S2R with ARROW full system and U59 ECU - Written Sept ‘05
The S2R I tried my cat replacement pipe on in the first S2R report came back with the Arrow system fitted to be tuned using the Ultimap U59 ECU. Unfortunately, due to a Brad induced error, my first attempt was something of a waste of (a lot) of time. But you learn from that and move on. As we did.
My screw up didn’t affect the high throttle results however, so all that stuff is still valid, and we can show the results. It’s always a mixture of fun and fear when you’re making a new map as it always depends on how close your initial starting map is. Given we don’t have any S2R maps to really work from (you can extract them using the Mathesis road test function, but it’s very tedious) we made a bit of an educated guess and went from there. I now know why my educated guess appeared so wrong at the time, and a simple mistake cost me a full days work and some expensive dyno time. My way of endearing myself to the boss.
I’ll start with a graph of all std in green, my cat eliminator (otherwise all std) in red and Arrow full system (otherwise std) in blue. The full system does have a midrange dip of sorts, but it occurs at higher RPM than the dip induced by the system I had made. I’d expect the addition of slip on mufflers to the pipe I had made to also reduce the dip, but it is still a function of the style and size. Certainly the result is still not the same better overall change that the 800M showed with its typical Ducati header design. Power first, then torque and air/fuel. Typically the rich bumps correspond to the dips.
Before any mapping started we did a 10,000km service on this S2R and checked the cam timing. I’m starting to wonder why Ducati bother fitting these adjustable pullies they could have saved a fair bit of money doing it the old way. Certainly the 749S we’ve reset haven’t been too bad, but the S4R we’ve checked and this S2R were quite off. The horizontal inlet was retarded 8 degrees (118 centreline) and the vertical retarded 6 degrees (116 centreline). The bike had been dyno’d before it came in for the 10,000 service and given the shape of the curve I wasn’t too sure what the result of advancing the cams 6 and 8 degrees was going to be. But, the result was what we’ve seen many times before basically lifting the whole curve. The graphs below show the power then torque and air/fuel changes from advancing the cams 6 and 8 degrees to the 110 degree inlet centreline spec. Green as delivered, red cam timing set.
What had concerned me about setting the cam timing was that the before curve was tapering a little at the top end. I was concerned we may lose a little top end, so didn’t go any further than the 110 degree centreline spec. Having seen the results though I’d be inclined to try 107 or even 105 just to bring up the middle some more.
Next we added a Ducati Performance air filter kit and the Ultimap U59 ECU. I ran some WOT fuel and spark runs to see what it liked in terms of mixture and ignition advance. The best power for this combo is shown below as compared to the previous, cam timing set graph. The air/fuel with the U59 ECU isn’t as yet optimised, but the various runs I did showed it did make it’s best power with an air/fuel of 12.6 12.7. Green is before, red is with U59 and DP air filter kit added.
Including a lightened std flywheel (around 1050 grams machined off) which we also did at the 10,000km service, the above changes (cam timing, DP air filter kit, U59 ECU) took 0.4 seconds off the time taken to accelerate the dyno roller from 60 to 160km/h, which is a pretty good improvement. The cam timing change alone taking credit for 0.25 seconds. Compared to the all std runs at the start, the total changes Arrow full system, DP air filter kit, revised cam timing, U59 ECU, Lightened std flywheel and 14 tooth front sprocket - have taken 1.1 seconds off the 60 to 160km/h dyno roller acceleration time. Going from 5.3 to 4.2 seconds, that’s about 20%.
The graph below shows from all std to the final result. A nice improvement all round. Power first, then torque