Wideband tuning?

[first timer]

There is a major problem with this approach. The narrow band sensors are just a switch, they tell you if you are richer or leaner than Lambda. But they do not and can not tell you how much richer or leaner since they are non linear nor temperature stable. The old theory of looking for .8 volt is meaningless.

With a separate carb per cylinder there is little to no value in installing separate sensors in each exhaust. This used to be done to find imbalanced flow and distribution in intake manifolds but with the fast electronics this can be done with one sensor now. This is common in todays cars to determine which cylinder needs correcting or may be developing an issue inducing a misfire. Basically they look at time periods when changes happen to determine which cylinder is having problems. A bit beyond what we have available at this time.

More common to check for variation between cylinders are the use of thermocouples. But getting repeatable results is hard to do. The thermocouples vary ± 150° and are sensitive to the position and depth installed in the pipes. And they really need to be recorded to determine any trends.

HUH? I am confused, these displays are complicated enough to display the reading of each cylinder when the o2 sensor is mounted at the collector?

It could be done in theory but would require the gauge to data log as well as be tied into the ignition, but that get real tricky since our ignitions fire every revolution. Either you would have to pull the data and look at it in a chart to see what each cylinder is doing before you could tune or have a switch on the gauge to change cylinders. By tying to the collector and reading a simple gauge you are just reading the average A/F of all 4 cylinders (which isn't a bad thing).

What is the recomended distance to mount a bung from the exhaust port? I have seen on stock Ducatis/Aprilias bungs mounted about 6" from the exhaust port on the header pipe. It seems mounting down by the collector would be to far away, don't the O2 sensors need to be right in the flame?

What is so wrong with getting a finer tune and using the wide band hooked up to each header pipe one at a time and tuning each carb? Is this just micro managing the carbs? Can the mix for each carbs be that far off? How much adjustment can you make on carbs? I doubt you are going to be able to dial your carbs in that finely once you go past the needles unless you start drilling your own jets.

[rcp]

Thanks for all the great info and links. Wish I could afford some aftermarket carbs like the RS Mikunis but in the mean time will be using the stock 34mm Mikuni CVs. What carbs are you using?

Will be using VM33 Smoothbores. No flatslides allowed as they're out of period.

- Richard

[Old Colt]

With the wideband units on the market you will not be able to differentiate between cylinders. It is in the fuel injection world that is done.

A wideband sensor should not be mounted close to the cylinders. These are heated sensors and the feedback loop would be driven nuts trying to manage the sensor temperature.
Narrowband sensors can be mounted closer so they warm up quicker and since they are not temperature stabilized it matters less.
Do not confuse the heated narrowband sensors with a wideband sensor, there is no similarity in operation.

Again, there is no value in using 1 sensor per cylinder on a performance bike engine. You have one carb per cylinder.
There is some variation in the intake ports between centers and outers on most of these engines. And the center cylinders will not cool as well as the outers.
That is all that would need to be compensated for.
The only other variable is in the exhaust system and if it is causing any variation it should be discarded and a proper one installed.

Also keep in mind when tuning an engine, mixture is not the final thing you tune for. It is a guide but you need to tune for torque. Different combustion chambers call for different amount of fuel to make power. The wideband is just a tool that allows you to understand what is happening and can not tell you what you need to do to make power.

I was just working with a vintage BMW car that due to the massive dome on the pistons, cruise mixture could not be leaner than 13:1 yet most 4 valve and some 2 valve engines can cruise at 17:1 mixture. The same variations are there when making power. I have seen 2 valve normally aspirated engines that need more fuel than some turbo engines at full chat.

[Suzuki_Don]

Some time ago, possibly years, someone here was trying to install an oxygen sensor on their exhaust to help with tuning. I just remember the thread as a trial and error test to get an accurate reading. Not sure what to search, but maybe someone else can confirm this. Seemed like a neat experiment.

Try the FLYING BANANA link from Perth, OZ.

http://www.theflyingbanana.com/dyno.htm

[80GS1000]

A couple of questions regarding mounting the 02 sensor on a bike:

Where's the ideal place on a 4-1 or 4-2-1 header to mount the O2 sensor? Can you mount it to the midpipe before the muffler?

How much electrical draw is there from the heated O2 sensor? Does the GS charging system have enough juice to leave it plugged in full time, or should it be disconnected after carb tuning?

[Old Colt]

The midpipe is fine, try to ensure no leaks at the slipjoint right in front of it.

The heater will draw up to 8 amps but this is an intermittent load so I would not consider it an issue. keep in mind you can not run with a wideband turned off, a cold sensor will foul.

[80GS1000]

Thanks for the info Old Colt. Those Tech Edge units look very nice - think I'll go that route when the time comes based off your recommendation.

In your experience, what's the best way to hook up the controller to the bike's wiring harness? An up to 8 amp intermittent draw is quite the load considering the high beam draws 5 amps. For safety's sake and so it won't flatten the battery it seems like you'd want the controller to be switched on/off by the ignition key and fuse-protected.

[Old Colt]

Just double checking my documents, the 2J1 calls for a 5 amp fuse in the power input, so it clearly draws less than what I stated previously.

You want it on a switched circuit, coil feed would be logical. Anything switched either directly by the key or the bar switch.

[82Shafty]

http://www.airfuelratio.com/manual.htm

http://www.thegsresources.com/_forum/showthread.php?t=138639&highlight=air+fuel+ratio&page=2

[tejasmud]

Okay, Wideband Tuning.

Here is my story and I am sticking too it.

Well,

Last Spring I bought a new bike to ride while I was supposed to be restoring the GS700E.

And, then I got a little sidetracked. Way sidetracked.....

I do run a LC-1/DB gauge kit on my little 200cc China bike as a stand alone. Did this for a while, but the data bug had bit, and has not let go. lol

I am now running the LMA3 and logging on a LM-1.

AFR
Acceleration (G force)
Speed
MAP
CHT
RPMs

It is basically a rolling Dyno in real time. I can tell when the AFR changes throughout the day. Jetting is a snap. One can go through several jet sizes without even pulling a plug.



Anyway, long story short, $1000 worth of electronics on a Chinese 2008 Lifan LF200-B, which cost $2500 out the door. Bwaaaaa-hahahaha.....

It has been fun. Just be careful, it can be addicting....

Now, back on track. Waiting on $1500 worth of parts for the 700E which will be in next week, and the tuning equipment will then be swapped over to the 700E. I'll post some logs when I get it all set up.

It is not too cheap for a whole set-up, but worth its weight in gold. I recommend running a LC-1 and DB gauge for tuning at minimum.

Or those who like to do it old school, that is cool as well. Have done it for years as well.


Peace,

Eric