Fatduc O2 manipulator - Ducati.ms

heffergm · May 12th, 2009, 6:02 am

Had a quick question related to the FatDuc O2 manipulator. I'll probably end up picking one up soon, but in the meantime I was wondering if anyone's had a Hyper on the dyno to measure AFR on a stock bike.

I'm curious how lean it actually is from the factory. I see the Fatduc ranges from 14.2/1 to 13.0/1, the leanest setting being slightly richer than stoichiometric (14.7/1). I'm guessing on a stock Hyper the leanest setting on the Fatduc would probably be adequate.

dukepilot · May 12th, 2009, 8:29 am

The targeted ratio is 14.7-1 with the stock ECU and 02 sensor. Not verified with a gas tester. This is the factory spec.

dave2riff · May 12th, 2009, 7:01 pm

Quote:

Originally Posted by heffergm

Had a quick question related to the FatDuc O2 manipulator. I'll probably end up picking one up soon, but in the meantime I was wondering if anyone's had a Hyper on the dyno to measure AFR on a stock bike.
I'm curious how lean it actually is from the factory. I see the Fatduc ranges from 14.2/1 to 13.0/1, the leanest setting being slightly richer than stoichiometric (14.7/1). I'm guessing on a stock Hyper the leanest setting on the Fatduc would probably be adequate.

The leanest setting on the FatDuc might be adequate, but the bike will run
noticeably better towards the middle of the FatDuc range. You probably
won't be satisfied with the change in performance at the leanest setting.
Richening the closed-loop range results in smoother off-to-on throttle
transition, reduced surging and exhaust popping, a smoother "feel" to the
way the engine runs at sub-5000 rpm, and can slightly reduce oil temps
as well, especially in heavy traffic or stop-and-go riding. Also, the
dreaded tendency to stall at closed throttle while approaching a
stop went away on my Hyper, though it was only an occasional
issue (mostly when the engine was quite hot).

There will be a roughly 5-8% hit in fuel economy while running part throttle
and under 4500 or so rpm. Once you're above quarter-throttle, the ECU will
begin to transition to open-loop mode and the FatDuc will have no effect on
fuel economy. So the net loss in fuel range is fairly small, depending on how
you are riding the bike.

08hyper · May 12th, 2009, 8:47 pm

Quote:

Originally Posted by dave2riff

The leanest setting on the FatDuc might be adequate, but the bike will run
noticeably better towards the middle of the FatDuc range. You probably
won't be satisfied with the change in performance at the leanest setting.
Richening the closed-loop range results in smoother off-to-on throttle
transition, reduced surging and exhaust popping, a smoother "feel" to the
way the engine runs at sub-5000 rpm, and can slightly reduce oil temps
as well, especially in heavy traffic or stop-and-go riding. Also, the
dreaded tendency to stall at closed throttle while approaching a
stop went away on my Hyper, though it was only an occasional
issue (mostly when the engine was quite hot).

There will be a roughly 5-8% hit in fuel economy while running part throttle
and under 4500 or so rpm. Once you're above quarter-throttle, the ECU will
begin to transition to open-loop mode and the FatDuc will have no effect on
fuel economy. So the net loss in fuel range is fairly small, depending on how
you are riding the bike.

The stock ECU is a closed loop ECU, and does not have a ability to "transition" to an open loop, all the FatDuc does (very cleverly) is to fake out the O2 sensor so the ECU can run richer, but is limited, as the stock ECU has a "fixed" range of fuel mapping, meaning you can't just make the ECU go full rich with the FatDuc, only as rich as the stock fuel map in the ECU will allow.

Only the DP ECU is an open loop system, which is why it doesn't need the O2 sensor, and why the Power Commander works so well with it, as they were designed to work with open loop systems. Aloha Alex

GMP · May 12th, 2009, 11:01 pm

Dave is correct. The stock Euro 3 ECU, as well as all Euro 3 or EPA ECUs even the one in your car, runs in both closed and open loop modes depending on throttle position, RPM, and other factors like temp. While in closed loop mode, it fine tunes a trim factor that it applies to the base map in open loop mode.

08hyper · May 12th, 2009, 11:18 pm

Quote:

Originally Posted by GMP

Dave is correct. The stock Euro 3 ECU, as well as all Euro 3 or EPA ECUs even the one in your car, runs in both closed and open loop modes depending on throttle position, RPM, and other factors like temp. While in closed loop mode, it fine tunes a trim factor that it applies to the base map in open loop mode.

This is the first I'v ever herd of this, my info came straight from the Dynojet people, according to them, the stock ECU is a totally closed loop system, and the new Power Commander V is designed to work with the totally closed loop system, as it will continually sense & change the engine fueling with the 02 senser for optimal performance depending on engine load, RPM, temp, & altitude.

Where did you get the info that the stock ECU runs in both the open & closed modes? Thanks Alex

GMP · May 13th, 2009, 8:42 am

Its somewhat common knoweledge related to all applications not just the Ducati. I did talk to a mechanic about it though. Do a search I'm sure it can be found here in other discussions. You mentiion Dynojet. That is exactly why they claim the current Power Commander will only work over 25% throttle, or over 5KRPM, because that is approx where the system switches to open loop mode. In closed loop mode all the fuel added would be trimmed out by the ECU. You can't run a continuous 14.7:1 mixture as the motor needs more fuel under higher load conditions, and a narrow band O2 sensor only works around 14.7:1 because that is where cat converters operate effeciently. So, the system is set up to run lean in closed loop under conditions that see the most use or run time, like cruising at partial throttle. No different than your car, when you stomp the pedal to pull out on the freeway your in open loop mode.

TylerL325 · May 13th, 2009, 8:58 am

This might be a stupid question, but it the FatDuc a "street-legal" mod?

GMP · May 13th, 2009, 9:07 am

Technically no, as it modifies the fueling. Thats why the dealers can't just swap in a DP ECU to fix some problem bikes that run lean and stall frequently, its a legal issue. They can sell you a Termi kit and even install it though, but the way things are going this is likely to change in the future.

JT992 · Aug 20th, 2009, 9:11 am

seem correct. On a dyno yesturday I put my 08 multi on with a fatduc the bike ran all stock 18A/F ratio. And two weeks ago we had a 08 all stock hyper on dyno and it also ran same fuel curve 18A/F tell 5500 then started dropping down to 13A/F. But anyway yesturday my bike still showed 18A/F ratio on the dyno tell 5500 like all stock. By adjusting fatduc we would see the bike richer on the other end of 5500 but not below. How ever the HP and TQ graph did go up so fuel was being added down low but not showing on the dyno A/F. Know doubt starts better,smoother, runs cooler etc. I also noticed going close to 13.5 gave more HP but would cut torque leaner. Going towards 13.2 richer she gained the TQ back but lost some HP. I set looked like 13.3 and kepted the TQ. I gained close to 5TQ and about 2.5 hp from stock. I also Last week after the dyno run I did install K&N filter and took air restrictors out of the air box. Now this was on a 08 multistrada. In a hot dyno room yesturday the bike made 82.25hp and 69.7 TQ. Just fatduc and air filter, restrictors out. Don't know if this helps but there ya go.