| Author | Message | ||
     Xoptimizedrsx |
I had stated you cant make a tune in one location to fit all conditions and fuel types everywhere. Blake stated "excerpt" to get us started on the debate only. "Seems to me that as long as the O2 sensor and other atmospheric sensors are being employed, a good tuner ought to be able to do a pretty good job of mapping an ECM to work well in most places." Oem's check and verify under many constraints. I need help finding my Atmospheric sensor/s on my XB's 2003, 2005 and 2007. I do not see it. I do not see a baro, maf, map, and ect. 16cm^2 of pressure at sea level. fixed physics as stated in the video at the end as well. (correction its 14.7 psi not as posted in video) But, some say just turn off a sensor and it will be just fine.... Which is it then? sensors Off or On in a FI engine (with limited sensors) something on all engines to get us going: http://video.answers.com/learn-about-car-engine-ai r-induction-76372623 No we start the debate so we all know Including Myself... Base from what sensors we have and what additional sensors we would benefit from having added to the system. (Message edited by xoptimizedrsx on March 04, 2011) | ||
| Crackhead |
I believe 03-07 use a combination Alpha-N at low rpms and switch to speed density at higher rpms. To adjust for atmospheric conditions you need a IAT, and map sensor to run before the Throttle body and a wide band. The older EFI system is to basic to be correct all the time. Also, it appears that some "tuners" disable the ecu learning functions. (There was a spat about this in the 1125 board) The learning function does take time to work correctly and requires going through the various drive cycles. So, if you are trailering your bike from Denver (1 mile elevation)to the Salt lakes, it will run lean until it adjusts the maps. For racing on the salt flats, disabling the learning function is fine and quicker if you have access to a dyno, and lock in all of the variables for each run. | ||
| Speedfreaks101 |
Stock engines with a stock tune do not all run the same. Some run richer - some leaner. This is a tune that was found to work in the all conditions in which it which the engine were tested. So yes a tune can be designed to work for a setup that is exactly the same across the board and get by and do so fairly well. This is considering that they will be running leaner for in order to pass emissions, compared to a engine running richer that is tuned for power. The leaner engine is more prone to detonation and hot spots (preignition). When tuning for power you want are not looking for a compromise. You can use a tune from an engine with the same setup as a base map but it can be improved. In your goal of increasing efficiency you run into variables: cam timing, head flow, tight/loose rings, blow by, engine wear, variation in sensors, etc. There are too many variables plug and run without testing with a wide band under load. I have run tunes both ways and tuning to a specific engine under load is the best way and without was only a step in a process to get it correct. I have run tunes from same engine setup as mine only to get a hiccup and fart out of the engine. All engines parts are not created equal, and increasing efficiency seems to only make the issue worse. As far as shutting off the sensor that seems to defeat the ability of the ECM to assist the engine in correcting for ambient conditions. Seems like to me that a better solution would be to see if we could add the second O2 sensor like the 2010 bikes to the other years. | ||
| Ericz |
The 10min video (a guy who has some good information but is too general with his remarks on what someone would need to do to increase hp or that a MAP sensor is needed to run forced induction) informs us that there is 16psi at sea level but it's actually 14.7psi. I don't think that it is the best video for uninformed people to watch and learn from. Air density is a function of air temperature and air pressure as seen here: http://en.wikipedia.org/wiki/Density_of_air and the DDFI systems have an intake air temperature sensor. That handles half of the equation. While the DDFI systems do not measure air pressure, they do measure air/fuel ratio. The air/fuel ratio is proportional to air density, and so with air/fuel ratio and air temperature, air density can be calculated. This is the main principle behind the DDFI systems. A fuel map that runs well at sea level will run exactly the same at a higher altitude at the same air/fuel ratio. Mike, your units are very confusing. What is cm^2 psi per Sq inch? A square centimeter pound per square inch per square inch? There are no sensors that should be turned off unless the user wants the engine management to work differently than it is designed. There is no debating this issue since the facts show that the DDFI systems have the ability to correct for altitude changes and temperature changes without the use of a MAP sensor or Mass Airflow Meter. | ||
| D_adams |
If you alter a stock ecm, then the only true way to retain those settings is to do exactly that, disable the learning loop mode. I may be way off on this, but if you don't, the ecm will revert right back to the EPA mandated settings, which are a little on the lean side. You can disable the learning mode and still utilize all the other available sensors. They will continue to compensate for atmospheric changes in temp, baro pressure, etc. Unfortunately, narrow band O2 sensors are only good for a very small range and will only report an on/off condition as the air/fuel mix passes by them. It's tough to really tune (to me anyway) with the stock O2 sensors in place. I wouldn't recommend doing this without some way of monitoring the engine and what it's doing, either a 4 or 5 gas analyzer or wideband controllers for both cylinders. I've also never understood the single cylinder tuning method on a v-twin. They definitely run different between cylinders, the stock fuel maps are a perfect example of this as they're not the same when compared front to rear. They may be similar, but not identical. I never looked at the ignition timing maps for them, but I'd assume they're probably different as well. If you alter just the rear to run correctly, that throws off your front cylinder. You can't just make changes all willy-nilly and just "hope for the best" with the expectation that it will run right. Making global adjustments isn't the answer either. Shifting the amount of fuel up or down to meet what ONE cylinder needs will have an effect on the other and it may not be what it really needs. This is where having a dual setup is (IMHO) an absolute necessity. Mind you, I'm not a tuner, nor do I really have a clue about what I'm doing. | ||
| Xoptimizedrsx |
This is not suppose to be about who is right or wrong. (unless direct equations are wrong as in the starter to get us going as Eric pointed out) That was used to get a topic started thats all. General data. I didn't pre check that info on the 16cm sq... My bad... 14.7 psi is correct as he posted. It's about what is right and what it wrong... Post should go as "How it works", "How I think it works", "How did they do that" style and so-fourth... ( I hope.) links and better data as well as video links are encouraged. | ||
| Blake |
Thanks Eric! Air temp is an atmospheric condition Mike. | ||
| Xoptimizedrsx |
What about the rest of the conditions and measurement sensors needed? This topic is not limiting to Just our bikes for gaining and sharing Knowledge for everyone. I am sure we all already understood air temperature is an Atmospheric condition. Blake | ||
| Ericz |
Mike, what conditions exist that the sensors on a stock buell can't compensate for? I don't know of any besides humidity and fuel composition, but I also don't know of any other mainstream engine management that can. | ||
| Sloppy |
Blake's right. Here's an example of a sensor that is a function of atmospheric conditions. Oxygen sensor The reading of residual oxygen is dependent upon mass of inlet oxygen (ambient condition), volumetric efficiency (throttle position sensor), efficiency of combustion (ignition advance) and fuel mass (injector pulse width). Mass of oxygen is a function of density = P / T. P = function of elevation. Anyone up for Physics 101 or my favorite topic, Thermodynamics??? | ||
| Xoptimizedrsx |
If a stock engine in a Buell can compensate 100% on its own,why in the world are their companies and individuals retuning the fuel maps to get a correct mapping for the bikes. Then said tuners maps actually run better than factory oem maps with O2 on. If tuned maps are better running and smoother running. The O2 is in the rear only header pipe. therefore its bias to adjusting to rear conditions only. If the front conditions are opposite it becomes corrected in an even worse condition to match the rear by global correction. This is the basic issue I see in the ecu. To correctly get corrections working you need an egt as well for (ignition advance) last I looked, neither NB nor WB can check other gas levels. Earlier Buell xb's also do not have the map sensor like later Buells have, another condition checking device as already pointed out. ddfi3 vs ddfi2... ddfi3 has two O2's and a map sensor which does 100% better than the ddfi2with correcting to the needed conditions. Three facts on the fueling and controlling fuel not in the fuel map. There are more but these are basic. Fact:1 fuel map per-say,the map does not have an effect on the actual mixture during acceleration condition. This area during that time is fully controlled by accel enrichment table and other factors. same for decel enrichment table.(actual fuel map values altered) Fact:2 If you do not change the maps in the ecm but only change decel and accel tables you can see a change on the dyno and in the O2 value during TP change, This is when acceleration and deceleration conditions are met every time at any rpm and tps degree. accel addition can boost or lower afr. Just as decel can cause less or more engine breaking. Fact:3 During these accel/decel moments, the O2/Gego are ignored until said conditions have met within accel/decel. At that time the ecm returns to standard functions closed/open loop. This topic seems to have gone the wrong direction. It was intended to gain other info and share info on "How things work" not try to beat up on anyone or any company. Maybe this addition gets things on track... | ||
| 1324 |
Mike, This should clear things up for you: http://www.engineeringtoolbox.com/air-temperature- pressure-density-d_771.html | ||
| Xoptimizedrsx |
I already have that... Like I stated this seems to have gone the wrong direction... add this as well... resolution Just ride it. If it breaks fix it...http://www.engineeringtoolbox.com/combustion-boiler-fuels-t_9.html (Message edited by xoptimizedrsx on March 05, 2011) | ||
| Ericz |
I think that a "correct" map is subjective. To compare different maps and their performance, you have to also understand the goals of the tuner. Did they go for max hp, did they want it a tad rich everywhere, were they tuning for max fuel efficiency, and how did they prioritize power, runability, and efficiency? | ||
| Xoptimizedrsx |
Very true Eirc. Which all depends on the settings in the ecu as its target values that control the stioch running condition. If targets are not adjusted it will closed and open loop default to 14.7 anyway with correction on. One is Gego Instant, the other delayed but both correct the fueling at all times(hence global AFV). As long as its with in range of the correction factors. Out side of this range you need a new map, its do to sensors and correction limits. If front and rear balance is opposite(one wanting less and the other more fuel.); a new map is needed to put it in balance and let the sensors do their intended job. The only issue I see as posted(IMO) is the balance from front to rear. Especially on a pipe mod and air box change. one cylinder may want a little more fuel and the other was already good say front for example. now the global was changed making the front to rich but the rear is now good. A never ending fight with a non balanced map using global settings to correct both maps as one setting. a slight change at humidity and baro pressure, not drastic though unless the balance was on the threshold of being too far off is something else spotted. I have ran mine all sorts of ways. rich most power (bad fuel mileage I can say) lean best mileage (a little hot). one cylinder rich the other lean to see what the datalogs was doing then reverse of that and repeted the logs. I have ran it with one row rpm row rich with the other rows in correct areas. This was done to see how fast the correction happens on the dash O2 LC1 xd 16 units front and rear... open loop takes about 3 seconds and closed is less than one to correct. The offset(map) one rich the other lean in the same cell locations was the best to see the movement on what is happening. If the rear was rich and front lean (on purpose) the rear was correcting to a good value but the front was going way lean do to global movement of both maps. When I flipped the values to lean rich in opposite order I got opposite results. Most running issues are only present when a imbalance in input in the front to rear relation. It actually ran well lean and rich balanced... It also corrected pretty well as long as a balance was set with out going to wild cell to cell on the values. I even put the O2 on a switch to flip from one to the other,you could watch the cells flip flop seeing the ecm do its job on correcting. I have done all sorts fuel settings, data logged and ect already. I have changed pipes and did it again. The pattern is pretty much random in values but in balance it seems to keep the steady rule. They got to be in sync or it gets goofy with all the apples in one basket (one O2). some pipes you see it quicker, others less as drastic, however, both do it the same at different intensity. DDFI2 is what I am referring to in these test. This is what I saw on my test and my opinion... be it right or wrong... | ||
| B1bomber |
Why is it that the Buell DDFI1/2 systems are so finicky , and hard to get right , unlike the other FI systems on other modified sportbikes I have ridden on , such as Ducati's , and the new BMW 1000RR ? Those seemed flawless . Are their FI systems better ? Is it because the DDFI2 works in such narrow parameters ? The one O2 sensor ? Or maybe because the XB's are air cooled , and temperature cannot be monitored and controlled as well as modern water cooled bikes ? I have always wondered about this . Do the newer Buell DDFI3 systems work better with the dual O2 sensors ? Are they easier to tune ? What about the 1125R FI system , is it easier to tune with better results ? All of the statements here are just my opinions , and I by no means know half of what you guys know about the FI systems , it has just been what I have read , and gone through with my XB . By the way , very interesting post all , thankyou . (Message edited by B1Bomber on March 06, 2011) (Message edited by B1Bomber on March 06, 2011) | ||
| B1bomber |
Sorry , kind of off topic . | ||
| Froggy |
Those are good questions B1, I'll comment on some of them.
Yes, the DDFI3 bikes are fantstic. There is more too it than just a second O2 sensor. The second sensor was only on 2010 XB models, but all 1125 models. The 1125 uses the same DDFI3 system as the XB, just a different programming for the different motor. The DDFI3 also supports additional sensors like MAP and Barometric pressure to allow even more control over the bikes operation, but they are used on the 1125 not XB. The early OEM tunes on the DDFI3 bikes weren't that great, but the current ones are fantastic given the need to meet EPA requirements. The Race ECM from Erik Buell Racing makes all the DDFI3 bikes run simply amazing. | ||
| B1bomber |
Wow, thats cool . Makes me wonder how his new bike runs . Probably fantastic ! | ||
| Sloppy |
This topic is more twisted than a bowl of spaghetti. Now who really believes that this subject can be covered in a bulletin board??? Move along, nothing to see here... | ||
| Xoptimizedrsx |
yep, it didn't go as planned,therefore it is time to move on to riding time. | ||
| B1bomber |
Mike , it was still informative , and I did learn from it things I did not know . I'm sorry if I got it of track . | ||
| Blake |
B1, "Why is it that the Buell DDFI1/2 systems are so finicky , and hard to get right , unlike the other FI systems on other modified sportbikes I have ridden on , such as Ducati's , and the new BMW 1000RR ? Those seemed flawless . Are their FI systems better ?" You might want to educate yourself on the world of motorcycle fuel injection, these flawless Ducatis EFI issues, including a recent safety recall for instance, or these BMW EFI issues, or maybe these Triumph EFI problems; maybe you also missed these others... KTM EFI problems Yamaha fuel injection problems Kawasaki fuel injection problems Suzuki EFI problems Yes, even Honda PS: Please enter at least your first name into your user profile. Thanks. | ||
| Blake |
One thing I try to always be mindful of, no matter what specific vehicle related forum I might be reading: These forums are very much about helping folks diagnose and resolve problems, so if we are led to believe that reports of issues on a vehicle forum are indicative of the vehicle in general, we are likely making a leap that is entirely unsupportable for the population at large. Here at BadWeB, we have close to 20,000 registered participants. We're going to read about a number of issues, some shared by a number of folks. Besides being aware of the statistical basis and avoiding false sweeping generalizations, we should also be mindful that a lot of folks bring on their own troubles through less than thorough understanding of the myriad modifications and aftermarket "upgrades" that they may introduce to their vehicle. This is a bit of a pet peeve for me, having been trying to sort fact from exaggeration on BadWeB for going on 13 years now. Best advice I've found anywhere on how to deal with worries about possible problems? Just ride the bike!  (Message edited by Blake on March 07, 2011) | ||
| Blake |
Mike, In reply to my statement following: "Seems to me that as long as the O2 sensor and other atmospheric sensors are being employed, a good tuner ought to be able to do a pretty good job of mapping an ECM to work well in most places." You commented that "I need help finding my Atmospheric sensor/s on my XB's 2003, 2005 and 2007." I replied advising you that the intake air temperature sensor is an atmospheric sensor. You then oddly rebutted that "I am sure we all already understood air temperature is an Atmospheric condition. Blake" Okay then.   As to your question, a good one, "what additional sensors we would (sic) benefit from having added to the system." The answer seems to be one additional O2 sensor as per the 2010 models. As to the rest of your posts, I can't follow them. You've done tests? Okay. I know enthusiasm gets the best of us all sometimes, but we should try to remember that if we don't really know the true programming and inner logic of the ECM and its DDFI systems, then we really ought to avoid making declarative statements about it. (Message edited by blake on March 07, 2011) | ||
| Blake |
Dean, When tuning the fuel mapping to adjust for a different muffler or other engine modifications, then it is indeed not only possible, but advisable to retain the function of the closed loop DDFI system, namely the O2 sensor(s). The tuner must be careful to maintain the required stoichiometry for all closed loop operations. That way adjustments can be made to the rest of the mapping (the open loop portions), like for large throttle openings and/or elevated engine speeds and the ECM will not ever perceive a need to adjust the AFV. That is what the good folks at American Sport Bike have known for some time now and is how they were able to create custom mappings for various aftermarket exhaust and intake configurations. That is what Erik Buell Racing provides as well. Disabling the closed loop mode is a really bad idea in my view. At the track it might make sense. But at the track, when is the bike ever in closed loop mode anyway? The cool down lap, maybe? (Message edited by blake on March 07, 2011) |
