Ducati 1098 and Nemesis Replacement ECU

Components

Ducati 1098 with;

Termignoni slip-on mufflers

Ducati Performance ECU

Stock adjustable exhaust valve in exhaust secondary

Nemesis replacement ECU from Competition Systems

1st phase;

Baseline power check of 1098 with stock 5.9M ECU on Dynostar dynamometer.

Chart 1. The baseline run on the Dynostar dynamometer indicated 143 HP with the DIN correction.

Repeat baseline of 1098 with stock 5.9M ECU on Dyna-Pro dynamometer.

Chart2. The baseline run on the Dyna Pro indicated 133HP with the DIN correction. This comparison doesn’t show anything other than the fact that there is a variation from one dyno manufacturer to another.

2nd phase;

During our second baseline on the Dyna Pro dynamometer we took a look at the idle AFR of both cylinders.

We put AFR 1 directly in the front cylinder pipe in the OE oxygen sensor bung while AFR 2 was taken from the 10mm X .8 fitting on the rear pipe.

Immediately we noticed that the rear AFR was nearly 12.5:1 while the front was around 13.5:1.

This was a reminder that the injectors needed to be checked.

We checked the injector flow rates of the original injectors and were considering that we might replace them with a matched pair if they are more than 1.5% apart.

Chart 2. Much to our surprise, the injectors were uncharacteristically well matched. The Weber designation for these injectors is IWP 189. Their static flow rate is 54 lbs/hr.

The IWP 189 injectors have a flow rate that is 11.6% greater than that of the IWP 069 found in all of the shower injector throttles from the 748R through the 999.

The IWP 189 injectors have 12 holes and a conical spray pattern that is virtually a fog.

Let me get back to the point about the cylinder-to-cylinder AFR variation.

At some point when I was doing something with the injectors, Fred mentioned that the idle bypass screw on the rear cylinder throttle body was open 1 turn, while the idle bypass screw on the front cylinder throttle body. That would be the cause of the AFR difference, provided that the throttle blades were synchronized.

A thorough understanding of the throttle bodies might be helpful.

The throttle choke isn’t your typical cylindrical shape. It isn’t an oval, it’s more like a circle cut in half with a rectangle between the two halves.

Photo 1. This is the front cylinder throttle body with the TPS on the left side of the photo.

This throttle is difficult to measure because the throttle body is tapering through the throttle blade area, but the dimensions of the throttle opening are 49.5mm by 68.5 mm.

This works out to 2,864.92 square millimeters or the equivalent of a round throttle which is 60.4 mm in diameter.

Photo 2. Notice the rocker-arm spindle directly above the port. This would be the upper limit for the port. As it is the port is very straight and severely down-draft.

This shape clearly isn’t chosen for throttle body space considerations, so I would imagine that it is a close approximation of the port. In fact the port does have this shape as a space consideration, allowing more room for the valve train mechanism above it by flattening the roof of the port.

Since the Testastretta engine has the opening rocker arms pivoting outside of the valves, (the Desmo-quattro had all of the rocker pivots inside of the valve stems) it means that the rocker-arm spindle is right above the ports. The inlet port is flattened to allow a little more room for that part of the casting. In Photo 2 you can see that the rocker-arm spindle is just above the inlet port.

Photo 3. This shows the throttle tapering and transitioning in aspect ratio to match the inlet port.

The throttle area sure is big enough so we should look at some of the other features.

Photo 4.  Each throttle body has two air bypass circuits, the traditional air bypass circuits that they have used since the 888 for separate cylinder adjustment, and the latest and greatest Idle Air Control system which adds air to both throttles equally. The IAC ports aren’t visible in this photo, but they are connected to the black neoprene tubes from the IAC stepper motor housing directly above the junction of the three tubes.

When we re-assembled the intake system we checked the vacuum synch and it was a tiny bit off and setting the bypass screws to the same number of turns out (or fractions thereof) resulted in equal AFR on the two cylinders at idle.

The bypass adjustments can be used to equalize the vacuum or to equalize the AFR and they do have a large influence on the idle AFR.

Throttle angle affects idle speed and AFR, the idle bypass circuits affect idle speed and AFR, and the Idle Air Control circuit affects idle speed and AFR.

On top of that, the ignition timing affects idle speed a lot and the AFR a small amount.

Fuel table values, warm-up enrichment-by-engine temperature values, ignition timing, and three different throttle body mechanical adjustments control/influence the start-up and idle quality.

When you consider that many of the complaints about the 1098s and 999s involve idle speed and killing at stop-lights, it is clear that start-up and idle are key factors in customer satisfaction.

Exhaust system valve

There is one more component in this system which has no effect on the replacement ECU but, obviously, does something in the stock system. I don’t know if it does anything with the DP ECU but it is assumed to serve some function with the stock ECU. That is the exhaust valve.

Photo 5.  This is the stock 1098 exhaust valve. It is open all of the time with the Nemesis ECU.

I’ve been told, by Mick Boasman of Competition Systems, the folks who produce the Nemesis, that the stock dash drives the exhaust valve. I am sure that is the case, but it must require some output from the stock ECU and the Nemesis doesn’t support this function.

Mapping

After adjusting the idle and start-up we began the mapping process. I left Fred alone and he finished that job himself.

The final WOT power and torque results were very little better than the baseline numbers and that isn’t all that surprising.

It’s quite common to be able to improve the WOT AFR without increasing the power or torque. I think it has something to do with the fuel condition of an injected engine versus that of a carbureted engine.

After adjusting the fuel table at all of the throttle positions and most of the pertinent RPMs, for both cylinders, and a bit of ignition timing adjustment to confirm MBT timing, the calibration is finished.

Chart 4. This is the final acceleration run after all the dinking around. We managed to gain only 2 HP, but the drivability and idle performance are much better than before.

Chart 5. The Dyna Pro graphing software has a DJHP (Dynojet Horse Power) check-box that changes (increases) the values by 8%. I would be curious to see if anyone has a Dynojet file with this combination to see how close the DJHP correction is.

The Nemesis ECU and Software

For the last several years I’ve been tuning a lot of Harley-Davidson motorcycles using the Screaming Eagle Race Tuner software and I’ve been spoiled by having access to so many of the files that influence other areas of the riding experience other than WOT fuel.

You may laugh at the mention of H-Ds but they can come with a greater variation of modifications than any Ducati I can think of.

That means that tuning Harleys has taught me how to create a calibration virtually from scratch. The starting point calibration usually has no relationship whatsoever to the engine you’re tuning.

When you’re tuning or attempting to tune a new combination, having the ability to control injection parameters other than the base fuel map isn’t just nice, it’s necessary.

That is precisely what the Nemesis offers. The software is stable and reliable and the hardware does exactly what you expect it to do.

If you want to perform calibrations quickly, then this may not be the tool for you, but if you want to tune to a high level of quality, it’s precisely what you need.

Figure 3. There is a lot of valuable information in good 3D graphics of the fuel maps and the Nemesis offers that. The adjustment windows offer several ways to adjust the injector time or ignition timing so it helps to make a tedious job easier and accurate.

The software is user friendly though the capabilities are extensive and the 3D graphs are very usable and even look good.

Like any software (and particularly, engineering/control software), it was a bit daunting at first, but that went away quickly and it has turned out to be quite easy to navigate.

Uploads and downloads are a fast and glitch-free, so what more could you ask for?