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This is part I of a 3 part series looking at improving the performance of my Ducati by focussing on changes to the intake / exhaust system and suspension setup. Part I covers the work performed on the bike, whilst in subsequent weeks, parts II (On the Road) & III (Taking it to the Track) will cover road and track reports on the changes.

Part I: The Work

I bought my used 2007 Ducati Monster S4Rs last year with the full termignoni (termi) system installed. This kit includes the 50mm exhaust system, a Ducati Performance (DP) ECU (which lifts the max engine speed to 11,000 rpm) and a freer flowing air filter. Compared to stock the kit makes a big difference in performance, adding more then 10 bhp at peak and much more in the mid-range. It is quite an expensive option (although perhaps not on a $ per bhp basis), but it looks and sounds great whilst removing a lot of excess weight including the ugly udder which contains the catalytic converter. Ducati makes a big deal about the termi system being designed for the Monster with the company’s blessing and that the DP ECU is optimized for it. Nevertheless on my bike the fueling was never very good at lower revs despite the strong upper midrange and top end performance (the bike doesn’t lack for pace!). The engine would hesitate before picking up revs when blipping the throttle and would run very roughly below 4,000 rpm. The engine would struggle to hold a constant engine speed preferring to either accelerate or decelerate which made running in traffic particularly difficult. Picking up the throttle from very low speeds would often result in a pause then surge as the power arrived in a rush quite out of proportion to that which was requested at the throttle.

On the positive side, power arrived with a strong surge at 5,000 rpm quickly building through 6,000 to a top end surge that didn’t let up until an indicated 11,000 rpm. This was great when running the bike hard up in the mountains or at the track. However, during group rides with the local Atlanta official Ducati Club (Wild Ducs), the lower rpm issues made it difficult to maintain a smooth rhythm at a brisk pace where usually 4th or 5th gears were more than enough to accelerate smoothly from turn to turn if only the engine would run smoothly.

I decided to attack this issue as part of the scheduled 7,500 mile service. I chose Ducshop because of their reputation and specialized Ducati experience and knowledge over the local dealer (you can find a review of Ducshop here). I asked Ducshop to do a number of things which I hoped would improved the situation. Firstly I asked them to run my bike on the dynamometer (dyno) and check the fueling, suspecting that the Throttle Position Sensor (TPS) would need adjusting. When the termi kit is installed the TPS needs to be adjusted and I wondered whether this might not have been done on my bike. Secondly I asked them to check the cam timing. Cam timing is often out of factory spec and this can make a significant difference to bottom end and mid range performance in particular. Finally I asked for the flywheel to be lightened. This last change was unrelated to the fueling problems but I thought a freer revving engine would accelerate better at all engine speeds and add to the Monster’s playful character. In addition to these jobs I asked for a new set of Pirelli Diablo Rosso tires to be mounted and the static sag to be appropriately set for my weight. The new tires will be subject to a review in a subsequent article.

It turned out the fueling on my bike was so lean (not enough fuel) at idle and lower revs that there was not enough adjustment available on the TPS to correct the problem so I agreed to have Ducshop install a Power Commander and create a custom map. Although you can download maps for most engine and exhaust configurations, a custom map ensures the optimal fueling for the quirks and vagaries of any individual machine. This can be done automatically in facilities that have Dynojet dynos with the tuning link software. This automatically optimizes the fueling at multiple combinations of engine speed and throttle opening. The key factor is the multiple throttle openings. It is one thing to optimize the engine at full throttle, but on the street, the majority of riding is not at 100% throttle and part throttle response is critical.

Interestingly Ducshop prefers to create the map manually arguing that the automatic software puts enormous strain on the drive train since the the dyno brake is used to mechanically pull the engine revs down even against an open throttle and an accelerating engine. It takes a lot longer but you get the same result in the end. In addition to the fueling the cam timing on my bike was indeed significantly out.

Before and after dyno runs clearly show the differences. The run after the modifications shows a stronger engine all the way through the upper midrange to the top end with a peak advantage of ~5 bhp. It is important to note that the dyno cannot indicate the promised improvements in part throttle response and ride-ability. Additionally the before curve was generated on a cold day and the after curve on a much warmer day. This means the actual differences could be larger than the chart suggests. Note that the lightened flywheel plays no part in the dyno curve. The lighter flywheel does not make any difference to engine torque and hence horsepower, but it does effect how fast the engine accelerates and therefore how fast the bike picks up speed.

So was all this work worth it? What is it like to ride now? Performance on the road will covered in Part II and race track performance in Part III. Look out for them on the site soon!!

As always, feel free to add your views in the comments.

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