Open or closed loop???
#21
05-01-2013 | 06:50 PM
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Road Captain
Joined: May 2011
Posts: 565
Likes: 2
From: Palmyra Missouri
First, the HD narrow-band O2 sensors work in the low-end and midrange (cruise range) and are disabled as TP (throttle position) or KPA (MAP) approach WOT. Next, wideband O2 sensors will not communicate with a stock HD ECM. Thus, if you want to run closed-loop with a stock HD ECM with no add-ons you are limited to the stock sensors. These work mostly as switches to keep AFR to spec so the engine runs within EPA mandates, and are adjustable only in a very narrow AFR range. They have utterly nothing to do with the bike's performance or fuel economy when the ECM is optimized properly to begin with.
Wideband systems that work in closed-loop do exist, however. The PCV with AT option works with the PCV, not the ECM. Thundermax is a replacement for the stock ECM and it works with wideband sensors in closed-loop. The Rev. Performance EMS works with widebands after RP reworks the ECM to run with them. The PCV-AT costs $300 for the PCV and $300 for AT, and both T'Max and EMS cost more.
Open-loop operation is not as limited as some think. I've been running open-loop with my Power Vision for >2 years and it works well without any feedback from O2 sensors. I have wideband sensors installed, but they are only used for datalogging and tuning, and do not function at all in normal operation except for monitoring purposes. I do monitor Lambda (AFR) in real time with the PV display unit and I can attest that open-loop does keep AFRs in a fairly tight range, usually ±2%. When I perform datalogs I see average variances usually ±1%, and that's good enough to be unnoticeable to the rider, unmeasurable in fuel economy, and unmeasurable by any performance yardstick. The ECM uses other sensors on the bike (FCHT, intake temp, and MAP). They do a surprisingly good job of keeping AFRs as specified in the AFR table, even as altitudes and temperatures change.
Wideband systems that work in closed-loop do exist, however. The PCV with AT option works with the PCV, not the ECM. Thundermax is a replacement for the stock ECM and it works with wideband sensors in closed-loop. The Rev. Performance EMS works with widebands after RP reworks the ECM to run with them. The PCV-AT costs $300 for the PCV and $300 for AT, and both T'Max and EMS cost more.
Open-loop operation is not as limited as some think. I've been running open-loop with my Power Vision for >2 years and it works well without any feedback from O2 sensors. I have wideband sensors installed, but they are only used for datalogging and tuning, and do not function at all in normal operation except for monitoring purposes. I do monitor Lambda (AFR) in real time with the PV display unit and I can attest that open-loop does keep AFRs in a fairly tight range, usually ±2%. When I perform datalogs I see average variances usually ±1%, and that's good enough to be unnoticeable to the rider, unmeasurable in fuel economy, and unmeasurable by any performance yardstick. The ECM uses other sensors on the bike (FCHT, intake temp, and MAP). They do a surprisingly good job of keeping AFRs as specified in the AFR table, even as altitudes and temperatures change.
#23
05-01-2013 | 07:11 PM
Extreme HDF Member
Joined: Sep 2005
Posts: 11,615
Likes: 48
From: Baton Rouge, LA
You already have the PV and you really don't need the AT-100 to get a good tune, as it merely approaches the tuning process in a different way. Jamie at Fuel Moto thinks it is a better way and I wouldn't doubt it, as otherwise why would they offer it as a $300 option. With Basic tuning with the NB sensors you tune at 14.6 across-the-board, then change the AFR tables to your specs when that's accomplished. With Pro (AT-100 with WB sensors) you specify the AFRs you want to run from the outset and the tune is created with software or via the new "Autotune" feature in newer versions of the PV firmware. Basic can also use the "Autotune" feature.
What I'm getting at is that since you have the PV now you really don't need a dyno tune, that is unless you have some unusual problem that needs to be solved or you need to extract the last fraction of a HP from the engine. When you change cams you can retune with the PV in the same manner. In fact, in a future firmware version (may be available now) there will be a way to inject cam profiles into the ECM, but that's one of those things I haven't grasped yet--mainly because I haven't researched it, don't plan on another cam change, and it thus doesn't affect me.
I didn't mention this before, but at some time in the future I expect DJ to offer a device that interprets WB signals and feed them as intelligible data to the ECM. IOW, communication between the two much like the RP EMS does, making the PV capable of running closed-loop with the WB sensors. I'm not sure I would buy it, though, as I think the present setup of tuning with the WB's and running open-loop works just fine.
Last edited by iclick; 05-01-2013 at 07:34 PM.
#24
05-01-2013 | 08:48 PM
Grand HDF Member
Joined: Jan 2007
Posts: 4,755
Likes: 2,851
From: Virginia
Ok, now we take all this mumbo jumbo and make it user friendly
In late model HD efi systems, your factory spec bike is optimized(believe it or not) for normal operation so it runs without detonation/pinging etc (the much talked about o2 sensors are a minor part of the equation). I've seen a lot of bad info traded back and forth on these forums and even from dealers that are more interested in selling stuff and lot of riders end up taking needless expense or spending big bucks on stuff that has small gains in performance. Worse, some end up with bikes that run worse than before they started. Allright, I know everyone has their opinions but this is to help folks that haven't gone down the road of live and learn. Most riders are going to do basically couple of levels of modifications to their bikes to improve performance.
1. Make mods that don't require any adjustments to the ecm programming as air and fuel intake parameters don't change. This would be generally be just changing slipons without changing headers.
2. Making mods that require a canned download (sometimes called stage 1 or stage 2downloads) to the ecm if available for common combinations of exhaust systems and hiflo air intakes. Or a piggy back type efi mgmt. device that takes the ecm output and alters it without doing anything to the maps loaded in the ecm. Examples would be the power commander, Fuelpak etc. I really like the new HD touring setup. I can take a factory spec 103, upgrade the air intake, change the cams to SE255 (good midrange cam), put some Rinehart slipons and I can put a stage 2 download that mimics the SE bikes mapping and I'm usually good to go. If I wanted to change the headers (like a TD system), then I would have to get the ECM remapped or get the piggyback controller adjusted with a run on the dyno. I don't do that anymore, usually keep factory headers and add an oil cooler to keep temps down.
3. Making mods beyond exhaust/air intake, like heads, cams, increasing displacement, pistons so on. Now the ecm has to be reprogrammed or replaced with an aftermarket ecm device. The best way to reprogram the factory ecm is using the SE Supertuner. Dynotuning is required to make it work right. I've given up going down this road years ago. I enjoy HD touring bikes for what they are, long distance comfort haulers that look good and run all day at decent highway speeds.
In late model HD efi systems, your factory spec bike is optimized(believe it or not) for normal operation so it runs without detonation/pinging etc (the much talked about o2 sensors are a minor part of the equation). I've seen a lot of bad info traded back and forth on these forums and even from dealers that are more interested in selling stuff and lot of riders end up taking needless expense or spending big bucks on stuff that has small gains in performance. Worse, some end up with bikes that run worse than before they started. Allright, I know everyone has their opinions but this is to help folks that haven't gone down the road of live and learn. Most riders are going to do basically couple of levels of modifications to their bikes to improve performance.1. Make mods that don't require any adjustments to the ecm programming as air and fuel intake parameters don't change. This would be generally be just changing slipons without changing headers.
2. Making mods that require a canned download (sometimes called stage 1 or stage 2downloads) to the ecm if available for common combinations of exhaust systems and hiflo air intakes. Or a piggy back type efi mgmt. device that takes the ecm output and alters it without doing anything to the maps loaded in the ecm. Examples would be the power commander, Fuelpak etc. I really like the new HD touring setup. I can take a factory spec 103, upgrade the air intake, change the cams to SE255 (good midrange cam), put some Rinehart slipons and I can put a stage 2 download that mimics the SE bikes mapping and I'm usually good to go. If I wanted to change the headers (like a TD system), then I would have to get the ECM remapped or get the piggyback controller adjusted with a run on the dyno. I don't do that anymore, usually keep factory headers and add an oil cooler to keep temps down.
3. Making mods beyond exhaust/air intake, like heads, cams, increasing displacement, pistons so on. Now the ecm has to be reprogrammed or replaced with an aftermarket ecm device. The best way to reprogram the factory ecm is using the SE Supertuner. Dynotuning is required to make it work right. I've given up going down this road years ago. I enjoy HD touring bikes for what they are, long distance comfort haulers that look good and run all day at decent highway speeds.
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