Mandrel vs. pressure bending...
05-11-2002, 11:32 AM
#1
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Mandrel vs. pressure bending...
i know madrel flows better...
i know the reason is partly because the piping is the same diameter all the way through...and with pressure bending it is not... but wouldnt the circumfrence be the same thereflow flowing nearly as good as mandrel?
i know the reason is partly because the piping is the same diameter all the way through...and with pressure bending it is not... but wouldnt the circumfrence be the same thereflow flowing nearly as good as mandrel?
05-11-2002, 04:57 PM
#3
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Originally posted by PATRICK94SE
Even if the two bends had the same inside diameter the mandrel bent bend would flow better because of all the turbulance caused by the ripples in the crushed pipe
Even if the two bends had the same inside diameter the mandrel bent bend would flow better because of all the turbulance caused by the ripples in the crushed pipe
The diameter of press bent pipes are smaller on the curves and bends, because simply put, it was pressed to turn, there's no way you can maintain the diameter if you forcefully turn the pipe without anything inside to keep the diameter the same.
Mandrel bends pretty much keep the diameter the same diameter all throughout the pipe.
Mandrel bending and press bending pretty much cost the same, maybe a little more for the mandrel bent. So if you can get the mandrel bent pipes, get it.
Since the mandrel bent flows much better, it might also cause you to lose more low end that with press bent, but it wouldn't be a damatic loss.
05-11-2002, 09:58 PM
#4
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i know the mandrel is better and keeps the same diameter throught the pipe, but i was just saying i dont understand how the mandrel can be so much better because shouldnt the pressure bent pipe still keep the same circumfrence, just not the diameter? and im not talking about the pressure bent pipes with ripples.
05-11-2002, 10:14 PM
#6
Originally posted by PATRICK94SE
I am confused...how could the diameter shrink but not the circumfrince
I am confused...how could the diameter shrink but not the circumfrince
05-11-2002, 10:25 PM
#7
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If you were looking at the pipe from the end (so you could see through it)
0
Diameter is the measurment from 0 degrees to 180degrees
Circumfrince is the measurement of the outside perimeter of the circle
Now now the diameter does not HAVE to be from 0-180 it could be from 90-270 ect. But you could not change one without the other.
0
Diameter is the measurment from 0 degrees to 180degrees
Circumfrince is the measurement of the outside perimeter of the circle
Now now the diameter does not HAVE to be from 0-180 it could be from 90-270 ect. But you could not change one without the other.
05-12-2002, 01:39 AM
#8
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i thought that because when the pressure bent pipes widen horizontally when bent and making this shap 0 oposed to O like mandrel bent pipes...
i thought that they widened but im not totally sure, so if they just kinda of get "sqeezed down" but keep the same width going left to right, and smaller from top to bottom...
damn, i cant find an easy way to say it..i know that is gonna be confusing.
i thought that they widened but im not totally sure, so if they just kinda of get "sqeezed down" but keep the same width going left to right, and smaller from top to bottom...
damn, i cant find an easy way to say it..i know that is gonna be confusing.
05-12-2002, 07:24 AM
#9
Originally posted by Sudesh
Mandrel bending and press bending pretty much cost the same, maybe a little more for the mandrel bent. So if you can get the mandrel bent pipes, get it.
Since the mandrel bent flows much better, it might also cause you to lose more low end that with press bent, but it wouldn't be a damatic loss.
Mandrel bending and press bending pretty much cost the same, maybe a little more for the mandrel bent. So if you can get the mandrel bent pipes, get it.
Since the mandrel bent flows much better, it might also cause you to lose more low end that with press bent, but it wouldn't be a damatic loss.
05-12-2002, 08:28 AM
#10
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Those pre bent pipes you can pick up in auto stores i don't really know about. For exhaust systems..i've found about 5 circumstances now where the mandrel bent was the same cost as the press bent or just a few dollars apart. My personal experience below.
When i did my exhaust system, i never knew there was a mandrel shop close to me in NY. So i paid roughly $180 for my cat-back press bent(installation and everything). Now there's a shop in flushing queens that will do mandrel bent cat-backs for $200.
The price is roughly the same, however some people charge a little more. Mandrel bending isn't all that hard..it's not like it takes any hard work to do, just a machine doing it..so they can't really charge alot.
When i did my exhaust system, i never knew there was a mandrel shop close to me in NY. So i paid roughly $180 for my cat-back press bent(installation and everything). Now there's a shop in flushing queens that will do mandrel bent cat-backs for $200.
The price is roughly the same, however some people charge a little more. Mandrel bending isn't all that hard..it's not like it takes any hard work to do, just a machine doing it..so they can't really charge alot.
05-12-2002, 08:36 AM
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About the circumfrence of th pipe..
Diameter - The length from one end to another end when you cut the pipe in half (180 degrees). The letter "D" shows the diameter of a circly cut in half. The straight line in the diameter.
Circumfrence - distance around the pipe (like a 3" exhaust pipe, 3" refers to the circumfrence).
Lets say you have a 3" diameter exhaust pipe. You press bent it.
The diameter obviously does change.
The circumfrence does NOT change.
Proof:
Lets look at the letter "O", lets say that's our original pipe before it's press bent and has a 3" circumfrence. Now lets press bend it into "0". Diameter is no longer relevant because it's not a circle anymore. But if you were to measure around it, it would still be 3", just shaped differently. You get it?
Diameter - The length from one end to another end when you cut the pipe in half (180 degrees). The letter "D" shows the diameter of a circly cut in half. The straight line in the diameter.
Circumfrence - distance around the pipe (like a 3" exhaust pipe, 3" refers to the circumfrence).
Lets say you have a 3" diameter exhaust pipe. You press bent it.
The diameter obviously does change.
The circumfrence does NOT change.
Proof:
Lets look at the letter "O", lets say that's our original pipe before it's press bent and has a 3" circumfrence. Now lets press bend it into "0". Diameter is no longer relevant because it's not a circle anymore. But if you were to measure around it, it would still be 3", just shaped differently. You get it?
05-12-2002, 08:45 AM
#12
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Also, I've seen press bent pipes with smooth bends..and press bent pipes with alot of ripples. I think you only get ripples on smaller diameter pipes, but i dunno (maybe the machine that does the bending?). Those ripples look ugly and restrictive. Mine is press bent and i don't see any ripples.
05-12-2002, 01:56 PM
#13
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Originally posted by Sudesh
About the circumfrence of th pipe..
Diameter - The length from one end to another end when you cut the pipe in half (180 degrees). The letter "D" shows the diameter of a circly cut in half. The straight line in the diameter.
Circumfrence - distance around the pipe (like a 3" exhaust pipe, 3" refers to the circumfrence).
Lets say you have a 3" diameter exhaust pipe. You press bent it.
The diameter obviously does change.
The circumfrence does NOT change.
Proof:
Lets look at the letter "O", lets say that's our original pipe before it's press bent and has a 3" circumfrence. Now lets press bend it into "0". Diameter is no longer relevant because it's not a circle anymore. But if you were to measure around it, it would still be 3", just shaped differently. You get it?
About the circumfrence of th pipe..
Diameter - The length from one end to another end when you cut the pipe in half (180 degrees). The letter "D" shows the diameter of a circly cut in half. The straight line in the diameter.
Circumfrence - distance around the pipe (like a 3" exhaust pipe, 3" refers to the circumfrence).
Lets say you have a 3" diameter exhaust pipe. You press bent it.
The diameter obviously does change.
The circumfrence does NOT change.
Proof:
Lets look at the letter "O", lets say that's our original pipe before it's press bent and has a 3" circumfrence. Now lets press bend it into "0". Diameter is no longer relevant because it's not a circle anymore. But if you were to measure around it, it would still be 3", just shaped differently. You get it?
05-12-2002, 02:51 PM
#14
Originally posted by Sudesh
Those pre bent pipes you can pick up in auto stores i don't really know about. For exhaust systems..i've found about 5 circumstances now where the mandrel bent was the same cost as the press bent or just a few dollars apart. My personal experience below.
When i did my exhaust system, i never knew there was a mandrel shop close to me in NY. So i paid roughly $180 for my cat-back press bent(installation and everything). Now there's a shop in flushing queens that will do mandrel bent cat-backs for $200.
The price is roughly the same, however some people charge a little more. Mandrel bending isn't all that hard..it's not like it takes any hard work to do, just a machine doing it..so they can't really charge alot.
Those pre bent pipes you can pick up in auto stores i don't really know about. For exhaust systems..i've found about 5 circumstances now where the mandrel bent was the same cost as the press bent or just a few dollars apart. My personal experience below.
When i did my exhaust system, i never knew there was a mandrel shop close to me in NY. So i paid roughly $180 for my cat-back press bent(installation and everything). Now there's a shop in flushing queens that will do mandrel bent cat-backs for $200.
The price is roughly the same, however some people charge a little more. Mandrel bending isn't all that hard..it's not like it takes any hard work to do, just a machine doing it..so they can't really charge alot.
now if in fact you're getting a mandrel bent pipe for the price of press bent..let me know ASAP!
05-12-2002, 03:36 PM
#15
I talked to someone that ownes a shop in AL about this and he said the machines are expensive and very few shops have them.
anyway he said mandrel bending machines use water (or sand I really cant remember which) and they fill it and pressurize it and that way when they bend it the pipe will not crease. I know there is a place in GA that does it fairly inexpensive because I was going to buy dual 3" header back for my Chevelle...its been a while but I think the price was $299 for dual 3" pipe from header to stock rear location (behind rear tire)
anyway he said mandrel bending machines use water (or sand I really cant remember which) and they fill it and pressurize it and that way when they bend it the pipe will not crease. I know there is a place in GA that does it fairly inexpensive because I was going to buy dual 3" header back for my Chevelle...its been a while but I think the price was $299 for dual 3" pipe from header to stock rear location (behind rear tire)
05-12-2002, 03:49 PM
#16
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you can find cheap seperate mandrel bends at JC whitney.. www.jcwhitney.com about 5 bucks each for aluminum...cheapest i have found.
05-12-2002, 06:10 PM
#17
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Originally posted by Sudesh
About the circumfrence of th pipe..
Diameter - The length from one end to another end when you cut the pipe in half (180 degrees). The letter "D" shows the diameter of a circly cut in half. The straight line in the diameter.
Circumfrence - distance around the pipe (like a 3" exhaust pipe, 3" refers to the circumfrence).
About the circumfrence of th pipe..
Diameter - The length from one end to another end when you cut the pipe in half (180 degrees). The letter "D" shows the diameter of a circly cut in half. The straight line in the diameter.
Circumfrence - distance around the pipe (like a 3" exhaust pipe, 3" refers to the circumfrence).
05-12-2002, 07:44 PM
#18
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Originally posted by DanNY
i think you're getting confused with press bent. the bend-pak machines are press benders. they are found in many shops. (according to my exhaust guy) mandrel bent piping requires some kind of solid filler inserted into the pipe then bent with the material inside. the filler will prevent the material to crush in, hence creating a mandrel bend. if you see the bender where they push a ram against a empty pipe over a curved die then that's press bent. you look closely there's a small indentation on where the die was on.
now if in fact you're getting a mandrel bent pipe for the price of press bent..let me know ASAP!
i think you're getting confused with press bent. the bend-pak machines are press benders. they are found in many shops. (according to my exhaust guy) mandrel bent piping requires some kind of solid filler inserted into the pipe then bent with the material inside. the filler will prevent the material to crush in, hence creating a mandrel bend. if you see the bender where they push a ram against a empty pipe over a curved die then that's press bent. you look closely there's a small indentation on where the die was on.
now if in fact you're getting a mandrel bent pipe for the price of press bent..let me know ASAP!
Dan..yeah i know what the mandrel and press bent is..but in either case..the distance around the pipe stays the same..just the diameter changes. When it's being custom made the price is pretty much the same..cause it's being done then and there..
I heard about the place in queens that does the mandrel bends from this thread:
http://forums.maxima.org/showthread....hlight=mandrel
It was discussed on altimas.net ALOT..unfortunately altimas.net doesn't seem to be working at the moment, when they start working again you can check the thread out.
05-12-2002, 11:17 PM
#20
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Posts: 1,030
Originally posted by awsm66
I talked to someone that ownes a shop in AL about this and he said the machines are expensive and very few shops have them.
anyway he said mandrel bending machines use water (or sand I really cant remember which) and they fill it and pressurize it and that way when they bend it the pipe will not crease. I know there is a place in GA that does it fairly inexpensive because I was going to buy dual 3" header back for my Chevelle...its been a while but I think the price was $299 for dual 3" pipe from header to stock rear location (behind rear tire)
I talked to someone that ownes a shop in AL about this and he said the machines are expensive and very few shops have them.
anyway he said mandrel bending machines use water (or sand I really cant remember which) and they fill it and pressurize it and that way when they bend it the pipe will not crease. I know there is a place in GA that does it fairly inexpensive because I was going to buy dual 3" header back for my Chevelle...its been a while but I think the price was $299 for dual 3" pipe from header to stock rear location (behind rear tire)
:And for every one else who doesnt understand why mandrel bending is better than compression bending think if it like this
drinking coke thru a straw, if you bend the straw 90 degree's the inner diameter begins to close up, and if you bend it even more, the less coke you can drink, then it gets to a point where you cant drink anymore coke.
05-12-2002, 11:28 PM
#21
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Well the thing with the bending straw analogy witch is waht I think Dummy was originaly talking about is no matter what the circumfrence will stay the same. Now if you bent the straw in half so the crease was running from 0 degrees to 180 degrees. The diameter if measured from 90 degrees to 270 degrees would get smaller. However the diameter if measured from 0 to 180 would increase. You would basicly be going from thisO to () Although the general passage for travel may still have the same Square inches to travel through the flow would be interupted by the shape of the bend.
I hope this is what you where talking about dummy
However Everything I said makes no sense since the terms diameter and circumfrence only apply to circles. If the pipe is bent by anything other then a mandrel bender it is no longer a circle. But you get the point.
I hope this is what you where talking about dummy
However Everything I said makes no sense since the terms diameter and circumfrence only apply to circles. If the pipe is bent by anything other then a mandrel bender it is no longer a circle. But you get the point.
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