Ducati 1198 Technical


Ducati Traction Control - DTC

By Kevin Ash

The system used on the new Ducati 1198 S and the 1098 R is almost identical to that used on Ducati’s World Superbike and MotoGP race machines. But one significant change has been made which singles out the 1198 S system as suitable for road use, and that’s cutting off the fuel supply rather than the spark when a major torque reduction is needed.

Duc11_Po_22Click on imageDTC constantly compares the speeds of the front and rear wheels, which sounds simple enough until you consider that a bike’s wheel speeds increase when it leans over as it moves onto a smaller radius part of the tyre. This can change by different amounts too depending on the tyre profile and even its pressure. Another factor to take into account is if the bike is freewheeling at 70mph the rear wheel speed is different to when it’s accelerating through 70mph or under load up a hill at 70mph, as any amount of power applied to the wheel causes it to creep slightly, while changes in weight distribution compress or unload the tyre and alter its rolling radius.

DTC’s electronics take all this into account and also monitor the engine revs, throttle position, gear selected and so on in order to decide if the rear wheel is beginning to spin more than a specified amount. If it is, then the torque at the back wheel is reduced. This is achieved first by retarding the ignition, but it’s only possible to lose up to 20 per cent of the torque this way before the possibility of inflicting damage on the engine, so the next step is to interrupt the combustion process. On the 1098 R and the race bikes the ignition is killed, but the problem for a road bike with this is unburnt fuel gets dumped into the exhaust system, which would damage the catalytic converters. As the 1198 S is as much a road bike as a track one, the fuel injection is stopped instead. These interruptions happen at very high speed and the supply is constantly restored then interrupted again, so the DTC’s action is surprisingly smooth, especially on the S compared with the 1098 R.

DTC measures the tyre creep so accurately it offers eight different levels of allowable spin, selectable even while riding. On level eight the system cuts in early, well before the rear tyre starts to feel as if it’s spinning properly, while on level one a lot of spin is allowed, enough to leave black lines on the road and have the back end of the bike sliding out slightly. But all the rider needs to do aside from pointing the bike in the right direction is keep the throttle wide open – DTC can cope, even if your brain is struggling...

* The 1198’s other technical changes

Duc11_Po_24Click on imageTo take the 1198’s capacity out to its full 1198.4 cc, the bore and stroke have been increased from 104 x 64.7mm to 106 x 67.9mm. The pistons are not only bigger than the 1098’s, they are also a different design, like the 1098 R’s with more pronounced webbing on the underside to increase strength, so the motor can still rev to the same 10,500rpm ceiling as the 1098.

To take advantage of the increased gas flow potential, the valve sizes are all increased by 1.5mm to 43.5mm inlet, 25.5mm exhaust, and the compression ratio is up to 12.7:1 from the 12.5:1 of the 1098. Steel conrods are used as opposed to the titanium rods of the 1098 R, and are 122.5mm long against the 1098’s 124mm to compensate for the increased stroke. The gearbox is essentially the same as the 1098R’s, using wider gears for more strength. Third to sixth gears are taller than the 1098’s too, and are the same as the R’s.

Ducati_1198S_power1198 makes at least 10bhp more than the 1098 from 6,000rpm up to 10,500rpm - Click on imageWhile these are typical changes associated with a capacity increase, a more significant improvement has been the use of Vacural casting technology for the new crankcases (although these are already used on the 848). In conventional vacuum die-casting the air is evacuated from the mould in order help the liquid metal flow in and to reduce the formation of bubbles, but with Vacural the vacuum is used to actively suck the metal in. This reduces bubble formation even further and allows the casting of thinner sections too. Along with a redesign of the rear of the casings the result is a reduction in weight of 6.6lb (3kg) – that’s a lot of mass to lose from a superbike!

The 1198 S comes as standard with DDA, or Ducati Data Analyser, improved to have 4Mb memory rather than the old version’s 2Mb and with an extra channel that records the intervention of the DTC. This allows you to read out information from your laps (of a race track, not the local one way system...) and to see where you could have given it more throttle out of corners where the DTC hasn’t intervened.

Duc11_Po_42Click on imageThe headlamp assembly is 1lb (0.4kg) lighter than the 1098’s due to the use of a magnesium instead of aluminium mounting frame and with lighter plastic internals. It might not seem like much but this is weight stuck right out at the front of the bike where it’s inertial moment is large compared with more centralised masses, so it has a conisderable effect on the bike’s rate of turn and agility. Likewise the 1198 S’s seven-spoke wheels are 2kg lighter, which improves agility, steering response and acceleration as well as grip thanks to the lower unsprung mass.

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