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Discussion Starter #1 (Edited)
I read and hear all the time that ......

1) I drilled out my exhaust
2) took the mufflers off
3) added new performance pipes

Or .....
1) I added a hi flow air filter
2) removed the rubber seal around air filter
3) modified air intake

The story usually goes like this .... They did one of the above mods and either the bike is running worse, hotter, popping or it did nothing.

I'm not a mechanic or rocket scientist although i fixed the toaster the other day:)

But in doing one of these simple mods on its own .....it will put your engine into a LEAN state for one. It can also cause a loss in back pressure and cause some extra popping on deceleration.

Today's fuel injected bikes are already set up to be in a lean air/fuel ratio to meet EPA numbers set by the powers that be. I think it's 13.6 to 1. And I believe the newest numbers may be 14 to 1. My point is Lean from the factory. Running lean engines make them run hot and if tampered with in a worse case scenario can melt a piston.

Engine mods need to be done as a package deal and air/fuel management has to be apart of any engine mod. We all want our bikes to sound just a little better and run a little faster. But by just adding more air you will lean the engine out more. Or adding new pipes you will lean the engine out more. Or just doing both .... Well you get the picture.

There a neat little mod for the Victory where you drill out the plate up the pipe with a 1 1/4" hole .... And you add a K&N type filter and then you disconnect the exhaust sensors. This is a cheap package deal, but in essence covers all three things you need to be concerned about. First your allowing more air in to cure the bikes asthma problem :) second your letting the air out to balance the flow. And thirdly your managing your air/fuel mixture by disconnecting the exhaust sensors. As when they are disconnected the bikes computer goes into safe mode and richen's up the mixture and takes it out of that too Lean state caused by adding more air and exhaust.

I'm not saying this is the best idea but it works and is cheap and covers all three issues when doing an engine mod.

The better way to go is obviously add a good air intake system, add good pipes made for your engine and add a fuel management system like a Power Commander or whatever. This is a package and will keep everything running as it should and as cool as it can with that little bit more of get up and go.

Just my thoughts hope it helps

Tank707
 

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All my Mods were done at once although bought 1 at a time on my Budget .. But they were installed all at one time Pipes First figured that's were might have the most problem then the Lloyds AC removing the factory seal ring as well .. Then Installed the PCV and took it 5 miles in 30 degree weather to the Local Dyno Wizard for tuning ..
 

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And thirdly your managing your air/fuel mixture by disconnecting the exhaust sensors. As when they are disconnected the bikes computer goes into safe mode and richen's up the mixture and takes it out of that too Lean state caused by adding more air and exhaust.
I've heard this story before. I don't buy it. I think it runs the same open loop map it runs with the O2 sensors installed, but obviously prevents inputs from the O2 sensors from allowing it to run any leaner.

I am willing to conduct a study on any willing participant. I will have you take four runs on your bike.

1. With both O2 sensors installed
2. With front cylinder O2 sensor removed
3. With rear cylinder O2 sensor removed
4. With both O2 sensors removed.

If anyone can tell me which run is which without knowing how I have them configured, they win the large beer of their choice.

Don't get me wrong, I have mine unhooked now too. I think there is some slight benefit in allowing my bike to disregard the leaning tendencies of the O2 sensors too. I damn sure wouldn't be changing the airflow with pipes and filters without either reflashing the ECU with a Stage 1 map or using some aftermarket gizmo to get the fueling closer to ideal.

Why would Vic even bother developing a Stage 1 map for their higher flowing parts if simply unplugging the O2s would serve the same purpose?
 

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Discussion Starter #6
As I stated in the beginning the simple cheap mod I referenced to was not the best idea but it works. As in it covers all three area that need to be covered .... More air.... More exhaust....more fuel.

In this simple set up the system is almost balanced, but it is limited.

I don't think running your bike with O2 sensors disconnected is a great idea, but it is a cheap way to get away from the Lean condition in a closed loop system during idle and cruising speeds. During heavy load and hard excelleration the system switches to an open loop anyways until it levels out and then closed loop kicks in to tweak it back into EPA standards.

My point in the post was not to neglect any of the three things to making good clean power.

Ultimately a good air/fuel management system should be used when doing complete and proper engine mods. This incorporates the use of wide band O2 sensors giving the person a better range of adjustments and at the same time keeping the bikes ECU intact.

Narrow band O2 sensors are just that.... And disconnecting them puts the system into safe or limp mode and richen's everything up a little to protect the motor. There are many other sensors that help to determine the air fuel mixture and the O2 is just the final tweak the system uses to meet emissions.

So back to the beginning in this closed loop conversation :) when doing engine mods ... Add air....add exhaust...and manage your air fuel ratio. Missing any of these three simple things and you will not be a happy camper.

Tank707
 

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As I stated in the beginning the simple cheap mod I referenced to was not the best idea but it works. As in it covers all three area that need to be covered .... More air.... More exhaust....more fuel.
I agree the more air that enters the system requires more fuel. There are MAP sensors that monitor this and make corrections to fueling on the input just like there are O2 sensors that make corrections on the output. I think in both cases they are fine tuning adjustments to an open loop map. Running without them just eliminates that fine tuning.

I have a PCIII on my FJR. It has an open loop map that has a whole bunch of cells that alter the ECU output based on throttle position and rpm. I can run it with the O2 sensors connected or not and it doesn't seem to make a hill of beans of difference on that bike either. Reset the open loop map back to stock and there is an enormous difference.

As you say, the ECU programming ignores the O2 sensors when accelerating or operating at high rpm. They are basically there to improve gas mileage and lower emissions when you plodding along at a cruising speed. O2 sensors make a great deal of sense when riding at high altitudes as the mix will get rich with the lower air density. The fine tuning they provide should be sufficient to fix that. I wouldn't count on it or "limp mode" being sufficient to account for significant changes to the air flow capacity of pipes, cams, and filters though.

Narrow band O2 sensors are just that.... And disconnecting them puts the system into safe or limp mode and richen's everything up a little to protect the motor.
That's the part I don't buy. I'll wager you a bag of jelly doughnuts that if I disconnect the O2 sensors you couldn't tell "limp mode" from normal mode. I know I couldn't when I did it.

As to selling parts, I'm sure Vic enjoys that. But I've ridden Cross bikes stock and mine with a Stage 1 and can tell you there is a marked difference in the two.
 

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Discussion Starter #9
I agree the more air that enters the system requires more fuel. There are MAP sensors that monitor this and make corrections to fueling on the input just like there are O2 sensors that make corrections on the output. I think in both cases they are fine tuning adjustments to an open loop map. Running without them just eliminates that fine tuning.

I have a PCIII on my FJR. It has an open loop map that has a whole bunch of cells that alter the ECU output based on throttle position and rpm. I can run it with the O2 sensors connected or not and it doesn't seem to make a hill of beans of difference on that bike either. Reset the open loop map back to stock and there is an enormous difference.

As you say, the ECU programming ignores the O2 sensors when accelerating or operating at high rpm. They are basically there to improve gas mileage and lower emissions when you plodding along at a cruising speed. O2 sensors make a great deal of sense when riding at high altitudes as the mix will get rich with the lower air density. The fine tuning they provide should be sufficient to fix that. I wouldn't count on it or "limp mode" being sufficient to account for significant changes to the air flow capacity of pipes, cams, and filters though.



That's the part I don't buy. I'll wager you a bag of jelly doughnuts that if I disconnect the O2 sensors you couldn't tell "limp mode" from normal mode. I know I couldn't when I did it.

As to selling parts, I'm sure Vic enjoys that. But I've ridden Cross bikes stock and mine with a Stage 1 and can tell you there is a marked difference in the two.

Your right and were on the same page ..... It might not make that much of a difference with your sensors disconnected as you are running a modified map set up. But in the poor little stock ECU it relies on these inputs for final adjustment because that's all it has.

As I said in the beginning I'm not a mechanic, and as I go through the mods for my bike I will be more able to test working theory .... As of right now my new filter showed up, and I'm working through an issue getting my auto tune working. Also while its apart I have a Zumo 665 GPS to install...... Holy crap spring is here :)

But I'll give you an example of how wide band O2 sensors do make a difference... With the auto tune for example it works exclusively with inputs from these sensors and make adjustments to your map in real time, giving you the option to update your main map later or leave it as is. It's not something you may notice right away, and small adjustments are made and averaged over time. That's why they say not to update your map from auto tune until you have put a good ride behind you.

I'm not sure if the difference is that the PCV with auto tune uses wide band sensors and the PCIII alone just uses the stock O2 sensors or not.

Did the PCIII come with new wide bands?
 

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From what I understand the Vic motor likes to run richer rather than leaner. A person may not get a seat of the pants feel of difference or even a sound difference with the O2 sensors unplugged but there is definitely a difference in how rich/lean it is running.

By unplugging the sensors the ECM senses this as a faulty or failed sensor and is programmed to go to a backup setting which is across the board richer. It's just how the manufacturers deal with the inevitable sensor failure that does not disable or harm the motor.

It's really no more complicated than that.
 

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Discussion Starter #11
From what I understand the Vic motor likes to run richer rather than leaner. A person may not get a seat of the pants feel of difference or even a sound difference with the O2 sensors unplugged but there is definitely a difference in how rich/lean it is running.

By unplugging the sensors the ECM senses this as a faulty or failed sensor and is programmed to go to a backup setting which is across the board richer. It's just how the manufacturers deal with the inevitable sensor failure that does not disable or harm the motor.

It's really no more complicated than that.
Yup :)
My Big Bang Theory .....lol ....more air, more exhaust, more fuel = Bigger Bang
 

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I'm not sure if the difference is that the PCV with auto tune uses wide band sensors and the PCIII alone just uses the stock O2 sensors or not.

Did the PCIII come with new wide bands?
The PCIII is a Dobeck style tuner using POTS. It will not work with O2 sensors. In fact to use this style tuner; the O2 sensors must be unplugged or removed from the system. There is really no reason to use a PCIII with an 08 or newer Vic even though it can be done.

The PC-V is leaps and bounds more advanced and configurable.

Many mechanics believe the Auto Tune does its job in a relatively short amount of time and can be disconnected from the system then. The only time to reconnect it would be if there were another change to the system like a timing wheel or better flowing intake or exhaust system.
 

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Discussion Starter #13
The PC-V is leaps and bounds more advanced and configurable.

Many mechanics believe the Auto Tune does its job in a relatively short amount of time and can be disconnected from the system then. The only time to reconnect it would be if there were another change to the system like a timing wheel or better flowing intake or exhaust system.
Thanks Bob I'm not familiar with the PCIII , I read that you can disconnect and not use auto tune once you have you map to where you want it, i even saw a guy selling his auto tune on a site because he was done making his map...... silly people.....I don't believe this is a good idea as auto tune also make adjustment on the fly to compensate for elevation , temp and changing conditions. I believe it to be an awesome system and when used to its fullest no dyno is ever needed and the bike will also make small changes as needed to keep you in your target

Thanks :)
 

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From what I understand the Vic motor likes to run richer rather than leaner. A person may not get a seat of the pants feel of difference or even a sound difference with the O2 sensors unplugged but there is definitely a difference in how rich/lean it is running.

By unplugging the sensors the ECM senses this as a faulty or failed sensor and is programmed to go to a backup setting which is across the board richer. It's just how the manufacturers deal with the inevitable sensor failure that does not disable or harm the motor.

It's really no more complicated than that.
According to the link below and others like it, a narrowband O2 sensor is nothing more than an ON/OFF switch. It is incapable of providing a continuous, variable signal needed to operate the ECU in true "closed loop" mode (i.e. no map). In effect, it only works when at a constant throttle/rpm. If it is ON, it tells the ECU to adjust metering by some constant if it is operating above or below its a/f threshold. The setpoint at that cruising condition is still likely to come from the open loop map too.

During all operation of a non-continuous nature, fuel injectors get their marching orders from an open loop map and the O2 sensors are ignored. The point is that the "limp mode" map is undoubtedly uses the same open loop map.

Think about it. If the "limp mode" map ran rich enough to operate the system with Stage 1 components correctly, it would probably foul the plugs in short order on a stock bike.

A car is the same way. When a sensor goes, it activates the check engine light. Aside from that, it isn't as if the car starts making monster power. Without the idiot light, you'd never know there was a problem.

http://www.autometer.com/tech_faq_answer.aspx?sid=1&qid=48

"Narrow Band O2 Sensors began to appear on vehicles with the advent of fuel injection in the 1980’s. Their purpose was to monitor component degradation (i.e. fuel injectors, vacuum leaks) of vehicles as they accumulated miles. Their basic job was to let the computer know whether the vehicle was running at an air/fuel ratio of 14.7:1 under idle (ideal ratio for gasoline engines), moderate acceleration, and cruise conditions, and if it wasn’t, to “trim” the injector pulse-width to either slightly lean or richen the engine. When the computer is paying attention to the input from the O2 sensor, the engine is operating in a “closed-loop” capacity. Under heavier acceleration or wide-open throttle the computer ignores the O2 sensor because it requires an air/fuel ratio other than 14.7:1, which is outside the design parameters of the sensor. This is known as “open-loop” operation. The sensor lets the computer know if the engine is running above or below 14.7:1 by sending voltage to the computer in a range between 0 and 1 volt, usually sweeping between the two extremes of this scale. Auto Meter’s traditional narrow-band air/fuel ratio gauges are simply a voltmeter for this signal. This can be seen by the repeated sweeping back and forth of the gauge in most idle, light throttle, and cruise conditions. To summarize, a narrow band O2 sensor is only able to tell a computer (or gauge, for that matter) whether an engine is operating above or below a 14.7:1 air/fuel ratio."
 

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Thanks Bob I'm not familiar with the PCIII , I read that you can disconnect and not use auto tune once you have you map to where you want it, i even saw a guy selling his auto tune on a site because he was done making his map...... silly people.....I don't believe this is a good idea as auto tune also make adjustment on the fly to compensate for elevation , temp and changing conditions. I believe it to be an awesome system and when used to its fullest no dyno is ever needed and the bike will also make small changes as needed to keep you in your target

Thanks :)
You are most definitely correct Tank. The good news is the ECM is adaptive enough to take care of any change in elevation and temperature we might have to experience on our bikes so the AT is basically redundant. It certainly does not hurt to have it running constantly but it is also not necessary much the same way a person, having had a bike professionally dyno'd, does not need to re-dyno the bike when seasons or elevations change.

Having said all that; one thing I like to do, since I do have the AT, is to create and save a Winter tune and a Summer tune because I live in one of those places that has an extreme temperature in the Summer time.

I have often thought about taking advantage of the feature with the PC-V that allows a switch to be connect that allows us to go from one to tune to another with the flip of that switch.

It would be great to have a performance tune and a mpg tune for just cruising the great highways and bi-ways of our nation.
 

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Discussion Starter #16
Confirmed ..... Pulling the O2 sensor on a stock bike or a lightly modified bike will make it run richer all the time not just during heavy exell or heavy load.

That was easy :) Yikes
 

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The PCIII is a Dobeck style tuner using POTS.
That is incorrect. The PCIII is a computer mapped system just like a PC-V. The advantage of the PC-V is that it has the ability to use wide band sensors to perform REAL closed loop operation.

But the point of it is not to use it in closed loop operation. The only reason to operate it closed loop is to find the optimal cell settings of an open loop map. If you know the a/f settings you wish to achieve across the rpm range, you set them and let the PC-V calculate the proper open loop map cell settings. Once calculated, you run it with them until and unless you plan on riding at a different altitude or change air flow components.

Without that closed loop capability, one has to take their bike to a tuner to set those cells to meet the proper a/f over the rpm range.

The problem with the PC-V auto tune is that without a knowledge of proper a/f across the range of one's machine, a home gamer could screw that up too. Ostensibly, a dyno tuner knows what those a/f values should be for a given machine or can find them by doing runs and finding the best output torques across the rpm range.
 

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To summarize, a narrow band O2 sensor is only able to tell a computer (or gauge, for that matter) whether an engine is operating above or below a 14.7:1 air/fuel ratio."
Thank you for proving my point. When the O2 sensors are disconnected the computer will see this as the motor running too lean and adjust it according to the pre-programmed settings.
 

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Discussion Starter #20
Having said all that; one thing I like to do, since I do have the AT, is to create and save a Winter tune and a Summer tune because I live in one of those places that has an extreme temperature in the Summer time.

I have often thought about taking advantage of the feature with the PC-V that allows a switch to be connect that allows us to go from one to tune to another with the flip of that switch.

It would be great to have a performance tune and a mpg tune for just cruising the great highways and bi-ways of our nation.
My switch came in a few days ago..... So ya I have to make up my mind which maps to save ..... My city goes from riding temps of 50 to 100 degrees so that's a good thought, or like you said fuel economy and performance. Hmmmmm need a three way switch ....lol I'm sure that's the next step multi map at a touch of a button
 
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