DP theory
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Re: DP theory (coneheadsracing)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by coneheadsracing »</TD></TR><TR><TD CLASS="quote">will you still have pulses, since the turbo is basically chopping the hell out of the air.....
I don't know about the 2 in exhaust having less resistance then an open downpipe. I don't know, I need to think about that one some more i guess
</TD></TR></TABLE>
please do, i look foward to ur input
I don't know about the 2 in exhaust having less resistance then an open downpipe. I don't know, I need to think about that one some more i guess
</TD></TR></TABLE>please do, i look foward to ur input
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Re: DP theory (95GSRTT)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95GSRTT »</TD></TR><TR><TD CLASS="quote">why do you assume that they would? and you meant turbine wheel correct?</TD></TR></TABLE>
yes lol, fixed, TY
because they are the same sized opening... just so long as what comes after the opening is not any smaller then the opening itself, the flow rate will be the same
yes lol, fixed, TY
because they are the same sized opening... just so long as what comes after the opening is not any smaller then the opening itself, the flow rate will be the same
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From: Simi Valley, CA, USA
Re: DP theory (DaZman69)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DaZman69 »</TD></TR><TR><TD CLASS="quote">http://www.turbod16.com/album_page.php?pic_id=3350
did u look at this yet?
Is this not the same princible?
Picture the top tube as a 2" DP on a 2" compressor wheel
and the bottom a 4" DP on a 2" compressor wheel
THESE TWO OPENINGS WILL EXPELL AIR AT THE EXACT SAME RATE</TD></TR></TABLE>
No they won't, what don't you get? Just use your head. The exhaust coming out the top port is going to be confined to the smaller tube. The exhaust pulses are going to push against each other as they go down the pipe. This creates a force vector that pushes agains the sides of the pipe. So the exhaust ends up pushing against the pipe walls which creates backpressure.
In the bottom port, the exhaust exits and has more volume to expand to so the oncoming pulses don't slam into each other and create backpressure.
Just revert back to the "straw" theory. Imagine the two ports were straws and you were blowing through them from the "tank" side of the diagram. The bottom "straw" would have less backpressure and would be easier to blow through.
did u look at this yet?
Is this not the same princible?
Picture the top tube as a 2" DP on a 2" compressor wheel
and the bottom a 4" DP on a 2" compressor wheel
THESE TWO OPENINGS WILL EXPELL AIR AT THE EXACT SAME RATE</TD></TR></TABLE>
No they won't, what don't you get? Just use your head. The exhaust coming out the top port is going to be confined to the smaller tube. The exhaust pulses are going to push against each other as they go down the pipe. This creates a force vector that pushes agains the sides of the pipe. So the exhaust ends up pushing against the pipe walls which creates backpressure.
In the bottom port, the exhaust exits and has more volume to expand to so the oncoming pulses don't slam into each other and create backpressure.
Just revert back to the "straw" theory. Imagine the two ports were straws and you were blowing through them from the "tank" side of the diagram. The bottom "straw" would have less backpressure and would be easier to blow through.
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Re: DP theory (DaZman69)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DaZman69 »</TD></TR><TR><TD CLASS="quote">http://www.turbod16.com/album_page.php?pic_id=3350
did u look at this yet?
Is this not the same princible?
Picture the top tube as a 2" DP on a 2" compressor wheel
and the bottom a 4" DP on a 2" compressor wheel
THESE TWO OPENINGS WILL EXPELL AIR AT THE EXACT SAME RATE</TD></TR></TABLE>
forget the rest of the pipe sections. Picture ur container filled with gas contained in the central cylinder of your picture there. Now put the 2" outlet with a 2" pipe that is say 1' in length. Now put another 2" outlet (as u have pictured) without any piping on it.
Your arguement is that with a 2" outlet, no matter if there is a pipe on it or not, will flow the same volume. That is a true statement.
Now take into account that you are dealing with hot compressed air in pulses. On the 2" outlet with the 1' pipe, the hot compressed air will stay hot and compressed, with the pipe providing resistance (backpressure) on the compressed air tank.
Now look at the 2" opening with no piping on it. The hot compress air makes its way out the 2" opening then is completly free from drag and allowed to expand pretty much unlimitedly. No drag, no back pressure. More power.
That was my stab at it...
did u look at this yet?
Is this not the same princible?
Picture the top tube as a 2" DP on a 2" compressor wheel
and the bottom a 4" DP on a 2" compressor wheel
THESE TWO OPENINGS WILL EXPELL AIR AT THE EXACT SAME RATE</TD></TR></TABLE>
forget the rest of the pipe sections. Picture ur container filled with gas contained in the central cylinder of your picture there. Now put the 2" outlet with a 2" pipe that is say 1' in length. Now put another 2" outlet (as u have pictured) without any piping on it.
Your arguement is that with a 2" outlet, no matter if there is a pipe on it or not, will flow the same volume. That is a true statement.
Now take into account that you are dealing with hot compressed air in pulses. On the 2" outlet with the 1' pipe, the hot compressed air will stay hot and compressed, with the pipe providing resistance (backpressure) on the compressed air tank.
Now look at the 2" opening with no piping on it. The hot compress air makes its way out the 2" opening then is completly free from drag and allowed to expand pretty much unlimitedly. No drag, no back pressure. More power.
That was my stab at it...
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From: Simi Valley, CA, USA
Re: DP theory (DaZman69)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DaZman69 »</TD></TR><TR><TD CLASS="quote">
just so long as what comes after the opening is not any smaller then the opening itself, the flow rate will be the same</TD></TR></TABLE>
It was proven in a thread somewhere (a few years ago) that the ideal exhaust system on a car would have a perfectly gradual increase in diameter from the turbo back to the muffler.
just so long as what comes after the opening is not any smaller then the opening itself, the flow rate will be the same</TD></TR></TABLE>
It was proven in a thread somewhere (a few years ago) that the ideal exhaust system on a car would have a perfectly gradual increase in diameter from the turbo back to the muffler.
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Re: DP theory (EnzoSpeed)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnzoSpeed »</TD></TR><TR><TD CLASS="quote">
It was proven in a thread somewhere (a few years ago) that the ideal exhaust system on a car would have a perfectly gradual increase in diameter from the turbo back to the muffler.</TD></TR></TABLE>
yah obviously, the air cools and becomes more dense as it reaches the tailpipe. I wasn't factoring in the cooling effect for simplicty's sake. Mine was a pressurized air tank, not hot gasses.
It was proven in a thread somewhere (a few years ago) that the ideal exhaust system on a car would have a perfectly gradual increase in diameter from the turbo back to the muffler.</TD></TR></TABLE>
yah obviously, the air cools and becomes more dense as it reaches the tailpipe. I wasn't factoring in the cooling effect for simplicty's sake. Mine was a pressurized air tank, not hot gasses.
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Re: DP theory (EnzoSpeed)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnzoSpeed »</TD></TR><TR><TD CLASS="quote">
It was proven in a thread somewhere (a few years ago) that the ideal exhaust system on a car would have a perfectly gradual increase in diameter from the turbo back to the muffler.</TD></TR></TABLE>
so shouldnt the diameter decrease...?
It was proven in a thread somewhere (a few years ago) that the ideal exhaust system on a car would have a perfectly gradual increase in diameter from the turbo back to the muffler.</TD></TR></TABLE>
so shouldnt the diameter decrease...?
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Re: DP theory (EnzoSpeed)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnzoSpeed »</TD></TR><TR><TD CLASS="quote">
Just revert back to the "straw" theory. Imagine the two ports were straws and you were blowing through them from the "tank" side of the diagram. The bottom "straw" would have less backpressure and would be easier to blow through.</TD></TR></TABLE>
Well this thread is officially over, I am wrong. I am so used to fluid properties. Which if that where the case, I would be right.
I just cut a straw about 1" and made one about 7 inches. The 1" i can blow a lot more air through. I'm still confused as to why.
Just revert back to the "straw" theory. Imagine the two ports were straws and you were blowing through them from the "tank" side of the diagram. The bottom "straw" would have less backpressure and would be easier to blow through.</TD></TR></TABLE>
Well this thread is officially over, I am wrong. I am so used to fluid properties. Which if that where the case, I would be right.
I just cut a straw about 1" and made one about 7 inches. The 1" i can blow a lot more air through. I'm still confused as to why.
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Re: DP theory (EnzoSpeed)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnzoSpeed »</TD></TR><TR><TD CLASS="quote">
In the bottom port, the exhaust exits and has more volume to expand to so the oncoming pulses don't slam into each other and create backpressure.
.</TD></TR></TABLE>
Exactly^^^^^
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DaZman69 »</TD></TR><TR><TD CLASS="quote">
yah obviously, the air cools and becomes more dense as it reaches the tailpipe. I wasn't factoring in the cooling effect for simplicty's sake. Mine was a pressurized air tank, not hot gasses.</TD></TR></TABLE>
Than your picture is irrelevant.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adictionbass »</TD></TR><TR><TD CLASS="quote">
so shouldnt the diameter decrease...?</TD></TR></TABLE>
No, because that would cause a backpressure at the turbine outlet.
Phil
In the bottom port, the exhaust exits and has more volume to expand to so the oncoming pulses don't slam into each other and create backpressure.
.</TD></TR></TABLE>
Exactly^^^^^<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DaZman69 »</TD></TR><TR><TD CLASS="quote">
yah obviously, the air cools and becomes more dense as it reaches the tailpipe. I wasn't factoring in the cooling effect for simplicty's sake. Mine was a pressurized air tank, not hot gasses.</TD></TR></TABLE>
Than your picture is irrelevant.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adictionbass »</TD></TR><TR><TD CLASS="quote">
so shouldnt the diameter decrease...?</TD></TR></TABLE>
No, because that would cause a backpressure at the turbine outlet.
Phil
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Re: DP theory (hondaguyef)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adictionbass »</TD></TR><TR><TD CLASS="quote">
so shouldnt the diameter decrease...?</TD></TR></TABLE>
yes, thats exactly what he said...but opposite. He said it should increase from tailpipe to turbo. Which is same thing as saying it should decrease from turbo to tailpipe
so shouldnt the diameter decrease...?</TD></TR></TABLE>
yes, thats exactly what he said...but opposite. He said it should increase from tailpipe to turbo. Which is same thing as saying it should decrease from turbo to tailpipe
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Re: DP theory (hondaguyef)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondaguyef »</TD></TR><TR><TD CLASS="quote">
No, because that would cause a backpressure at the turbine outlet.
Phil </TD></TR></TABLE>
as the air cools, it becomes more dense and would slow down in a given diameter of pipe. gradually decreasing the piping size (if there was a way to base exhaust size at a given point with the temp of exhaust gases at that same point) would keep a constant exhaust velocity without any added backpressure
No, because that would cause a backpressure at the turbine outlet.
Phil </TD></TR></TABLE>
as the air cools, it becomes more dense and would slow down in a given diameter of pipe. gradually decreasing the piping size (if there was a way to base exhaust size at a given point with the temp of exhaust gases at that same point) would keep a constant exhaust velocity without any added backpressure
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From: south, jersey, us
Re: DP theory (hondaguyef)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondaguyef »</TD></TR><TR><TD CLASS="quote">
Exactly^^^^^
Than your picture is irrelevant.
No, because that would cause a backpressure at the turbine outlet.
Phil </TD></TR></TABLE>
right, wrong, wrong
Exactly^^^^^Than your picture is irrelevant.
No, because that would cause a backpressure at the turbine outlet.
Phil </TD></TR></TABLE>
right, wrong, wrong
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Re: DP theory (DaZman69)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DaZman69 »</TD></TR><TR><TD CLASS="quote">
yes, thats exactly what he said...but opposite. He said it should increase from tailpipe to turbo. Which is same thing as saying it should decrease from turbo to tailpipe</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnzoSpeed »</TD></TR><TR><TD CLASS="quote">
It was proven in a thread somewhere (a few years ago) that the ideal exhaust system on a car would have a perfectly gradual increase in diameter from the turbo back to the muffler.</TD></TR></TABLE>
yes, thats exactly what he said...but opposite. He said it should increase from tailpipe to turbo. Which is same thing as saying it should decrease from turbo to tailpipe</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnzoSpeed »</TD></TR><TR><TD CLASS="quote">
It was proven in a thread somewhere (a few years ago) that the ideal exhaust system on a car would have a perfectly gradual increase in diameter from the turbo back to the muffler.</TD></TR></TABLE>
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Re: DP theory (adictionbass)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adictionbass »</TD></TR><TR><TD CLASS="quote">
as the air cools, it becomes more dense and would slow down in a given diameter of pipe. gradually decreasing the piping size (if there was a way to base exhaust size at a given point with the temp of exhaust gases at that same point) would keep a constant exhaust velocity without any added backpressure</TD></TR></TABLE>
Having it progressively get smaller would be defeating the purpose of starting it out at a larger dia. Would it not? If it's 4" at the turbine outlet and 2" at the talpipe, it might as well just been a complete 2" system as that would create exaust pressure and back up the exaust gasses leaving the turbine.
as the air cools, it becomes more dense and would slow down in a given diameter of pipe. gradually decreasing the piping size (if there was a way to base exhaust size at a given point with the temp of exhaust gases at that same point) would keep a constant exhaust velocity without any added backpressure</TD></TR></TABLE>
Having it progressively get smaller would be defeating the purpose of starting it out at a larger dia. Would it not? If it's 4" at the turbine outlet and 2" at the talpipe, it might as well just been a complete 2" system as that would create exaust pressure and back up the exaust gasses leaving the turbine.
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Re: DP theory (hondaguyef)
the gas is cool and dense when it hits the outlet, therefore, to obtain the same velocity and pressure you dont need as big as opening
Modified by DaZman69 at 4:27 AM 5/16/2006
Modified by DaZman69 at 4:27 AM 5/16/2006
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Re: DP theory (hondaguyef)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondaguyef »</TD></TR><TR><TD CLASS="quote">
Having it progressively get smaller would be defeating the purpose of starting it out at a larger dia. Would it not? If it's 4" at the turbine outlet and 2" at the talpipe, it might as well just been a complete 2" system as that would create exaust pressure and back up the exaust gasses leaving the turbine. </TD></TR></TABLE>
it would not.
Having it progressively get smaller would be defeating the purpose of starting it out at a larger dia. Would it not? If it's 4" at the turbine outlet and 2" at the talpipe, it might as well just been a complete 2" system as that would create exaust pressure and back up the exaust gasses leaving the turbine. </TD></TR></TABLE>
it would not.
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Re: DP theory (DaZman69)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DaZman69 »</TD></TR><TR><TD CLASS="quote">the gas is cool and dense when it hits the outlet, therefore, to obtain the same velocity and pressure you dont need as big as opening</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adictionbass »</TD></TR><TR><TD CLASS="quote">
it would not. </TD></TR></TABLE>
Maybe I need to take a fluid/Thermo dynamics class
(but, I still think reducing it wouldn't work 
). Enough debate for me tonight guys. Goodnight.
Phil
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adictionbass »</TD></TR><TR><TD CLASS="quote">
it would not. </TD></TR></TABLE>
Maybe I need to take a fluid/Thermo dynamics class
(but, I still think reducing it wouldn't work ). Enough debate for me tonight guys. Goodnight.Phil
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Re: DP theory (hondaguyef)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DaZman69 »</TD></TR><TR><TD CLASS="quote">
I just cut a straw about 1" and made one about 7 inches. The 1" i can blow a lot more air through. I'm still confused as to why.</TD></TR></TABLE>
Simple, you're blowing hot air through a thin straw. The air is going to immediately try to expand after leaving your mouth, pushing against the sides of the straw creating resistance. This resistance = backpressure.
Really, the best exhaust setup for a turbo is no exhaust at all.
I just cut a straw about 1" and made one about 7 inches. The 1" i can blow a lot more air through. I'm still confused as to why.</TD></TR></TABLE>
Simple, you're blowing hot air through a thin straw. The air is going to immediately try to expand after leaving your mouth, pushing against the sides of the straw creating resistance. This resistance = backpressure.
Really, the best exhaust setup for a turbo is no exhaust at all.
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From: Japan Dammit Japan
Re: DP theory (adictionbass)
DaZman69 - you are totally misising the point of using a larger diameter DP. The main purpose is to alleviate as much unnecessary back pressure as possible. If we were trying to maintain the outlet pressure then a DP that is the same diameter as the outlet would be sufficient.
Larger diamter DP's have been proven time and time again to produce more HP with better power curves. Do I know how the gains are made from using larger diameter piping? YES!
The dynamics of hydraulics and turbocharged automotive exhaust flow are not comparable. With hydraulics you want to maintain line pressure but with exhaust flow you want to decrease backpressure that is caused by restrictive piping and/or exhaust design.
An exhaust that decreased in diameter would increase backpressure and rob power.
Larger diamter DP's have been proven time and time again to produce more HP with better power curves. Do I know how the gains are made from using larger diameter piping? YES!
The dynamics of hydraulics and turbocharged automotive exhaust flow are not comparable. With hydraulics you want to maintain line pressure but with exhaust flow you want to decrease backpressure that is caused by restrictive piping and/or exhaust design.
An exhaust that decreased in diameter would increase backpressure and rob power.
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Re: DP theory (DaZman69)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DaZman69 »</TD></TR><TR><TD CLASS="quote">
this is exactly what happens when u stick ur thumb in a garden hose. The smalller opening forces the water too move much faster.</TD></TR></TABLE>
The water might move faster, but once it leaves the faucet the same amount is actually leaving.
You can't compare liquid to gases really.
Also take into consideration that temperature effects the rate of gas flow. If you take a 2.5 pipe and heat it up, will the gases flow better then with a cold pipe..................
this is exactly what happens when u stick ur thumb in a garden hose. The smalller opening forces the water too move much faster.</TD></TR></TABLE>
The water might move faster, but once it leaves the faucet the same amount is actually leaving.
You can't compare liquid to gases really.
Also take into consideration that temperature effects the rate of gas flow. If you take a 2.5 pipe and heat it up, will the gases flow better then with a cold pipe..................
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Re: DP theory (90blackcrx)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DaZman69 »</TD></TR><TR><TD CLASS="quote">I just cut a straw about 1" and made one about 7 inches. The 1" i can blow a lot more air through. I'm still confused as to why.</TD></TR></TABLE>
i think your not accounting for bends in the dp/exhaust system. there was a test on here way back where two exhaust for an srt4 where built. the 2.5" system had few bends (to a total of 100 degress if i remeber correctly) an was for the most part completely straight from the oil pan back. the 3" system followed the stock exhaust route ( over 360 degress of bends). the 2.5" system outflowed the 3" system even though the entire setup had a .5" smaller id.
what your saying is correct (smaller tube = less volume greater velocity) BUT what happens when that tube take a 90? does the gas velocity speed up when it hits a wall? well what if you had a much lager volume of gas in a larger tube with less velocty and hit a 90 bend? what would happen then. would both those 90's create the same amount of backpressure?
i think your not accounting for bends in the dp/exhaust system. there was a test on here way back where two exhaust for an srt4 where built. the 2.5" system had few bends (to a total of 100 degress if i remeber correctly) an was for the most part completely straight from the oil pan back. the 3" system followed the stock exhaust route ( over 360 degress of bends). the 2.5" system outflowed the 3" system even though the entire setup had a .5" smaller id.
what your saying is correct (smaller tube = less volume greater velocity) BUT what happens when that tube take a 90? does the gas velocity speed up when it hits a wall? well what if you had a much lager volume of gas in a larger tube with less velocty and hit a 90 bend? what would happen then. would both those 90's create the same amount of backpressure?