MOTA and the new MOTA-X.          
  You can ask questions anytime by email  ...   email us .....

The new MOTA version 6.30 for Windows® is now available.
The world's leading 2-stroke engine simulation software available ready-to-run on your PC, at only AUD$255
( Australian Dollars ) including GST and delivery within Australia  ..... or only AUD$239 including postage exported to most countries.

                                       MOTA 2 stroke engine dyno software

For a limited time MOTA-X v1.0 will be included with the purchase of MOTA version 6.3 at no additional cost.

MOTA-X contains all the features found in MOTA plus expansion chamber optimisation code.

The optimiser searches automatically for the expansion chamber dimensions that give the maximum power or torque for your engine over a speed range that you input. It runs the tried and tested MOTA simulator many times, altering the expansion chamber dimensions intelligently between simulations, to produce an optimal expansion chamber design. This expansion chamber is not the product of simple correlations as for other products that abound on the web, but an "automatic" design created by MOTA which is a full wave action 2-stroke engine simulator.

Because the optimisation process performed by MOTA_X is inherently slow, the use of  facilities found in multi core processors is exploited in the code. This means that to run MOTA-X, you will need a post 2010 computer which is preferably a desktop, driven by an intel i7 4-core processor. Processors with a lower number of cores will run the MOTA-X expansion chamber optimiser, as will the latest i5 duo core processors, but at greatly increased execution times. An optimisation on an i7 4-core processor based desktop takes typically 15 minutes, but can range in time between 5 minutes and 30 minutes. A laptop with the same specifications as a desktop will take typically 2-3 times longer to run the same optimisation.

MOTA v6.3 does not require such high end machines to run, and, as always, will run on nearly any computer made after 2000. However, MOTA 6.3 does not have the expansion chamber optimisation capability provided by MOTA-X.

We also have a simple 2-stroke expansion chamber design program. This will get you started by providing, for your engine,  the dimensions of an expansion chamber with a 2-stage or 3-stage diffuser.   Free download here  . Of course the dimensions so provided could be inserted in a MOTA engine data file and MOTA-X then used to provide an optimum expansion chamber design for your engine over your choice of speed range.

The earlier MOTA version 6.10 was an evolution of the v6.00 that includes some fabulous new tools.

Power/Torque Curves Cursor Bar 
The display of Power/Torque curves has been enhanced by the inclusion of a vertical cursor bar which extends over the entire height of the plotting area and whose position can be controlled by the mouse. Where the bar intersects each curve a horizontal cursor is drawn and, to the right of the plotting area, the corresponding power and torque values and the engine speed are displayed.

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. A sub-menu offers the two selections "Constructing the Development Pattern of a Cone" and "Printing the Development Pattern of a Cone". It is the options provided under the second selection which have been added to MOTA. You can now print the development pattern of a cone and this may extend over several A4 pages. Of particular note, you can produce the pattern of a cone having either end or both ends angled to the cone axis. A set of explanatory diagrams with text can be displayed. You may also define a single straight cone and print the patterns of each of the pieces which, when welded together, will provide an equivalent bend section. The number of pieces and the overall bend angle are entered through the keyboard. A MOTA engine data file may also be accessed and the pattern of each section of the expansion chamber printed. Alternatively, any one section may be selected and patterns suitable for the construction of an equivalent bend section printed.

We now have a simple 2 stroke expansion chamber design program.   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.  It calculates the dimensions for both double and triple stage diffuser expansion chambers from a few basic engine dimensions.  The information used in the program's calculations was taken from the books ‘The Basic Design of the Two Stroke Engine’ and the book ‘Design and Simulation of Two Stroke Engines’; both books are written by Professor G.P. Blair of Queens University Belfast, and published by the Society of Automotive Engineers.  You are well advised to read at least one of the books mentioned above, since they contain the author’s academic lifetime of knowledge on the two-stroke engine.

There are several coefficients used in the design of the expansion chamber – these are a function of the engine’s state of tune. Those used in this program  have been chosen for petrol engines, and are in the range 50cc up to about 500cc per cylinder. It is doubtful these formulae would work on small capacity glowplug engines, since the exhaust gas temperature is much lower, and the engine speed is much higher.

How it all began  ....... 

MOTA® is the brainchild of Dr Julian Van Leersum, mathematics graduate from Monash University in Melbourne, Victoria.  He is of Dutch/Swiss parentage, but now permanently resident in Australia.

With the successful MOTA® software, Dr Van Leersum has managed to combine his professional interests in computing & mathematics with his enthusiasm for karting and motorcycle racing.

"It occurred to me that most home tuners cannot afford the expense of hiring time on a dynamometer to check the viability of adjustments or special parts" said Julian, "yet many people these days have a home computer which could easily run a suitably designed tuning programme."

"Although there is really no shortage of books on the subject of 2-stroke tuning and preparation, I knew that an active software programme would be able to offer so much more."    So, this is how MOTA® was conceived.

is an engine simulation program suitable for everyone from the enthusiast to the university researcher - from the beginner racer to the professional tuner. See testimonials. You can test your own engine and then re-test and compare your modifications - or build your ultimate engine right on the screen. Millions of fluid and thermo-dynamic calculations are made by MOTA representing the conditions inside your two-stroke engine throughout it's complete operating cycle.

No previous knowledge of the two-stroke cycle engine is required - just input the required data and then run MOTA to set in motion this powerful process. Test your own theories on porting and exhaust pipe design; explore the limits of various intake methods; or just look for the highest power output from your own engine.

MOTA will accept a single-cylinder design, which will also cater for many multi's where 2, 3 or more cylinders of the same basic layout are repeated. Easy-to-operate, accurate and hours of fascinating results to enjoy! Excellent graphics you can analyse and compare. MOTA's "Two-stroke Dyno" will give you and your PC the equivalent of many experts knowledge.

MOTA and it's related set of programs have been developed to simulate the performance of high-output single cylinder two-stroke engines. It will simulate one of the cylinders of a multi-cylinder two-stroke engine provided that the cylinders are identical in layout and dimensions and each cylinder has a seperate exhaust and induction system. It allows simulation of engines with reed-valve, rotary-valve and piston port timed induction systems. Simulation of engines with either a box-silencer or an expansion chamber is also possible.

Because MOTA solves the equations describing the conservation of fluid and thermodynamic properties throughout an engine, it requires specification of the full engine geometry. This is accomplished through a menu driven environment, which prompts you for the required dimensions which are easily entered via the keyboard.

The output from MOTA is provided in two forms; a file, which summarises the engine geometry and performance, and a graphical interface which allows you to plot the various performance variables. The output file and these plots can be printed if you have a printer connected to your computer.

How MOTA works for you
The strength in MOTA lies not so much in it's ability to predict accurately the performance of an engine, but in it's ability to allow evaluation of two different engine configurations. For example, if you have the MOTA produced power curve for an engine, and you want to see if modifying one of the exhaust pipe dimensions will increase or decrease power, then you can change the particular dimension and re-run the MOTA simulator. Comparison of the new power curve with the old will allow you to determine whether or not the change will be worth making.

Where is MOTA different to other computer programs and tuning manuals - and what can it do?
MOTA operates in the "real world" and it will:-
a) accept most any dimension and variations of dimensions.
b) operate on anyone's exhaust pipe theory by accepting almost all shapes.
c) operate within the limitations set under certain racing regulations.
d) accept that the data you input is from an engine that is running already, and will output it's predicted performance as a base for you to work from.
e) accept alteration to one engine dimension at a time - either real or imagined, and produce all of the new
outputs with the new dimension.
f) accept that ignition timing can be varied, and allows you to input such changes - possible or not, you can make the alteration to see what would happen.
g) does not ask complex technical questions - data inputs are easily measured and entered on the screen via the keyboard.
h) accept almost limitless variations, so you can test ideas beyond any current theories or practises.

So how does this help you?
Most everyone will have an actual engine that they wish to play with, or make perform better. MOTA can do that easily and quickly. It does not trouble you with the in-depth why's and wherefore's of two-stroke engine design theory - you are not trying to build an engine from scratch. You can do one alteration, or many, and MOTA works with that.

System Requirements for MOTA v6.30

Special features include

  1. Suitable for Kart, Motorcycle, chainsaw, personal watercraft, Model Aero and most similar engines.
  2. Accepts most expansion chamber designs.
  3. Methanol or petrol fuels accepted.
  4. Will test almost any reed valve material.
  5. Ignition timing can be varied, and 'curves' accepted.
  6. Integrated, box type or separate muffler designs accepted.

Price:   AUD $255 Australian Dollars including postage within Australia  ...
                    or AUD $239 exported including airmail post to any country.

Details for purchasing upgrades ........... The current version of MOTA is v6.30
MOTA  version 6.30 for Windows® is now available , should you wish to upgrade.
The cost is AUD$125 if upgrading from versions 4.xx or 5.xx or 6.xx  --  price is  including postage.

Your program number must be quoted when ordering -- it is written on both your dongle and distribution disk(s).
The earlier version distribution disks are not required to be returned when ordering an upgrade.

Purchasing MOTA
If you want an order form
to purchase the MOTA software , or an upgrade, we have two available.
In .pdf format to fax back ......... click here       or an .xls file to email us
 ........ click here