Please please please tell me this is a joke! Please learn about reflected pressure waves and resonance. You are talking about scavenging and there is no "about here" when the expansion chamber reflects the pressure waves. It will have some reflective effect at each taper transition and the tuned length will give the overall timing for the main reflected pressure wave that happens. There is also a reflected wave as each pulse exits the stinger(silence exit). Please learn more about 2 stokes...
@YAMR1M I know everything about 2 strokes. Much more than you and your anal retentive slide rule boring perfection text. The world aint as exact as your Pretend analysis of two stroke resonance theory. Are you a JOke??? WHY, YES YOU ARE.....
on the subject of exspanon exhausts i have a 180 cc 2 stroke which when it was running put excessive oil into exhaust, now engine wan't start and wets spark plug with petrol at every attempt to pull start , have you come around this ?robin
I see u did a great job with ur honda dio. I've seen ur videos many times and i bought a dio for my wife as a present for her birthday (but shhhh.... It's a secret) So me and my nephews decided to customize and personalise it for her. I promise to take pics as we get on with it and post them We are from Argentina and you are a great inspiration 4 those who like scooters, mechanics, customization, personalizing and tuning.
the pressure wave rebounds as a negative pressure wave as the area of the expansion chamber increases... this sucks the spent charge from the motor, aswell as directly sucking fresh charge from the carb (meaning that the reed valves are actually open for almost 360 degrees!)
when the pressure pulse reaches the section of reducing area it is partially rebounded as a positive pressure pulse which fills the cylinder before the exhaust port closes
@dorkusmajorus ABOUT 100% WRONG, SONNY. THIS IS MY CHANNEL AND I AM ALWAYS 1000% PERCENT RIGHT ON EVERYTHING. THAT IS RULE NO.2#. I WOULD LOVE TO SEE YOUR VIDEOS ON THE SUBJECT, BUT SADLY, YOU .........DONT.........HAVE.........ANY. 8.7 MILLION VIEWS CANT BE WRONG...
I guess because George Bush was elected with more than that many votes, he must be an even bigger two stroke expert. LETS ASK HIM !
Read your 30 year old Bell book. it will explain what I have said exactly. well apart from the reed valve bit, that was only found in last couple years@Queens Uni so you'l have to see SAE paper for that one.
Iv already provided a link to show my real two stroke work. I dont need to emasculate myself by counting how many 12 year olds have watched.
G'day mate ..Great explanation I thought that the expansion chambers purpose was letting unburnt fuel and gasses expand further after leaving the combustion chamber but as you explained it allows the engine to be more efficient. Visit anytime Perth western australia...its no fraser island. but hey.
@stdavross666 I really want to come to Australia. The people seem so nice. The expansion chamber basically acts like a vacuum cleaner sucking more fuel and air thru the engine. THe more fuel and air and engine can push thru it- the more horsepower is created. Hence= the bigger the engine the more horsepower. turbos and blowers do the same thing, they force more air and fuel thru a small engine creating more horsepower, simple physics. I love Australia, except for those Drop Down Bears.. RH DSD
So painful to watch... the fumbling and bumbling. You have all those fancy books arranged on your shrine, why don't you read them and learn correct terminology.
Some of the best doers are not the best explainers, who cares, nice lookin work. I was wondering, I rode a yz250 this weekend doing enduro style riding and it wore this 60 year old out, damn it's explosive or nothing. Is there a way to fatten up the mid-range and make it more suitable to my slower reflexes? I was wondering if I increased the back pressure by snufflin the exhaust if it'd kill some of the top end and make it more rideable. It'd been a long time since I rode a 2 stroke, it was fun
@505197 I have not ridden a YZ since I had a new one in 75'. I imagine they are pipier now. I would suggest not changing the delicate engine ratio, but try changing the back sprocket gear ratio or the front tooth gear ratio. This would keep the powerband in tact, but change the jerkiness, I hope. Good luck and I wish I had one. RH DSD
@505197 DiospeedDemon made a great point about changing the gearing, and If it still hasn't tamed the beast enough, you could try adding a flywheel weight as well. Lots of people including myself have used this combo for woods riding 2 stroke mxers.
@NSDwowz - obviously you don't know shit about the principles of 2 stroke exhaust, the gas Does come back to the cylinder again hence the cone shape at the end of the exhaust, the reverberating wave of gases aids in compression of the engine, why even have an expansion chamber otherwise, they figured that out in the 1930's jackass, read a fucking book, I'll bet you didn't finely tune anything and paid an experienced professional to do it for you. i don't see you with any videos on here.
I think that it is sad that most of the smack talkers here have no idea about the "Gospel according to Jennings". they should find a copy and read it cover-to-cover at least three times. here is a hint trash talkers....it is the red book!
Interesting. I've always wanted to know more about how these 2 strokes work myself. Been out of bikes for many years, but am about to be completely rebuilding a now vintage 85 to 87 Husqvarna 500XC, to get back into riding. Would love to have some idea of pipe changes, and how they might affect the power output. As well as porting mods. Not much info out there. Not many sources ever did exist for pipes for these bikes, and no real porting info. Should be fun though.
I use FMF, they got it figured out pretty good. But I would like to know why The expansion chamber itself is so important rather than the taper of the tail section which controls the reverberation or the first part of the pipe that dictates the initial exhaust velocity. High pressure waves create a negative pressure (vacuum) in their wake, so is'nt the expansion chamber more dictated by engine cc"s rather than rpm range? I want to pick your brain, talk to me.............
@bligrigs According to what I read the expansion chamber / divergent cone lengthens the returning negative pressure waves so that they have a better chance of reaching the engine while the exhaust port is open. This way the negative pressure can "suck" out the exhaust gases. Longer wave = better chance that at least part of it will hit while the exhaust port is open.
Source:
How Two-Stroke Expansion Chambers Work, and Why You Should Care.
@TheMaverickScientist I think a smaller diameter expansion chamber with a slightly larger diameter divergent cone pipe would give a stronger hit down low and rev out much further over the top, if only there were more room to make it a few inches longer............
I see most your bikes are Honda. I would like to get a expansion chamber for my Yamaha Razz. I did the jet work however it seems to have lowered my top speed to 26-28 MPH When it use to go 30-32 MPH It does seem to take off faster getting up to 20 MPH rather fast. But I would like to go 50 MPH & take hills at 30-35 Please any help would be greatly appreciated. Thank you
FOR CALHOLLI.The sonic wave is not caused by resonance, the sonic wave is caused by the fuel being ignited in the cylinder which then travels through the port and on into the header pipe at the speed of sound ( hence the SONIC wave ) the gasses then reach the first part of the expansion chamber ( the first cone ) where the super heated gas expands and creates negative pressure behind it, which helps to pull the next charge of fuel mixture into the cylinder head through the transfer ports.
FOR CALHOLLI.The sonic wave is not caused by resonance, the sonic wave is caused by the fuel being ignited in the cylinder which then travels through the port and on into the header pipe at the speed of sound ( hence the SONIC wave ) the gasses then reach the first part of the expansion chamber ( the first cone ) where the super heated gas expands and creates negative pressure behind it, which helps to pull the next charge of fuel mixture into the cylinder head through the transfer ports.
seems like you are shooting for the best pipe that is tuned for max revs... but I myself wouldn't want such a pipe, because I ride more trails than not.. so It all depends on what you are shooting for..... but, great video.
that sonic wave happens by RESONANCE..... depending on the size of your pipe, it will return at that resonant frequency... by changing the pipe size (or "tuning") .. all it is doing is plucking a different chord on a guitar, so to speak....... which makes it return at different times.... there is no, "perfect" tuning for any particular motor... because you give up one for the other in the powerband.. either strong low end torque that revs weak, or high rev power that bogs in the low end.
@calholli That is a simple answer. Resonant tuning in quantum physics is a little different than this easy explanation. You need to leave the answer to us experts.
@DIOSpeedDemon .. bwhahaha... whoa.. easy there high horse... from how you explained it, and some of your other videos. your no expert... I've studied up and experimented with tuning too..... anyone can just say " yeah it takes a super computer, or a math genius"... when they don't understand the formulas... I know this much, a bigger pipe volume gives you more low end.. and a smaller pipe is more for dragging.... you can tune the pipe all you want, but it is only moving the powerband.
@DIOSpeedDemon That's BS. You don't need quantum mechanics to explain, nor to understand, resonance. Even less a resonating pipe. It's enough with helmholtz resonance.
@QSQCaito I would challenge you or anyone to design an expansionchamber pipe to match an existing engine, from scratch. You cant do it. I am speaking of Sterlings theory of push/pull resonance factored for millisecond repeating waves. Again this is above your head. YOu sound about 3 feet tall.
@DIOSpeedDemon Still, quantum mechanics has nothing to do with this. Don't try to complicate things even further. I have deep studies of quantum mechanics, and you really don't need them to tune a pipe. Don't try to sound smart.
@QSQCaito You have six videos and 44 views, I have 4,000,000 views. Molecular science and laws of physics at this level work differently then you could fathom. Stick to making cover songs and leave the videos to us million users.
@DIOSpeedDemon You see, you think a couple of views gives you knowledge. Studying gives you knowledge, not uploading videos. That's why I have knowledge, because I study. Enough to know you don't need to go quantum to explain a resonating pipe, that's just basic physics. Leave quantum and Eisenberg for what they're worth it. Limit yourself to explains things as they're and don't try to sound smart saying things that are wrong.
@QSQCaito Why dont you get the hell off of my channel and go bother someone else. You are obviously a uneducated peasant and you really need to get off my channel and get a life.
@QSQCaito Is that you with the mini bike engine? I might have guessed it, a 15 year old asshole who thinks he knows it all. I am not going to respond to you any more, in fact I wouldn't cross the street to piss on you if you were on fire.
@DIOSpeedDemon Bla bla, you are just words talking to youtube believing you are something for that. Still, to the ignorance I shall respond with silence.
@DIOSpeedDemon damn dude ppl r a fuckin pain in the ass niggers talkin all this shit im 15 been working on motors for 4 or 5 years now i can do anything that duzint need pricey tools i never know how a power band workd intell your video thanks good job i put a vid up there and im goin to get bitchd at for looking bad lol
@Scootertuner1000 man i have tryd to find some one on my level but we r dieing out theres not meny left its like only 5% of the world knows how to put a carb on dude i fab weld build shape
@QSQCaito Dud you are a complete fucking asshole. I would like to see you build a moped that is as fast as this guy's. Yiu fucking cocksucker, you haven't got a fucking clue what you are on about. This guy's scooter rocks. Fucking retard.
@Scootertuner1000 You see, your knowledge equals zero. Give me a sustained reason why something I said is wrong, and we shall talk. Insults only show you are empty of knowledge. This guy has no idea the factors involved in an expansion chamber. Quantum is not needed just basic physics, something youtube users seem to lack. If you want I can recommend you some books, bye bye.
@QSQCaito What are you talking about?? He doesn't mention quantum once, at least not that I heard. I didn't hear anything about Eisenberg either. What the hell is wrong with you. This is how an expansion chamber works exhaust system used on a two-stroke cycle engine to enhance its power output by improving its volumetric efficiency. It makes use of the energy left in the burnt exhaust exiting the cylinder to aid the filling of the cylinder for the next cycle
@QSQCaito The high pressure gas exiting the cylinder initially flows in the form of a "wavefront" as all disturbances in fluids do. The exhaust gas pushes its way into the pipe which is already occupied by gas from previous cycles, pushing that gas ahead and causing a wave front. Once the gas flow itself stops, the wave continues on by passing the energy to the next gas down stream and so on to the end of the pipe.
@QSQCaito If this wave encounters any change in cross section or temperature it will reflect a portion of its strength in the opposite direction to its travel. For example a high pressure wave encountering an increase in area will reflect back a low pressure wave in the opposite direction. A high pressure wave encountering a decrease in area will reflect back a high pressure wave in the opposite direction
@QSQCaito When the descending piston first exposes the exhaust port on the cylinder wall, the exhaust flows out powerfully due to its own pressure without assistance from the expansion chamber and so the diameter/area over the length of the first portion of the pipe is constant or near constant with a divergence of 0 to 2 degrees which preserves wave energy.
@QSQCaito This section of the system is called the "head pipe" (the exhaust port length is considered part of the head pipe for measurement purposes). By keeping the head pipe diameter near constant, the energy in the wave is preserved because there is no expansion until needed later in the cycle. In any case the flow leaving the cylinder during most of the blowdown process is sonic or supersonic and therefore no wave could travel back into the cylinder against that flow.
@QSQCaito When the transfer is complete the piston is on the way back up on its compression stroke but the exhaust port is still open, an unavoidable problem with the two stroke design. To help prevent the piston pushing fresh mixture out the open exhaust port a strong high pressure wave from the expansion chamber is timed to arrive during the compression stroke. The port blocking wave is created by reducing the diameter of the chamber.
@QSQCaito This is called the convergent section (a.k.a baffle cone or section). The outgoing high pressure wave hits the narrowing convergent section and reflects back a high pressure wave to the cylinder which arrives in time to block the port during the compression stroke and can push back into the cylinder any fresh mixture drawn out into the head pipe. The convergent section is made to converge at 8 to 90 degrees depending on requirements.
@QSQCaito Combined with the high pressure wave there is a general rise in pressure in the chamber caused by deliberately restricting the outlet with a small tube called the stinger. The stinger restricts flow out of the chamber to cause higher pressure during the compression cycle and empties the chamber during the compression/power stroke to ready it for the next cycle.
@QSQCaito im going to have to agree with you. i am a mechanic, and for one, it doesnt take a mathematical genious to make a good chamber. its barely intermediate math.
Also, this explaination is mediocre. FOR ANYONE who would liek to really learn 2 stroke, try wikipedia. there is an awesome GIF illustration that makes it too easy to understand
@VforVicious IF you can build one, then DO IT and put it on youtube. The mathematics for the project is far beyond you. (Learn to spell correctly before you attempt to build this pipe).
@DIOSpeedDemon liek was obviously a typo. One of the main parameters involved in expansion chamber design is the speed of sound, this governs the speed of the pressure pulses that we use in the chamber. Where:-
T exc is Exhaust gas temperature in Celsius
273 added to T exc to convert to Kelvin R is 287 the Gas Constant of air in J/kgK
g is 1.4 the Specific Heat Ratio of air a 0 is the speed of sound in m/s
@DIOSpeedDemon liek was obviously a typo. One of the main parameters involved in expansion chamber design is the speed of sound, this governs the speed of the pressure pulses that we use in the chamber. Where:-
T exc is Exhaust gas temperature in Celsius
273 added to T exc to convert to Kelvin R is 287 the Gas Constant of air in J/kgK
g is 1.4 the Specific Heat Ratio of air a 0 is the speed of sound in m/s.
@DIOSpeedDemon BMEP is used in several of the expansion chamber design parameters, and is calculated as shown. Where:- kW is engine power, kW (1bhp=746W) SVcc is swept volume, cc RPM is engine speed, rpm BMEP is in Bar
Blair’s formula assumes that the tuned length of the expansion chamber is from the face of the piston to the beginning of the stinger and is given by the formula below. Where:- L t is tuned length, mm 83.3 = metric constant
A 0 is speed of sound in m/s Q ep is exhaust duration, degrees.
@DIOSpeedDemon The best and easiest way to calculate the dimension you need is to by expansion chamber design software. It will work it all out for you and you simply build what the software tells you to.
Its not A super charge effect as you say...but using the waves as measured in Mil/sec....tuning by wave dies not in crease power so much as it tunes the the point where at the moment the finale charge is about to exit the cylinder through the power valve At that tuned moment as you say instead of supercharge..Its more like A mil/sec valve...in that it blocks the gas/air mix from venting with the spent gasses...although some fuel does get out...
@motoman9477 From what Ive read, ex. chambers create a vacuum, so imagine a supercharger sucking burnt gasses OUT, instead of blowing air/fuel mixture IN, so really its a turbo effect. It all comes down to a larger evacuation volume with a turbo.
@60spastlife A turbo has nothing to do with evacuation,in fact A turbo blocks exaust flow.but uses it to drive more gas/air charge into the combustion...It is in no way like A turbo...it is more or less the same as comparing long vs short headers.... long tube headers give the same effect.your understanding is off...
@60spastlife You are half way correct but you did not go far enough. The resonance wave also pulls more fuel into the combustion chamber as it is sucking out spent gas. This creates a bigger bang, hence more power. I have many different pipes and they all work differently on motor rpm's.
@motoman9477 It provides for more fuel and air to be burned in a given engine and this is a supercharged effect according to the immutable laws of creating horsepower.
@SRT480 This is correct, but unlike the carb, the pipe expansion chamber can be manufactured to different lengths, or "tuned". This tuning allows the pressure wave to be longer or shorter, in milliseconds, and created a different power range for the motor. That is why alot of after market pipes look different from each other. They create power at different "set" rpm's.
@DIOSpeedDemon Ive also noticed all of my life, that they not only look different, but sound different, dur to reasons stated already. Hell...just callme mr. obvious i guess.
@suz384 No dude, if the exhaust is designed propery not only are the gasses pushed out but the exhaust pulls it out and then when the resonance wave hits the rear end of the reverse cone, it bounces the pulse (sound wave) back at just the right time to stop the new change going out with the exhaust. Time it just right and the fresh charge that goes out the exhaust is pushed back in.
for a exhaust to work properly you need the port map ( where the ports are in the barrel) the dimentions determine the shape and size of the pipe to work to its maximum , a shorter front pipe will make the rev band higher. over the counter pipes give a good compromise , but you can improve on them by designing your own.
@cronauer1985 I have the top of the line port mapping two stroke software. Check out my video on it and where to download from the genius that built it.
@645shaiboy The expansion chamber was sold to me as just a big pipe for over 100cc engine. Any Leo Vince pipe you can get is excellent. I have had a few, but they are rare for American Elite engines. If you can find one, buy it and dont let it go. They make smaller expansion pipes for your size and the trick is to find the right one for your riding style.
to find the perfect video is named "pre-procution" planning camera shots, words, material etc. "spontaneous" video is named documental and is intended to capture situations not controled, so, pre-produce and try to document
@youutubestinks I shoot all of my videos in one shot with just a basic premise in my mind. I call that spontaneous as the videos are not cut, polished, edited or tampered with in any way. You will notice in all my 520 videos, there are no special effects, because I simply dont know how to do it. 3 million views so far from a man with no camera training, no acting training, no voice training, no story telling training. I should make movies for the big screen.
If one had the tooling to make each section telescopic a few mm, then one could messure the final output of HP to see the results of expansion chamber.
Or spend 50k for some.
What might be a second find, is complex squeeze baffling inside combined with reflector plates.
2 stroke have a place, but it's getting to a point to where 4 stroke is just twice the results & easier to solve w/o so much wasted fuel, noise, smoke.
Your video is very well done to explain this complex feature. Cheers.
This is just my simple explanation.The actual physics and sound wave calculus figures are easy to talk about, but it is like building a working space shuttle to actually build one by hand.
Hey, watched most of your videos and you've explained everything so clearly. Was just wondering if your scooter project has finished and do you have a video of it running?
@A13X0001 The 120cc Dio is running but my new blue repsol panels are not installed due to cold weather. I have to have patience during cold weather for base coat, primary coat, and clear coat drying. I will make a video soon as it is put together.
@A13X0001 The 120cc Dio is running but my new blue repsol panels are not installed due to cold weather. I have to have patience during cold weather for base coat, primary coat, and clear coat drying. I will make a video soon as it is put together.
To be honest, it would take an engineer with a calculus degree to explain how this work. It takes a super computer to even design these pipes for a given bike, say a honda cr125. The equations for this design would give Einstein a run for his money. I am speaking simply how the pipe works, but it is almost as complicated as the space shuttle to build one from scratch and have it actually work as desired. Its invention at all was a miracle. RH DSD
Have you checked out the Bi-zeta 50cc engines? I used to race minimoto, we were getting 18.5hp from a 50cc. I now run a hybrid engine using a Polini bottom end mated to a BZM cylinder. The cylinder is an exact miniature copy of a TZ 250 GP cylinder, they are a work of art.
So as you explained it, basically you do not need the blue muffler for the backpressure theory to work ?
I recently bought an old 2 stroke dirtbike, without a muffler and was told by my auto tech teacher ( Im 16), that I would need a muffler, for the backpressure to fully work. But in this case it seems as I don't need it ?
I believe you need a muffler, remember I am not a sonic wave engineer here. I would always use a muffler as it does not let the expansion chamber wave dissipate so quickly.
you should look into dutch and french scootersites, they have real fast scooters. They know how to put 20.000rpm and up to 24 hp from a 70cc 2stroke engine
the sonic/sound wave travels down the pipe? dont you mean the pressure from the detonation? suckion from the piston going down? dont you mean its compressed by the piston in the crank casing and when the ports are uncovered its forced in? its sucking? dont you mean its scavenging the exhaust gasses for higher compression? i do no what your saying though
sorry you got the superchaging effect (higher compression almost right you was just a little off its just a little after the intake ports are opened you only get 1 back pressure effect per turn and like you was saying it goes on how fat and long it is to what rpm range you get the superchaging effect (i have mine between 3000-4000rpm then the power drops off steeply. the boost pressure you get is a bit like turbo lag when it kicks in you get a massive cough of power.
obviously its nothing like a turbo apart from it giving you more compression. the best idea i have seen is a variable expansion chamber that slides out for lower revs and slides back for higher revs but that kind of technology has passed by because 2strokes are getting outlawed in most countrys so theres not really any investment finatialy viable
A turbo or belt supercharger, does the same thing= they force more air and fuel thru an engine, creating more horsepower. There methods are different but the outcome is the same. The expansion chamber in a pipe has the same effect as the top two, to a different degree. It forces more fuel and air thru the motor, not through over-pressure, but thru vacuum effect. The end is all the same, more horsepower. RH DSD
find out for yourself,but one thing i will tell you is that the function of an tuned pipe is not to return gasses as you have stated on you tube. do you think a pipe can halt and return rapidly exiting exhaust gasses and separate and return just a fresh charge? and against a upmoving piston?
Find out for myself? That is a coward answer. You tell us how it works then. Write it right here on this channel. I bet you cant because your all talk. I knew it.
@gilessmokey You're funny. Ever heard of a reflected pressure wave? You can't say the exhaust is a constant pressure and velocity...since the engine isn't putting out exhaust all 360 degrees of rotation.
stop picking fault with the guy mate he's trying to hel people out it works a lot like a turbo mate the idea's and principles are very similar. but i will say you both need to stop calling those transfer ports inlet ports!!! lol
Michael , I appreciate you finding my flaws with this theory and correcting me. I completely rebuilt a 1966 chevy turbo corvair with a flat-six and 180 Horsepower. The cartridge, turbine and impeller were all Rajay inc. When I was 17, I built a 800 horsepower 1968 SS camaro with 427 Cubic inches. Mated to a Weiland full race blower manifold, Cragar three inch belt drive, 6-71 blower, 2 Holley 660 center squirt carbs. This stuck out of my Z-28 hood, 18 inches. I KNOW OF WHAT I SPEAK...RH DSD
I also have pictures of my supercharging work of 30 years ago, when I was a young man, if you would like to see and discuss them. My facts are based in the field, not in some discussion group from a library. RH DSD
i dint really mean to question your knowledge on engines sorry about that i no people who find stuff hard to put into words but when it comes to engines there the best i am learning at collage at the momment. i guarantee you know more about diagnostics and engine building then me. i do understand why you feel that way tho because i wouldnt like a student correcting me or a random person when i have been doing it for 30years when they have only been doing it for 3 years
Son, we are all students and never stop learning. I have alot of people dissing my little hobby like I am building the space shuttle or nasa rocket. It is just a moped. Go out and learn everything from as many people as possible and keep an open mind. If three out of four people tell you the same answer to your question then its probably close to the truth. No disrespect taken. RESPECT= RH DSD
i use to have a suzuki road bike which i read on the fiekds it was a 100cc and i put a 50cc motocross exhaust on it. and it sounded like a super bike im sure it went faster aswell
I have a 76 RM 250 suzuki, ive seen afternarket pipes, but i learned that only the stock pipe wil make it run right, and not an aftermarket one that loooks good but is wrong for the engine,
I saw the piston in the bore,
its ok looking,
not burned .
020 size, but it loooked like it had no compression,
but the bore gasket and the head gasket were missing,
The way I understand it, is the pipe is tuned for a certain rpm level. Say one for top end , another for bottom end. You dont really gain overall power, the tuned pipe just directs power to your application, lets say track racing versus drag racing. RH DSD
chambers even help to suck through transfers, they blow back charge lost through exhaust and suck before exhaust is open to help scavenge.
a high pressure pulse has momentum, when the pulse stops its momentum creates a pressure drop, this pulse is also reflected back from stinger to coincide with blowing lost charge back in.
Very hard to explain on videos, my mind goes blank!
Your bike sounds like it needs more top end power although it will be reliable.
The expansion chamber is just that -- a back-pressure generating chamber which pressurizes the cylinder between strokes as there are no valves on a 2 stroke engine, using heat expansion principles to generate back pressure as the gases exit the chamber.
I have a ported Honda Aero 125 with a 55mm bore, stock stroke, domed piston. I can modify a Dio exhaust to fit. I need a nice chamber exhaust and I will get a Dio Intake and reeds and OKO 28 or 30 MM carb with power jet. What kind of pipe do you recommend? The bike pulls to 50 on straights and 60 downhill, but it starves for gas after 30 seconds of full-throttle, even with a 230 jet. I know the carb is inadequate. What pipe would be good? It can't be too loud, but needs nice top end.
i always wondered what that thing on my dirt bike was lol
tylerdugray 1 week ago
Please please please tell me this is a joke! Please learn about reflected pressure waves and resonance. You are talking about scavenging and there is no "about here" when the expansion chamber reflects the pressure waves. It will have some reflective effect at each taper transition and the tuned length will give the overall timing for the main reflected pressure wave that happens. There is also a reflected wave as each pulse exits the stinger(silence exit). Please learn more about 2 stokes...
YAMR1M 2 months ago
@YAMR1M I know everything about 2 strokes. Much more than you and your anal retentive slide rule boring perfection text. The world aint as exact as your Pretend analysis of two stroke resonance theory. Are you a JOke??? WHY, YES YOU ARE.....
DIOSpeedDemon 2 months ago
@DIOSpeedDemon YAMR1M is correct lol.
briggsandclones 1 month ago
on the subject of exspanon exhausts i have a 180 cc 2 stroke which when it was running put excessive oil into exhaust, now engine wan't start and wets spark plug with petrol at every attempt to pull start , have you come around this ?robin
robindeakin 5 months ago
damn is that a 150cc?
MultiWoogie 7 months ago
@MultiWoogie THIS ONE IS 1300CC SINGLE PISTON. I LIKE BIGG ENGINES!!!!
DIOSpeedDemon 7 months ago
@DIOSpeedDemon no way thats 1300cc
kdougall652 5 months ago
@DIOSpeedDemon wtf????1300cc??? with only a cylinder????also its to small
nikos157 4 months ago
@nikos157
He's being sarcastic, genius. You've been whooshed.
opmike343 2 months ago
Hello buddy
I see u did a great job with ur honda dio. I've seen ur videos many times and i bought a dio for my wife as a present for her birthday (but shhhh.... It's a secret) So me and my nephews decided to customize and personalise it for her. I promise to take pics as we get on with it and post them We are from Argentina and you are a great inspiration 4 those who like scooters, mechanics, customization, personalizing and tuning.
Good luck, peace and keep on like that...
Luis from Argentina
SuperSirGawain 7 months ago
This guy knows his shit
jplumber100 8 months ago
bout 80% right
sonic wave? you mean pressure wave
the pressure wave rebounds as a negative pressure wave as the area of the expansion chamber increases... this sucks the spent charge from the motor, aswell as directly sucking fresh charge from the carb (meaning that the reed valves are actually open for almost 360 degrees!)
when the pressure pulse reaches the section of reducing area it is partially rebounded as a positive pressure pulse which fills the cylinder before the exhaust port closes
dorkusmajorus 9 months ago
@dorkusmajorus ABOUT 100% WRONG, SONNY. THIS IS MY CHANNEL AND I AM ALWAYS 1000% PERCENT RIGHT ON EVERYTHING. THAT IS RULE NO.2#. I WOULD LOVE TO SEE YOUR VIDEOS ON THE SUBJECT, BUT SADLY, YOU .........DONT.........HAVE.........ANY. 8.7 MILLION VIEWS CANT BE WRONG...
DIOSpeedDemon 9 months ago
@DIOSpeedDemon
I guess because George Bush was elected with more than that many votes, he must be an even bigger two stroke expert. LETS ASK HIM !
Read your 30 year old Bell book. it will explain what I have said exactly. well apart from the reed valve bit, that was only found in last couple years@Queens Uni so you'l have to see SAE paper for that one.
Iv already provided a link to show my real two stroke work. I dont need to emasculate myself by counting how many 12 year olds have watched.
dorkusmajorus 9 months ago
@dorkusmajorus you are 100% correct - SONIC BOOM!
nicksnicknet 8 months ago
G'day mate ..Great explanation I thought that the expansion chambers purpose was letting unburnt fuel and gasses expand further after leaving the combustion chamber but as you explained it allows the engine to be more efficient. Visit anytime Perth western australia...its no fraser island. but hey.
stdavross666 9 months ago
@stdavross666 I really want to come to Australia. The people seem so nice. The expansion chamber basically acts like a vacuum cleaner sucking more fuel and air thru the engine. THe more fuel and air and engine can push thru it- the more horsepower is created. Hence= the bigger the engine the more horsepower. turbos and blowers do the same thing, they force more air and fuel thru a small engine creating more horsepower, simple physics. I love Australia, except for those Drop Down Bears.. RH DSD
DIOSpeedDemon 9 months ago
listening to paint dry
MegaLuckydog1 11 months ago 2
I Like this pipe! How much can i buy it?
Denmad92 1 year ago
@Denmad92 call up vtcycles.com and see if they have one in stock. I get all my dio parts and exhaust pipes from them,,It is a great pipe. RH DSD
DIOSpeedDemon 1 year ago
So painful to watch... the fumbling and bumbling. You have all those fancy books arranged on your shrine, why don't you read them and learn correct terminology.
diamondnik 1 year ago 3
@diamondnik Your Gay shut up lol
Everything2Stroke 10 months ago
he never says he is an expert, but he does. You know, gets his hands dirty as oppossed to just spouting about it.
AMORANTORI 1 year ago
i understand buddy thnx ! is that a 125cc ? greetings from birmingham england
joohop 1 year ago
@joohop Greeting from the Great city of Walla Walla, Washington state. Nice to meet you , mate. RH DSD
DIOSpeedDemon 1 year ago
Some of the best doers are not the best explainers, who cares, nice lookin work. I was wondering, I rode a yz250 this weekend doing enduro style riding and it wore this 60 year old out, damn it's explosive or nothing. Is there a way to fatten up the mid-range and make it more suitable to my slower reflexes? I was wondering if I increased the back pressure by snufflin the exhaust if it'd kill some of the top end and make it more rideable. It'd been a long time since I rode a 2 stroke, it was fun
505197 1 year ago
@505197 I have not ridden a YZ since I had a new one in 75'. I imagine they are pipier now. I would suggest not changing the delicate engine ratio, but try changing the back sprocket gear ratio or the front tooth gear ratio. This would keep the powerband in tact, but change the jerkiness, I hope. Good luck and I wish I had one. RH DSD
DIOSpeedDemon 1 year ago
@505197
u can get spacers for the header to lengthen the header pipes.
lower rpm power.
a yz will have about 55bhp so it will be quick.
maybe get a 4 stroke trail bike?
tpvalley 1 year ago
@505197 DiospeedDemon made a great point about changing the gearing, and If it still hasn't tamed the beast enough, you could try adding a flywheel weight as well. Lots of people including myself have used this combo for woods riding 2 stroke mxers.
2smokefinny 1 year ago
Interesting. How do you develop it? By trial and error or by maths? Can you just have a standard chamber and vary the length of the pipe?
bomaoneuk 1 year ago
god you sound like a jackass. Give it up.
DennisH8706 1 year ago
oh gawd, what a waste of 7.30.
get to the point! i can explain how they work to a women in less than two minutes!
and they understand!
headsmess 1 year ago
YOU DONT KNOW A SHIT ABOUT 2STROKE PIPE. Yea, some of the exhaust gas comes back, but never to the CYLINDER AGAIN !!
I have highly tuned Malossi MHR aprilia sr50... i know almost everything
NSDwowz 1 year ago
@NSDwowz - obviously you don't know shit about the principles of 2 stroke exhaust, the gas Does come back to the cylinder again hence the cone shape at the end of the exhaust, the reverberating wave of gases aids in compression of the engine, why even have an expansion chamber otherwise, they figured that out in the 1930's jackass, read a fucking book, I'll bet you didn't finely tune anything and paid an experienced professional to do it for you. i don't see you with any videos on here.
yeoma04 1 year ago
I think that it is sad that most of the smack talkers here have no idea about the "Gospel according to Jennings". they should find a copy and read it cover-to-cover at least three times. here is a hint trash talkers....it is the red book!
circletree 1 year ago
Interesting. I've always wanted to know more about how these 2 strokes work myself. Been out of bikes for many years, but am about to be completely rebuilding a now vintage 85 to 87 Husqvarna 500XC, to get back into riding. Would love to have some idea of pipe changes, and how they might affect the power output. As well as porting mods. Not much info out there. Not many sources ever did exist for pipes for these bikes, and no real porting info. Should be fun though.
SixSpeedSS 1 year ago
I use FMF, they got it figured out pretty good. But I would like to know why The expansion chamber itself is so important rather than the taper of the tail section which controls the reverberation or the first part of the pipe that dictates the initial exhaust velocity. High pressure waves create a negative pressure (vacuum) in their wake, so is'nt the expansion chamber more dictated by engine cc"s rather than rpm range? I want to pick your brain, talk to me.............
bligrigs 1 year ago
@bligrigs According to what I read the expansion chamber / divergent cone lengthens the returning negative pressure waves so that they have a better chance of reaching the engine while the exhaust port is open. This way the negative pressure can "suck" out the exhaust gases. Longer wave = better chance that at least part of it will hit while the exhaust port is open.
Source:
How Two-Stroke Expansion Chambers Work, and Why You Should Care.
By Eric Murray , Apr. 23, 1996
TheMaverickScientist 1 year ago
@TheMaverickScientist I think a smaller diameter expansion chamber with a slightly larger diameter divergent cone pipe would give a stronger hit down low and rev out much further over the top, if only there were more room to make it a few inches longer............
bligrigs 1 year ago
How to install and use nitrous oxide lol
rebelsoutherner 1 year ago
I see most your bikes are Honda. I would like to get a expansion chamber for my Yamaha Razz. I did the jet work however it seems to have lowered my top speed to 26-28 MPH When it use to go 30-32 MPH It does seem to take off faster getting up to 20 MPH rather fast. But I would like to go 50 MPH & take hills at 30-35 Please any help would be greatly appreciated. Thank you
Xxoo0o0o0ooxX 1 year ago
@Xxoo0o0o0ooxX THere are yamaha forums with adding aluminum nicosil cylinders and stroker cranks, but I have had no personal work with yamahas.
DIOSpeedDemon 1 year ago
i assume long pipes are better for low rpms and short ones are best for high revs?
danthemanzizzle 1 year ago
This has been flagged as spam show
FOR CALHOLLI.The sonic wave is not caused by resonance, the sonic wave is caused by the fuel being ignited in the cylinder which then travels through the port and on into the header pipe at the speed of sound ( hence the SONIC wave ) the gasses then reach the first part of the expansion chamber ( the first cone ) where the super heated gas expands and creates negative pressure behind it, which helps to pull the next charge of fuel mixture into the cylinder head through the transfer ports.
hthedog 1 year ago
FOR CALHOLLI.The sonic wave is not caused by resonance, the sonic wave is caused by the fuel being ignited in the cylinder which then travels through the port and on into the header pipe at the speed of sound ( hence the SONIC wave ) the gasses then reach the first part of the expansion chamber ( the first cone ) where the super heated gas expands and creates negative pressure behind it, which helps to pull the next charge of fuel mixture into the cylinder head through the transfer ports.
hthedog 1 year ago
seems like you are shooting for the best pipe that is tuned for max revs... but I myself wouldn't want such a pipe, because I ride more trails than not.. so It all depends on what you are shooting for..... but, great video.
calholli 1 year ago
that sonic wave happens by RESONANCE..... depending on the size of your pipe, it will return at that resonant frequency... by changing the pipe size (or "tuning") .. all it is doing is plucking a different chord on a guitar, so to speak....... which makes it return at different times.... there is no, "perfect" tuning for any particular motor... because you give up one for the other in the powerband.. either strong low end torque that revs weak, or high rev power that bogs in the low end.
calholli 1 year ago
@calholli That is a simple answer. Resonant tuning in quantum physics is a little different than this easy explanation. You need to leave the answer to us experts.
DIOSpeedDemon 1 year ago
@DIOSpeedDemon .. bwhahaha... whoa.. easy there high horse... from how you explained it, and some of your other videos. your no expert... I've studied up and experimented with tuning too..... anyone can just say " yeah it takes a super computer, or a math genius"... when they don't understand the formulas... I know this much, a bigger pipe volume gives you more low end.. and a smaller pipe is more for dragging.... you can tune the pipe all you want, but it is only moving the powerband.
calholli 1 year ago
@DIOSpeedDemon You experts? Thanks, I needed a good laugh...........
goose1260 1 year ago
@DIOSpeedDemon That's BS. You don't need quantum mechanics to explain, nor to understand, resonance. Even less a resonating pipe. It's enough with helmholtz resonance.
QSQCaito 1 year ago
@QSQCaito I would challenge you or anyone to design an expansionchamber pipe to match an existing engine, from scratch. You cant do it. I am speaking of Sterlings theory of push/pull resonance factored for millisecond repeating waves. Again this is above your head. YOu sound about 3 feet tall.
DIOSpeedDemon 1 year ago
@DIOSpeedDemon Still, quantum mechanics has nothing to do with this. Don't try to complicate things even further. I have deep studies of quantum mechanics, and you really don't need them to tune a pipe. Don't try to sound smart.
QSQCaito 1 year ago
@QSQCaito You have six videos and 44 views, I have 4,000,000 views. Molecular science and laws of physics at this level work differently then you could fathom. Stick to making cover songs and leave the videos to us million users.
DIOSpeedDemon 1 year ago
@DIOSpeedDemon You see, you think a couple of views gives you knowledge. Studying gives you knowledge, not uploading videos. That's why I have knowledge, because I study. Enough to know you don't need to go quantum to explain a resonating pipe, that's just basic physics. Leave quantum and Eisenberg for what they're worth it. Limit yourself to explains things as they're and don't try to sound smart saying things that are wrong.
QSQCaito 1 year ago
@QSQCaito I'm not saying you don't know what you're talking about, but really, don't lie to viewers that trust in what they're watching.
QSQCaito 1 year ago
@QSQCaito You are really not saying much at all, time for you to take a hike.
DIOSpeedDemon 1 year ago
@QSQCaito Why dont you get the hell off of my channel and go bother someone else. You are obviously a uneducated peasant and you really need to get off my channel and get a life.
DIOSpeedDemon 1 year ago
@DIOSpeedDemon You see, people who has knowledge, answer with knowledge. People without knowledge have your kind of attitude.
QSQCaito 1 year ago
@QSQCaito Make a video to refute me, I bet you cannot. Put your money where your mouth is.
DIOSpeedDemon 1 year ago
@QSQCaito Is that you with the mini bike engine? I might have guessed it, a 15 year old asshole who thinks he knows it all. I am not going to respond to you any more, in fact I wouldn't cross the street to piss on you if you were on fire.
Scootertuner1000 1 year ago
@QSQCaito I have studied for eons. It is posers like you that talk Bullshit. Money , and Video talks, Bullshit like you , walks.
DIOSpeedDemon 1 year ago
@DIOSpeedDemon Bla bla, you are just words talking to youtube believing you are something for that. Still, to the ignorance I shall respond with silence.
QSQCaito 1 year ago
@QSQCaito Thank God for that, now get the fuck off my videos and my channel, Loser.
DIOSpeedDemon 1 year ago
@DIOSpeedDemon Don't insult. Your ignorance have been discovered, I understand that you are mad. Instead of insulting, go study.
QSQCaito 1 year ago
@QSQCaito You have to be one of the most arrogant and ill informed people I have had the misfortune of communicating with on Youtube.
Scootertuner1000 1 year ago
@DIOSpeedDemon damn dude ppl r a fuckin pain in the ass niggers talkin all this shit im 15 been working on motors for 4 or 5 years now i can do anything that duzint need pricey tools i never know how a power band workd intell your video thanks good job i put a vid up there and im goin to get bitchd at for looking bad lol
dragonballz20 1 year ago
@dragonballz20 Nothing against 15 year olds, just assholes like QSQCaito, who thinks he knows it all, but know nothing in reality.
Scootertuner1000 1 year ago
@Scootertuner1000 man i have tryd to find some one on my level but we r dieing out theres not meny left its like only 5% of the world knows how to put a carb on dude i fab weld build shape
dragonballz20 1 year ago
@QSQCaito Dud you are a complete fucking asshole. I would like to see you build a moped that is as fast as this guy's. Yiu fucking cocksucker, you haven't got a fucking clue what you are on about. This guy's scooter rocks. Fucking retard.
Scootertuner1000 1 year ago
@Scootertuner1000 You see, your knowledge equals zero. Give me a sustained reason why something I said is wrong, and we shall talk. Insults only show you are empty of knowledge. This guy has no idea the factors involved in an expansion chamber. Quantum is not needed just basic physics, something youtube users seem to lack. If you want I can recommend you some books, bye bye.
QSQCaito 1 year ago
@QSQCaito What are you talking about?? He doesn't mention quantum once, at least not that I heard. I didn't hear anything about Eisenberg either. What the hell is wrong with you. This is how an expansion chamber works exhaust system used on a two-stroke cycle engine to enhance its power output by improving its volumetric efficiency. It makes use of the energy left in the burnt exhaust exiting the cylinder to aid the filling of the cylinder for the next cycle
Scootertuner1000 1 year ago
@QSQCaito The high pressure gas exiting the cylinder initially flows in the form of a "wavefront" as all disturbances in fluids do. The exhaust gas pushes its way into the pipe which is already occupied by gas from previous cycles, pushing that gas ahead and causing a wave front. Once the gas flow itself stops, the wave continues on by passing the energy to the next gas down stream and so on to the end of the pipe.
Scootertuner1000 1 year ago
@QSQCaito If this wave encounters any change in cross section or temperature it will reflect a portion of its strength in the opposite direction to its travel. For example a high pressure wave encountering an increase in area will reflect back a low pressure wave in the opposite direction. A high pressure wave encountering a decrease in area will reflect back a high pressure wave in the opposite direction
Scootertuner1000 1 year ago
Comment removed
Scootertuner1000 1 year ago
@QSQCaito When the descending piston first exposes the exhaust port on the cylinder wall, the exhaust flows out powerfully due to its own pressure without assistance from the expansion chamber and so the diameter/area over the length of the first portion of the pipe is constant or near constant with a divergence of 0 to 2 degrees which preserves wave energy.
Scootertuner1000 1 year ago
@QSQCaito This section of the system is called the "head pipe" (the exhaust port length is considered part of the head pipe for measurement purposes). By keeping the head pipe diameter near constant, the energy in the wave is preserved because there is no expansion until needed later in the cycle. In any case the flow leaving the cylinder during most of the blowdown process is sonic or supersonic and therefore no wave could travel back into the cylinder against that flow.
Scootertuner1000 1 year ago
Comment removed
Scootertuner1000 1 year ago
@QSQCaito When the transfer is complete the piston is on the way back up on its compression stroke but the exhaust port is still open, an unavoidable problem with the two stroke design. To help prevent the piston pushing fresh mixture out the open exhaust port a strong high pressure wave from the expansion chamber is timed to arrive during the compression stroke. The port blocking wave is created by reducing the diameter of the chamber.
Scootertuner1000 1 year ago
@QSQCaito This is called the convergent section (a.k.a baffle cone or section). The outgoing high pressure wave hits the narrowing convergent section and reflects back a high pressure wave to the cylinder which arrives in time to block the port during the compression stroke and can push back into the cylinder any fresh mixture drawn out into the head pipe. The convergent section is made to converge at 8 to 90 degrees depending on requirements.
Scootertuner1000 1 year ago
@QSQCaito Combined with the high pressure wave there is a general rise in pressure in the chamber caused by deliberately restricting the outlet with a small tube called the stinger. The stinger restricts flow out of the chamber to cause higher pressure during the compression cycle and empties the chamber during the compression/power stroke to ready it for the next cycle.
Scootertuner1000 1 year ago
@QSQCaito im going to have to agree with you. i am a mechanic, and for one, it doesnt take a mathematical genious to make a good chamber. its barely intermediate math.
VforVicious 1 year ago
Also, this explaination is mediocre. FOR ANYONE who would liek to really learn 2 stroke, try wikipedia. there is an awesome GIF illustration that makes it too easy to understand
VforVicious 1 year ago
@VforVicious IF you can build one, then DO IT and put it on youtube. The mathematics for the project is far beyond you. (Learn to spell correctly before you attempt to build this pipe).
DIOSpeedDemon 1 year ago 4
@DIOSpeedDemon liek was obviously a typo. One of the main parameters involved in expansion chamber design is the speed of sound, this governs the speed of the pressure pulses that we use in the chamber. Where:-
T exc is Exhaust gas temperature in Celsius
273 added to T exc to convert to Kelvin R is 287 the Gas Constant of air in J/kgK
g is 1.4 the Specific Heat Ratio of air a 0 is the speed of sound in m/s
Scootertuner1000 1 year ago
This has been flagged as spam show
@DIOSpeedDemon liek was obviously a typo. One of the main parameters involved in expansion chamber design is the speed of sound, this governs the speed of the pressure pulses that we use in the chamber. Where:-
T exc is Exhaust gas temperature in Celsius
273 added to T exc to convert to Kelvin R is 287 the Gas Constant of air in J/kgK
g is 1.4 the Specific Heat Ratio of air a 0 is the speed of sound in m/s.
Scootertuner1000 1 year ago
@DIOSpeedDemon BMEP is used in several of the expansion chamber design parameters, and is calculated as shown. Where:- kW is engine power, kW (1bhp=746W) SVcc is swept volume, cc RPM is engine speed, rpm BMEP is in Bar
Scootertuner1000 1 year ago
@DIOSpeedDemon Tuned Length of the Expansion Chamber
Blair’s formula assumes that the tuned length of the expansion chamber is from the face of the piston to the beginning of the stinger and is given by the formula below. Where:- L t is tuned length, mm 83.3 = metric constant
A 0 is speed of sound in m/s Q ep is exhaust duration, degrees.
Scootertuner1000 1 year ago
@DIOSpeedDemon Effective Exhaust Diameter (EXD)
This is the diameter of a pipe whose area matches that of the exhaust port. Where:- EXD is effective diameter, mm Width is port width, mm
Height is port height, mm
Scootertuner1000 1 year ago
@DIOSpeedDemon The best and easiest way to calculate the dimension you need is to by expansion chamber design software. It will work it all out for you and you simply build what the software tells you to.
Scootertuner1000 1 year ago
@VforVicious What is Blair's formula?
Scootertuner1000 1 year ago
Everybody go to worldwidetriples and find the animated video of all of this actually working. You will stare at it for a long time !!
twostrokeornill1 1 year ago
Its not A super charge effect as you say...but using the waves as measured in Mil/sec....tuning by wave dies not in crease power so much as it tunes the the point where at the moment the finale charge is about to exit the cylinder through the power valve At that tuned moment as you say instead of supercharge..Its more like A mil/sec valve...in that it blocks the gas/air mix from venting with the spent gasses...although some fuel does get out...
motoman9477 1 year ago
@motoman9477 From what Ive read, ex. chambers create a vacuum, so imagine a supercharger sucking burnt gasses OUT, instead of blowing air/fuel mixture IN, so really its a turbo effect. It all comes down to a larger evacuation volume with a turbo.
60spastlife 1 year ago
@60spastlife A turbo has nothing to do with evacuation,in fact A turbo blocks exaust flow.but uses it to drive more gas/air charge into the combustion...It is in no way like A turbo...it is more or less the same as comparing long vs short headers.... long tube headers give the same effect.your understanding is off...
motoman9477 1 year ago
Yeah, dont know what i was thinkin lol
60spastlife 1 year ago
@60spastlife You are half way correct but you did not go far enough. The resonance wave also pulls more fuel into the combustion chamber as it is sucking out spent gas. This creates a bigger bang, hence more power. I have many different pipes and they all work differently on motor rpm's.
DIOSpeedDemon 1 year ago
@motoman9477 It provides for more fuel and air to be burned in a given engine and this is a supercharged effect according to the immutable laws of creating horsepower.
DIOSpeedDemon 1 year ago
by creating a pulse that leaves a low preassure in its wake, isnt that "suck"? Same concept as how a carb works utilizing low pressure.
SRT480 1 year ago
@SRT480 This is correct, but unlike the carb, the pipe expansion chamber can be manufactured to different lengths, or "tuned". This tuning allows the pressure wave to be longer or shorter, in milliseconds, and created a different power range for the motor. That is why alot of after market pipes look different from each other. They create power at different "set" rpm's.
DIOSpeedDemon 1 year ago
@DIOSpeedDemon Ive also noticed all of my life, that they not only look different, but sound different, dur to reasons stated already. Hell...just callme mr. obvious i guess.
60spastlife 1 year ago
a note: the exhaust doesnt 'suck' out the gases, they are
'pushed' out by the incoming fuel-air mixture that was compressed in the crankcase.
suz384 1 year ago
@suz384 Just a note:: The exhaust gases work exactly as I say they do, because #1 Rule- I am never wrong. #2: "see rule no.1".
DIOSpeedDemon 1 year ago
@suz384 No dude, if the exhaust is designed propery not only are the gasses pushed out but the exhaust pulls it out and then when the resonance wave hits the rear end of the reverse cone, it bounces the pulse (sound wave) back at just the right time to stop the new change going out with the exhaust. Time it just right and the fresh charge that goes out the exhaust is pushed back in.
Scootertuner1000 1 year ago
for a exhaust to work properly you need the port map ( where the ports are in the barrel) the dimentions determine the shape and size of the pipe to work to its maximum , a shorter front pipe will make the rev band higher. over the counter pipes give a good compromise , but you can improve on them by designing your own.
cronauer1985 1 year ago
@cronauer1985 I have the top of the line port mapping two stroke software. Check out my video on it and where to download from the genius that built it.
DIOSpeedDemon 1 year ago
i would buy that sweet exhaust i would
hanghoodiescum 1 year ago
yeah...i was planyng on editing the comm...but you get my idea...no offence again
freshmakerr 1 year ago
no offence man...but you're not realy goof at explayning....
freshmakerr 1 year ago
@freshmakerr no offence man...but you're not realy guud at spellingg...
DIOSpeedDemon 1 year ago
hey dsd is that the v8 expansion chamber you can get on ebay? and what do you think of the leo vince expansion chamber zx pipe for a 72cc kit
645shaiboy 1 year ago
@645shaiboy The expansion chamber was sold to me as just a big pipe for over 100cc engine. Any Leo Vince pipe you can get is excellent. I have had a few, but they are rare for American Elite engines. If you can find one, buy it and dont let it go. They make smaller expansion pipes for your size and the trick is to find the right one for your riding style.
DIOSpeedDemon 1 year ago
hey can you answer some questions about the 2 stroke muffler? email me back
RUSSELL826 1 year ago
I like you :-)
cosast54 1 year ago
to find the perfect video is named "pre-procution" planning camera shots, words, material etc. "spontaneous" video is named documental and is intended to capture situations not controled, so, pre-produce and try to document
youutubestinks 1 year ago
@youutubestinks I shoot all of my videos in one shot with just a basic premise in my mind. I call that spontaneous as the videos are not cut, polished, edited or tampered with in any way. You will notice in all my 520 videos, there are no special effects, because I simply dont know how to do it. 3 million views so far from a man with no camera training, no acting training, no voice training, no story telling training. I should make movies for the big screen.
DIOSpeedDemon 1 year ago
@youutubestinks Except documental is not a word and neither is pre-procution.
nilbud 6 months ago
hmm zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
sory i fell asleep!
cosast54 1 year ago
@cosast54 Hey- WAKE THE FUCK UP!!!!!!
DIOSpeedDemon 1 year ago
If one had the tooling to make each section telescopic a few mm, then one could messure the final output of HP to see the results of expansion chamber.
Or spend 50k for some.
What might be a second find, is complex squeeze baffling inside combined with reflector plates.
2 stroke have a place, but it's getting to a point to where 4 stroke is just twice the results & easier to solve w/o so much wasted fuel, noise, smoke.
Your video is very well done to explain this complex feature. Cheers.
Philscbx 1 year ago
This is just my simple explanation.The actual physics and sound wave calculus figures are easy to talk about, but it is like building a working space shuttle to actually build one by hand.
DIOSpeedDemon 1 year ago
Thank you , i always wondered why 2 strokes ran better with them on then off.
Hollrobb 1 year ago
iv never really thought about it but always thought it was just a little back pressure to keep some of the unburned fuel and pressure in the cylinder
lane83180 1 year ago
Hey, watched most of your videos and you've explained everything so clearly. Was just wondering if your scooter project has finished and do you have a video of it running?
A13X0001 1 year ago
@A13X0001 The 120cc Dio is running but my new blue repsol panels are not installed due to cold weather. I have to have patience during cold weather for base coat, primary coat, and clear coat drying. I will make a video soon as it is put together.
DIOSpeedDemon 1 year ago
@A13X0001 The 120cc Dio is running but my new blue repsol panels are not installed due to cold weather. I have to have patience during cold weather for base coat, primary coat, and clear coat drying. I will make a video soon as it is put together.
DIOSpeedDemon 1 year ago
To be honest, it would take an engineer with a calculus degree to explain how this work. It takes a super computer to even design these pipes for a given bike, say a honda cr125. The equations for this design would give Einstein a run for his money. I am speaking simply how the pipe works, but it is almost as complicated as the space shuttle to build one from scratch and have it actually work as desired. Its invention at all was a miracle. RH DSD
DIOSpeedDemon 1 year ago
is this a scooter engine?
moraisinimputavel 2 years ago
This is a highly modified Honda 50cc engine.
DIOSpeedDemon 2 years ago
@DIOSpeedDemon
Have you checked out the Bi-zeta 50cc engines? I used to race minimoto, we were getting 18.5hp from a 50cc. I now run a hybrid engine using a Polini bottom end mated to a BZM cylinder. The cylinder is an exact miniature copy of a TZ 250 GP cylinder, they are a work of art.
SPOOKSTR 2 years ago
Randy,
So as you explained it, basically you do not need the blue muffler for the backpressure theory to work ?
I recently bought an old 2 stroke dirtbike, without a muffler and was told by my auto tech teacher ( Im 16), that I would need a muffler, for the backpressure to fully work. But in this case it seems as I don't need it ?
Any help would be nice, thanks :)
Honda4wheelin 2 years ago
I believe you need a muffler, remember I am not a sonic wave engineer here. I would always use a muffler as it does not let the expansion chamber wave dissipate so quickly.
DIOSpeedDemon 1 year ago
oh okay I see, thanks for the help!
Honda4wheelin 1 year ago
Nicee video
northlondonsfinest1 2 years ago
Good video but please script your dialogue so things are a little clearer. Again good video.
lakewood85 2 years ago
Yet again, exellent video that teaches alot of us ALOT :)
FrostbornX 2 years ago
interesting to fing out how the chamber works mate nice one
CR125MANIAC 2 years ago
you should look into dutch and french scootersites, they have real fast scooters. They know how to put 20.000rpm and up to 24 hp from a 70cc 2stroke engine
btroost1984 2 years ago 3
@btroost1984
See my vids on ''motolites'' i run an 80cc Honda CR engine, its putting out just over 30hp at the rear wheel.
Good vid too by the way.
SPOOKSTR 2 years ago
@btroost1984 Yes and even higher hp with nitrous oxide.
dnbwriter 1 year ago
do you no what the compression ratio is on this engine?
micheals1992 2 years ago
I do not, I should look into that, good idea.
DIOSpeedDemon 2 years ago
the sonic/sound wave travels down the pipe? dont you mean the pressure from the detonation? suckion from the piston going down? dont you mean its compressed by the piston in the crank casing and when the ports are uncovered its forced in? its sucking? dont you mean its scavenging the exhaust gasses for higher compression? i do no what your saying though
micheals1992 2 years ago
sorry you got the superchaging effect (higher compression almost right you was just a little off its just a little after the intake ports are opened you only get 1 back pressure effect per turn and like you was saying it goes on how fat and long it is to what rpm range you get the superchaging effect (i have mine between 3000-4000rpm then the power drops off steeply. the boost pressure you get is a bit like turbo lag when it kicks in you get a massive cough of power.
micheals1992 2 years ago
obviously its nothing like a turbo apart from it giving you more compression. the best idea i have seen is a variable expansion chamber that slides out for lower revs and slides back for higher revs but that kind of technology has passed by because 2strokes are getting outlawed in most countrys so theres not really any investment finatialy viable
micheals1992 2 years ago
A turbo or belt supercharger, does the same thing= they force more air and fuel thru an engine, creating more horsepower. There methods are different but the outcome is the same. The expansion chamber in a pipe has the same effect as the top two, to a different degree. It forces more fuel and air thru the motor, not through over-pressure, but thru vacuum effect. The end is all the same, more horsepower. RH DSD
DIOSpeedDemon 2 years ago
and previously you were telling people the function of an expansion chamber was to return gasses from the pipe,wrong.
gilessmokey 1 year ago
WRONG??? Ok, why dont you explain the way the pipe works and correct this old man? Bet you wont do it. I am waiting......RH DSD
DIOSpeedDemon 1 year ago
find out for yourself,but one thing i will tell you is that the function of an tuned pipe is not to return gasses as you have stated on you tube. do you think a pipe can halt and return rapidly exiting exhaust gasses and separate and return just a fresh charge? and against a upmoving piston?
gilessmokey 1 year ago
Find out for myself? That is a coward answer. You tell us how it works then. Write it right here on this channel. I bet you cant because your all talk. I knew it.
DIOSpeedDemon 1 year ago
high there again,what i dont like is misinformation put out on u tube, you are starting myths
gilessmokey 1 year ago
gilessmokey.
If it's a myth, it's an old one.
johnsenkenn 1 year ago
@gilessmokey You're funny. Ever heard of a reflected pressure wave? You can't say the exhaust is a constant pressure and velocity...since the engine isn't putting out exhaust all 360 degrees of rotation.
akromix 1 year ago
@akromix tell us some more,how it works and what it achieves
gilessmokey 1 year ago
@gilessmokey you're the smart one here. Use google genius.
akromix 1 year ago
stop picking fault with the guy mate he's trying to hel people out it works a lot like a turbo mate the idea's and principles are very similar. but i will say you both need to stop calling those transfer ports inlet ports!!! lol
leicestergux 2 years ago
Michael , I appreciate you finding my flaws with this theory and correcting me. I completely rebuilt a 1966 chevy turbo corvair with a flat-six and 180 Horsepower. The cartridge, turbine and impeller were all Rajay inc. When I was 17, I built a 800 horsepower 1968 SS camaro with 427 Cubic inches. Mated to a Weiland full race blower manifold, Cragar three inch belt drive, 6-71 blower, 2 Holley 660 center squirt carbs. This stuck out of my Z-28 hood, 18 inches. I KNOW OF WHAT I SPEAK...RH DSD
DIOSpeedDemon 2 years ago
I also have pictures of my supercharging work of 30 years ago, when I was a young man, if you would like to see and discuss them. My facts are based in the field, not in some discussion group from a library. RH DSD
DIOSpeedDemon 2 years ago
i dint really mean to question your knowledge on engines sorry about that i no people who find stuff hard to put into words but when it comes to engines there the best i am learning at collage at the momment. i guarantee you know more about diagnostics and engine building then me. i do understand why you feel that way tho because i wouldnt like a student correcting me or a random person when i have been doing it for 30years when they have only been doing it for 3 years
micheals1992 2 years ago
Son, we are all students and never stop learning. I have alot of people dissing my little hobby like I am building the space shuttle or nasa rocket. It is just a moped. Go out and learn everything from as many people as possible and keep an open mind. If three out of four people tell you the same answer to your question then its probably close to the truth. No disrespect taken. RESPECT= RH DSD
DIOSpeedDemon 2 years ago
@DIOSpeedDemon
And now that you're done beating your drum, which of those had an expansion chamber?
JuniorHRP 2 years ago
non of them two strokes
gilessmokey 1 year ago
i use to have a suzuki road bike which i read on the fiekds it was a 100cc and i put a 50cc motocross exhaust on it. and it sounded like a super bike im sure it went faster aswell
hurryingj 2 years ago
I have a 76 RM 250 suzuki, ive seen afternarket pipes, but i learned that only the stock pipe wil make it run right, and not an aftermarket one that loooks good but is wrong for the engine,
I saw the piston in the bore,
its ok looking,
not burned .
020 size, but it loooked like it had no compression,
but the bore gasket and the head gasket were missing,
so that might have something to do with it,
kirkconway 2 years ago
is this a tuned pipe?
datzfast 2 years ago
I let the professinals take care of my expansion Chambers J&R are the folks that got me to victory circle more times than I can remember.
Giminey 2 years ago
So in effect the pipe is "Tuned" to give varius levels of performance ?
auto4union 2 years ago
The way I understand it, is the pipe is tuned for a certain rpm level. Say one for top end , another for bottom end. You dont really gain overall power, the tuned pipe just directs power to your application, lets say track racing versus drag racing. RH DSD
DIOSpeedDemon 2 years ago
chambers even help to suck through transfers, they blow back charge lost through exhaust and suck before exhaust is open to help scavenge.
a high pressure pulse has momentum, when the pulse stops its momentum creates a pressure drop, this pulse is also reflected back from stinger to coincide with blowing lost charge back in.
Very hard to explain on videos, my mind goes blank!
Your bike sounds like it needs more top end power although it will be reliable.
tpvalley 2 years ago
The expansion chamber is just that -- a back-pressure generating chamber which pressurizes the cylinder between strokes as there are no valves on a 2 stroke engine, using heat expansion principles to generate back pressure as the gases exit the chamber.
Sanosuke004 2 years ago
so the pipe is like a Cam in a 4 stroke right it Determinants where you power band is.
seroyer2 3 years ago
for the most part, yeah
i know if i have a very large diamater short stinger on my engine, i have i very short but very powerful powerband in the high rpm range
long and more narrow, much wider
slide4squad 2 years ago
I have a ported Honda Aero 125 with a 55mm bore, stock stroke, domed piston. I can modify a Dio exhaust to fit. I need a nice chamber exhaust and I will get a Dio Intake and reeds and OKO 28 or 30 MM carb with power jet. What kind of pipe do you recommend? The bike pulls to 50 on straights and 60 downhill, but it starves for gas after 30 seconds of full-throttle, even with a 230 jet. I know the carb is inadequate. What pipe would be good? It can't be too loud, but needs nice top end.
kidznscooters 3 years ago