Drivetrain Turbo question?
#1
#2
#4
#5
ok im still a lil confused about the physics of this. if you pump air into the manifold with a larger inlet it will do it faster but if the manifold is at 20 psi forcing air into the engine and the smaller turbo forces the same amount at a slower rate is the engine not getting the same amount of air. because the pressure is the same because if the larger turbo is pushing more air the psi would be higher.
#6
#7
Trending Topics
#8
20 is just a number so basicly the bigger turbo move more air at the same amount of pressure?? because im thinking of it this way say you take a bigger turbo and you are filling a ballon the larger turbo will fill the ballon till it pops faster. the smaller turbo will fill the same ballon at a slower rate but it will still pop at the same point. so if your manifold has 20 psi in it that means the air density will be the same no matter what because the volume of air will be the same.. and would the lil bit of time it took for the bigger turbo to get up to pressure not be worth is for the time it takes to spool up?
Last edited by AkFarina; 02-12-2009 at 05:05 PM.
#9
20 is just a number so basicly the bigger turbo move more air at the same amount of pressure?? because im thinking of it this way say you take a bigger turbo and you are filling a ballon the larger turbo will fill the ballon till it pops faster. the smaller turbo will fill the same ballon at a slower rate but it will still pop at the same point. so if your manifold has 20 psi in it that means the air density will be the same no matter what because the volume of air will be the same.. and would the lil bit of time it took for the bigger turbo to get up to pressure not be worth is for the time it takes to spool up?
#11
Unless the laws of thermodynamics have changed in the 35 years since I got my engineering degree, if the manifold pressure is at a constant 20 lbs, you are moving the identical amount of air through the system regardless of what is creating that prssure upstream. This, of course, is assuming a constant temperature as well. However, as indicated previously, a smaller turbo will have a greater tendency to heat the air stream, reducing air density. Hence less air, even at the same pressure. Best bet: forget about a larger turbo and put in one of those intercoolers that are 3-4 times larger than stock.
#12
ok im still a lil confused about the physics of this. if you pump air into the manifold with a larger inlet it will do it faster but if the manifold is at 20 psi forcing air into the engine and the smaller turbo forces the same amount at a slower rate is the engine not getting the same amount of air. because the pressure is the same because if the larger turbo is pushing more air the psi would be higher.
#13
5th Gear
iTrader: (2)
Join Date: Apr 2008
Location: Seattle
Posts: 873
Likes: 0
Received 0 Likes
on
0 Posts
Unless the laws of thermodynamics have changed in the 35 years since I got my engineering degree, if the manifold pressure is at a constant 20 lbs, you are moving the identical amount of air through the system regardless of what is creating that prssure upstream. This, of course, is assuming a constant temperature as well. However, as indicated previously, a smaller turbo will have a greater tendency to heat the air stream, reducing air density. Hence less air, even at the same pressure. Best bet: forget about a larger turbo and put in one of those intercoolers that are 3-4 times larger than stock.
If you upgrade the size of your turbo, you generate less heat in the compression stage, and will cool to roughly the same temperature as with the smaller turbo due to the intercooler (a larger intercooler will be needed), you will have a lot more oxygen in that air.
It's a game. You want a bigger turbo so there's more room to compress. Too big of a turbo and you'll be so laggy, it will seem like you don't have a turbo for the first half of your usable rpm range.
at least this is what i am gathering after a few hours of reading of the past month or so.
#14
Unless the laws of thermodynamics have changed in the 35 years since I got my engineering degree, if the manifold pressure is at a constant 20 lbs, you are moving the identical amount of air through the system regardless of what is creating that prssure upstream. This, of course, is assuming a constant temperature as well. However, as indicated previously, a smaller turbo will have a greater tendency to heat the air stream, reducing air density. Hence less air, even at the same pressure. Best bet: forget about a larger turbo and put in one of those intercoolers that are 3-4 times larger than stock.
ill just put a nos fogger pre bigger intercooler that will get you air temp and o2 up hah just kidding
#15
#16
And consequently lowering the pressuring at the manifold unless you've got something to drive more air into the system .
#17
the typical place to measure boost is right before the intake manifold.....if its 20 psi right before the intake manifold with the small turbo and its 20psi in the same spot with the larger turbo its the same amount of air flowing into the engine regardless of the size of the turbo.
#18
No: despite the fact that the larger turbo has a greater air handling capacity, tthe intercooler on the MINI appears to be undersized for the KO3 turbo**. Aftermarket ICs about 3 times larger than stock are showing some great hp gains (15-20). A KO4 turbo could void the warranty. The IC is unlikely to.
**Explanation: The IC will reduce the downstream temperature of the charge as well as the dowbstream pressure, allowing the turbo to spool faster (more air)for an equivalent amount of exhaust flow that is driving the turbo.
**Explanation: The IC will reduce the downstream temperature of the charge as well as the dowbstream pressure, allowing the turbo to spool faster (more air)for an equivalent amount of exhaust flow that is driving the turbo.
Last edited by lhoboy; 02-13-2009 at 04:26 AM.
#19
No: despite the fact that the larger turbo has a greater air handling capacity, tthe intercooler on the MINI appears to be undersized for the KO3 turbo**. Aftermarket ICs about 3 times larger than stock are showing some great hp gains (15-20). A KO4 turbo could void the warranty. The IC is unlikely to.
**Explanation: The IC will reduce the downstream temperature of the charge as well as the dowbstream pressure, allowing the turbo to spool faster (more air)for an equivalent amount of exhaust flow that is driving the turbo.
**Explanation: The IC will reduce the downstream temperature of the charge as well as the dowbstream pressure, allowing the turbo to spool faster (more air)for an equivalent amount of exhaust flow that is driving the turbo.
http://www.gnttype.org/techarea/turbo/turboflow.html
Turbos differ in efficiency, or the amount of energy transferred to compressing the charge vs. the amount of energy wasted by creating heat due to friction in the bearings. Other factors, such as the size/shape/angle of the wheel's blades on both the compressor side and the exhaust side effect overall performance.
Keep in mind that as you increase the size of the intercooler (3-4 fold) you are in essence tripling (or quadrupling) the volume of air that has to be pressurized, thus increasing lag. A large intercooler would be ideal for a system with a large turbo to flow a high CFM at a lower temperature which will quickly pressurize the system.
Just my $0.02
Last edited by lnkncontiverto; 02-13-2009 at 10:41 AM.
#21
Keep in mind that as you increase the size of the intercooler (3-4 fold) you are in essence tripling (or quadrupling) the volume of air that has to be pressurized, thus increasing lag. A large intercooler would be ideal for a system with a large turbo to flow a high CFM at a lower temperature which will quickly pressurize the system.
Just my $0.02
Just my $0.02
#22
Here's a good technical article about turbo sizing, it is focused on 86-87 Turbo Buicks, but it gets the point across (these guys have been perfecting the theory through trial and error for the better part of the last two decades):
http://www.gnttype.org/techarea/turbo/turboflow.html
Turbos differ in efficiency, or the amount of energy transferred to compressing the charge vs. the amount of energy wasted by creating heat due to friction in the bearings. Other factors, such as the size/shape/angle of the wheel's blades on both the compressor side and the exhaust side effect overall performance.
Keep in mind that as you increase the size of the intercooler (3-4 fold) you are in essence tripling (or quadrupling) the volume of air that has to be pressurized, thus increasing lag. A large intercooler would be ideal for a system with a large turbo to flow a high CFM at a lower temperature which will quickly pressurize the system.
Just my $0.02
http://www.gnttype.org/techarea/turbo/turboflow.html
Turbos differ in efficiency, or the amount of energy transferred to compressing the charge vs. the amount of energy wasted by creating heat due to friction in the bearings. Other factors, such as the size/shape/angle of the wheel's blades on both the compressor side and the exhaust side effect overall performance.
Keep in mind that as you increase the size of the intercooler (3-4 fold) you are in essence tripling (or quadrupling) the volume of air that has to be pressurized, thus increasing lag. A large intercooler would be ideal for a system with a large turbo to flow a high CFM at a lower temperature which will quickly pressurize the system.
Just my $0.02
#23
#24
Some references...
http://forums.vwvortex.com/zerothread?id=3896131
Don't worry about a bigger intercooler, and a turbo is all about volume. You got a huge turbo like the one in my thread @ 20psi, it'll push a lot more air volume and you'll make power. Soon I'll have some logs to show what I'm talking about on the mini
#25
Wait, so adding this giant ALTA intercooler is supposed to make more power than if I added a larger turbo? I'm sorry, but that power just isn't there. Maybe ALTA's intercooler isn't big enough?