Drivetrain Anyone heard of this...rear mounted turbo?
6th Gear
Joined: Jan 2003
Posts: 1,882
Likes: 0
From: Wyckoff, NJ
Originally Posted by macncheese
So you're saying that if all you want is a 7 PSI foo foo turbo system, you dont have to follow all of Andy's "Corky Bell Maximum Boost" rules? I'll agree with that. 
http://i.b5z.net/i/u/1473169/f/Video/gto1.wmv
6th Gear
Joined: Jan 2003
Posts: 1,816
Likes: 2
From: New Jersey
Meb,
The intercooler's job isnt to increase density, its to remove kinetic energy/heat so you can take full advantage of the potential energy of the charge. (A hot intake charge is very volatile and hard to control. By cooling the charge, you can optimize the engine's dynamics.)
The difference between what goes in an intercooler and what comes out is the pressure its at. The pressure drop isnt due to expansion but due to the molecules calming down and bumping into things less. No mass is created in the intercooler.
The intercooler's job isnt to increase density, its to remove kinetic energy/heat so you can take full advantage of the potential energy of the charge. (A hot intake charge is very volatile and hard to control. By cooling the charge, you can optimize the engine's dynamics.)
The difference between what goes in an intercooler and what comes out is the pressure its at. The pressure drop isnt due to expansion but due to the molecules calming down and bumping into things less. No mass is created in the intercooler.
6th Gear
Joined: Jan 2003
Posts: 3,301
Likes: 1
Originally Posted by macncheese
Meb,
The intercooler's job isnt to increase density, its to remove kinetic energy/heat so you can take full advantage of the potential energy of the charge. (A hot intake charge is very volatile and hard to control. By cooling the charge, you can optimize the engine's dynamics.)
The difference between what goes in an intercooler and what comes out is the pressure its at. The pressure drop isnt due to expansion but due to the molecules calming down and bumping into things less. No mass is created in the intercooler.
The intercooler's job isnt to increase density, its to remove kinetic energy/heat so you can take full advantage of the potential energy of the charge. (A hot intake charge is very volatile and hard to control. By cooling the charge, you can optimize the engine's dynamics.)
The difference between what goes in an intercooler and what comes out is the pressure its at. The pressure drop isnt due to expansion but due to the molecules calming down and bumping into things less. No mass is created in the intercooler.
I think I wrote, perhaps not clearly, that the drop in pressure causes the expansion and therefore cooling across the IC - at least the outlet side. I also wrote the same with regard to the turbo; as the air enters the turbine area it is allowed to expand due to the relative size differences in the path to the turbine. This expansion or release of energy is also part of the equation. I understand that expansion is due to pressure drop, and not the reverse.
My question is, and you may have touched upon it, what is the very character of the relationship between hot and cold air that makes one more desirable to engine dynamics and the other not? Mass is niether created nor lost as you wrote. So, is molecular organization the only real difference with respect to an engine's operation? Organized air burns more efficiently? What then of the notion cold air is more dense? If it is more dense, where'd the extra mass come from? I also seem to remember a topic in college physics called mutual association. This may be a miss-applied term here, but I'll run with it. Hot and cold air do have a mutual association; work cannot occur with just one. Rather, the controlled changing values in temp/pressure/volume between to two is where work can be performed. Sounds right???
I am definately brain fading something very fundamental??? I'll blame it on old age an teeange children.
6th Gear
Joined: Jan 2003
Posts: 1,816
Likes: 2
From: New Jersey
Meb,
We're a bit off topic now but when people speak about cold air intakes, they're increasing the charge density (potential energy) of the air that flows through the throttle body. Thats sort of a different ballgame. Once we're past the positive displacement blower, we can only work with what the blower provides.
There is no extra mass in a steady state examination but controlling the temp of the intake charge starts the dynamic process. Now that we've got a cooler, less volatile, intake charge, we dont have to worry (as much) about knock and other ugliness wasting our precious potiential energy.... We can bump up the boost.... how about a little more timing? Now we're cooking Controlling the intake temps on FI engines (thats the temp going into the CC, not the temp of the air in the convention intake sense) is the single most important factor to determining optimum performance.
ABSOLUTELY. This is, in my opinion, the cardinal rule of high performance tuning. When you can organize your intake charge the way you want and where you want it, the sky is the limit. Most intake charges currently dont even come close to a complete efficent burn. Obviously we're getting way off topic now, with intake manifold, port designs, cylinder fillling, CC designs, etc. The idea behind all these is to organize/control the flow!
To get this back on topic, the idea behind this turbo system (in my opinion) is that you sacrifice a lot of the rules of proper turbo system design in order to achieve a mediocre ammount of boost for engines not designed for any boost. The result is probably decent performance.
We're a bit off topic now but when people speak about cold air intakes, they're increasing the charge density (potential energy) of the air that flows through the throttle body. Thats sort of a different ballgame. Once we're past the positive displacement blower, we can only work with what the blower provides.
There is no extra mass in a steady state examination but controlling the temp of the intake charge starts the dynamic process. Now that we've got a cooler, less volatile, intake charge, we dont have to worry (as much) about knock and other ugliness wasting our precious potiential energy.... We can bump up the boost.... how about a little more timing? Now we're cooking
Controlling the intake temps on FI engines (thats the temp going into the CC, not the temp of the air in the convention intake sense) is the single most important factor to determining optimum performance.
Originally Posted by meb
Organized air burns more efficiently?
ABSOLUTELY. This is, in my opinion, the cardinal rule of high performance tuning. When you can organize your intake charge the way you want and where you want it, the sky is the limit. Most intake charges currently dont even come close to a complete efficent burn. Obviously we're getting way off topic now, with intake manifold, port designs, cylinder fillling, CC designs, etc. The idea behind all these is to organize/control the flow!To get this back on topic, the idea behind this turbo system (in my opinion) is that you sacrifice a lot of the rules of proper turbo system design in order to achieve a mediocre ammount of boost for engines not designed for any boost. The result is probably decent performance.
Maybe this will help
Originally Posted by meb
Okay, lets not forget that this is a dynamically perpetual process once the key is turned. Those are my words and they may seem, uhm well dumb.
I like the question, "where does the extra mass come from?" I cannot answer that question readily. However, correct me if I'm wrong, but an intercooler increases density by cooling the air charge. And though the process is under pressure, the inlet side of an IC is still hotter than the outlet side. So, how do we get air that is more dense? And it must be, other wise an IC would not work. If the psi in the SC were higher relative to that in the IC, that would explain part of it; the air cools thru expansion via a pressure drop - relatively. I'm probably not helping here because I'm taking my input slightly off topic. ButI'll continue hoping there is something here.
So, we have really reduced this conversation down to the relationship between cold and hot air. Everything in this world flows from high to low pressure. Hot air cannot fall into cold air because it is more dense. So, cold air naturally falls down into warm air, that is the direction. As cold air warms, the molecules become more excited and velocity is increased. But as hot air expands via increasing volume, it cools and the expansion process also has energy. So which is at work here? My intuition tells me that this is a perpetual forward and back process so long as the fuel supply remains constant.
I cannot tell jlm, are you saying the hot gas/cold gas volume thing is bozo? Volume is defined by four walls if you will. Pressure, and therfore temperature cannot change this unless the four wall explode or implode. I think you are saying this. However, a given gas of either different temp or pressure will not equal the same volume. Else why do tires lose pressure when it gets cold and gain pressure when hot. Although this may only be true for a closed system with a given amount of - mass of air.
Minipilo, I would argue the point about hot or cold air not being important for reasons stated in my post above. As a hot gas cools thru expansion, energy is given off and can be put to good use. A turbo my be glowing hot, but if the air entering the turbo impeller area is allowed to expand, it will in fact act with some force in addition to all the others acting on the turbine. This will only occur in an environment rich in heat. Velocity is part of the process, but so is heat.
I like the question, "where does the extra mass come from?" I cannot answer that question readily. However, correct me if I'm wrong, but an intercooler increases density by cooling the air charge. And though the process is under pressure, the inlet side of an IC is still hotter than the outlet side. So, how do we get air that is more dense? And it must be, other wise an IC would not work. If the psi in the SC were higher relative to that in the IC, that would explain part of it; the air cools thru expansion via a pressure drop - relatively. I'm probably not helping here because I'm taking my input slightly off topic. ButI'll continue hoping there is something here.
So, we have really reduced this conversation down to the relationship between cold and hot air. Everything in this world flows from high to low pressure. Hot air cannot fall into cold air because it is more dense. So, cold air naturally falls down into warm air, that is the direction. As cold air warms, the molecules become more excited and velocity is increased. But as hot air expands via increasing volume, it cools and the expansion process also has energy. So which is at work here? My intuition tells me that this is a perpetual forward and back process so long as the fuel supply remains constant.
I cannot tell jlm, are you saying the hot gas/cold gas volume thing is bozo? Volume is defined by four walls if you will. Pressure, and therfore temperature cannot change this unless the four wall explode or implode. I think you are saying this. However, a given gas of either different temp or pressure will not equal the same volume. Else why do tires lose pressure when it gets cold and gain pressure when hot. Although this may only be true for a closed system with a given amount of - mass of air.
Minipilo, I would argue the point about hot or cold air not being important for reasons stated in my post above. As a hot gas cools thru expansion, energy is given off and can be put to good use. A turbo my be glowing hot, but if the air entering the turbo impeller area is allowed to expand, it will in fact act with some force in addition to all the others acting on the turbine. This will only occur in an environment rich in heat. Velocity is part of the process, but so is heat.
http://auto.howstuffworks.com/engine13.htm
http://auto.howstuffworks.com/turbo7.htm
6th Gear
Joined: Jan 2003
Posts: 3,301
Likes: 1
Hey norm,
I don't take anyone trying to help me as a smart$$$. Most of what I looked is basic info. I'm just missing some of the finer subtle airmass/flow/hot/cold stuff. But I'll chaeck the site out a bit more later.
One portion of my post(s) above which may a bit puzzling to some surrounds the notion of a hot gas cooling. This cooling effect I described as expansion when in fact hot air expands. However, when hot air cools when passing into a larger volume, energy is given off. This also helps to spin the turbine. I'm calling this expansion too, but I don't feel I'm using the correct word??? Anyone?
Any minute now folks a really big explosion will take place in his brain and all will be well.
I don't take anyone trying to help me as a smart$$$. Most of what I looked is basic info. I'm just missing some of the finer subtle airmass/flow/hot/cold stuff. But I'll chaeck the site out a bit more later.
One portion of my post(s) above which may a bit puzzling to some surrounds the notion of a hot gas cooling. This cooling effect I described as expansion when in fact hot air expands. However, when hot air cools when passing into a larger volume, energy is given off. This also helps to spin the turbine. I'm calling this expansion too, but I don't feel I'm using the correct word??? Anyone?
Any minute now folks a really big explosion will take place in his brain and all will be well.
meb, I think you will find the second link pertains to the intercoolers purpose.
From my days in AC&R work, simply stated, hot flows to cold.
A little experiment, take a 16 oz soda with a screw on top, rinse it out using the hot water from your tap, fill it up then dump the water out and immediately screw on the top and put it in the freezer. Take it out in about 10 min. What's is happening here?
From my days in AC&R work, simply stated, hot flows to cold.
A little experiment, take a 16 oz soda with a screw on top, rinse it out using the hot water from your tap, fill it up then dump the water out and immediately screw on the top and put it in the freezer. Take it out in about 10 min. What's is happening here?
6th Gear
Joined: Jan 2003
Posts: 1,816
Likes: 2
From: New Jersey
Originally Posted by meb
Hey norm,
I don't take anyone trying to help me as a smart$$$. Most of what I looked is basic info. I'm just missing some of the finer subtle airmass/flow/hot/cold stuff. But I'll chaeck the site out a bit more later.
One portion of my post(s) above which may a bit puzzling to some surrounds the notion of a hot gas cooling. This cooling effect I described as expansion when in fact hot air expands. However, when hot air cools when passing into a larger volume, energy is given off. This also helps to spin the turbine. I'm calling this expansion too, but I don't feel I'm using the correct word??? Anyone?
Any minute now folks a really big explosion will take place in his brain and all will be well.
I don't take anyone trying to help me as a smart$$$. Most of what I looked is basic info. I'm just missing some of the finer subtle airmass/flow/hot/cold stuff. But I'll chaeck the site out a bit more later.
One portion of my post(s) above which may a bit puzzling to some surrounds the notion of a hot gas cooling. This cooling effect I described as expansion when in fact hot air expands. However, when hot air cools when passing into a larger volume, energy is given off. This also helps to spin the turbine. I'm calling this expansion too, but I don't feel I'm using the correct word??? Anyone?
Any minute now folks a really big explosion will take place in his brain and all will be well.
6th Gear
Joined: Jan 2003
Posts: 3,301
Likes: 1
Yes, yes. I just realized in my last post, that I double dipped...very interesting phrase. Never saw that in my physics book.
Okay, and sorry to take you away from the more technical folk here, but what hapens as a hot gas cools? Energy must be released?
I have to perform the experiment above, but I require more detail. I'm actyually going mad...must warn others
Okay, and sorry to take you away from the more technical folk here, but what hapens as a hot gas cools? Energy must be released?
I have to perform the experiment above, but I require more detail. I'm actyually going mad...must warn others
6th Gear
Joined: Jan 2003
Posts: 3,301
Likes: 1
Originally Posted by norm03s
meb, I think you will find the second link pertains to the intercoolers purpose.
From my days in AC&R work, simply stated, hot flows to cold.
A little experiment, take a 16 oz soda with a screw on top, rinse it out using the hot water from your tap, fill it up then dump the water out and immediately screw on the top and put it in the freezer. Take it out in about 10 min. What's is happening here?
From my days in AC&R work, simply stated, hot flows to cold.
A little experiment, take a 16 oz soda with a screw on top, rinse it out using the hot water from your tap, fill it up then dump the water out and immediately screw on the top and put it in the freezer. Take it out in about 10 min. What's is happening here?
do you mean a soda bottle with a screw top? If so I'm with you. I'll perform this experiment soon. Will the test be verbal or written?
Does this help?
http://www.taftan.com/thermodynamics/ISENEFF.HTM
These turbochargers are simple turbines. A Multi-stage compound turbo compressor could be designed with a tuned expansion exhaust pipe behind it if you were looking for the very last bit of compressor power.
I have had some thoughts on a very small gas turbine running on fractional exhaust gas and fuel, driving a supercharger/turbine compressor for boost, independent of engine power.
These turbochargers are simple turbines. A Multi-stage compound turbo compressor could be designed with a tuned expansion exhaust pipe behind it if you were looking for the very last bit of compressor power.
I have had some thoughts on a very small gas turbine running on fractional exhaust gas and fuel, driving a supercharger/turbine compressor for boost, independent of engine power.
Thread Starter
|
2nd Gear
Joined: Jan 2005
Posts: 87
Likes: 0
Wow! It was just a simple question to see if anyone has heard of a rear-mounted turbo! It has been great watching the great physics debate with regard to turbos--I have personally learned alot from everyone who has contributed. This is what NAM is all about.
Thanks.
Thanks.
6th Gear
Joined: Jan 2003
Posts: 3,301
Likes: 1
Originally Posted by norm03s
http://www.taftan.com/thermodynamics/ISENEFF.HTM
These turbochargers are simple turbines. A Multi-stage compound turbo compressor could be designed with a tuned expansion exhaust pipe behind it if you were looking for the very last bit of compressor power.
I have had some thoughts on a very small gas turbine running on fractional exhaust gas and fuel, driving a supercharger/turbine compressor for boost, independent of engine power.
These turbochargers are simple turbines. A Multi-stage compound turbo compressor could be designed with a tuned expansion exhaust pipe behind it if you were looking for the very last bit of compressor power.
I have had some thoughts on a very small gas turbine running on fractional exhaust gas and fuel, driving a supercharger/turbine compressor for boost, independent of engine power.
3rd Gear
Joined: Apr 2003
Posts: 183
Likes: 0
From: greensboro, nc
I guess the next thing to accomplish is a triplecharged mini. We've got one with a super and turbo, now someone just needs to add another turbo. If this is physically impossible, please ignore me because I wasn't really being serious in the first place. Though a triplecharged mini could potentially create lava in the engine bay.
6th Gear
Joined: Sep 2003
Posts: 1,443
Likes: 0
From: Wichita, Kansas
Ok, Im going to ask a basic question here.
If you put a turbo on the end of an air hose, just forcing cool air into the turbo at the same velocity as you would get the exhaust gas from a combustion engine. does it spin at the same speed?
If you put a turbo on the end of an air hose, just forcing cool air into the turbo at the same velocity as you would get the exhaust gas from a combustion engine. does it spin at the same speed?
6th Gear
Joined: Oct 2002
Posts: 3,652
Likes: 6
From: Lansdale, PA
IMHO, you would need a huge amount of airflow and pressure to get turbine speeds up to the 150,000 rpm or so that a modern turbo sees. In a normal turbo installation you are making use of the tremendous amount of energy stored in the hot exhaust gasses (and the temperature difference between that gas and ambient temp). Without that heat, you need to impart considerably more work (see the Corky Bell reference earlier, roughly 3 times as much work).
6th Gear
Joined: Jan 2003
Posts: 3,301
Likes: 1
Originally Posted by planeguy
Ok, Im going to ask a basic question here.
If you put a turbo on the end of an air hose, just forcing cool air into the turbo at the same velocity as you would get the exhaust gas from a combustion engine. does it spin at the same speed?
If you put a turbo on the end of an air hose, just forcing cool air into the turbo at the same velocity as you would get the exhaust gas from a combustion engine. does it spin at the same speed?
For any given size hose - using your example - there is a maximum efficient velocity - ft/sec - afterwhich more velocity begins to create more friction resulting in less than optimum performance. The shape of the hose also plays a role as does the material - smooth or rough interior surface.
1st Gear
Joined: May 2005
Posts: 32
Likes: 0
resonator room?
if space is the issue what about combining this kit with the resonator elimination setup i have seen or even the alta exhaust system that only uses one side of the rear exhaust area...it could clear up some space to make this system possible
Thread
Thread Starter
Forum
Replies
Last Post
silence2-38554
R50/R53 :: Hatch Talk (2002-2006)
3
Nov 12, 2015 09:39 AM
Mini Mania
Vendor Announcements
0
Aug 11, 2015 09:01 AM
ClayTaylorNC
R50/R53 :: Hatch Talk (2002-2006)
6
Aug 10, 2015 09:19 PM
