The old adage of stuffing cases on every project just isnt true any more. I use the tsr computer software to calculatepredict the horsepower. 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. The trend in high performance two strokes has continued towards more case volume, however each engine and application differ. The worlds leading 2stroke engine simulation software available readytorun on your pc, at only. Great book, but ill guess the world has moved past that info. In motocross its usually a compromise between best peak hp and good early off the pipe power. 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. A narrow port reduced power but improved reliability. 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. Aussie twostroke engine invention motorbike writer. 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. Hi performance two stroke porting software program youtube.
Below are notes on my free spreadsheet of free 2 stroke calculators. 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. 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. 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. Two stroke motors are more efficient that four strokes for a few reasons.
Racingsm software for 2stroke development, also for 4strokes in some modules, create 2t exhaust. Everything you need to know about the twostroke cylinder. 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. 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.
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. Port matching, porting and trenching twostroke engine cases. Moreover you can have advices for the development of the engine thanks to the help of tested formulas for intake, exhaust, blowdown and transfer. Small values of kh are best suited to grand prix engines with narrow power bands, larger.
A taller port restored lost power but made the power band unacceptably narrow. Software for fine tuning and design of two stroke engine. Our goal is to achieve the biggest power gains as possible, while maintaining reliability on your 2 stroke engine. Nov 05, 2011 a simple 3 stage two stroke exhaust calculator based on formulas of g. Other books to his credit are modern engine tuning, twostroke performance tuning and forced induction performance tuning. In a two stroke engine, power is expended in compressing the airfuel mix in the crankcase and delivering this mix to the engine cylinder. But because of the limited worldwide activity in two stroke engine development, program sales were limited and further development was curtailed. The peak power and length of powerband are mostly controlled by the design of the. Every electric guitar rig should have a boost pedal, and eq pedals are great for fine tuning your tone before it hits your amp. Note that you do not require a paypal account as you can use your credit card. 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.
Finally, enter the exhaust duration of 184deg and the peak power speed of 12500 revsmin and click the design now button. The software uses mathematical formulas that are approximations of. The businesses and individuals that purchased the original dynomation 2 stroke program were pleased with the capability and accuracy of the software. 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. 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. 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. Engineering acousticssonic supercharging of 2 stroke engines.
The complete engine geometry together with these two exhaust systems is simulated using an engine simulation software package virtual. 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. The ports found within a twostroke cylinder in combination with the exhaust system have the greatest influence on power, torque, and the. It seems to be trying to fix a non problem of two strokes, their pumping losses, two strokes dont have significant pumping losses. The morbidelli 125 twin road racer is a rotary valve engine. The exhaust port opens and combustion gas starts down the pipe at supersonic speeds. Contents chapter 1 introduction 9 chapter 2 the cylinder. On the other hand, while the twostroke engine does not commonly require large. The piston crown opens and closes the exhaust and transfer ports.
But because of the limited worldwide activity in twostroke engine development, program sales were limited and further development was curtailed. There are exhaust manufacturers now that are mating up tuned pipes to tuned ported engines to get the best possible supercharging effect at given. 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. Software for optimal setting and design of engines and racing. How twostroke expansion chambers work, and why you should care. In an attempt to acquire that understanding i began a study of the highspeed, highoutput two stroke engine that has led to the. Software for fine tuning and design of two stroke engine by. An engines exhaust port can be thought of as a sound generator. Two stroke engine and exhaust design software north. Two stroke petrol engines are preferred when mechanical simplicity, light weight, and high power toweight ratio are design priorities. The cylinder pressure drops, and the fresh charge transfers thru the transfer ports, over the top of the piston, and out the.
A tuned pipe has a set of cones divergent meaning the cone gets. 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. Basic two stroke tuning by eric gorr changing the power band of your dirt bike engine is simple when you know the basics. With up to 12db of boost available, you can highlight your solos or push a tube amp into overdrive territory. A rare technical guide to the fundamentals of the crank train, cylinder heads, expansion chambers, port timing. The inlet port opens 30 after bdc and closes 79 after tdc. Two stroke designmodification software the following are spreadsheets for different aspects of 2 stroke designmodification. We use computer design software to maximize power and torque at any elevation. The engine has been studied from the perspective of the two stroke otto. You dont normally see twostroke engines in cars, however. The official home page of our 2 stroke wizard tuned pipe. 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. Implementation of an exhaust system for an opposed piston two. Blair of queens university belfast, and published by the society of automotive engineers.
There are many ways to boost the power, one of which is by installing a tuned pipe. Sep 30, 2012 arlan lehman talks about 350 power valve cylinder porting duration. Two stroke motors are very touchy in the tuning process, if they run too rich, they bog down and quit. Graham bell is an acknowledged expert on engine tuning, with many years experience in this field. They are so simple and fun that ive always enjoyed tinkering with them. 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. 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. 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. Purchase with immediate download from digital river, shareit. You can also save and load the data by using the provided functions. In an attempt to acquire that understanding i began a study of the highspeed, highoutput twostroke engine that has led to the. 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.
A myriad of different aftermarket accessories is available for you to custom tune your bike to better suit your needs. Heat is the enemy of twostroke engines and stretching the compression ratio to give a 10% power increase will possibly result. Since modifying the 2 stroke engines require not only a big budget in funding but also modification strategies. This coefficient kh is called the horn coefficient, with typical values between one and two. For instance pipe calculators would determine the belly diameter based on blairs maximum size 2. 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. You can work change variables with the bhp brake horsepower formulae. Moped dick at bonneville world finals 2019 50cc two stroke landspeed bike duration. Oct 24, 2017 10 ways to gain power in a 2 stroke engine for free. Next enter the cylinder bore and stroke which are 40. The newest info i have is the two stroke tuners handbook by gordon jennings.