Dynomatontwostroke is a dosbased simulation that was originally released in the mid1990s. One other old way of calculating the dimensions of an expansion chamber relied on generic formulas that put the emphasis on the wrong things. Expansion chamber calculations by an excel workbook file. Software for fine tuning and design of two stroke engine.
How twostroke expansion chambers work, and why you should care. Free download here this program is not a part of mota, but it has been put together by the same engineers as a starting point for those wishing to begin from scratch. With the traditional lubrication technique of mixing oil into the fuel, they also have the advantage of working in any orientation, as there is no oil reservoir dependent on gravity. Direct comparison between different types of exhausts for the two stroke engine, on the left you can see the engine and its exhaust, in the.
Nov 02, 2019 for further investigate of the operation of two stroke engines with tuned exhaust pipes it is most appropriate to analyze actual test data. 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. Free 2 stroke expansion chamber calculator software update. The software uses mathematical formulas that are approximations of reality, and the. The arrangement of the intake and exhaust ports in a two cycle engine affords a unique opportunity to use the exhaust system to influence the intake sequence.
Building your own racing expansion chambers rdrz 350 ypvs why should i even bother making them. Engineering acousticssonic supercharging of 2 stroke. New version of 2t exhaust calculator it is a freeware 2 stroke expansion chamber exhaust calculator program download at. This software covers the 3 stage diffuser type expansion chamber exhaust as per equations provided in his book entitled design and simulation of twostroke engines published in 1996. The arrangement of the intake and exhaust ports in a two cycle engine affords a unique opportunity to use. I didnt like bimotions pipe design software so i bought and used yours. As the forces in a twostroke pipe design have become more wellunderstood, designers have been able to create engines that take more advantage of them and in fact require an expansion chamber to run at all. The software uses mathematical formulas that are approximations of reality, and the software made for homecomputers uses even more simplified formulas because good simulation of expansion chambers requires much more. A complete twostroke pipe has properly tuned header, convergent, belly, divergent and stinger sectionsa difficult process. Varying 2stroke stinger diameter motorcycle engineering. Exhaust pipe muffler for 2 stroke 47cc 49cc engine mini pocket bike condition. File type pdf two stroke engine expansion chamber design software two stroke engine expansion chamber design software unlocking the secrets of 2 stroke expansion chamber exhausts e1 this is the first video in a series looking at the science and mysteries of 2. Direct comparison between different types of exhausts for the twostroke engine, on the left you can see the engine and its exhaust, in the. Racingsm software has features for many different areas 2 stroke exhausts development, drag racing features, simulators, carburetor tuning, connectingrod analysis etc with all this knowhow along with lufo racing heritage, we believe this is a very fair price.
Each page of this document contains the template for fabricating the exhaust. How twostroke expansion chambers work, and why you should. Improve the performance of your twostroke engine with a torqsoft designed exhaust system. Building your own racing expansion chambers rdrz 350 ypvs.
Additions to the expansion chamber construction utilities the expansion chamber construction utilities have been extended considerably and are now accessed under a separate item on the main mota menu. How to plot two stroke expansion chamber cones on paper from. An expansion chamber is an exhaust system used on a twostroke cycle engine to enhance its poweroutput by improving its volumetric efficiency. Two stroke designmodification software the following are spreadsheets for different aspects of 2 stroke designmodification. Two stroke tuning by alexander graham bell excellent book. So whether you have a 50cc road bike, a 500cc motocrosser or a classic racer. As the forces in a two stroke pipe design have become more wellunderstood, designers have been able to create engines that take more advantage of them and in fact require an expansion chamber to run at all. We also have a simple 2stroke expansion chamber design program. Racingsm software has features for many different areas 2stroke exhausts development, drag racing features, simulators, carburetor tuning, connectingrod analysis etc with all this knowhow along with lufo racing heritage, we believe this is a very fair price.
Its a good book to start with if you want to understand how a twostroke engine including exhaust works. Two stroke engine and exhaust design software post by dawid. If you really found out what goes on with expansion chambers, you know its a fairly complicated thing. One last thing regarding design, computer software can help you with the design, but dont expect superdesign from the software. This program calculates the dimensions for both double and triple stage diffuser expansion chambers from a few basic engine dimensions. Moreover you can have advices for the development of the engine thanks to the help of tested formulas for intake, exhaust, blowdown and transfer. Jan 15, 2005 megaphone exhausts are the four stroke equivalent of an expansion chamber, in that they are tuned to utilize the pressure pulses of the exhaust flow to increase exhaust scavenging and hp.
A racing engine exhaust system uses an expansion chamber at the end of the pipe which is basically two cones that reverse themselves prior to the end stinger where the spent exhaust is allowed to exit the chamber. Multiple dual exhaust pipes were simulated using virtual 2stroke software to find the optimal single. Two stroke petrol engines are preferred when mechanical simplicity, light weight, and high powertoweight ratio are design priorities. The placement and shape of the forward cone generates vaccuum to help drag out the old, spent charge and help pull the fresh charge up from the cases while the transfer and exhaust ports are all open scavenging. Sonicspeed shock waves are timed to arrive just in time to stuff the fuelair that escaped through the twostrokes exhaust port back into the cylinder just before closing four stroke exhausts can work in similar ways, but because the fourstroke is more like a positive pump, and not. The exhaust designer programme enables the user to design a twostroke exhaust system with ease, then with one click of the mouse, create a pdf document in any of the common paper sizes a4, a3, letter. So whether you have a 50cc road bike, a 500cc motocrosser or a classic racer, we will design the perfect exhaust system for you. We also have a simple 2 stroke expansion chamber design program. Advanced two stroke tuned exhaust system the challenge the society of automotive engineers clean snowmobile challenge 2002 sae csc 2002 is an engineering design competition for college and university student members of the society of automotive engineers sae. It would be outstanding to use a temp slippy to finetune a design before committing to a center section length i.
Thank you for your interest in dynomationtwostroke designed for windows98xp. Two stroke design modification software the following are spreadsheets for different aspects of 2 stroke design modification. Jan 28, 2011 i bought an expansion chamber design program, and it produced numbers more in line with what i though i should have from what ive been reading. Without a pair of really good chambers you will never get much power from you rd 350 ypvs. So i put formulas based on that in an excel workbook file to analyze an existing expansion chamber, or help design a new one. Any donations greatly appreciated, please use paypal link. The businesses and individuals that purchased the original dynomation 2 stroke program were pleased with the capability and accuracy of the software. You can also save and load the data by using the provided functions.
To learn more about how expansion chamber exhaust systems work, read this great primer. Engineering acousticssonic supercharging of 2 stroke engines. Software for fine tuning and design of two stroke engine by. The exhaust designer programme enables the user to design a two stroke exhaust system with ease, then with one click of the mouse, create a pdf document in any of the common paper sizes a4, a3, letter.
By rayivers, november 5, 2009 in motorcycle engineering. Just a quick update on the progress of the freeware 2 stroke expansion chamber calculator software. For further investigate of the operation of twostroke engines with tuned exhaust pipes it is most appropriate to analyze actual test data. Fourstroke expansion chambers general dirt bike discussion.
A submenu offers the two selections constructing the development pattern of a cone and printing the development pattern of a cone. Torqsoft twostroke exhaust system designer programme. We shall send you a pdf document with the templates for manufacturing your exhaust. It also took a solid month or two for me to learn the factors involved and how to maximize the tuning. The program takes your info and spits out a sheet with lengths and diameters. We now have a simple 2 stroke expansion chamber design program. He reportedly said youll know when you have the design right, because the chamber will then be impossible to fit on the motorcycle without having it drag the ground, burn the riders leg, or.
For this we can go to the tfx website where they demonstrate their testing and data analysis software, or read the paper referenced below titled exhaust gas flow behavior in a twostroke engine. I believe this scavenging effect is tuned to a specific rpm range, the megaphone may reduce power somewhat outside the tuned range. Bigger carburetors, higher compression ratios, altered port timings and expansion. Very simplified explained, a good expansion chamber works like this.
Method 1 and method 2 two and three stage diffuser. A complete two stroke pipe has properly tuned header, convergent, belly, divergent and stinger sectionsa difficult process. Blair of queens university belfast, and published by the society of automotive. The size at the cylinder also has to be larger then 90% of the pipes out there. But because of the limited worldwide activity in twostroke engine development, program sales were limited and further development was curtailed. Two stroke engine and exhaust design software post by dawid sat jan 16, 2016 7. For a 2 stroke engine the tuned pipe is the section of the exhaust system that 2 stroke wizard tuned pipe design software ian williams tuning 15 replies. Jan 23, 2019 2 stroke exhaust expansion chamber calculator using 3 methods. Two stroke engine expansion chamber design software. Two stroke tuners handbook 2 another mistake commonly made, sometimes even by those who have enjoyed some success in modifying twostroke engines, is to believe in a kind of mechanistic magic. Npp neils power pipes handcrafted custom pipes and. I have plans this winter to put my yz 125 motor in it but i would like to see how this little motor runs with a good pipe vs the stock one that i think is holding it back. For this we can go to the tfx website where they demonstrate their testing and data analysis software, or read the paper referenced below titled exhaust gas flow behavior in a two stroke engine.
The expansion chamber is the most tunable component on the modern two cycle engine and dramatic gains in power can be achieved with the correct design. Performance fabrications is dedicated to manufacturing the finest bespoke hand crafted exhaust systems available. I guess 2 stroke exhaust system design is all about tradeoffs, and i think for woods riding it may be better to lose unburnt charge out the tailpipe at high rpm longer pipe then push burnt gases back into the motor at low rpm shorter, but thats just my totally nonexpert opinion. I bought an expansion chamber design program, and it produced numbers more in line with what i though i should have from what ive been reading. This coefficient kh is called the horn coefficient, with typical values between one and two. That sort of expansion chamber creates a very strong positive wave reflection back up the exhaust pipe, and this positive pulse. Exhaust pipe design with cone layout software by paul crowe if you have ever tried to layout a conic section on sheet metal, cutting just the right piece, that when rolled over and joined on edge, you have a cone with the exact shape, size and angled openings desired, you know its not easy. How to design a two stroke expansion chamber performance exhaust step 2. The chambers is the single most important thing when it comes to tuning the 2 stroke engine. The calculations are assuming a speed of sound in the exhaust gas, which is not known exactly. Twostroke petrol engines are preferred when mechanical simplicity, light weight, and high powertoweight ratio are design priorities. Jul 25, 2007 exhaust pipe design with cone layout software by paul crowe if you have ever tried to layout a conic section on sheet metal, cutting just the right piece, that when rolled over and joined on edge, you have a cone with the exact shape, size and angled openings desired, you know its not easy. The shape of a 2t expansion chamber works kissncousins to a supercharger, with no mechanical moving parts. This will get you started by providing, for your engine, the dimensions of an expansion.
On a twostroke engine, an expansion chamber or tuned pipe is a tuned exhaust system used to enhance its power output by improving its volumetric efficiency. Freeware 2 stroke expansion chamber exhaust calculator program. It is the twostroke equivalent of the tuned pipes or headers used on fourstroke cycle engines. My professional 2 stroke expansion chamber design software is more sophisticated than other programs that only use a few basic formulas. The intent of the competition is to provide universities with an. Two stroke design instead you can enter the data of your cylinder with extreme facility and precision, and then analyze the port areas and the timing area in the engine cycle timing for each phase. May 03, 2018 how to design a two stroke expansion chamber performance exhaust step 2. Calculator mention in video sent to me by nico as called cone layout. File type pdf two stroke engine expansion chamber design software two stroke engine expansion chamber design software unlocking the secrets of 2 stroke expansion chamber exhausts e1 this is the first video in a series looking at the science and mysteries of 2 stroke expansion chamber exhausts.
Expansion chamber design virtual 2stroke engine simulation. This small java applet uses design rules according to, and, to size a tuned pipe for a 2 stroke piston engine. Two stroke engine and exhaust design software north. Improve the performance of your two stroke engine with a torqsoft designed exhaust system. The information used in the programs calculations was taken from the books the basic design of the two stroke engine and design and simulation of two stroke engines. How to design a two stroke expansion chamber performance. In a twostroke engine, every stroke leaving top dead. Dans motorcycle two stroke motorcycle exhaust pipes. A simple 3 stage two stroke exhaust calculator based on formulas of g.
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