engine pulley).
although both have the same function (to increase engine performance), the two are still different and a turbocharger is not a supercharger.
although both have the same function (to increase engine performance), the two are still different and a turbocharger is not a supercharger.
