ST4S With FIM 5.9M Replacement ECU

Something many have been waiting for, this is a new ECU manufactured by FIM, using Weber Marelli based software (so it works with all std diagnostic tools) and adjustable with FIM software just like that for custom mapping the Weber 1.5M ECU, found in SS/M ie models. Fitted with the right connectors, this ECU may even make a good 1.6M replacement (or P7 for the 851?), given the number of them that seem to blow up (mainly Guzzi ones it seems).

Why a new ECU you may ask? Well, Duane spent a while trying to get into the 5.9M, but came to the conclusion his time would be better spent developing his own ECU. Weber Marelli obviously intend to use this ECU for some time, and their intellectual security has increased markedly with the advancing years. In inverse proportion to the size of the ECU itself it seems. Also, due to the fact they are an OEM supplier, they are not in a legal position to just hand out the ability to adjust their ECU willy nilly. And, more importantly for them, they have a lot of money invested in it’s intellectual property.

So, we now have the ability to adjust the 5.9M bikes. Not as easily as we have been able to in the past, when we ran with the original ECU, but that’s the way it goes. The ECU will retail for around $825 in Australia, a little bit more than a Power Commander, but with many more features. Things like thermo fan switching points on those models where the cooling fans are run by the ECU, starting lockouts, all that sort of stuff can be adjusted, or even turned off. Given the variation Ducati is now building into new models from year to year – S4 and ST4S especially – this means the maps for each year model are also slightly different. Just in the side function areas. And the replacement ECU will be just that – a generic piece that is the same for any model. It’s just the map inside that’s different. So you could run the ECU over pretty much the whole range, just reflashing the maps as appropriate.

How about a photo? As you can see, the FIM ECU at the rear is a bit thicker than the original 5.9M (in the foreground). Apart from that, however, it is pretty much visually the same. The connectors are exactly the same as the std Weber ECU, coming from the same supplier, so it’s all an easy fit. The FIM ECU screws to the std Weber heatsink of the 5.9M, meaning the assembled piece is a bit thicker than the std ECU. This only seems to be an issue on the ST4S, and is easily solved with a custom heatsink/bracket. Duane may choose to revise this a little in the near future anyway.

For more info, go to the FIM/Ultimap website : www.fuelinmoto.com.au

So, we come to the first application, the ST4S, which was Ducati’s biggest selling model in Australia last year. Just more proof of the fact that if you build something, people always want it with the biggest engine. The S4R Monster with the 996 engine will no doubt echo this. The ST4S is quite a good piece, and one that I have previously dyno’d with the Ducati Performance Power Kit. Given we had something of a standard for comparison, Duane was keen (and rather anxious) to see how his ECU came up.

The bike FIM used for the testing was a ’02 model ST4S, with a couple of mods. First up was the usual slip on mufflers, in this case Staintune. To make sure the testing was based on a known subject, we also checked and reset the cam timing. This was out between 3 and 6 degrees on all 4 cams – all retarded – which is pretty good for the "as delivered" Desmoquattro engine. We reset them to the std spec, for two reasons :

• That’s what Duane likes to start with.
• Given the shorter duration inlet cams, I wasn’t convinced that changing the specs would be worthwhile. Maybe a couple of degrees would help, but in the grand scheme of things, I didn’t see the point confusing the issue.

So, we gave Duane a ST4S with cam timing on spec and a clean fuel filter, and off he went. A couple of weeks later he bought it back to town, and I met him at the dyno for the moment of truth. He has maps for two set ups, simply being slip on mufflers with std airbox lid, and slip on mufflers with open airbox lid. The open airbox lid is becoming much more accepted these days as a way to get some more power, although it does make quite a bit of noise. Up to the owner, really.

I was quite surprised how unsure of the result he was. Maybe he’s just a little too cynical these days, but about 10 minutes later his mood had changed quite dramatically. The graphs below show why. The first graph shows the std airbox lid configuration. Green is the "base", which is cam timing reset to spec, Staintune slip ons and idle mixture trimmed as required. Red is with the FIM ECU, and no other change. Blue is this bike with Staintune mufflers before the cam timing was reset, or how it came "out of the box" if you like. This is included just to show how much difference the dialing the cams made.

The difference between the red and green lines is ECU only, and it’s fairly obvious why Duane was so happy. Frankly, I was quite surprised to see so much difference from an ECU change, but there it was. Also the rev limit is around 10,600 instead of 10,000 RPM, not that many ST4S owners will be revving them that hard I would imagine. Could very well be wrong.

The next graph shows the torque and lambda curves for these runs. I have a couple of reservations about the accuracy of the lambda curve for the after (red) run, as it seems to start a bit later than the others. It also shows the variation between what the dyno lambda sensor reads and what Duane gets with his probes (one in each header, close to the exhaust port) in an on road situation. With these maps, the on road result is a flat lambda reading all through the range.

Next we ran it with the open airbox lid and corresponding map in the ECU. This pair of graphs shows the same curves as the previous graphs, with the open airbox lid curve added in yellow. There is an increase of up to 5 Hp in places through the range, in line with results I’ve seen from other bikes when run with open airbox lids.

Next is the corresponding torque graph. I haven’t included the lambda curves, as the yellow curve pretty much mirrors the "red" one from the previous torque graph, and with them the graph gets rather crowded. The increase at the torque peak (7,000 RPM) is around 12% better than this bike had in "as delivered with slip ons" trim. This is rather noticeable on the road, although there is more noise too. Depends on how you like it. The basic shape of the curves has not changed through all the mods, which is expected given that all we’ve done has been minor cam timing, airbox lid and ECU mods.

The next graph shows the full before/after for this job, both power and torque. Keep in mind the before is with Staintune mufflers fitted, and the changes are those stated above (cam timing, airbox lid and ECU). Not much work for a change that looks very impressive on paper, and rides just as nicely on the road. Readers need to remember that a well mapped chip or ECU will make its impact felt all through the RPM/Throttle range, not just at WOT as these graphs show. On that point, the man who owns this bike is very happy, and rather impressed given his somewhat cynical view of how much difference an ECU could make prior to the mapping being done. He reports the bike feels much stronger, particularly in mid range roll ons– the area he spends most of his time in. Its ability to cope more easily with a pillion (and still be pretty damn quick) was also something he was quite surprised, and very impressed with. Green is before, red is after.

Comparing this bike to the one from the previous DP kit report, we see quite a bit of difference in the under 8,000 RPM range. Why I’m not really sure, as the DP ECU had a good lambda curve (on the dyno at least) as well. Obviously better fuel and ignition timing settings in the FIM ECU, making quite a bit of difference. Certainly apparent on the dyno anyway. I’ve included the before runs for the two bikes featured too, just to show how they compare. Green is before, red after for the FIM ECU bike. Yellow is before, blue is after for the DP kit bike. So you can see that, in std (well, std with slip on mufflers) trim, the bike that got the DP kit was a bit stronger. Being that the DP kitted bike was a ’03 model, with its std adjustable cam pullies, I would expect the cam timing on that bike to be very close to what we set the FIM ECU bike to. The DP ECU is available from Ducati Performance as a separate part (to the complete kit), for around twice the price of the FIM ECU. Which makes the decision very easy.

Next is the corresponding torque graph. Those 4 or so extra ft-lbs. under 7,000 RPM will make the FIM ECU’d bike feel very fat indeed.

From the shown graphs, Duane definitely has reason to be happy with his efforts, as the results pretty much speak for themselves. An adjustable 5.9M ECU is something I’m happy to see as well. All we need to do now is a whole lot of testing to get base spec maps for the various models, then we can start playing with them all. Lots of seriously good fun.

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