Can I run straight pipes?
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Danzig
- Posts: 4431
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- Real Name: Paul File
- Location: Van Orin, Illinois
Can I run straight pipes?
If a person were to make dual straight pipes and I mean true duals, not a Y pipe going into 2 pipes. I am thinking for a future idea on the Liquifire is to design a header type manifold and make straight pipes. Has anyone ran straight pipes? Not stingers, straight pipes.
1973 JDX8
1978 Liquifire 340
1980 Liquifire 440 CC Racer
1980 Liquifire 440
1982 Liquifire 440
"Gotta Lick It Before You Stick It"
1978 Liquifire 340
1980 Liquifire 440 CC Racer
1980 Liquifire 440
1982 Liquifire 440
"Gotta Lick It Before You Stick It"
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Matt
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Can I run straight pipes?
In short, straight pipes do not benefit 2-stroke engines. It will hurt performance. They do require some back pressure, which is why stingers are used. I'm sure others can go in to more detail.
Matt - JDsleds.com AdministratorCan I run straight pipes?
You could run no stingers but you need tuned pipes that have a very small outlet to create backpressure. You cant just use exhaust pipe. Basically what Im saying is if you had aftermarket twin pipes you could get away without the stingers probably. But this wont win you any points with neighbors,cops or dep. The other side is if you every heard a race type sled with open pipes you wouldnt want to ride it very long very very loud. Ive got tripple pipes on my zrt with tripple stingers and the packing is beat in the stingers and the noise is just plan annoying.
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ICCSF 108
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Can I run straight pipes?
AAen made pipes at one time for the Liquifires 80-84, I'm sure they still would have the jigs there to make some up. I think we have a set or 2 laying around in MN (sorry there not for sale) I know I gutted the stingers on one set, "why have twin pipes & not want the sound rattling around in your head also"????
Kenny
Kenny
AKA: Kenny, Grumpy, Mr. Richard Head
"I Hunt For it, Purchase it, Haul it, Sometimes Repair it, Sometimes Break it, Then Fix it Again, Label it, Warehouse it, Talk About it, So NOW, HOW Can I Take Any Less $$ For It?"
"God I love the smell of KLOTZ in the morning, That smell, you know that Gasoline/Oil Smell, MAKES the whole place SMELL like.. LIKE VICTORY. You know someday the 2 strokers are gonna end..."
Do Anti-War Protesters have reunions? If so what do they TALK about?
"I Hunt For it, Purchase it, Haul it, Sometimes Repair it, Sometimes Break it, Then Fix it Again, Label it, Warehouse it, Talk About it, So NOW, HOW Can I Take Any Less $$ For It?"
"God I love the smell of KLOTZ in the morning, That smell, you know that Gasoline/Oil Smell, MAKES the whole place SMELL like.. LIKE VICTORY. You know someday the 2 strokers are gonna end..."
Do Anti-War Protesters have reunions? If so what do they TALK about?
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ICCSF 108
- Posts: 4369
- Joined: Sun Jul 17, 2005 12:00 am
- Real Name: Kenny Heins, AKA Grumpy
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Can I run straight pipes?
From Aaen's web site under vintage pipes
http://aaenperformance.com/VintagePipes.asp
JOHN DEERE
Liquifire 80-82 TWIN VIN-J12511 $499.00
Liquifire 76-78 TWIN VIN-J12502 $499.00
They do have different part numbers from the Kawasaki Invader pipes, I do know that the 2 sets we have fit the Liquifires perfectly, I don't believe the Invaders pipes would.
Kenny
http://aaenperformance.com/VintagePipes.asp
JOHN DEERE
Liquifire 80-82 TWIN VIN-J12511 $499.00
Liquifire 76-78 TWIN VIN-J12502 $499.00
They do have different part numbers from the Kawasaki Invader pipes, I do know that the 2 sets we have fit the Liquifires perfectly, I don't believe the Invaders pipes would.
Kenny
AKA: Kenny, Grumpy, Mr. Richard Head
"I Hunt For it, Purchase it, Haul it, Sometimes Repair it, Sometimes Break it, Then Fix it Again, Label it, Warehouse it, Talk About it, So NOW, HOW Can I Take Any Less $$ For It?"
"God I love the smell of KLOTZ in the morning, That smell, you know that Gasoline/Oil Smell, MAKES the whole place SMELL like.. LIKE VICTORY. You know someday the 2 strokers are gonna end..."
Do Anti-War Protesters have reunions? If so what do they TALK about?
"I Hunt For it, Purchase it, Haul it, Sometimes Repair it, Sometimes Break it, Then Fix it Again, Label it, Warehouse it, Talk About it, So NOW, HOW Can I Take Any Less $$ For It?"
"God I love the smell of KLOTZ in the morning, That smell, you know that Gasoline/Oil Smell, MAKES the whole place SMELL like.. LIKE VICTORY. You know someday the 2 strokers are gonna end..."
Do Anti-War Protesters have reunions? If so what do they TALK about?
Can I run straight pipes?
Performance demands a long header tube before the first bend and a expansion area before the stinger to capture required back pressure. The best design for power goes straight out and has no angles, this would be the most effiecent and create the most exhaust power. Mega phones clear the engine quickly of exhaust as the engines cycles but are ineffient in creating true power. Loud though!
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Joliet Jake
- Posts: 122
- Joined: Mon Feb 05, 2007 1:00 am
- Location: Joliet,IL
Can I run straight pipes?
The largest contribution to the current high levels of horsepower in a two stroke engine comes from the ever increasing knowledge of exhaust systems and their designs.
On the original engines a straight pipe was used to just get rid of exhaust gases as fast as possible. But then designers learned about pressure waves and how to use them to scavenge the cylinder of exhaust gases.
Danzig understanding exhaust design begins with understanding how sonic waves travel through pipe. The waves travel at a speed determined by the temperature and speed of the exhaust gas. The speed is around 1675 ft.per second.
The sonic waves have a strange property of being reflected back along the pipe they are traveling through, regardless of whether the pipe has an open or closed end.
Now add to this the law of acoustics which causes a pressure wave to invert its sign once it reaches an open end of the pipe. So a positive pressure wave upon reaching the open end of the pipe turns into a negative pressure wave, but a reflection from a pipes closed end does not change sign,
So when the exhaust port opens up a positive wave charges down the pipe on reaching the end of the pipe it is reflected back up the pipe as a negative wave, when the negative wave reached the exhaust port and if it is open it will assist in the cylinder evacuation. And even pull a good amount of fuel air mixture through the cylinder and into the pipe.
Now the wave goes down and is reflected back as a positive wave and if it is of the proper length will arrive and push in the extra fuel charge that remained in the pipe just as the exhaust port closes. These positive waves can pack up to 6 psi back into the combustion chamber, a kind of backwards supercharger!
This is a very crude explanation of the modern expansion chamber design without me elaborating on the reverse cone and diffuser or megaphone, these items were the breakthrough in exhaust design.
If you want the math for your open pipe
Length = ED X 42545 divided by RPM
Length = length in MM
ED= Exhaust duration in degrees
RPM = engine speed exhaust is tuned to work best at.
On the original engines a straight pipe was used to just get rid of exhaust gases as fast as possible. But then designers learned about pressure waves and how to use them to scavenge the cylinder of exhaust gases.
Danzig understanding exhaust design begins with understanding how sonic waves travel through pipe. The waves travel at a speed determined by the temperature and speed of the exhaust gas. The speed is around 1675 ft.per second.
The sonic waves have a strange property of being reflected back along the pipe they are traveling through, regardless of whether the pipe has an open or closed end.
Now add to this the law of acoustics which causes a pressure wave to invert its sign once it reaches an open end of the pipe. So a positive pressure wave upon reaching the open end of the pipe turns into a negative pressure wave, but a reflection from a pipes closed end does not change sign,
So when the exhaust port opens up a positive wave charges down the pipe on reaching the end of the pipe it is reflected back up the pipe as a negative wave, when the negative wave reached the exhaust port and if it is open it will assist in the cylinder evacuation. And even pull a good amount of fuel air mixture through the cylinder and into the pipe.
Now the wave goes down and is reflected back as a positive wave and if it is of the proper length will arrive and push in the extra fuel charge that remained in the pipe just as the exhaust port closes. These positive waves can pack up to 6 psi back into the combustion chamber, a kind of backwards supercharger!
This is a very crude explanation of the modern expansion chamber design without me elaborating on the reverse cone and diffuser or megaphone, these items were the breakthrough in exhaust design.
If you want the math for your open pipe
Length = ED X 42545 divided by RPM
Length = length in MM
ED= Exhaust duration in degrees
RPM = engine speed exhaust is tuned to work best at.
72 300
75 LIQUIFIRE
76 LIQUIFIRE
78 LIQUIFIRE
78 CYCLONE
80 TRAILFIRE
81 SRX
83 LIQUIFIRE
83 SPRINTFIRE
88 650 INDY
94 MACH Z
2000 MACH Z
2005 MACH Z
S 35 BONANZA
75 LIQUIFIRE
76 LIQUIFIRE
78 LIQUIFIRE
78 CYCLONE
80 TRAILFIRE
81 SRX
83 LIQUIFIRE
83 SPRINTFIRE
88 650 INDY
94 MACH Z
2000 MACH Z
2005 MACH Z
S 35 BONANZA
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JoeRainville
- Posts: 4355
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- Real Name: "John Deere Joe"
- Location: Fort Worth, Texas
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Can I run straight pipes?
Hi Guys,
I was avoiding this thread like a subpena from El-Queda because I didn't want to start a debate. But, since Jake posted such a nice explination, I thought I would add to it.
There are several things at work on the expansion chamber/muffler set up. Aside from the sonic waves that can and do travel opposite of the direction of flow of the exhaust gas, is the expantion from a pulsed flow with lots of sound pressure (noise) to a more uniform flow with less sound pressure.
Once your exhaust gas leaves the exhaust port, it begins to expand and slow down in the expansion chamber portion of the exhaust pipe. It's this expansion that helps to pull or scavange additional exhaust out the engine, along with pulling freash air and fuel into the combustion chamber. This is what Jake is saying by turning a positive pulse into a negitive pressure wave.
The timed reflection and contraction of this pulse is what back feeds into the exhaust port, sort of creating a standing wave to push back into the chamber. Since the intake port closed first, and the scavanging pulled some air/fuel into the exhaust manifold, this reverse wave help to build cylinder pressure before the port closes. Then it starts all over again as the exhaust port opens.
Once this exhaust flow re-contracts, accelerates and squeezes into the outlet of the expansion chamber, it still contains a lot of sound pressure that needs to be delt with. The muffers job is to break up the sound pressure with minimal pressure drop. It's the muffer portion of the exhaust system that can be removed for power gains, not a proper expansion chamber.
For example, I landed hard from a jump into a rough mogal field a few years ago racing SnoCross. My sled felt like it lost about 1/3 of its HP. Upon inspection, my pipe jumped off the exhaust manifold and was held off center by the exhaust springs. It ran so badly that I thought I either blew it up or a carb popped out of a mounting flage. It wouldn't run right until I replaced the exhaust donut and put the pipe back in place.
Note the most modern sleds use an expansion chamber and separate muffer combination, just like Deere did for the 295/s, 340/s and Liquidator from 74-76. Although the earlier Deeres used an OK tuned Donaldson muffer (most have a little D logo on them somewhere), the 76-84 sleds had a much better tuned pipe/muffer combination.
That is why the 82-84 Snowfires make more power than the same exact motor in a Spitfire. The muffer is better!
Later Liquidator,
-Rainville
B)
I was avoiding this thread like a subpena from El-Queda because I didn't want to start a debate. But, since Jake posted such a nice explination, I thought I would add to it.
There are several things at work on the expansion chamber/muffler set up. Aside from the sonic waves that can and do travel opposite of the direction of flow of the exhaust gas, is the expantion from a pulsed flow with lots of sound pressure (noise) to a more uniform flow with less sound pressure.
Once your exhaust gas leaves the exhaust port, it begins to expand and slow down in the expansion chamber portion of the exhaust pipe. It's this expansion that helps to pull or scavange additional exhaust out the engine, along with pulling freash air and fuel into the combustion chamber. This is what Jake is saying by turning a positive pulse into a negitive pressure wave.
The timed reflection and contraction of this pulse is what back feeds into the exhaust port, sort of creating a standing wave to push back into the chamber. Since the intake port closed first, and the scavanging pulled some air/fuel into the exhaust manifold, this reverse wave help to build cylinder pressure before the port closes. Then it starts all over again as the exhaust port opens.
Once this exhaust flow re-contracts, accelerates and squeezes into the outlet of the expansion chamber, it still contains a lot of sound pressure that needs to be delt with. The muffers job is to break up the sound pressure with minimal pressure drop. It's the muffer portion of the exhaust system that can be removed for power gains, not a proper expansion chamber.
For example, I landed hard from a jump into a rough mogal field a few years ago racing SnoCross. My sled felt like it lost about 1/3 of its HP. Upon inspection, my pipe jumped off the exhaust manifold and was held off center by the exhaust springs. It ran so badly that I thought I either blew it up or a carb popped out of a mounting flage. It wouldn't run right until I replaced the exhaust donut and put the pipe back in place.
Note the most modern sleds use an expansion chamber and separate muffer combination, just like Deere did for the 295/s, 340/s and Liquidator from 74-76. Although the earlier Deeres used an OK tuned Donaldson muffer (most have a little D logo on them somewhere), the 76-84 sleds had a much better tuned pipe/muffer combination.
That is why the 82-84 Snowfires make more power than the same exact motor in a Spitfire. The muffer is better!
Later Liquidator,
-Rainville
B)
Honorary Tech Editor
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Joliet Jake
- Posts: 122
- Joined: Mon Feb 05, 2007 1:00 am
- Location: Joliet,IL
Can I run straight pipes?
I believe that Joe?s comments on the subject were right on and I thank him for the explanation.
I would like to restate that the number 42545 is a constant that takes into account the fact that the sonic wave always travels at the speed of sound.
The temperature of the exhaust gas at or near peak power in a two stroke engine is calculated and that factor goes into the final average,??. so the speed of sound in hot gas is about 1675 ft per second.
The reason that variable exhaust valves or ?power valves? have been introduced was to widen the power band. They really don?t produce any significant increase in peak horsepower. The only true power valves were Yamaha?s old cable drive one?s
As far as variable timing it was and is a great improvement over the old single setting system. The reason for this is that as a two stroke engine gets to it?s peak power RPM?s it becomes much more efficient at atomizing the intake charge as well as filling the combustion chamber.
The flame propagation in this environment is much faster therefore needs less advance to completely burn, but the real benefit is prevents detonation!!
One instance of variable timing being used with the exhaust pipe is in snow cross were the cold pipe can be quickly warmed by the rider pushing a button to retard the timing putting heat in the pipe.
The combination of a cold fuel charge in a semi warm engine along with a hot pipe produced a very quick start!!.....and a lot of wins??..until the competition found out!
I am truly done now!
I would like to restate that the number 42545 is a constant that takes into account the fact that the sonic wave always travels at the speed of sound.
The temperature of the exhaust gas at or near peak power in a two stroke engine is calculated and that factor goes into the final average,??. so the speed of sound in hot gas is about 1675 ft per second.
The reason that variable exhaust valves or ?power valves? have been introduced was to widen the power band. They really don?t produce any significant increase in peak horsepower. The only true power valves were Yamaha?s old cable drive one?s
As far as variable timing it was and is a great improvement over the old single setting system. The reason for this is that as a two stroke engine gets to it?s peak power RPM?s it becomes much more efficient at atomizing the intake charge as well as filling the combustion chamber.
The flame propagation in this environment is much faster therefore needs less advance to completely burn, but the real benefit is prevents detonation!!
One instance of variable timing being used with the exhaust pipe is in snow cross were the cold pipe can be quickly warmed by the rider pushing a button to retard the timing putting heat in the pipe.
The combination of a cold fuel charge in a semi warm engine along with a hot pipe produced a very quick start!!.....and a lot of wins??..until the competition found out!
I am truly done now!
72 300
75 LIQUIFIRE
76 LIQUIFIRE
78 LIQUIFIRE
78 CYCLONE
80 TRAILFIRE
81 SRX
83 LIQUIFIRE
83 SPRINTFIRE
88 650 INDY
94 MACH Z
2000 MACH Z
2005 MACH Z
S 35 BONANZA
75 LIQUIFIRE
76 LIQUIFIRE
78 LIQUIFIRE
78 CYCLONE
80 TRAILFIRE
81 SRX
83 LIQUIFIRE
83 SPRINTFIRE
88 650 INDY
94 MACH Z
2000 MACH Z
2005 MACH Z
S 35 BONANZA
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Matt
- Posts: 4747
- Joined: Wed Jul 13, 2005 12:00 am
- Real Name: Matt
- Location: Coopersburg, PA
- Contact:
Can I run straight pipes?
Topic trimmed wayyyy down and moved to FAQ.
Matt - JDsleds.com Administrator