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[Gearheadfmc]

Anyone ever see a bike dyno tuned on a dyno without using sniffers?  Just using the data from the CPU/O2 sensors through the cable and into TTS loaded computer?

If so, how would the results be better or worse?


Thanks in advance

Gearheadfmc

[Heatwave]

Can't be done with stock O2 sensors and no sniffers.

[kraut]

never even heard of it.

1. the results would be without significance

2. why would anybody even try it

you need the data gathered behind the mufflers for effective tuning.

[Heatwave]

never even heard of it.

1. the results would be without significance

2. why would anybody even try it

you need the data gathered behind the mufflers for effective tuning.

Actually a typical O2 sniffer collects its reading in front of the muffler.

[Midnight Rider]

Can't be done with stock O2 sensors and no sniffers.

Wouldn't that be basically like doing a V Tune, except on a Dyno?

[Heatwave]

Wouldn't that be basically like doing a V Tune, except on a Dyno?

Somewhat but even a v-tune with stock O2 sensors is only going to read the exhaust O2 up to around 3500rpm. Beyond that you'll need to swap out the stock O2 sensors for WB sensors or you'll need to use the sniffers that are used during a dyno tune.

[Widows Son]

Heatwave's right. Stock 2-wire NB O2 sensors are only good with an air fuel ratio of 14.2 to 15 unlike 4-wire WB sensors are capable of sub 12 to above 15...If your running maps that are richer and leaner than the capabilities of your O2 sensors, you'll end up clipping the signals.

[Steve Cole]

Sorry guys but I need to jump in and correct a few of your thoughts here. You can tune with stock O2 sensors up to 6000 RPM with a TTS system without issue. Regardless of what type of O2 sensor you are trying to use to gather your readings you are truely trying to read the exhaust in the head pipe as close to the cylinder head as possible. The problem is that if you get to close you can overheat the sensor if your not careful. The problem with getting to far down the pipe is that the closer to the end you get the bigger the chance of getting a false reading is. As and engine runs it does not produce a continues exhaust flow it is truely pulses. On a HD with a single pipe per cylinder once the pulse travels out of the pipe it draws air back into the pipe. This drawing of air back into the pipe can and does screw up readings being take to close to the end of the pipe.

A stock sensor can read from ~13.2 - 15.5 but is most accurate from 14.25 - 14.8. So with this in mind you can tune without a sniffer but a more accurate tune at WOT can be done if you have a PROPERLY installed Wide Band Sensor. As for all your part throttle operations a sniffer on a factory equipped O2 sensor bike is not needed.

So the answer is yes you can tune on a dyno without a sniffer but you might not get 100% of all the possible power at WOT from the engine that way. There has been many of our customers that have done there own tune with Vtune and our instructions and gone to a dyno afterwards and have a dyno operator only find a couple HP at WOT more than what they did on there own. So if that's good enough for you, you can do it that way.

[glens]

I love this...

I just want to add that a stock sensor can "read" 9.0:1 just fine if you're running pure ethanol.  Technically, the sensors don't read "AFR" anyway, they read lambda, or even more properly, the aftermath of near stoichiometric burn. 

We'd be hard-pressed to find much lambda @ 14.7:1 fuel nowadays; when are we all going to quit tossing around "AFR" numbers in this manner?  Brings to mind Andre the Giant in "The Princess Bride" where the one guy is always saying "inconceivable" and Andre's character says to him something like "You keep saying that; maybe it doesn't mean what you think it means."  In context, "14.7" doesn't mean what it used to mean.  "14.7" now is about what "15.2" used to be while lambda remains steadfastly "1".

[Heatwave]

Good luck to those that are looking to properly tune their bike using a dyno, V-Tune, Smarttune or any other automated approach with the stock NB O2 sensors, above 3500rpms. If you have a map that has the upper rpms already match to your configuration, you'll be OK but that's only because the map you started with was originally tuned on a dyno with sniffers. If your starting map isn't closely matched to your engine configuration...well... let me repeat....good luck.

[glens]

Really not any luck involved with it.  Many of us have great success doing exactly that.  All you're doing is setting the VE tables; you're not going to leave the fuel table set closed-loop that high when done.

[Steve Cole]

What people need to understand is that ANY O2 sensor does not measure fuel mixture at all. I do not care how you rate it as what they ALL read is the difference in the amount of oxygen in the pipe versus the amount of oxygen in the surrounding air. This is true of each and every type of oxygen sensor and that is why they are called oxygen sensors! The stock narrow band, the Broadband or a true wide band all read oxygen. It has no idea of how fast the engine is running nor does it care. It simply generates a voltage based on the difference in oxygen from inside the pipe to the outside air, that's it.

The range that I posted above were based on running todays gasoline mixture but as Glens accurately pointed out those numbers can and do change based on what fuel you are using. The same is true for ALL O2 sensors on the market today and if you do not know how or have the tools to calibrate any of the sensors will give a wrong AFR reading as the fuel changes. This is why AFR is not a good benchmark to use but most everyone in the HD world is stuck on that scale.

[cvobiker]

What people need to understand is that ANY O2 sensor does not measure fuel mixture at all.

here is good article that explains well


The Basics of Air Fuel Ratio

What is lambda, and the difference between narrow band and wide band 02 sensors?
One the most important aspects of the combustion motor is the air to fuel ratio in the cylinder. Like all things that explode, having the proper amount of combustible fuel to the amount of air to sustain the burn is important. Having lots of air but no fuel will cause the combustion to burn very rapidly and hot, while having lots of fuel, but no air will cause the mixture to burn very cool and slowly. Having an overly gross amount of either fuel or air will cause the combustion to not even occur at all.

What is Lambda?
Lambda is scale that relates the air to fuel ratio of ANY fuel. 1.0 is stoic for every fuel. (the chemically perfect ratio of air to fuel for a complete burn). However, stoic is different for every fuel. Some fuels may need 14.7 lbs of air some may need 6 lbs of air for a complete burn. Lambda 1.0 is always the perfect ratio for the fuel in use.
Some tuners argue that it is better to read air to fuel ratio’s in lambda since it will be accurate with any fuel. To be fair though, most aftermarket gauges will read lambda and convert that number to an a/f ratio for gasoline. If the user then knows the stoic, lean, and rich ratio’s for gasoline, he can apply those numbers to any fuel used and it won’t matter.
What I mean is that if you are running 14.7 (stoic) on a gasoline A/F gauge and you then convert to alcohol ( or E85 ), 14.7 will still be stoic on the gasoline gauge. This is because the gauge is going to read a stoic lambda reading of 1.0 for any fuel, and the gauge is going to output that number as 14.7 on you’re A/F gauge even though we know the true ratio for alcohol is 7.1-9.1.
Many times I have then seen people try and richen the cars tuning map to get down to that A/F value, not realizing that they are already at a stoic burn if the gauge set up for gasoline reads 14.7.

Narrow Band vs Wide Band o2 Sensors
A narrow band o2 sensor is an oxygen sensor that is only calibrated to know three things. Rich, stoic, and lean. What I mean by this is that it only has a narrow window that it see’s the air fuel mixture through. The sensor can tell the computer when it’s stoic. If it’s not stoic, it can tell the ECU that it’s either Rich, or Lean, but that’s it. It doesn’t really output any particular value other than that. How rich the car is the sensor has NO IDEA about. Same with how lean the car is. All it does know is that it’s not stoic. The ecu with a narrowband o2 sensor, when in closed loop mode, will then lean on the fuel map if it is receiving a rich signal from the o2 sensor till its stoic. The opposite would be true if the sensor was telling the ECU that it was currently running lean, it would richen the fuel map till the o2 sensor was reading stoic.

A wideband o2 sensor is much more sophisticated than a narrowband sensor, and can be relied upon to be used as a tuning tool. Wideband sensors not only are a lot faster acting in the reading, but can tell you the exact a/f ratio that the motor is currently at. So instead of just telling the ECU that the motor is running rich, it will read a voltage that correlates to an actual value, like 11.2. One thing to remember with a wideband sensor is that it has a heating element that needs to be heated up before the sensor will be accurate in its readings. This usually only takes a few seconds, but just remember that for those first few seconds the gauge is not useful. Wideband sensors give the ECU the ability to tune exact A/F value’s to a tenth of a decimal instead of just richening and leaning the mixture till a stoic value is seen.

What is Stoic, Rich, and Lean?
Stoic, rich, and lean are terms that we use to describe the burn ratio of fuel to air in the combustion chamber. The perfect ratio for good combustion of every fuel is called stoic. A stoic value will always give the motor a good clean burn while taking gas mileage into account as well.
Rich refers to conditions in the air fuel value were there is more fuel present than is ideal to the air content. Rich conditions will cause the burn to use more fuel, but can also offer more power at the same time.
Lean refers to conditions in the air fuel value were there is more air than fuel. This causes the combustion to occur rapidly and burn very hot. While this is great for gas mileage, often the vehicle will be down on power and become dangerous to the motors internals.

[glens]

I have a post composed in another browser window somewhere around here...  I never submitted it.  In it I asked the question "how nice would it be if the "AFR" meter folks just went with Lambda instead?". 

Attribution for that article would be nice, by the way.

One thing I sort of disagree on and think maybe needs expounding is that the "wideband" sensors aren't any faster at sending out a signal.  In fact, they have to be slower because of the fact that they are exactly the same type of sensing element, only with an extra component that actively alters the balance between sample gas and reference O2.  This takes place under the direction of the sensor's own closed-loop controller.  This controller determines which way it had to alter the balance in order to get the sensing element itself to the point where it's effectively sampling lambda=1.  Since the sensing element itself is otherwise exactly the same type as the "narrowband" sensors, its speed is going to be the same.  But there's extra latency in the process of controlling the sample/reference balance, so how can these sensors be faster?  They cannot.

Another point worth mentioning is that since the controller is effectively altering the pressure differential across the element, if the controller doesn't know what that differential was to start with, it cannot accurately determine what the actual lambda value is on the sample side of the element.  It must assume something, like there is no initial pressure differential, or maybe it's some fixed value.  Without knowing this it's really going to be putting out nothing but a guess.

I'm going to go ahead and cut/paste part of my unsubmitted response.  It's actually pretty similar to what was submitted in the previous post, only this comes from my own head:

Say you know that the fuel you're using actually burns stochiometric at a true AFR of 14.2:1 and you want to set the cruise areas at 13.9:1 because you don't want all the heat of stoich combustion.  Your understanding of things is that the stock sensors won't reliably read "13.9" so you are going to run the bike open-loop.  You put the bike on your dyno and set all the pertinent VE tables so that your AFR probes tell you "13.9".  You must be good to go, right?

Did you take into consideration that your AFR probes are going to tell you "14.6" no matter what fuel you're burning at its stoich combustion mixture?  So you've taken your "14.2" fuel and set the probes to read "13.9" and the result is that with that "14.2" fuel you're now running an actual "13.5"!  This is the fallacy of using "AFR numbers" on your probe; values that pertain only to one type of fuel; a type of fuel which you're likely not going to find "in the wild".

Let's look at this same scenario again only this time using lambda values.  Stoichiometric burn results in a lambda of 1.0.  Doesn't matter what the fuel composition is.  If it's burning completely with no extra O2 left, it's at "lambda=1", and this is the number your probe should show in that case.  If you like to set your cruise areas just rich of stoich exactly as in the first example (13.9/14.2, which is the same as 14.3/14.6, or 8.8/9.0, etc.) you'd set the VEs to achieve a lambda of 0.979, using a probe which indicates "1.0" at stoich.  Of course you'd still want to make changes to either the VE tables (or the fuel table if running all open-loop) if you later change fuel composition, but you could at that time simply sample just a couple spots, note the difference obtained from your target, and modify the entire table by that percentage.  (though you could leave the bike in closed-loop and let the ECM take care of that for you on the fly :-)

[Steve Cole]

Other than a few mistakes there is one thing that most people do not know or understand and that article does not cover. That there are three types of sensors not two and MANY call the wrong sensor the wrong thing. Narrow Band, Broad Band and Wide Band are the three types, a TRUE wide band will do most of what that article states with a few exceptions but that is NOT what most use. DynoJet, DTT, Rev. and most (98%) other aftermarket AFR/Lambda gauges use a Broad Band sensor and you cannot confuse those results with a true Wide Band sensor which by the way is what they are describing in that article. A broad Band sensor is built using the same technology as a narrow band sensor and as Glens pointed out they are slower than a narrow band. They also cost about $50 bucks each, a true Wide band sensor is going to run you about $650.00 each........ BIG difference!