Ducati 2 Valve 1100 - Individual Cylinder Fuel maps?

[gt6racer2]

Hi, I'm about to purchase a fuel map device for my Hypermotard.
As background, the stock system has a single O2 sensor located after the two header pipes come together which provides a signal for closed loop feedback at low throttle and rpm. (<20%throttle, <5,500rpm). Above this range the stock system then goes to map based open loop.
My new device (Power Commander V) will not change basic process for low throttle operation, but will move the map base a little more rich. For higher throttle/rpm, the new device will have an autotune capability, whereas the signal from an additional O2 sensor(s) will be used to automatically develop the fuel map to a predefined air/fuel ratio map.
My question is whether it is considered that the fuelling needs of the two cylinders are likely to be different enough (due to temperature difference etc..) that I should have two sensors, one for each cylinder, or if one would be sufficient. My concern would be that if the difference between the fueling needs of the two cylinders is significant, with one sensor I'm running an average - ie one cylinder rich and one lean. Cons of two sensor setup are cost and complexity - I'd need three O2's - the stock one plus one in each header.
Thanks, Andrew

 

[gt6racer2]

Update : The weather has improved and it is riding time. The bike is running great with a map I downloaded from Tuneboy, but my datalogging shows I'm down at 12:1 AFR at idle, 12.5 at cruise and 13.7 at higher throttle/RPM. To me that's a bit backwards - I'd expect to want to be lean at cruise and have a bit more free fuel at higher throttle/rpm. I'm thinking to make some changes.
I am able to build a target AFR map in Tuneboy, which the Tuneboy software will then generate a new fuel map that it expects will give the desired AFR. However, I'm not sure what I want to use as targets.
I suspect this question may be akin to "how long is a piece of string" (dependent on engine and performance goal variables), but knowing that I am running the Ducati 2 valve 1100, stock other than inlet/exhaust mods (no CAT), can anyone recommend suitable AFR targets ?

 

[BrianPetersen]

13.7 at full throttle on an aircooled engine is too lean, 12.5 at cruise is unnecessarily rich.

For a ruff guess, try 14:1 or thereabouts with throttle position below 20%, 12.8 or thereabouts at 50% throttle and above, and smoothly blend them in between. It is distinctly possible that you will get a rough, unstable idle. If that happens, add a little more right down at idle speed and throttle.

On a liquid-cooled engine you can run "lean cruise" for better fuel economy, but without EGT and/or cylinder head temperature monitoring, I'm not sure I'd try it in your case. Below 20% throttle, there is so little load on the engine that it shouldn't be a problem.

 

[gt6racer2]

Brian,
Thanks for the comment - it seems very logical to me and in line with my own thinking. At the bottom end, the bike stock (with CAT and closed loop control)ran OK but was always notchy/digital/jumpy at small throttle, and the extra fuel it has now has certainly smoothed that out, but I think it is more than needed. I'll move that to 14 and then adjust a little if I see that issue coming back. For mid range/cruise I will lean it up as I have lost some tank range - a significant concern as the tank is small. I'll move high end to 12.7.
I'm aware that modern engines with appropriate designs, materials and controls run much leaner than this, which is why I particularly appreciate your focused response. Thanks for that.
BTW I'm logging invidual cylinders now (conveniently the later 1100 models have twin 02s so it was an easy header swap to gain the wide band mounting points), and will initially use the same AFR target for both cylinders to see where the fuel maps come out. I know what the frt/rr fuel map delta was stock ( rear gets a litle more fuel ) and I will compare that with what I get after tuning. I suspect I might then have to give the rear some more fuel, to keep it cool.

Andrew

 

[SimonO88]

Does the power commander allow ignition changes as well or only fuel? Ideal targets are obviously stoich for idle and cruise then tapering down to 12.4 (ideally)at high rpm's. Easiest way to do it is find a local braked dyno with a bike rig and try to get some time to spend on the maps

 

[gt6racer2]

Simon,
I have Tuneboy, and yes I can change ignition too, but I haven't changed it at all. I've talked to the local dyno guys, and they had suggested I build a few maps that run well and then make a run with each of the maps to see which is best. ( They don't want to use Tuneboy to tune real time on the dyno).
However, I'm not out for the last ounce of performance, so I'm going to just use the AFR gauge/data, my butt dyno and fuel economy to set my direction.
BTW I have my maps set up and loaded as per AFR targets recommended by Brian. The bike runs great, and is revving at high end more eagerly now. Fuel efficiency is back to what it was before I started playing, so life is good and I can get back to riding.

Thanks to all for the input.

Andrew