LAPTOP AND CALCULATOR TO HAND, DAVE FINCH HAS A POKE ABOUT INSIDE EPICYCLE'S ENGINE MANAGEMENT SYSTEM.

STREETBIKE features its fair share of trick eight-valve Ducatis. Some mild, some pretty wild. One problem their owners have often lamented is the lack of a user interface to the Weber-Marelli engine management system (EMS). With an obvious factory eye on warranty and reputation, the system was never designed for use by those outside the factory, so the knowledge of the structure and content of the data files is limited to those with the time and expertise to crack the code.

Another annoying limitation for the tuner is the fact that the fuel and ignition data is held on an Erasable, Programmable, Read-Only Memory (EPROM) chip. As the name implies, this is a read-only memory store which cannot be written to while in service. This means new data must be programmed or 'burned' into a new ROM in a separate ROM programmer and the new chip then installed in the Weber.

The tuning option for most people has been to seek out reprogrammed ROM chips from aftermarket suppliers who have spent time cracking the factory software. A variety of modified chips has become available from local and overseas sources.

Such chips are usually datafilled to suit a few levels of modification. Stage one may be less restrictive mufflers combined with some mild polling. The next stage may include hotter cam profiles. The hottest chip may be for full race engines with big valves, larger headers and a big bore kit. The obvious problem with this system is that unless your bike's modifications match exactly the specs of the engine for which the data was originally compiled, the set-up will not be optimised for your bike. You can mix and match the modifications but you can't mix and match the software.

Some people report no drama using these generic chips while others suffer a bike less happy than it was on the original factory chip. Such compromises can now be avoided.

Enter Peter Smith, one of Sydney's acknowledged Ducati gurus who has been developing, tuning and servicing the twins for a bloody long time under the banner of his Epicycle outfit in the suburb of Carlingford. He now offers a replacement electronic control unit (ECU) for Ducatis (and Weber-Marelli equipped Guzzis and Laverdas) which offers onboard remapping of fuel and ignition data, full time exhaust gas analysis, engine and chassis datalogging and a host of other features. It has been designed from the outset with a user friendly and quite powerful customer interface and its use of flash memory means that separate ROMS are a thing of the past. It's a bolt-in affair which replaces the Weber-Marelli system in a few minutes.

The heart of Epicycle's EM4 system is a Motec M4 sequential engine management system. This housed in a preimpregnated carbon fibre tray with aluminium honeycomb sandwiched in the base added strength. The tray is secured to the three existing Weber mounts and the proprietary Weber wiring connector plugs straight in. It utilises all the existing sensors, injectors and ignition components so it really is a drop in, ride away item.

The Motec engine management system is a very smart Australian development which has been around for 10 years, mostly in car racing. This year Motec systems were in 11 starters at the Le Mans 24 hour, 25 starters at Daytona and they're also being used in British touring car and Formula Three racing

Locally, viewers of the Shell 2+4 series may have seen graphics in the form of a car's dashboard plastered across the telly showing the speed, revs, gear, oil pressure and any number of other parameters of the target car. All this info is shown in real time as the car zaps around the circuit. Welcome to Motec, though its main purpose is much more intricate than this emulation of an arcade game!

The user interface to the EM4 is via software loaded into an IBM compatible PC with the physical connection via a standard serial port. I've run the software on an early 386SX machine with 4MB of RAM so you won't need the latest Pentium. Total software load is just over 3MB. At present it's a DOS based application and progression through the menus seems logical to me.

The basic function of any EMS is to take information from a number of sensors on the bike and apply this information to a series of lookup tables to arrive at the ideal amount of fuel to squirt into the inlet tract of a cylinder, the timing of that squirt, and also the timing of the ignition spark.

In EMS terms both the EM4 and the Duke's original Weber Marelli systems are known as 'Alpha – N’ systems. Consider this as 'Alphabetical Numerical’ where the columns in the data tables are defined as the 'N' or numerical value, almost exclusively revs and the rows of alphabetical value equate to a load usually throttle position on bikes, though it's often intake manifold pressure on cars.

The tables we have reproduced from the EM4 database utilise revs and throttle position, as does the Weber. The data is actually for the genuine factory 916SP chip which comes with the bike to be fitted with the SP's large diameter Termignoni mufflers. In Ducati parlance it's an 056 chip.

The system's main tables for fuel pulse and ignition timing are configurable for up to 40 engine speed points and up to 21 separate throttle points. In most of the tables reproduced in this story the engine speeds are set every 500rpm with the throttle positions spaced every five per cent. Please be aware that the photos are a snapshot of the table only; the data points go outside the shown screen and cover throttle points from zero to 100 percent and revs from zero to 12,000rpm. The PC's cursor control keys allow you to scroll the rest of the table onto screen.

Obviously the five percent spacing for throttle position on our tables uses all 21 available points, yet the 500rpm spacing on the revs uses only 25 points so another 15 are available if required. This means that if you're having trouble getting the performance optimised in a certain rev range you can add more points, say every 10Orpm, to give greater resolution in the problem area. You could also do the same with the throttle position, though in our demo table you'd have to open some of current five percent spacing points to 10 percent (or another value) to free up some of the 21 data points.

Look at Table 1. This is the main fuel screen of the EM4. The lower half of the screen is the actual table and the visible portion runs from 4000 to 8000rpm with throttle positions from 20 to 50 percent.

But what do all those three-digit numbers in the table mean? These are actually percentages of the basic fuel pulse width (called IJPU) that is enteredinto the system's set-up tables when the system is installed on the bike. The cursors in the table are set to cross reference 5000rpm and 25 per cent throttle and the highlighted table value at this point is 21.0 percent. Note that low throttle positions are given a short fuel pulse, as you'd expect.

The upper half of the screen shows the instantaneous state of the bike. Let's look at each field.

The rpm is 5000. The Eff Point (efficiency) and Load Point are both equal to the throttle position, in this case 25 per cent. The Lambda is the residual oxygen in the mixture, but more on that later. The TP is the throttle position, again 25 per cent. The battery voltage, engine temp and air temp are easy. The diagnostic errors field increments each time info from one sensor is considered spurious by the system. Considering the 33MHz speed of the processor the three errors noted in the table are irrelevant.

The word 'Fuel' is written in its own box. The three boxes to the right list the current data the bike is using for fuel control. The 'pulse width' is the time the injector will be open, in this case 3.9 milliseconds. The duty cycle lists how long the injector is open as a percentage of the time taken for the engine to turn its 720 degree, four-stroke cycle. In our case 16 percent. The INJ Time' tells us when the injector will end its fuel pulse, in this case when the crankshaft is 420 degrees before top dead centre on the compression stroke.

The word 'Ignition' is also written in its own box. The two fields to the right list the current parameters for the engine's ignition and the final box is for mixture control.

Now look at Map 1. You can toggle instantly between the fuel table and this graphical representation of it. The base axes are revs and throttle position with the vertical component representing the fuel pulse width. The cursor keys move the coloured lines which you'll see intersect at 4500rpm and per cent throttle. The pulse width is listed as 21.5 per cent, agreeing with the table as you'd expect.

It's interesting to note that the general shape of the map at 100 per cent throttle follows the power curve of the same bike on the dyno. The same dip at 4500rpm, another one at 10,000. Pity it's not as simple as pushing the fuel curve into a nice straight line to remove the bike's flat spots!

Obviously under normal use the revs rarely correspond exactly to one of the 500rpm data points. Likewise the throttle is rarely exactly at one of the five per cent marks. What happens then? The software looks at the four points in the table around the actual point and calculates a value based on the proximity of the actual value to those four points.

There are also user adjustable correction factors for engine and air temperature. The system even compensates for battery voltage variations which affect the speed of injector opening.

How do you modify the tables? Here's where we start to see how the EM4 makes home tuning a simple affair.

Changing the tables is very simple. You may want to lengthen the fuel pulse, retard the ignition and alter the injection timing. If you have a 916SP you may choose to vary the balance between the two injectors feeding each pot. On your PC you simply move the cursor to the value on any of the tables and simply type in a new value.

You can also change the value directly on the map screens. Pull up the map, move the cursors to the data point you want to change and the PC's page up/page down keys drag the hills and valleys of the map to your desired setting. When you toggle back to the table you'll see the table will have updated to comply with the new map values. Blissfully simple!

You can change data one point at a time, or by applying a trim factor across the whole table. Table 1 lists -5% in the trim field, this means the ECU will calculate a value five per cent lower than each data point and will use the revised figure. Trim is handy to alter a whole map to richen the mixture after major engine work while you run-in the new engine.

Table 2 and Map 2 are for the ignition advance. These are in degrees BTDC. Note that the trim is set to zero on this table. Unfortunately when we took these photos the demo motor was not running so we have a zero RPM and duty cycle figure. However, the ignition map itself is the focus here.

The EM4 offers the option of running separate fuel and ignition data for each cylinder. This gives the advantage of fine tuning each cylinder to account for such things as different airflow down each intake port due to the shape of the airbox and intake plumbing. The main fuel and ignition tables covered above are for the front pot or cylinder number two. We've discussed how trim factors work and that's how the EM4 calculates things for the other cylinder.

Table 3 is the trim table for the rear cylinder and each data point is a percentage correction factor which is applied to the main fuel table. For example, the cursors on the trim table cross at 8000rpm and 90 per cent throttle with a percentage value of three. The EM4 will look at the fuel pulse width on the main fuel table (Table 1) at this point and increase the value by three per cent to determine the actual pulse to be delivered to the rear pot. Note how the trim table shows that the rear cylinder is programmed to run richer up to around 8000rpm yet runs into negative values or leaner settings above this point.

The '1p, 2p, 1s, 2s' box at the right of Table 3 lists the trim factors for the primary and secondary injectors for both cylinders. Yes, all this can be trimmed separately although we haven't shown the tables here.

The advantage of using a trim table to set the data on the other cylinder rather than a separate map is that any changes made to the main table will be extended to the other cylinder save for the small trim factors.

All of this may sound like you need a professorship in computers, yet after an hour or two browsing through the screens it all seems very sensible.

At this stage we've covered what the screens mean. We've also discussed how to change the values. Now we'll look at how to decide what to change!

Let's consider the fuel table. You can use the seat of the pants method and increase or decrease the fuel pulse according to whether the bike feels lean or rich under certain conditions. It's the way I've changed jets at home since I was a wee lad.

More accurate by far is to fit a Lambda probe to the bike's header pipe and let it do all the work. The probe measures the residual oxygen in the exhaust gas and offers a pretty accurate reading of the state of the mixture. A Lambda value of 1.00 indicates a "neutral" mixture; higher numbers are leaner and lower are richer. A value of 0.88 is usually the target for maximum power.

Take the bike for a ride and when you get home you can download the data from the EM4 to the PC and get a readout of your mixture map as shown at Table 4.

On this graph the Lambda values are on the vertical axis while the horizontal axis is engine speed. Below the graph is a band listing the throttle positions, in percentage form as usual, with a highlight around 60. The thousands of tiny green dots on the graph indicate the Lambda value for each time you hit the 60 per cent throttle position during the ride. The larger white dots are a line-of-best-fit which averages all the individual Lambda values.

Yet another table in the EM4 is the Lambda target table. Suffice to say that the EM4 can compare the target Lambda values to the engine's actual Lambdas from the graph at Table 4 and can calculate revised fuel pulses for the main fuel table.

Suspicious of marketing claims as we are at Streetbike, we wanted proof of the compatibility of the EM4 to the existing Ducati sensors. We arranged to hook the system up to Frank Davidson's 916SP after this issue's comparison and compare it to the Weber. Frank had been in the position where he'd purchased one of the aftermarket chips and had found power down by one or two horsepower compared to the factory 056 software which came with the bike. He also said the bike was more jerky at low revs under light throttle with the new chip fitted and this annoyed him more than the slight power loss.

Peter Smith had data files ready to load into the EM4 with the same maps as both the 056 Ducati chip and the aftermarket chip Frank had used. I'd done lots of kilometres on the bike with the 056 chip as part of our comparison and I managed to put a few hundred kilometres on the bike with the aftermarket chip in the days before this story. I couldn't pick any power difference but Frank was certainly right in saying the bike was not happy on light throttle around 3000 to 3500rpm.

I confess that while I had no doubt about the ability of the EM4 to be tuned to suit a bike, I had doubts about the mobility of the Weber's code to the Motec. I figured there were likely to be differences in the electronics such as different current sent to the injectors resulting in a longer energising period, a shorter fuel pulse and a lean mixture.

We popped in the EM4 and ran it with the 056 code. The bike ran exactly as it had on the Weber. We then uploaded the aftermarket chip's code from the PC, a short 30 second job. The same hesitation at low revs was the result.

The EM4 also offers two digital and two analogue auxiliary inputs. These can be used in conjunction with additional sensors to feed data to the EM4 covering wheel speeds, gear position, oil pressure and many other parameters. Data from these auxiliary sensors can be combined with the permanent EMS sensors (rpm, throttle position, engine temp, Lambda etc) to provide a comprehensive chassis/engine datalog capability. They can be uploaded to the PC and displayed in graphical form such as Table 5.

This table has four traces covering rpm, rear wheel speed, wheel slip (the speed difference between front and rear wheels) and throttle position over a lap of Oran Park. The base axis is time in seconds, the vertical axis is split into four relevant groups to match the traces. Note the cursor is set at 108 seconds; to see the exact values for all the available engine and chassis parameters at this time you can look at the text box at right. You can also change which traces you want on the screen to any of those from the text box with a maximum of four on screen at once. With each sensor sampled twice a second, as with our graph, you can fit over two hours of ride time in each file..

It you want the armchair ride the same datafile can be played back in dashboard mode as show in Table 6.

Table 6

If I sound impressed you're right. The EM4 has great potential for the race mechanic seeking peak power and I think it's got even greater potential for the road rider who can fit road biased mods to his bike and use the EM4's flexibility to optimise the mixtures at the engine speeds and low throttle positions critical for nice road manners. Limited space means I can't expand on many of the system's other features including adjustable rev limiter, launch control, traction control, starting and cold running enrichment, the comparison function that instantly identifies all different data points between different files, etc

So how much does all this cost? The basic EM4 runs to $4150. For this you get the EM4 loaded with the data to suit your bike. You get unlimited access to all basic tables, maps and datalogging functions. However, you only get six hours access to the Lambda interrogation software. This limit is set by the parent Motec company and is intended to be enough to get the mixture correct for the initial engine configuration. After six hours of operation the Lambda software is partitioned off by the system. To take advantage of this six hour window you'll also need a Lambda probe fitted to the exhaust pipe to take readings. Peter at Epicycle will rent you one to save you buying it for only six hours use. After the six hours is up you can still use all the other functions but you'll be back to seat-of-the-pants feel to determine any changes to the maps.

For an extra $950 Motec will give you permanent access to the Lambda software. To me this is too large an ask, even though Motec has lots of software development dollars to recoup. Yet if you intend to race the bike or modify an engine in stages this is the only real option to maximise the system's benefits. You'll still need the Lambda probe and Epicycle will supply an ideal wideband unit . As for help in the initial configuration of the system, Peter is one of those gents who tends to offer so much help he ends up spending far too many hours in the wee small hours catching up on the rest of his Epicycle business.

While the EM4 appears expensive it is a very powerful tool. There are alternatives available to tune the existing Weber at home but they are arguably less versatile, usually more expensive, offer no chassis datalogging capability and lack the powerful displays of the EM4.

For proof of the system's worth you need look no further than Gary Amos's home grown 996 included in this issue's Ducati feature. The EM4 fitted to it has tracked its growth from a single injector '91 Strada through twin-injector 955 up to its current 996 guise with factory 60mm twin injector throttle bodies. It has 146 rear wheel horses and so much datalogging capability that Gary can't sneeze without his mechanic knowing. That's impressive.