| Author | Message | ||
     Spatten1 |
I live in the mountains, and have found that with the XB9 if you change altitude dramatically while riding above 4k rpm and/or in constant throttle transition, it does not seem to adjust the open loop mixture and runs poorly. After running a steady cruise for a few minutes at the new altitude in closed loop, it does seem to adjust and runs well in open loop again. Are there any additional sensors or a different algorithm with the new system that will cause the system to adjust to new altitudes differently? | ||
| Bob_thompson |
Excellent question Scott, I likewise would have that problem but alas my current M2 just runs slightly richer but not enough to matter. I leave 4200ft. and usually go into canyons to 9500ft. during even a short ride. Even people back east in the lower altitude mountains would share from a better "learn as you go" system and much more for people going cross country. Lets hope the factory addressed this issue.????? | ||
| Fullpower |
Ya mean like a modern fuel injected automobile with a MAP sensor that reads exact ambient atmospheric pressure at engine start-up and meters fuel accordingly? GOOD IDEA ! | ||
| Bob_thompson |
Anybody out there care to comment on Spatten1's original question along with Fullpowers statement. How about you current XB riders that ride with elevation changes. Similar experience to Scott's? Anybody else with similar F.I. systems. I am ignorant on these matters as I have never had a F.I. bike. My M2 of course has a carb and my vehicles seem to respond fine to these changes except at 13000 feet; not enough air and they just stop running at higher RPM's. Where is Buell's F.I. engineer? Please! (Message edited by bob_thompson on July 25, 2007) (Message edited by bob_thompson on July 25, 2007) | ||
| Unibear12r |
Stop and think about it.... If your ecm could update from the o2 sensor fast enough, or at any rpm, or during varying throttle conditions a map sensor is not needed at all. I once chatted many years ago with a guy from GM about this and he told me that at first they were only interested in map sensors for varying loads at steady rpms and throttle settings like at idle. Like when the AC compressor kicks in or when the vehicle is in park vs in drive an a stop with your foot on the brake. | ||
| Unibear12r |
But I too would love to hear more about the new FI! | ||
| Anonymous |
DDFI II and DDFI III both auto adjust for altitude constantly. No steady cruise is required. At least that is how they work stock. Once components on bikes get modified/changed, all that becomes questionable. But we do massive altitude change testing out in the Rockies with fast riders, and there really is no issue at all. | ||
| Fresnobuell |
I run up to about 7,500 feet often enough to notice a decrease in power, but the bike seems to be running fine. I don't know enough about AFV to know what is really going on, but the above seems to be the case. | ||
| Anonymous |
That would be correct. As altitude goes up air density goes down so power goes down, but the O2 sensor is constantly sampling the exhaust so the fuel delivery is reduced to keep the mixture right with the lower air mass. So at the top of Pikes Peak, the bike has noticeably less power, but runs very smoothly. Ride a carbureted bike to the top of the Peak, and it's not a pretty experience! | ||
| Spatten1 |
Anony, If you keep the ECM in open loop mode during altitude changes by riding over 4k RPM, does it still adjust constantly? | ||
| Anonymous |
It isn't in open mode automatically over 4000 rpm. If you hold it WOT the whole way up the mountain, never closing the throttle though, that could be an issue. | ||
| Spatten1 |
Thanks for the feedback. This is an unusual opportunity, you guys are GREAT! Many of us are confused about what conditions are necessary for the AFV value to update, and when it does not update. The situations in which we have had perplexing results range from dyno testing with exhaust swaps to trucking the bike to a new altitude, to riding with constant throttle transitions and high rpm through altitude changes. We just want to understand when the AFV updates, and when it does not. Any insight you can give us would be greatly appreciated. | ||
| Bob_thompson |
Thanks so much Anonymous and others, Really puts my mind at ease and those who will ride in the "hills" or cross country. Glad I already have my deposit down. Getting much more interested every day. | ||
| M1combat |
From what I can tell it will adjust any time you drop below 4500 RPM on a twelve. I run up a hill from about 1600 feet to about 5800 feet over 120MPH (it's a racetrack that I always do one lap of when going from Phoenix to Prescott...). I have no issue when I get to the top. That said... GAINING elevation will give you MORE fuel compared to air IF the system isn't adjusting. Since the bike runs pretty lean anyhow it's not a bad thing to richen it up a bit. I would try to run over 120 going down the hill on that there racetrack but I'd have to let off the throttle or die so that would ruin the test (or more correctly... would prove that the FI is just fine in that situation  ). Mine works fine . Oh.... and ALL IC engines that aren't boosted have less power at higher elevation. It's about 3%/1000'. There's no way around it. | ||
| Unibear12r |
Thank you Anony | ||
| M1combat |
Unibear ... Long time no read... | ||
| 98s1lightning |
Uh, I'm a fast rider, errrrr could I test ride one? | ||
| Spatten1 |
GAINING elevation will give you MORE fuel compared to air IF the system isn't adjusting. Agreed. I trucked my bike down from Summit Point to Philly a couple of years ago. It ran like ass until I got it on the highway for a steady state ride, then it cleaned right up. When gaining altitude, it is definitely much more noticable on the 9 than the 12, probably because power is more marginal at altitude anyway. Many of us are confused about what conditions are necessary for the AFV value to update, and when it does not update. The situations in which we have had perplexing results range from dyno testing with exhaust swaps to trucking the bike to a new altitude, to riding with constant throttle transitions and high rpm through altitude changes. We just want to understand when the AFV updates, and when it does not. Any insight you can give us would be greatly appreciated. PLEASE HELP US TO UNDERSTAND WHEN THE SYSTEM UPDATES AND WHEN IT DOES NOT. PLEASE, PLEASE, PLEASE. (Message edited by spatten1 on July 26, 2007) | ||
| Spatten1 |
bump | ||
| Unibear12r |
I lurk a LOT Don and almost jumped in on a few of your recent conversations.... Like when a certain person proved himself to be closed minded and biased by the use of one word in his statement. An open minded person wanting to argue the opposing view with no axe to grind would have used the word "many" not "none". But I suffer from too much foot in mouth disease so it was good I could slap my hands away from the keyboard.  I'm with Spatten, I'd LOVE to see more detail on the DDFI III. | ||
| M1combat |
Same here... We all had a HECK of a time trying to figure out the DDFI-II so... I hope they didn't change it too entirely much. I hear that the current HD system has a few of the same features that the III has so I'm kinda wondering if they jumped over to that manufacturer (Can't remember which uses Delphi and which uses Magnetti). If they did... There may be a Daytona Twin-Tec on the market for the 1125. From what I hear that's a pretty sweet piece of kit. | ||
| M1combat |
Oh and... While I don't generally let serious transgressions like that pass... I always forgive them because I can be closed minded myself . We've all seen it happen I'm sure . | ||
| Spatten1 |
BUMP: Many of us are confused about what conditions are necessary for the AFV value to update, and when it does not update. The situations in which we have had perplexing results range from dyno testing with exhaust swaps to trucking the bike to a new altitude, to riding with constant throttle transitions and high rpm through altitude changes. We just want to understand when the AFV updates, and when it does not. Any insight you can give us would be greatly appreciated. PLEASE HELP US TO UNDERSTAND WHEN THE SYSTEM UPDATES AND WHEN IT DOES NOT. PLEASE, PLEASE, PLEASE. | ||
| M1combat |
Go take a look at "the box" in the dynojet power commander manual on their website. The Buell specific page (I think page 14 or 18) outlines a "box" that is the throttle positions and RPM ranges where the ECM learns and does not learn. That "Box" was designed for DDFI I. I think the DDFI II extends this box out to 4500 RPM. If you REALLY want to know , either look there or call Al at American Sport Bike. I'd recommend though, that if you call Al JUST to pick his brain that you also buy something as he is a very busy guy . | ||
| Spatten1 |
Don, I've read what Al has, and it leads me to believe that the system will not adjust unless you can keep it in closed loop, steady state. I did a 12,500 foot pass this weekend with a guy on an XB12, my XB9, a Road King, and a VFR. We had to go very slow, in heavy traffic. My bike ran fine, and so did the VFR. The Road King with the “primitive” open loop system ran like a champ. My buddy’s XB12 hardly idled and ran horribly. However, on the way home over the same pass it did just fine. This is an example of why we would like to know more about when and how the DDFI adjusts, and what is different with the new system on the 1125. Annony, if you PM me I’ll give you his name and contact info. | ||
| M1combat |
"the system will not adjust unless you can keep it in closed loop, steady state. " Well that's true . I thought you were looking for more detailed information is all. Like what RPM you need to stay under, where the throttle will take the bike into open loop, etc... Bump anyhow... If Anonny can provide a bit more information I'd be happy to hear it . | ||
| Spatten1 |
Don, you are right, that is the info I'm looking for. It's just that Anony said it should adjust anyway, which contradicts the information that we have available. I just want to get the right info from the source, since Anony said the system should adjust anyway. If Anony were to confirm the info that Al has posted for us, that would be enough. Then the next question would be, how is the new system different? | ||
| Spatten1 |
BUMP: How does the new DDFI update open loop maps differently than the DDFI on the XBs? Many of us are confused about what conditions are necessary for the AFV value to update, and when it does not update. The situations in which we have had perplexing results range from dyno testing with exhaust swaps to trucking the bike to a new altitude, to riding with constant throttle transitions and high rpm through altitude changes. We just want to understand when the AFV updates, and when it does not. Any insight you can give us would be greatly appreciated. PLEASE HELP US TO UNDERSTAND WHEN THE SYSTEM UPDATES AND WHEN IT DOES NOT, AND HOW THE 1125 WILL BE DIFFERENT. | ||
| Anonymous |
We do not let out detailed information on DDFI II or DDFI III because it is proprietary. Those who claim they know the system do not, because we see what they are doing with aftermarket add-ons. In fact some of these actually screw up what the system is supposed to do because they do not know how it works. It is much more difficult that you think to go into the system and get the code out. The newer systems are far beyond the original DDFI, and as such there is a lot of misinformation out there. For example the system adjusts itself in many more ways than people think it does. This may indeed be an issue for people doing radical modifications, but that's the way it is, as we legally have to protect the product from tampering as much as possible. The advanced race ECU and software is the way to tune for radical race engines. |
