Two stroke performance tuning chapter 3 porting and cylinder scavenging today, when we take a look down the cylinder of a two stroke engine, we find its walls literally filled with ports to handle the induction, transfer and exhaust phases of gas flow through the engine. There are many ways to boost the power, one of which is by installing a tuned pipe. We will include automatic pipe squelton and cad support in order to have. How a 2 stroke works your 2 stroke motor is an air pump. Follow the link to my software site and go to the 2t exhaust calc menu item and download either the stand alone program or a installer package. The diameter is the internal diameter of the exhaust flange.
The calculations are assuming a speed of sound in the exhaust gas, which is not known exactly. There is software out there that will help you immensely with your calculations on timing. When we got it right we would have an exhaust pipe that would carry a positive pressure wave of exhaust pulse down the pipe to the open end. Improve the performance of your two stroke engine with a torqsoft designed exhaust system. Calculate the needed exhaust and transfer port durations to match the desired peak power rpm. Each intake port can be locked to a fixed timing relation with the exhaust. How to bend a conetwo stroke pipe model solidworks forums.
This is the place to talk about anything related to two stroke road race bikes. Assign fixed relationships between transfers and exhaust port. Here are some useful resources with several 2 stroke porting theories and formulas. Two stroke exhaust pattern if i were doing this the first thing i would do is model the entire design as a single solid body no wall thickness, no separate components. New feature of racingsm software, the 2 stroke exhaust segment splitter. Mota software, 2 stroke engine simulation software, 2 stroke exhaust design.
After our trial and test, the software was found to be official, secure and free. Each cone is hand cut, pounded and welded to our stringent manufacturing guidelines. The objectives of this project are to study, develop and maybe sell a software for pipe designing. But because of the limited worldwide activity in two stroke engine development, program sales were limited and further development was curtailed. This is often called the dynamic compression ratio.
You can also save and load the data by using the provided functions. How eccalc agrees with the real life exhaust pressure graphs from blair. Calculates port heights from durations, or durations from port heights. Since modifying the 2 stroke engines require not only a big. Pro circuit has built a reputation around our exhaust systems. The exhaust port opens and combustion gas starts down the pipe at supersonic speeds.
This is the length from the piston face to the end of the exhaust flange. The inputs will be engine specification and the outputs will be pipe dimensions. Design and simulation of two stroke engines gordon p. Why trajectory is important in 2 stroke porting, scavenging. You should only rely on the experience of the very best. On a two stroke engine, an expansion chamber or tuned pipe is a tuned exhaust system used to enhance its power output by improving its volumetric efficiency history. 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. Changing the power of 2stroke engine is really very simple when you know the basic techniques of 2 stroke engines. By rayivers, november 5, 2009 in motorcycle engineering. In either mode you can enter values for the exhaust, and main transfers by right mouse click from the durations vs rpm graph. For port work, one company that will help you is 2 stroke porting. Our goal is to achieve the biggest power gains as possible, while maintaining reliability on your 2 stroke engine. North american twostrokes general two stroke discussion. The worlds leading 2stroke engine simulation software for 3.
Near the end you will be presented with the latest and best software for design and analysis of 2 stroke pipes. Direct comparison between different types of exhausts for the two stroke engine, on the left you can see the engine and its. This is not a rehash of the old outdated port timearea formulas but rather it relies on the true blowdown time the time it takes for the exhaust pulse to go. Great tool for those who are building exquisite format exhausts, one of the largest benefits of this module is that it can be used with any exhaust formula results. Scalvini two stroke factory works pipes are handassembled conebycone to make an exhaust that looks as good as it performs. Split your calculated 2 stroke exhaust up to 42 sections with regular length or even more with irregular lengths. My professional 2 stroke expansion chamber design software is more sophisticated than other programs that only use a few basic formulas. However, you shouldnt just pick any business that you can find anywhere. He is a master pipe welder and has software based on the engine parameters that will make a pipe that will work. The following are spreadsheets for different aspects of 2 stroke design modification.
This coefficient kh is called the horn coefficient, with typical values between one and two. Discussion in 2 smokers started by dorkpunch, jan 28, 2011. I guess 2 stroke exhaust system design is all about tradeoffs, and i. This is your opportunity to have a real works pipe and performance without the expense associated with parts of this caliber. We also have a simple 2stroke expansion chamber design program. This cylinder has two exhaust ports and five transfer ports so enter 2 in the no. So whether you have a 50cc road bike, a 500cc motocrosser or a classic racer, we will design the perfect exhaust. Performance fabrications is dedicated to manufacturing the finest bespoke hand crafted exhaust systems available. This phenomenon was first discovered in the 1950s by walter kaaden, who was working at the east german company mz. The way a two stroke motor works causes them to be f. How twostroke expansion chambers work, and why you should. For a 2 stroke engine the tuned pipe is the section of the exhaust system that begins at the exhaust port and ends at.
Scooter exhaust with expansion chamber and silencer. Twostroke waveaction engine simulation motion software. Its pretty easy to identify a 2 stroke exhaust design from a 4 stroke exhaust. In a two stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust or scavenging functions occurring at the same time. Enter this data into the compression ratio programme as shown. Once i have that completed i would understand the geometry that i need and have an envelopescaffold defining the geometry. We shall send you a pdf document with the templates for manufacturing your exhaust. Lots of calculations needed, exhaust duration, exhaust port diameter desired rpm for peak power etc. Two stroke engine and exhaust design software north. Most of the errors is to choose a less appropriate combination of engine components so that the engine actually ran worse than standart, ever experienced. The resultant trapped compression ratio is calculated as 8.
These are the files that can function manually without using. This software covers the 3 stage diffuser type expansion chamber exhaust as per equations provided in his book entitled design and simulation of two stroke engines published in 1996. Those of us who have grown up in the japanese two stroke. A simple 3 stage two stroke exhaust calculator based on formulas of g.
The businesses and individuals that purchased the original dynomation 2 stroke program were pleased with the capability and accuracy of the software. The graph is a plot of port durations vs rpm from a. So now i will build a expansion exhaust for my ported and modified yamaha tzr250 tuned cafe racer using this program. Featured items newest items bestselling alphabetical. The software is called 2 stroke wizard, bought it here. How to pick the best 2stroke exhaust for your dirt bike. We use computer design software to maximize power and torque at any elevation. Small values of kh are best suited to grand prix engines with narrow power bands, larger. Free 2 stroke expansion chamber calculator software update.
Engineering acousticssonic supercharging of 2 stroke. New feature of racingsm software, the 2stroke exhaust segment splitter. Our goal is to protect you from all the mental roost thrown your way so you can make an informed decision on the best 2 stroke exhaust system for your ride. Here is the official description for 2 stroke wizard tuned pipe. For introductory material on 2 stroke engines please see the following links. There it would collapse and create a negative pressure wave that. Cold rolled sheet metal i used 18 gaugelots of welding rod i used a 110v wire feed welderrubber stoppers for isolation. Racingsm software 2stroke exhaust calculator lufo youtube. Look very good and i understand this program gave excellent performing pipes to others. An engines exhaust port can be thought of as a sound generator. Method 1 and method 2 two and three stage diffuser.
The official home page of our 2 stroke wizard tuned pipe. They are so simple and fun that ive always enjoyed tinkering with them. Good evening folks, i have been trying to make a two stroke exhaust, and would like to use solidworks to curve all the conic sections, because doing this. Two stroke engines often have a high powertoweight ratio, power being available in a narrow range of rotational speeds called the power. Kaaden understood that there was power in the sound waves coming from the exhaust system, and opened up a whole new field in two stroke theory and tuning. If you are aiming for these qualities, modifying your 2 stroke engine is a great strategy. If youre looking to upgrade or replace the exhaust system on your 2 stroke youve come to the right place. Split your calculated 2stroke exhaust up to 42 sections with regular length or even more with irregular lengths. The software does complete cycle simulation of the whole internal combustion process including the gasdynamics in the pipesducts, ports and plenums air boxes, boost bottles, exhaust boxes etc. The revisions were to be so extensive on the authors the basic design of two stroke engines that what was to be a second edition evolved into a new book. This is one of the reasons why the ignition timing needs to be reduced with higher crank speed in a 2 stroke engine. It will simulate one of the cylinders of a multicylinder two stroke engine provided that the cylinders are identical in layout and dimensions and each cylinder has a seperate exhaust and induction system.