If you have your acceleration tables appropriately enrichened, then there shouldn't be an issue... most of the acceleration happens at or near WOT... which the EFI system determines..and I believe it designates 'being close to WOT' as WOT... I don't remember the % now, but I 'think' I remember it being above 85% open.

One caveat is that I run the TTS Mastertune system, which uses the stock EFI system and the stock narrow band sensors. I have no problems.

 

Sorry to hound you but you know what you're talking about and I am a student of EFI! So at or near WOT there is no correction based on O2's, which means you have to make manual corrections in these ranges in your TTS map, correct? I am curious how you program these systems since it appears that data entry is usually in AFR, but since you are using the narrow band you can't do this... yet if the motor on the bike is modified then the at or near WOT requires a longer cycling of the injectors. Seems like without a wide band sensor it's just a guess since the actual AFR isn't ever measured. Then the data entry is in duty cycle? Pardon my ignorance, I want to learn this so I get the right system for my bike and tune it correctly.

 

I was digging around the internet and found this excerpt which is interesting:

Because of the large amount of questions I receive about the O2 sensors and all of the incorrect information we have seen on the Harley EFI, I will further explain how the closed loop EFI system works on the Harley Delphi system and why Dynojet has developed the Power Commander with O2 sensor eliminators. First I will start by explaining how the narrowband O2 sensor works. Keep in mind the O2 sensor is only one of the many sensors which monitors engine functions in the speed density system and with the O2 sensor eliminators installed your EFI system will continue to constantly adjust for changing conditions as you ride such as temperature, altitude, humidity, etc.. based on the ECM's programming and lookup tables which are very accurate at providing the proper fuel and ignition timing requirements for the stock components (although the calibrations are very lean which is why we are tuning in the first place). The O2 sensors are not used to calculate fuel requirements, it is simply a feedback device to ensure the air fuel ratio in the cruse areas is within EPA requirements to maintain a 14.7:1 A/F ratio. The narrowband O2 sensor can only accurately measure a small area within 14.7:1 stoichiometric air/fuel ratio range and works by providing a voltage signal to the ECM which then will continuously monitor the stoichiometric mid point crossover and adjust accordingly until the A/F is in the 14.7:1 range. The ECM is only using the O2 sensor feedback signal when the system is in closed loop mode. Closed loop mode occurs only under certain conditions which are light load, steady speed part throttle, constant mode below approx 40% throttle. It is only after these conditions that the will EFI go into closed loop mode and the ECM will adjust until the O2 crossover point is in the 14.7:1 A/F range. Simply put, an narrowband O2 sensor only works for adjusting low load/cruise area and does not work well in performance applications because it can only monitor a small area within the stoichiometric A/F range. With that being said, yes the stock EFI can adjust itself on the these Harley models. That is if you consider the small amount of time it is in closed loop, and then when the ECM is able to adjust A/F it can only adjust it within the 14.7:1 range which is WAY too lean. For reasonable performance and drivability this 14.7:1 A/F is extremely lean and this is the reason for the 07-08 bikes to run very hot with poor drivability. This condition gets even worse when you change your exhaust or air cleaner. Optimum A/F ratio for cruise area is 13.4-13.8:1 and 12.8-13.2:1 for wide open throttle. When you install an aftermarket EFI module (regardless of manufacturer) for the ability to tune below 40% throttle you will need to utilize O2 sensor eliminators. This will prevent the EFI from going into closed loop mode and you will be able to tune to an optimum A/F ratio for the bike to run properly, otherwise the stock O2 sensors and closed loop mode will try to lean the mixture within the 14.7:1 range. Even with the Harley Screamin Eagle Race Tuner in which you can retain the O2 sensors, again you can still only work within the stoichiometric range which is the only voltage the O2 sensors can measure. Dynojet certainly has the technology to develop a Power Commander for the Harley models with a Wideband sensor that replaces the stock O2 sensor which would be able to tune in real time to target A/F ratios, Power modes etc.. although with the relatively simple design of the Harley/Delphi injection the current Power Commander USB is more than capable of adjusting what we need to adjust at the moment. Keep in mind in Japanese applications the Power Commander is widely used as well in EFI systems that are far more complex than the Harley Delphi system with technology such as Dual ECU's, computer controlled secondary throttle blades, multiple staged injectors for each cylinder, fly by wire throttle and servo operated variable intake length. From our experience tuning bikes everyday we know the Power Commander is the best EFI module available and works like no other to effectively adjust the EFI in the full range of RPM's and throttle positions, including the light load/steady cruise areas. Keep in mind that our maps are developed using different modes for light load/cruise area and for upper RPM full throttle performance. We have seen excellent results on the these bikes and with these mods you will see substantial performance and cooling which will increase your riding enjoyment. I hope this has helped with any questions.

 

As to the closed loop operation, the TTS allows you to modifiy the AFR by adding a bias setting to the signal, as stated in that excerpt you posted. All of the other tables are "lookup" tables, that the system uses when not in closed loop. There are quite a few tables. What the TTS and most other systems are doing, is maintaining the AFR based on what it knows about the engine. My software allows me to map the VE (volumetric efficiency) of each cylinder. It then merges that information into the 'map' that gets downloaded into the Delphi ECM. The cool thing about the TTS, is you can do your own "tuning" runs, which is to say more specificially, you can perform your own datalogging of RPM vs: Throttle position, and mapping of the both cylinder's VE.

As for guessing what should be good settings.... bikes been running on carbs for years... .. all the lookup tables are allowing you to do, is electronically make carb/timing adjustments.

 

Got it, your explanation is clear, thanks.

 

I recently bought my bike and previous owner had the SE stage 1 air cleaner and Python Staggered Duals (without baffles) put on, but didn't have anything else done to it. I didn't think anything of it as I am just getting back on a bike after a 6 year hiatus and never had a EFI bike before.
Anyways, bike just wasn't right, ended up having a PCIII put in, dyno tuned, the cylinders mapped, and added baffles for some back pressure. What a difference, runs great.

 

I would recommend getting a tuner for your ride. You will be happy with a good tune. Get it dyno'd for best performance.

 

If you have no problems after checking plugs let me know. the only issue i foresee is overheating of cylinders

 

This comment has me a little confused:

Keep in mind the O2 sensor is only one of the many sensors which monitors engine functions in the speed density system and with the O2 sensor eliminators installed your EFI system will continue to constantly adjust for changing conditions as you ride such as temperature, altitude, humidity, etc.. based on the ECM's programming and lookup tables which are very accurate at providing the proper fuel and ignition timing requirements for the stock components (although the calibrations are very lean which is why we are tuning in the first place.

However the O2 sensors are the only true feedback sensors, i.e. in closed loop the aggregate of the base map as adjusted by all the "other" sensors is trumped when the O2 senses an AFR other than stoichiometric. It seems everyone likes the PC III but my understanding is that you have to disconnect the O2's - wouldn't this mean you would lose the fine tuning the O2's provide while in closed loop to compensate for modest imperfections (as adjusted +/- by the other engine sensors) in the base map? Wouldn't the TTS system would be best since it lets you actually change the ECM map, maintaining utilization of the stock O2's to provide their signal to the ECM, so that consequently fuel adjustments are constantly being made to maintain the correct AFR, maximizing engine performance in closed loop, while still allowing adjustability in open loop?

 

Just to add my two cents and opinion. You have to take a lot of what a manufacture says that happens to sell a product with a grain of salt. I've heard that Dynojet has been telling us for years that they have the best product out there, then add on something a competitor does much better and now it is the best product out there, really it is. They want to sell and will spin their marketing content, not that its wrong or incorrect, just leaves out distracting opinions or data.

The quality of fuel from tank to tank and station to station has become inconsistent in recent years. Unless there is a plenty of margin built into the fueling maps, these variations can cause havoc in any open loop system, causing potential harm. The biggest advantage to O2 sensors is that the O2 sensor provides indirect feedback about the quality of the fuel in your tank at the time, therefore you can tune closer to the edge without worry. The ECU will adjust when and how much fuel is squirts, and when to light it off to provide optimum power and mpg for the fuel you happen to be using.

As far as what tuning tools like TTS, the engine is an air pump with efficiency and flow characteristics (known as the VE) that vary from engine to engine off the production line. The better you can characterize the engine VE for each rpm and throttle position, the better the ECU can provide optimum fuel mix. TTS gives the DIYer the tools to calibrate directly the engine VE for about 85% of the operating range (normal street riding) and allows you to intelligently extend the measured values to cover 100%, both open and closed loop. The open loop (WOT) VEs are very important as the VE table, along with what the ECU learned about the fuel quality while operating closed loop, is used to determine how much fuels is needed to reach the target AFR you or HD set. TTS base maps also offer more performance oriented algorithm tweaks (fuel delivery and timing) than the emission optimized OEM.

So you have your VE indirectly calibrated (as a dyno operator would), have your AFR maps set so that the ECU only has to make minimum adjustments (it feels better) and your target AFR is set as you want (as a dyno operator would). Since you have the O2 sensors to adapt to fuel quality, you don't need to build in power and mpg robbing enrichment margins that a closed loop system must do.

It gets much more complicated once you go beyond pipes, airfilter, and mild cam, but that's the basic advantages for the street. There is no substitute for a good pro if you want to get the most out of a bike for your riding style, but sometimes good is good enough.

As most here have said, you can't go wrong with a good tool like the TTS tuning kit in your box, but you certainly can have plenty of riding enjoyment just riding anything from stock or a bike any of the named tuning products. And your satisfaction is such a personal judgment call, that there is not one answer that fits everyone. There are those of us that just enjoy the ride and those that fret the details.