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Tuning your fuel injected motorcycle
Riding at low throttle and low rev zone my bike suffered the snatchiness described. I have owned a few Ducati motorcycles and thought this was quite normal for a 90° (“L”) twin; this is a problem because small throttle openings combined with low RPM response is critical to normal road riding. Checking out one of the Ducati forums I found similar problems being described, the cheap fix being to merely change the gearing, recommending a 14 tooth sprocket on the front (primary sprocket). Nice for acceleration but no real change in the snatchy feeling and this would probably affect the overall fuel consumption. With this in mind I opted for the more expensive Power Commander route, but further research found me exploring other ways of improving torque and mid range power. I turned to the internet once again and found an article that confirmed, using data from a dyno, that there was little to gain from fitting free flow end cans unless you are interested in outright power. The place where real gains could be made are in the air intake department and surprise, surprise there is a modified air box lid and filter listed in the Ducati Performance parts catalogue. In step JHS (www.jhsracing.co.uk) - an independent dealer specialising in Ducati servicing and tuning racing motorcycles. James, the owner and his team have looked after my bikes for a few years and have always done a great job, nothing is too much trouble (edit=AndyW: I'll second that - best thing I ever did with my SV1000 was take it to JHS to get the ECU remapped. Great service!). I rang James and discussed in detail what I had planned for my bike, he agreed with the intended modifications and would tune the bike with torque and small throttle opening in mind rather than out right power. Parts were ordered and a rolling road (Dyno) session booked.
The first run was in standard trim. The engine managed 94.9bhp with a torque reading of 57.78ft-lbs at the rear wheel which I’m reliably informed is about right for a standard ST4. [Ducati claim a slightly higher figure of course!] The interesting bit came after the modifications were done and with James’s expertise in optimising the fuel / air ratio; the outright power was up by 10bhp and a healthy boost in torque to 63.13ft-lbs. To understand what’s going on you need to study the dyno graph below which shows a linear power delivery from about 2500rpm through to 9500rpm. You will note there are two dips in the original graph presumably around 6000rpm to meet emissions control legislation and at 8000rpm to keep the noise down.
However the real story lies out on the road.........and what a difference; the air-box mods give a nice throaty roar when the throttle is opened, certainly not too much to live with. The engine is dead smooth, the snatch down low is gone and the big shudder from too much throttle at low revs is much reduced. The increased torque in the midrange is impressive. This bike normally returns about 45mpg; I have checked this on a long club run and confirm 50mpg +, so all in all a slight but welcome improvement in fuel consumption as well! I have been advised that what I have done will not affect my next MOT which is nice to know. However it is important to let your insurance company know of any modifications to your motorcycle, although my insurer was not that interested because the bike itself has been modified as such. Finally a note of caution - I am not a automotive engineer and therefore cannot recommend anything I mention here without seeking professional advice. In other words don’t blame me if your pride and joy blows up!!
The PC uses original equipment style connectors so that no splicing or cutting of the bikes original wiring harness is required. Most installations take less than 15 minutes, some as little as 5 minutes. Changes are made to the bikes fuel curves via the PC's onboard microprocessor. Using this technology we are able to offer a large area of adjustment without making any permanent changes to the bikes' ECU. Removing the PC returns the bike to its previous stock condition. The Power Commander can be ordered preprogrammed with a your choice of several settings, based on the modifications to your bike. The unit also comes complete with software and cable link that allows you to change between different maps or make adjustments to a map file. < Back |
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