Well, is a little more subtle... When you modify your bike with more air flow and more fuel flow, in closed loop the ECU have as target lean moistures to reduce emissions and to save fuel. But anyway more air and more fuel is being delivered: so you can expect better driveability and get rid on 2000 to 4000 RPM jerkyness...Great so in the closed-loop it does not really matter as the ECU will regulate according to what lambda says, but at higher revs and open-loop it now provides the bike with the fuel it needs in able to make the HP's it was designed for, right?
Yes, your post is some kind off topic. Because this was about a BUDGET way to increase performance in a small displacement engine. But unless we got again "Super's 😘 Red Censorship" 🤣, this is a free topic. So let's understand what you are talking about💸 :Been browsing these forums for a while thought I would add up what I have found. Don't mean to hijack the thread, and apologies for straying off topic but I started responding and got too carried away typing.
I have been datalogging this bike with Hptuners MPVI2 via OBD2 adapter. This records internally (with the pro features option)
It does not officially have support for this ECU, but it grabs quite a few PID's through standard OBD2 canbus.
I have also installed an AEM UEGO wideband O2 on a cat eliminator. This particular model also will send its reading over OBD2 via an insert adapter you can see below. That way the data stream is entirely synced up and you can see more precisely what's going on. The AEM wideband I am using is the fastest response time of any wideband you can get with the exception of 1 or 2 others.
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I am also running a open top airbox of my own design and a powertronic ecu.
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This is one way to properly datalog this bike....but even then this is 1/2 the data I really need to tune this properly. Any more would require some canbus sniffing and likely carrying around a laptop.
Here is the PID's I am pulling. The 1 highlighted in red is from the AEM UEGO Wideband which merges into the OBD datastream.
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Basically I can tell you these injectors do have enough flow to get all the way to .8 lambda at 8500 RPM at full load and even richer.
There is no need to ever throw larger injectors in this bike, unless you are significantly increasing airflow way beyond an airbox lid and exhaust.
The problem is in the stock mapping.
Contrary to popular belief, this bike enters open loop all the time.
Closed loop operation happens at part throttle and cruising. But open loop is entered as low as 1500 rpm.
This is in an acceleration state. You can see below. (this was a a blip of the throttle at the lights, as you can see the only changes are map pressure and the narrowbands o2 reading. (The lack of MAF is just a design choice. Ford uses MAF, Dodge uses MAP, GM uses both. It does the same job as a MAF. People seem to think every vehicle requires a MAF but you can go either way, and there are +and - to both.)
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At the open loop portion it enters the matrix of its multiple fueling maps, there are at least 7. Some are for component protection (dumping fuel to protect the catalytic converter and O2 sensor) and some are combustion and efficiency tables. These get referenced and out comes your injector pulse.
I haven't fully discovered the logic as to when it enters into acceleration mode, but suffice to say whenever you punch it...you are there.....not just 65% throttle and 8500 RPM as some have stated (powertronic themselves i believe) it is usually accompanied by a fast twist of the throttle.
I can fully back this claim up as well with hard data. In my logs....literally every time I accelerate hard it is in open loop. The other clue is the STFT or short term fuel trims, which are responding to the stock narrowband and completely disable and show zero during all open loop operation, these completely coincide with the open loop states.
What I have found is stock, with no piggyback computer and cat eliminated and open top airbox...the stock ECU and injectors will hit as rich as .8 lambda at 8500 rpm full load. (Load is an OBD specified and inferred parameter but the MAP sensor also shows when you are there).
Where it runs into a little trouble is 5500-7000 RPM where with this combo it can effectively lean out to 1.15 Lambda and above....
Now at low load, a little lean is no big deal. At full load this is very dangerous. And it will happen with stock ecu and airflow mods.
This is effectively where the piggybacks come in. I am dialing in my Powertronic tables now incrementally.
While increasing the fuel pressure should help open loop operation, it can in a lot of vehicles be negated by the LTFT (long term fuel trim)
This can be reset by disconnecting the battery, however the ECU learns the LTFT over time from the info it receives by watching the STFT (STFT is near instantaneous and isnt kept in memory after turned off...you can see it in my logs)
LTFT's job is generally to adjust to changing conditions (wear, lower compression, dirty plugs ect) and is sometimes referenced and multiplied by the open loop tables. I have no reason to believe this is indeed the case for the Duke ECU, but there are some other reasons it may be better not to play with pressure.
A lot of data internal logic that would usually require sensors is inferred by this ECU....engine knock protection being the biggest one. The ECU infers things like octane and combustion limits from the combinations of sensors it has, and the change in fuel pressure could screw that up. There are at least 13 different ignition tables in this ECU....most of them are divided into high octane and low octane categories, which it has to infer from available sensors.
I'm not saying not to do it....just given any other option (like a piggyback) I likely wouldn't touch pressure unless I know there is a table for pressure and a pressure sensor as these modern ECU's are getting pretty advanced logic, and you don't know how a seemingly unrelated value will cascade. Some newer Dodges actually run neural networks instead of certain tables....suffice to say a lot going on in there.
Just FYI, scaling injectors properly is probably the single hardest part of any tuning job as there is way more that just pressure. There usually will be entire tables referencing injector response (not sure in the Dukes case) and almost always you need data supplied by the injector manufacturers unless you literally want to spend $15k on dyno time dialing in the injectors.
The pic below shows a Ford V10 Copperhead ECU injector controls. Each button shown leads to a separate table.
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As I told you this is a free topic and any point of view is welcome. No need to delete or move nothing.
Now I better understand your statement... So yes: there's need to enrich after flow mods. Nice info.
Octane rate is a measure that indicates the resistance to auto ignition of a fuel, or in other words resistance to knocking. 95 octane fuel is less resistant (prone to knocking) than 98 octane fuel. Pure ethanol is 120 octane (or more depending on the content % of water). Fuel Octane is determined by refinery. Higher octane fuels are indicated for high compression engines, so they can run more efficiently without Knocking issues. KTM recommend 95 octane fuel for this engine. So using 98 octane fuel as I recommend after a flow upgrade, provides additional safety margin against knocking.
Except for flex fuel vehicles, the only indirect (and cost effective) way for a ECU to know something is wrong with fuel's octane (or also lean AFR, or too advanced ignition, or cooling system malfunction, or intake hot air temperature, or chamber carbon deposit hot spots...) is knock sensor. Flex vehicles are more resistant to adulterated and low quality fuels. This Is why I stated several times in this topic that factory maps are conservative and able to cope with different and extreme conditions. Of course it comes at cost in form performance. Knock sensing system systems and their correction policy's aren't also perfect. The only perfect ECU is SAAB ION SENSING.
Tuning just for AFR doesn't grant max power nor efficiency. It only grants no lean or rich issues. To tune a vehicle you just need a Dyno (able to deal with partial loads to determine ignition advance maps). If you don't have means for that, do FPR tuning. I don't mind STFT at closed loop.
Factory settings have to comply with emissions regulations and yes, they kind of suck. But the way factory comply with that is optimal. As a result stock engine run most of the time at lean side but they are designed with this in mind. If you read carefully my recipe I work to minimize knocking issues by all means available. FPR tuning can arrive to 20% enrichment on this bike. But my calculations lead me to estimate that a 15% increase (4 Bar FPR) @ injector duty cycle with my setup is more than enough to avoid knocking with the stock ECU.
Interesting!And I would buy another piggyback if it had ion sensing
There is a bunch of DIY guys playing with it on home built ecu’s….very technical to calibrate from what I gather.
Hello Kevin. That is a good point.Hello Alf, grateful for your guide, I'm riding a 2021 Svartpilen, motor same as KTM 390, also paid/downloaded repair Manual; currently researching cure for lean and jerky fuelling on the Euro-5 2021 model. This spoils ride in urban traffic, on open road at high rpm bike is fine. Working through your numbers, appears that injection pressure is higher than the 3.0 Bar you quote; on the later bike already 3.2...3.7 Bar, possibly to improve emissions and fuel atomisation? Intend stripping the tank and pump, what extra pressure do you suggest to cure low speed lean running? Boosterplug is not made for bikes after 2019, shame. View attachment 54051
In fact Kevin, it would be great using an external FPR and gauge setup. But you first will need to pull out the stock FPR.Even more useful Alf, thanks. The factory special tool test tubing rig has a restrictor nozzle bleed off, presumably to mimic an injector, pump capacity is always excess to throttle body demand (my ultralight aircraft external pump shifts 130 litres per hour, but demand average 8l/hr). That system has an external Fuel Pressure Regulator with gauge in the tank return line, to keep closed until 3 bar is reached. On a motorcycle you could add a small FPR with separate return line to tank, but that would merely be 'short cut' by the internal tank Relief Valve, bleeding back to tank before it leaves out to the filter. More thought needed 🤔
Thank you Alf for sharing your experience! MauroWell ladies & guys: just pay attention because these are pictures that until now were unable to be found with such detail on Google...
First of all we have to distinguish between old style fuel pump and new style ones.
This is oval shaped old style one:
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These use standard FPR rated at a fixed pressure. You need to replace the FPR by other one rated at higher pressure to adjust air intake and exhaust mods. The good news: is very easy just remove the fuel pump and free the iron wire clamp and make the FPR replacement. The bad news: you have to purchase the new higher pressure rated FPR.
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And this is the new style fuel pump: it occupy less volume inside the tank so more fuel can be carried with a smaller tank. It also features far better sealing gasket and torque plate.
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The good news: it features adjustable stock FPR, no need to buy nothing. The bad news: the procedure is slightly more tricky:
Free the plastic enclosure of the fuel pump and retract the pump to make room to pull out the FPR. No need to remove the fuel filter bag.
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Insert a thin screw driver 5mm into the FPR hole and make some sort of lever to gently pull out the FPR.
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Use a CD pen to make a mark between FPR housing and the screw to see how much additional compression in form or screw turns you put on the inner spring.
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Adjust clockwise with an allen key until you reach the desired opening pressure.
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This is a safe and budget setup to a FPR. Air density is lower than gas density so to achieve 3,5 BAR opening pressure with gasoline, you have to adjust the screw to open the FPR with 3,2 BAR air. I set mine to 3,8 BAR on gasoline.
Make sure FPR o-ring is in good shape. Reverse mount everything.
For safety reasons, when dealing with fueling systems always disconnect the battery. This is also needed to reset the ECU, and force it to learn again closed loop operation with the new (or adjusted) FPR, air box lid, decat pipe...
The inmediate seat of the pants experience for this setup is better and consistent idling, getting rid of jerkyness from 2.000 to 4.000 RPM (better driveability), faster acceleration transitions and power increase noticeable from 6.000 RPM and up.
I need to get this Dyno proven, but not for me: just for all of you. 😉
Until then, enjoy your ride...