999S With DP 57mm 2-1-2 Muffler Kit
The newly available 2 -1 - 2 muffler kits from Ducati Performance are the source of much speculation at the moment, as everyone wants to know how it works before they buy one. Of course, if no one buys and then tests it, how does anyone gauge its worth?
The first one of these we fitted I didnt get to dyno, the second one I did. Also, just like the 996 (of which Ive never dynod a std bike), most of the 749/999 we sell now get DP mufflers kits of some sort at pre delivery, so I dont get to dyno std bikes. And, for a comparison to the DP mufflers kits keeping the 45mm asymmetrical headers, we need someone to buy and fit the cheaper system, then buy and fit the more expensive 2-1-2 so we can test both. Which doesnt usually happen.
Ive been told the Testastretta engines like a bigger exhaust, which, given the shorter duration cams, bigger valves and throttle bodies I can accept as more than likely. I had just never seen any actual comparative proof of this. I was also very surprised by the result I had seen for the std 45mm asymmetrical system, with a local (tuned elsewhere) 999S making 140ish hp with the DP muffler kit and a Dynojet PCIII. Which seemed to show the 45mm header size wasnt too bad after all. But, the race bikes are now up to 62.5mm I believe for their 2-1-2 systems, and everyone loves the race stuff.
There seems to be quite a bit of derision of the std 45mm asymmetrical system, mainly based on the belief that any exhaust that doesnt have equal length pipes cant be any good. And the misunderstanding that you cant tune it properly if the pipes are different lengths. Which is rubbish. Tuning to suit any configuration exhaust when you have a fuel map for each cylinder is very easy, and every Weber ECU since 93 has had that capability. Whether or not the supplied tuning is any good is another, un-related point.
Anyway, enough rambling. The bike here is a 999S. Plenty fast enough as std in my opinion, most owners want the sound to go with the speed. This owner had ordered a full 57mm 2-1-2 system with Ti muffler, and I was keen to do some before/after runs to get a feel for the result. The dyno runs were the easy part, fitting the system took a little more effort. To some extent, fitting systems like this is something of an "each one is a bit different" thing, but with the usual amount of pushing, shoving and name calling, it was on. Im actually surprised how well they fit, given the size of them. I had to space out the LH lower rear fairing mount on this bike to clear the horizontal header pipe, but apart from that, it was pretty easy.
These systems sound quite a lot different to the cheaper power kits, which retain the std short rear header. They are also far quieter, being 102 Db rated, which makes them much quieter than even the older Termi slip on muffler for the 996/998 etc. The sound is much like the traditional 4V style sound, not the flat-ish, sort of Subaru WRX-ish noise the cheaper, unbalanced systems make.
Not that Im saying theres anything wrong with what Im calling the "cheaper" system. Theyre just different.
The base dyno run caused me a little concern though. Being the first 999S I had dynod, the curve (very similar to our 999 demo) and 120 hp maximum made me wonder if there was something wrong. I even lifted the rear rocker cover and checked to make sure it had the right cams (it did), so had to accept it as "how it was" in the end. The comparison from std exhaust to 57mm was the main question anyway, and that we got.
The graph below shows the power and air/fuel curves. The ECU supplied with the 57mm kit gives a very rich air/fuel trace, especially under 7,000 RPM, but this should be much better when we reset the cam timing to the specs we like to run for these engines. The big system gives 6 hp at the top end, with no improvement under 7,800 RPM. Although, the excessive richness under that may be hiding a mid range improvement. Getting the fuel right would give more power all through Id expect, so further tuning would likely give a more impressive result.
Dynograph courtesy of DYNOBIKE (03) 9553 0018
So, the improvement is probably not as much as some think it should be, based on the usual speculation and conjecture. It would seem, however, that the std systems work rather well, and improving on that can be hard if the best is not far away. Whether or not changing the cam timing will help the top end Im not sure, but I dont usually expect it to.
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