MOTA version 8 is now available.

The latest development of the original MOTA has branched into 2 different software products, MOTA v8.0 and MOTA-7.   Both are included in the new MOTA package.   

MOTA v8.0 contains everything that was in the previous MOTA versions with the addition of an Expansion Chamber Optimiser and Piston Ports Optimiser.  It can still be run as a 2-stroke engine simulator only, just as it did in all the earlier MOTA v4.xx, v5.xx and v6.xx.  

MOTA v8.0 has an added optimisation simulation feature that designs optimal exhaust systems and piston ports that give maximum power or torque over specified speed ranges of 2-stroke engines. Unlike many software products, which use empirical equations to size exhaust systems, MOTA v8.0 uses the same 2-stroke engine simulation package as in the previous versions of MOTA to evaluate each exhaust system and ports configuration. It searches systematically through a large number of configurations and chooses that set of dimensions that best matches the user’s criteria. For example, a user can ask for the design that maximises power at a particular speed or speed range for a given engine. MOTA v8.0 varies the user selected pipe and port dimensions systematically until it comes up with a set of dimensions that appear to give the most power at the nominated speed or speed range. These dimensions will be referred to as optimal. Various combinations of port and pipe dimensions can be selected for the optimisations.

MOTA-7 is a 2-dimensional simulation model, the exact same program we have been supplying as a trial with the later MOTA v6.3 programs. It is a 2-stroke engine simulator only, based on the MOTA simulator, but with a 2-dimensional scavenging model. The only change for this release is to a PDF format User Manual.

The MOTA-7 2-dimensional model of cylinder flow is achieved by "squashing" the cylinder about a plane running through the centre of the exhaust port and the axis of the cylinder, and assuming scavenge port symmetry each side of this plane. The resulting cylinder section is then divided into a large number of cells (limits are 99 points diametrically and 99 points axially from BDC to TDC), and the thermodynamic conservation equations are applied at each point for each time step. Clearly, this represents several orders of magnitude increase in computational effort over the original "pipe only" equations in the MOTA simulator.

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 MOTAv8 then used to provide an optimum expansion chamber design for your engine over your choice of speed range.

Purchasing MOTA

Price is AUD $265 Australian Dollars , plus postage.  Delivery by post to different destinations around the world varies in cost, so as a guide prices are $15 across Australia, $17 to New Zealand, $21 to the USA, Canada and most of Asia, $27 to the UK, Europe and Brazil.

Details for purchasing upgrades ........... the current version of MOTA is v8.0
  version 8.0 for Windows® is now available , should you wish to upgrade.
The cost is AUD$195 if upgrading from versions 4.xx or 5.xx or 6.xx  --  plus postage.

Your program number must be quoted when ordering -- it is written on both your dongle and distribution disk(s) or USB.
The earlier version distribution disks are not required to be returned when ordering an upgrade ,  and you do not have to remove the earlier versions of MOTA if they are still running on your computer.

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

Here is the hard part , determining if your computer will run MOTA v8.0

MOTA v8.0 requires a CPU which supports the AVX or AVX2 instruction set extensions.  MOTA uses these extensions in order to execute its code quickly.

Most Intel CPU model numbers i3, i5, i7 and i9 manufactured after 2013 do support these extensions, whereas many Intel processors manufactured before 2013 do not.  Even current Pentium and Celeron processors do not support these extensions.  Only a few relatively recent AMD Ryzen processors will support the instruction set extensions.

You need your processor model number before you can determine what instruction sets it supports.  To find the model number of your processor, press the windows symbol key, generally located at the bottom left of your keyboard.  Depending on your windows version, the resultant screen will show a “settings” or “control panel” button.  Press whichever button you can find and select the “system” option.  You may have to scroll down and select the “About” option, or the information regarding the processor model number might be on the screen if “control panel” was selected.  Note the processor model number.

The simplest method of determining if your INTEL processor will run MOTA v8.0 is to visit the web page: and in the search box provided in the top right hand box, type in the model number of your CPU, eg I7-8750H.  

The Intel database may or may not identify your processor.  If the Intel database does recognise your processor model, you will be presented with a scrollable list of its properties once you click on the model number.  Go down to find the heading “Advanced Technologies”, and look for the sub-heading “Instruction set extensions”.   If supported, one or both of AVX and AVX2 will be listed here.

Once you have carried out the above, please advise IWT of the result.  We may be able to make a copy of MOTA for you if neither AVX nor AVX2 is supported by your processor, or perhaps if your processor does not appear in the Intel database.  We will definitely be able to make a copy of MOTA for you if either AVX or AVX2 is supported.

Another way of determining if your computer will support the AVX or AVX2 is to download from the web ( ), and download with the LIGHT GREEN (bottom) button on the left pane (Installer for Win32 and win64).  Install and run the utility hwinfo -  it might install as hwinfo32 or hwinfo64.  When you run it, you will see in the left hand window under “FEATURES” a list of CPU properties.  Those coloured green are supported by your CPU.  If either or both of AVX or AVX2 is coloured green, then you can run MOTA v8.0.  Please advise IWT of these properties, even if AVX2 and AVX are greyed out.  In the latter event, we might still be able to make a version of MOTA for you.

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.

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.