The complete engine geometry together with these two exhaust systems is simulated using an engine simulation software package virtual. Estimating two stroke horsepower richdubbya automotive 27 may 05 10. Let p1 be the pressure in the crankcase at some point between tdc and bdc in the engine cycle. Hi performance two stroke porting software program youtube. Two stroke motors are more efficient that four strokes for a few reasons. Two stroke engine and exhaust design software north. There are many ways to boost the power, one of which is by installing a tuned pipe. Software for optimal setting and design of engines and racing. Moreover you can have advices for the development of the engine thanks to the help of tested formulas for intake, exhaust, blowdown and transfer. With up to 12db of boost available, you can highlight your solos or push a tube amp into overdrive territory. It seems to be trying to fix a non problem of two strokes, their pumping losses, two strokes dont have significant pumping losses. The inlet port opens 30 after bdc and closes 79 after tdc.
The official home page of our 2 stroke wizard tuned pipe. The businesses and individuals that purchased the original dynomation 2 stroke program were pleased with the capability and accuracy of the software. The trend in high performance two strokes has continued towards more case volume, however each engine and application differ. Blair of queens university belfast, and published by the society of automotive engineers. Great book, but ill guess the world has moved past that info. The piston crown opens and closes the exhaust and transfer ports. The newest info i have is the two stroke tuners handbook by gordon jennings. Graham bell is an acknowledged expert on engine tuning, with many years experience in this field. The old adage of stuffing cases on every project just isnt true any more.
Two stroke motors are very touchy in the tuning process, if they run too rich, they bog down and quit. Our goal is to achieve the biggest power gains as possible, while maintaining reliability on your 2 stroke engine. Thanks to the software 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. Software for fine tuning and design of two stroke engine by. Oct 24, 2017 10 ways to gain power in a 2 stroke engine for free. On the other hand, while the two stroke engine does not commonly require large dollar inputs to raise its power output, it does require an indepth under standing on the part of the man doing the modifications. For instance pipe calculators would determine the belly diameter based on blairs maximum size 2. This coefficient kh is called the horn coefficient, with typical values between one and two.
In an attempt to acquire that understanding i began a study of the highspeed, highoutput twostroke engine that has led to the. Below are notes on my free spreadsheet of free 2 stroke calculators. Small values of kh are best suited to grand prix engines with narrow power bands, larger. In motocross its usually a compromise between best peak hp and good early off the pipe power. In a two stroke engine, power is expended in compressing the airfuel mix in the crankcase and delivering this mix to the engine cylinder. There are exhaust manufacturers now that are mating up tuned pipes to tuned ported engines to get the best possible supercharging effect at given. From a 49cc racing engine, to a gp 125 engine, or a 1500 mercurial triple engine, or a 250 kart engine, racingsm software suits all. Next enter the cylinder bore and stroke which are 40. Racingsm software for 2stroke development, also for 4strokes in some modules, create 2t exhaust. The way a two stroke motor works causes them to be fairly noisy and a bit inefficient. In contrast, a twostroke engines valve timing may be altered simply by reshaping the holes in its cylinders, and its power output markedly changed by utilizing inertia and resonant effects in its intake and exhaust tracts. On the other hand, while the twostroke engine does not commonly require large dollar inputs to raise its power output, it does require an indepth under standing on the part of the man doing the modifications. Aussie twostroke engine invention motorbike writer.
Thats because twostroke engines have a couple of significant disadvantages that will make more sense once we look at how it operates. This section describes the basic function and the most important processes in the 2 stroke cycle a tuner need to consider in general and with the bimotion tuning software in particular. Implementation of an exhaust system for an opposed piston two. Contents chapter 1 introduction 9 chapter 2 the cylinder. Heat is the enemy of twostroke engines and stretching the compression ratio to give a 10% power increase will possibly result. The information used in the programs calculations was taken from the books the basic design of the two stroke engine and the book design and simulation of two stroke engines. Other books to his credit are modern engine tuning, twostroke performance tuning and forced induction performance tuning. Since modifying the 2 stroke engines require not only a big budget in funding but also modification strategies. The cylinder pressure drops, and the fresh charge transfers thru the transfer ports, over the top of the piston, and out the. Basic two stroke tuning by eric gorr changing the power band of your dirt bike engine is simple when you know the basics. But because of the limited worldwide activity in two stroke engine development, program sales were limited and further development was curtailed. Nov 02, 2019 the operation of a two stroke engine equipped with a properly tuned pipe is shown in the animation below, for a step by step description of the process, please follow the link below the animation. Jan 19, 2008 he will do one of two things,hang up, or if he is a good one,start explaining the complex nature of fluid dynamics, sonic wave pressures and the effects temperature on the speed and timing it takes to hit an open exhaust port at 6500 rpmsthis being said.
The worlds leading 2stroke engine simulation software available readytorun on your pc, at only. Finally, enter the exhaust duration of 184deg and the peak power speed of 12500 revsmin and click the design now button. Two stroke designmodification software the following are spreadsheets for different aspects of 2 stroke designmodification. You can work change variables with the bhp brake horsepower formulae. 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 software uses mathematical formulas that are approximations of. Unless you have a deep passion for two stroke tuning, are willing to spend money on software and porting equipment, and are comfortable throwing away botched cylinders, i would recommend having a reputable professional carry out any desired port modifications. The ports found within a twostroke cylinder in combination with the exhaust system have the greatest influence on power, torque, and the. A tuned pipe has a set of cones divergent meaning the cone gets. Change bmep and power units between psibar, hpkw measure portmap horizontal mm, cord, %bore, and vertical mm, crank degrees distances you can add extra ports to the portmap image eg using mspaint, load the new image and trace the new ports.
One other old way of calculating the dimensions of an expansion chamber relied on generic formulas that put the emphasis on the wrong things. But because of the limited worldwide activity in twostroke engine development, program sales were limited and further development was curtailed. You dont normally see twostroke engines in cars, however. There is no 2stroke displacement limit for our software, for example you can have a 125, 250, 500, 700 singlecylinder and our modules will work flawlessly. The exhaust port opens and combustion gas starts down the pipe at supersonic speeds. The engine has been studied from the perspective of the two stroke otto. 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. Two stroke performance tuning back in europe two stroke engineers were battling excessive ring and cylinder wear, due to the exhaust port width being too great. Oct 04, 2011 changing the power of 2 stroke engine 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.
They are so simple and fun that ive always enjoyed tinkering with them. A myriad of different aftermarket accessories is available for you to custom tune your bike to better suit your needs. Note that you do not require a paypal account as you can use your credit card. I use the tsr computer software to calculatepredict the horsepower. Purchase with immediate download from digital river, shareit. You can also save and load the data by using the provided functions. We use computer design software to maximize power and torque at any elevation. 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. A rare technical guide to the fundamentals of the crank train, cylinder heads, expansion chambers, port timing. Nov 05, 2011 a simple 3 stage two stroke exhaust calculator based on formulas of g. Everything you need to know about the twostroke cylinder.
Moped dick at bonneville world finals 2019 50cc two stroke landspeed bike duration. The morbidelli 125 twin road racer is a rotary valve engine. A narrow port reduced power but improved reliability. 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. Two stroke performance tuning a disc partially cut away and attached to the end of the crankshaft opens and closes an inlet port in the side of the crankcase. Every electric guitar rig should have a boost pedal, and eq pedals are great for fine tuning your tone before it hits your amp. For manufacter and tuner of two stroke engine, ntproject has developed a series of software to help in the development of the engine and its components from the bellmouth of the carburetor, to the insert of the reed valve and the reed petals, at the studied of the cylinder ports, until to the balance of the crankshaft, thanks at our software you could optimize your engine and to develop new. Tom turner, master two stroke tuner, pipe builder, and the man that developed tsr two stroke racing software designed and built his 424cc yamaha rd400 dragbike to develop and prove his racing design software and prove it, it did.
On the other hand, while the twostroke engine does not commonly require large. How twostroke expansion chambers work, and why you should care. Turbo and even supercharger setups of various configurations can be very useful, however, they are often more complicated with 2 stroke tuning than with 4 stroke applications on a tangent, i did witness a 50cc turbo 2 stroke bike that would do over 150mph, but i digress. Port matching, porting and trenching twostroke engine cases. In an attempt to acquire that understanding i began a study of the highspeed, highoutput two stroke engine that has led to the. Sep 30, 2012 arlan lehman talks about 350 power valve cylinder porting duration. Engineering acousticssonic supercharging of 2 stroke engines. A taller port restored lost power but made the power band unacceptably narrow. The peak power and length of powerband are mostly controlled by the design of the. Two stroke petrol engines are preferred when mechanical simplicity, light weight, and high power toweight ratio are design priorities. A tuned pipe has a set of cones divergent meaning the cone gets bigger and convergent meaning the cone gets smaller that are built to cause echoes or pressure waves to reflect back, which if done properly can increase the power of the engine.