S4R Monster With Ducati Performance Power Kit

Of course leading to the obvious question “Which kit?”. In this case, part number 96439503B, being mufflers, muffler pipes, ECU and air filter kit. And some mounting brackets and bolts (but no instructions in ours). See photo below.

I was curious to see how the kits work, and how the 996 Monster worked in general with the different style exhaust. The std system uses 40mm OD header pipes (like the S4, 851, 888) into a central muffler/catalytic convertor box that sits under the back of the engine, looking rather like an over full nappy. Then two pipes out of that to two high mounted mufflers on the right. Apart from the high mounted mufflers I think they’re a pretty spiffy looking jigger. Your opinion may vary. I’d like an all black one with the paintwork redone in orange (Hemi orange, or perhaps Lone oranger) with a black skinny/fat/skinny 3 stripe scheme down the middle and orange stripes around the rim edges. Yes, even with the black wheels.

Power wise I was curious to see how the shape of the curve compared to the ST4S – identical apart from the exhaust system. And whether the smaller headers hurt the power or if the crappy nappy actually worked. The S4R also has a single air inlet to the airbox, being rectangular shaped, whereas the ST4S has two round ones. Probably equal in area in real terms. On the road I’d been quite surprised by the power of the S4R as it reached the top end, but the response was a bit lacking I thought. The gearing however, is, for once, spot on. 15/42 with the 1.84 primary drive ratio and wide ratio gearbox is about as much as I could hope for. The ST4S struggles along with 15/38, and we’ve had quite a few ST4S owners go to15/43.

The first graphs are before and after for this bike. Green is all std, red is the power kit fitted. I’d expect the air filter kit – being the cut open lid and BMC filter – to account for quite a bit of the increase, but it’s still a nice result. Certainly gives the bike more pep in its step. The air/fuel trace is fairly consistant before and after, which is nice too. First graph is power, the torque and air/fuel.

Like a Multistrada with some slip on mufflers (our demo has Staintune) the noise isn’t as loud as most would expect. Just like many of the BMW R series that have central cat boxes, much of the noise muffling occurs there also. So while it’s quite a nice note – certainly not too loud – it just won’t do for some. I’d call it quite livable even without ear plugs – just like my 600M, unlike my 851. Up to you.

Next we’ll compare it to the ST4S, which shares the same engine, inlet system and basic frame design. The only real difference affecting engine performance is the exhaust system. Std, the difference isn’t that great, which is how they feel to ride. Red is S4R, green is ST4S.

Add the muffler kits however, and the difference is much more obvious. Both the full ST4S kit and this S4R kit have slip on mufflers, ECU and air filter kits. It’s the exhaust header pipes where it all goes bad. Red is S4R, green is ST4S.

That’s a pretty big difference – up to 10 hp @ 8,000 RPM. Not that you notice something you haven’t got, but it would certainly be an arm stretcher with that extra performance. Why they decided to do without it in a market niche that trades on performance is somewhat beyond me.

I’d expect that fitting a system in 45mm (or even bigger, I’m sure everyone will want 50) that started at the end of the header stubs (about 120mm from the exhaust port) and made in the usual 2-1-2 style ala 996 with a x-over at the side and mufflers as desired will see the potential of this engine released. We already know what it’s capable of. Arrow has already released a system like this I believe, as have others such as Spark and Marving.

After I’d finished this report it occurred to me that I hadn’t compared it to the S4. So I did, mainly to see if the 9% capacity increase delivered a 9% torque increase. Surprisingly, it didn’t. In fact, for much of the RPM range, it didn’t do much at all. Which is a real pity, and probably the reason some S4 owners who’ve tried the S4R haven’t been so enthused after riding it. Whether it’s the exhaust that’s the issue here I’m not sure, but you’d think someone at Ducati would have worked it out. Power first, then torque. S4R is red, S4 is green. Both have the DP slip on muffler / ECU / air filter power kits, although all std is much the same story.

I had been hoping to get hold of an S4R for some playing, as it would appear there’s plenty of playing to do. I’ll have to wait and see – and maybe move some of the others to make room.

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