SC or Turbo for VG
05-13-2005, 10:25 AM
#42
That didn't really make a whole lot of sense to me sorry.
Usually makers like to use low displacement w/ boost
SC usually make MORE low rpm torque
Longer life is the one thing I agree with. Or more correctly, less warranty issues with SC as it's harder to up the boost on vs turbo applications
Usually makers like to use low displacement w/ boost
SC usually make MORE low rpm torque
Longer life is the one thing I agree with. Or more correctly, less warranty issues with SC as it's harder to up the boost on vs turbo applications
Originally Posted by internetautomar
larger displacement with a desire for lower torque and longer life is the reason for a blower in OEM applicationa
05-13-2005, 01:27 PM
#44
a roots blower tends to lose some boost at higher rpms. i think a screws is a bit better at keeping full boost throughout the rpm range but i'm not positive. a s/c definitely can't spike since their boost is fully dependent on how fast the pulley is spinning but they can definitely lose boost by the belt slipping or breaking.
that's one of the big problems with an s/c also. if the belt breaks and its the same belt that runs one of your more important accesories (water pump or alternator) you're pretty much screwed. unless you carry extra belts and the tools needed to change it you're going to get stranded. if a turbo were to go out you'd be a lot less likely to be stranded. mine broke before and i made it home fine.
s/c units themselves tend to be more reliable than turbochargers but if you take care of the turbo properly (proper cool downs and such) it should last you a very long time.
that's one of the big problems with an s/c also. if the belt breaks and its the same belt that runs one of your more important accesories (water pump or alternator) you're pretty much screwed. unless you carry extra belts and the tools needed to change it you're going to get stranded. if a turbo were to go out you'd be a lot less likely to be stranded. mine broke before and i made it home fine.
s/c units themselves tend to be more reliable than turbochargers but if you take care of the turbo properly (proper cool downs and such) it should last you a very long time.
05-13-2005, 05:52 PM
#45
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Join Date: Jul 2004
Location: BFE, UT
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Originally Posted by Jeff92se
kcidmil 2/26/04, 4:40 pmyeah, that's a tight squeeze. I've been thinking of putting the new 3.5 in my 90. who needs a super or turbo when you have that engine
Yep that's right. Why bother with those when you can go all motor 3.5Surprised you even remember that thread Jeff. And I'm still working on the plans for the motor swap.
05-13-2005, 09:22 PM
#46
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Join Date: Apr 2005
Location: NY
Posts: 2,553
Originally Posted by mtcookson
yeah, s/c's would be good for gasoline tow vehicles but really in the end.... s/c's are just plain outdated. the best tow vehicles out there use turbochargers. granted they're on diesel engines but that just shows that they're superior. if s/c's were superior they would be on the heavy duty tow vehicles and not turbos.
its kind of like a pushrod engine versus a dual overhead cam engine. sure the pushrod engines are still used and can make gobs of power (with gobs of displacement) but the majority of vehicles today are dohc due to their higher efficiency which is exactly what the differen is between an s/c and turbo.
a turbo is way more efficient than s/c's simply due to the fact that they aren't run on a belt, which means no parasitic losses. granted there are still losses with a turbo, its not free power, but the losses are basically just due to higher backpressure in the exhaust system. (higher backpressure makes it a bit harder for the piston to come up which is where the power drain for a turbo would come from).
also, a roots type blower is actually just that... a blower. it actually doesn't do any compressing itself. it blows air into the engine so fast that it compresses the air inside the intake manifold, which doesn't make it very thermal efficient. they actually run quite hot. a lot of roots s/c guys can gain an incredible amount of power but installing an air/water intercooler.
a screws type s/c compresses the air between the screws making it more efficient than a roots and giving it much more power potenital a la kenne bell cobra, most drag cars (john force's car for instance), etc. etc.
a centrifugal s/c is more efficient than the positive displacement superchargers but as i mentioned before suffers greatly due to its lag and no peak boost till redline. in some cases they can actually be more thermal efficient than a turbo... but you still have your parasitic losses and its greatest weakness as just said, no peak boost till redline. that is the single most killer of the centrifugal s/c.
my idea for a good centrifugal would actually be to have a cvt type pulley setup to where you have instant full boost and it keeps it there to redline. that might actually compete heavily with a turbo... but then again may not due to the parasitic losses yet again. spinning that much weight takes away some good amount of power out of the engine. with a vgt (variable geometry turbine/turbo) that basically totally takes superchargers out of the scene.
what a vgt turbo can do is change the way the exhaust flows through the turbine giving you nearly instantaneous boost off the line then adjusting the airflow to keep that boost till redline. so now you have a turbo that can spool nearly as fast as a positive displacement supercharger, has no parasitic losses, and is much more efficient than the s/c's. the more they start being used the prices will start to drop and you'll see them around on nearly everything. once they're out there... i wouldn't be surprised if they start really killing the sales of the s/c's. only the diehard s/c's enthusiasts would be left to support them (why i don't know considering it has nearly all of the benefits of a supercharger and all of the benefits of a turbo). they run anywhere between $2,000 to $4,000 or so brand new. definitely worth it though if you're looking for the absolute best setup you can get.
its kind of like a pushrod engine versus a dual overhead cam engine. sure the pushrod engines are still used and can make gobs of power (with gobs of displacement) but the majority of vehicles today are dohc due to their higher efficiency which is exactly what the differen is between an s/c and turbo.
a turbo is way more efficient than s/c's simply due to the fact that they aren't run on a belt, which means no parasitic losses. granted there are still losses with a turbo, its not free power, but the losses are basically just due to higher backpressure in the exhaust system. (higher backpressure makes it a bit harder for the piston to come up which is where the power drain for a turbo would come from).
also, a roots type blower is actually just that... a blower. it actually doesn't do any compressing itself. it blows air into the engine so fast that it compresses the air inside the intake manifold, which doesn't make it very thermal efficient. they actually run quite hot. a lot of roots s/c guys can gain an incredible amount of power but installing an air/water intercooler.
a screws type s/c compresses the air between the screws making it more efficient than a roots and giving it much more power potenital a la kenne bell cobra, most drag cars (john force's car for instance), etc. etc.
a centrifugal s/c is more efficient than the positive displacement superchargers but as i mentioned before suffers greatly due to its lag and no peak boost till redline. in some cases they can actually be more thermal efficient than a turbo... but you still have your parasitic losses and its greatest weakness as just said, no peak boost till redline. that is the single most killer of the centrifugal s/c.
my idea for a good centrifugal would actually be to have a cvt type pulley setup to where you have instant full boost and it keeps it there to redline. that might actually compete heavily with a turbo... but then again may not due to the parasitic losses yet again. spinning that much weight takes away some good amount of power out of the engine. with a vgt (variable geometry turbine/turbo) that basically totally takes superchargers out of the scene.
what a vgt turbo can do is change the way the exhaust flows through the turbine giving you nearly instantaneous boost off the line then adjusting the airflow to keep that boost till redline. so now you have a turbo that can spool nearly as fast as a positive displacement supercharger, has no parasitic losses, and is much more efficient than the s/c's. the more they start being used the prices will start to drop and you'll see them around on nearly everything. once they're out there... i wouldn't be surprised if they start really killing the sales of the s/c's. only the diehard s/c's enthusiasts would be left to support them (why i don't know considering it has nearly all of the benefits of a supercharger and all of the benefits of a turbo). they run anywhere between $2,000 to $4,000 or so brand new. definitely worth it though if you're looking for the absolute best setup you can get.
really appreciate it. you sure know alot about cars for a 20 yr old. must have been growin up around this stuff.that VGT sounds good to me.. i was actually thinkin tho, if one cant get his hands on such a great turbo, would it be possible to s/c an engine and turbo it at the same time
s/c for low to mid range torque, and turbo for mid to high end torque. that would be amazing to see. i can only imagine the noises that would come out of that car. this guy i know who teaches at an automotive school, told me its not very efficiant to do. you either do one or the other, not both.
Originally Posted by Jeff92se
Usually makers like to use low displacement w/ boost
05-13-2005, 11:26 PM
#47
the only thing i fear about going turbo is that the studs on the rear bank has began to break for the second time. so unless i run the turbo only on the front bank i would have to worry about the exhaust leak. that is actually one of the reasons why i am exploring the s/c route. also i think it would be kinda interesting to do somthing different. so far im only aware of only one s/c max that was mentioned earlier. also i dont mind cutting a big hole in my hood. my car dont exactly have that "show quality" look so im not so concerned 
.
.
05-14-2005, 06:52 PM
#48
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Join Date: Apr 2005
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Posts: 2,553
Originally Posted by fastflyingasian
the only thing i fear about going turbo is that the studs on the rear bank has began to break for the second time. so unless i run the turbo only on the front bank i would have to worry about the exhaust leak. that is actually one of the reasons why i am exploring the s/c route. also i think it would be kinda interesting to do somthing different. so far im only aware of only one s/c max that was mentioned earlier. also i dont mind cutting a big hole in my hood. my car dont exactly have that "show quality" look so im not so concerned .
.
05-17-2005, 08:43 AM
#49
because turbos are better... 
if you put in the turbo studs, get a good flex section, and support the downpipe properly you won't break any studs.
the only problem is you'd have to do some crazy valving system to where you can close off the pipe to one unit while the other is boosting (in the case of a remote mounted pd s/c) because i would think there'd be a chance you could leak boost past the turbo until it spools (which in that case would spool extremely late if at all and even take the chance of ruining the turbo a la exhaust trying to spin it one way and the s/c trying to spin it another. i could be wrong on that but i'm not sure.
if the s/c was right on the manifold you probably could but you're still not fixing any of the inefficiencies. basically you'd help out the bottom end but you'd still have the parasitic losses on your engine and even more weight than necessary. what would be better, if you want some low end launching power, is just a small shot of nitrous. that'll get you off the line real well and spool the turbo very quickly.
a very interesting setup would be a sort of twin turbo setup. run one turbo on the exhaust manifold and dump the exhaust from it to the inlet of another turbo. the compressor outlet from the first turbo would go to the compressor inlet of the second, then to the aftercooler and engine. (this type of setup is actually where the term intercooler is supposed to be. a lot of these setups had an air cooler between the two compressors therefore being call an intercooler. the air coolers that are used on all common turbo setups are call aftercoolers (not to be confused with only be air/water.) any air cooler cooling the air after it has been compressed is called an aftercooler.)
doing that setup should double the boost from my understanding. if turbo 1 is making 15 psi and turbo 2 is also set to 15 psi there should be 30 psi going into the intake (i'm pretty sure this is how it works). they use this setup on a lot of turbo diesels pushing an incredible amount of boost (semi trucks well in excess of 100 psi and smaller diesel trucks pushing well over 50 psi).
in the end it might not be practical for street gasoline engine as it would be a bit heavier and hotter and a bit more expensive to do. considering single turbo setups work just fine (and these days better than most TT setups) there's really no reason to do something that extreme. if you want something different though.... that'd definitely be it.
no problem at all. i actually didn't really start getting into cars till about 17 or 18.
if you put in the turbo studs, get a good flex section, and support the downpipe properly you won't break any studs.
that VGT sounds good to me.. i was actually thinkin tho, if one cant get his hands on such a great turbo, would it be possible to s/c an engine and turbo it at the same time s/c for low to mid range torque, and turbo for mid to high end torque. that would be amazing to see. i can only imagine the noises that would come out of that car. this guy i know who teaches at an automotive school, told me its not very efficiant to do. you either do one or the other, not both.
if the s/c was right on the manifold you probably could but you're still not fixing any of the inefficiencies. basically you'd help out the bottom end but you'd still have the parasitic losses on your engine and even more weight than necessary. what would be better, if you want some low end launching power, is just a small shot of nitrous. that'll get you off the line real well and spool the turbo very quickly.
a very interesting setup would be a sort of twin turbo setup. run one turbo on the exhaust manifold and dump the exhaust from it to the inlet of another turbo. the compressor outlet from the first turbo would go to the compressor inlet of the second, then to the aftercooler and engine. (this type of setup is actually where the term intercooler is supposed to be. a lot of these setups had an air cooler between the two compressors therefore being call an intercooler. the air coolers that are used on all common turbo setups are call aftercoolers (not to be confused with only be air/water.) any air cooler cooling the air after it has been compressed is called an aftercooler.)
doing that setup should double the boost from my understanding. if turbo 1 is making 15 psi and turbo 2 is also set to 15 psi there should be 30 psi going into the intake (i'm pretty sure this is how it works). they use this setup on a lot of turbo diesels pushing an incredible amount of boost (semi trucks well in excess of 100 psi and smaller diesel trucks pushing well over 50 psi).
in the end it might not be practical for street gasoline engine as it would be a bit heavier and hotter and a bit more expensive to do. considering single turbo setups work just fine (and these days better than most TT setups) there's really no reason to do something that extreme. if you want something different though.... that'd definitely be it.
thanks for the info really appreciate it. you sure know alot about cars for a 20 yr old. must have been growin up around this stuff.
05-17-2005, 08:56 AM
#50
Originally Posted by fastflyingasian
the only thing i fear about going turbo is that the studs on the rear bank has began to break for the second time. so unless i run the turbo only on the front bank i would have to worry about the exhaust leak. that is actually one of the reasons why i am exploring the s/c route. also i think it would be kinda interesting to do somthing different. so far im only aware of only one s/c max that was mentioned earlier. also i dont mind cutting a big hole in my hood. my car dont exactly have that "show quality" look so im not so concerned .
.yeah..
right...
ok.
also what makes you think you can run twin turbos (you referring to front and rear banks).
05-17-2005, 09:07 AM
#51
geez man...you writing your term paper here? 
cliff notes?
cliff notes?
Originally Posted by mtcookson
because turbos are better...
if you put in the turbo studs, get a good flex section, and support the downpipe properly you won't break any studs.
the only problem is you'd have to do some crazy valving system to where you can close off the pipe to one unit while the other is boosting (in the case of a remote mounted pd s/c) because i would think there'd be a chance you could leak boost past the turbo until it spools (which in that case would spool extremely late if at all and even take the chance of ruining the turbo a la exhaust trying to spin it one way and the s/c trying to spin it another. i could be wrong on that but i'm not sure.
if the s/c was right on the manifold you probably could but you're still not fixing any of the inefficiencies. basically you'd help out the bottom end but you'd still have the parasitic losses on your engine and even more weight than necessary. what would be better, if you want some low end launching power, is just a small shot of nitrous. that'll get you off the line real well and spool the turbo very quickly.
a very interesting setup would be a sort of twin turbo setup. run one turbo on the exhaust manifold and dump the exhaust from it to the inlet of another turbo. the compressor outlet from the first turbo would go to the compressor inlet of the second, then to the aftercooler and engine. (this type of setup is actually where the term intercooler is supposed to be. a lot of these setups had an air cooler between the two compressors therefore being call an intercooler. the air coolers that are used on all common turbo setups are call aftercoolers (not to be confused with only be air/water.) any air cooler cooling the air after it has been compressed is called an aftercooler.)
doing that setup should double the boost from my understanding. if turbo 1 is making 15 psi and turbo 2 is also set to 15 psi there should be 30 psi going into the intake (i'm pretty sure this is how it works). they use this setup on a lot of turbo diesels pushing an incredible amount of boost (semi trucks well in excess of 100 psi and smaller diesel trucks pushing well over 50 psi).
in the end it might not be practical for street gasoline engine as it would be a bit heavier and hotter and a bit more expensive to do. considering single turbo setups work just fine (and these days better than most TT setups) there's really no reason to do something that extreme. if you want something different though.... that'd definitely be it.
no problem at all. i actually didn't really start getting into cars till about 17 or 18.
if you put in the turbo studs, get a good flex section, and support the downpipe properly you won't break any studs.
the only problem is you'd have to do some crazy valving system to where you can close off the pipe to one unit while the other is boosting (in the case of a remote mounted pd s/c) because i would think there'd be a chance you could leak boost past the turbo until it spools (which in that case would spool extremely late if at all and even take the chance of ruining the turbo a la exhaust trying to spin it one way and the s/c trying to spin it another. i could be wrong on that but i'm not sure.
if the s/c was right on the manifold you probably could but you're still not fixing any of the inefficiencies. basically you'd help out the bottom end but you'd still have the parasitic losses on your engine and even more weight than necessary. what would be better, if you want some low end launching power, is just a small shot of nitrous. that'll get you off the line real well and spool the turbo very quickly.
a very interesting setup would be a sort of twin turbo setup. run one turbo on the exhaust manifold and dump the exhaust from it to the inlet of another turbo. the compressor outlet from the first turbo would go to the compressor inlet of the second, then to the aftercooler and engine. (this type of setup is actually where the term intercooler is supposed to be. a lot of these setups had an air cooler between the two compressors therefore being call an intercooler. the air coolers that are used on all common turbo setups are call aftercoolers (not to be confused with only be air/water.) any air cooler cooling the air after it has been compressed is called an aftercooler.)
doing that setup should double the boost from my understanding. if turbo 1 is making 15 psi and turbo 2 is also set to 15 psi there should be 30 psi going into the intake (i'm pretty sure this is how it works). they use this setup on a lot of turbo diesels pushing an incredible amount of boost (semi trucks well in excess of 100 psi and smaller diesel trucks pushing well over 50 psi).
in the end it might not be practical for street gasoline engine as it would be a bit heavier and hotter and a bit more expensive to do. considering single turbo setups work just fine (and these days better than most TT setups) there's really no reason to do something that extreme. if you want something different though.... that'd definitely be it.
no problem at all. i actually didn't really start getting into cars till about 17 or 18.
05-17-2005, 10:45 AM
#52
cliff notes eh?
- turbochargers > supchargers
- turbo studs = less stud worries
- intake valving might be needed for s/c and t/c combination
- inline twin turbo setup would be interesting and unique, but may not be worth it on a street car
- aftercooler is the correct term for the air coolers that are mounted after the compressor, intercooler is the correct term for an air cooler between two compressors
- semi-trucks usually run over 100 psi of boost
- i didn't get into cars till about 17-18 years of age
- turbochargers > supchargers
- turbo studs = less stud worries
- intake valving might be needed for s/c and t/c combination
- inline twin turbo setup would be interesting and unique, but may not be worth it on a street car
- aftercooler is the correct term for the air coolers that are mounted after the compressor, intercooler is the correct term for an air cooler between two compressors
- semi-trucks usually run over 100 psi of boost
- i didn't get into cars till about 17-18 years of age
05-17-2005, 11:06 AM
#53
Novel.....
Originally Posted by mtcookson
because turbos are better...
if you put in the turbo studs, get a good flex section, and support the downpipe properly you won't break any studs.
the only problem is you'd have to do some crazy valving system to where you can close off the pipe to one unit while the other is boosting (in the case of a remote mounted pd s/c) because i would think there'd be a chance you could leak boost past the turbo until it spools (which in that case would spool extremely late if at all and even take the chance of ruining the turbo a la exhaust trying to spin it one way and the s/c trying to spin it another. i could be wrong on that but i'm not sure.
if the s/c was right on the manifold you probably could but you're still not fixing any of the inefficiencies. basically you'd help out the bottom end but you'd still have the parasitic losses on your engine and even more weight than necessary. what would be better, if you want some low end launching power, is just a small shot of nitrous. that'll get you off the line real well and spool the turbo very quickly.
a very interesting setup would be a sort of twin turbo setup. run one turbo on the exhaust manifold and dump the exhaust from it to the inlet of another turbo. the compressor outlet from the first turbo would go to the compressor inlet of the second, then to the aftercooler and engine. (this type of setup is actually where the term intercooler is supposed to be. a lot of these setups had an air cooler between the two compressors therefore being call an intercooler. the air coolers that are used on all common turbo setups are call aftercoolers (not to be confused with only be air/water.) any air cooler cooling the air after it has been compressed is called an aftercooler.)
doing that setup should double the boost from my understanding. if turbo 1 is making 15 psi and turbo 2 is also set to 15 psi there should be 30 psi going into the intake (i'm pretty sure this is how it works). they use this setup on a lot of turbo diesels pushing an incredible amount of boost (semi trucks well in excess of 100 psi and smaller diesel trucks pushing well over 50 psi).
in the end it might not be practical for street gasoline engine as it would be a bit heavier and hotter and a bit more expensive to do. considering single turbo setups work just fine (and these days better than most TT setups) there's really no reason to do something that extreme. if you want something different though.... that'd definitely be it.
no problem at all. i actually didn't really start getting into cars till about 17 or 18.
if you put in the turbo studs, get a good flex section, and support the downpipe properly you won't break any studs.
the only problem is you'd have to do some crazy valving system to where you can close off the pipe to one unit while the other is boosting (in the case of a remote mounted pd s/c) because i would think there'd be a chance you could leak boost past the turbo until it spools (which in that case would spool extremely late if at all and even take the chance of ruining the turbo a la exhaust trying to spin it one way and the s/c trying to spin it another. i could be wrong on that but i'm not sure.
if the s/c was right on the manifold you probably could but you're still not fixing any of the inefficiencies. basically you'd help out the bottom end but you'd still have the parasitic losses on your engine and even more weight than necessary. what would be better, if you want some low end launching power, is just a small shot of nitrous. that'll get you off the line real well and spool the turbo very quickly.
a very interesting setup would be a sort of twin turbo setup. run one turbo on the exhaust manifold and dump the exhaust from it to the inlet of another turbo. the compressor outlet from the first turbo would go to the compressor inlet of the second, then to the aftercooler and engine. (this type of setup is actually where the term intercooler is supposed to be. a lot of these setups had an air cooler between the two compressors therefore being call an intercooler. the air coolers that are used on all common turbo setups are call aftercoolers (not to be confused with only be air/water.) any air cooler cooling the air after it has been compressed is called an aftercooler.)
doing that setup should double the boost from my understanding. if turbo 1 is making 15 psi and turbo 2 is also set to 15 psi there should be 30 psi going into the intake (i'm pretty sure this is how it works). they use this setup on a lot of turbo diesels pushing an incredible amount of boost (semi trucks well in excess of 100 psi and smaller diesel trucks pushing well over 50 psi).
in the end it might not be practical for street gasoline engine as it would be a bit heavier and hotter and a bit more expensive to do. considering single turbo setups work just fine (and these days better than most TT setups) there's really no reason to do something that extreme. if you want something different though.... that'd definitely be it.
no problem at all. i actually didn't really start getting into cars till about 17 or 18.
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