Budget AFR/EGO Setup

[pete]

I'm sure I had a thread on this once before but have no idea what it was called so I guess I'll start a new one...

Anyway, if you've followed any of my build progress, you'll know I'm struggling to find time to put the Colortune to use to tune my carbs.

Always in the back of my mind is this Jaycar kit that's been around for donkey's years to work with an EGO sensor to display mixture ratios:

http://www.jaycar.com.au/productView.asp?ID=KC5195&form=CAT2&SUBCATID=965#11

My thinking is I should be able to make up the kit and be able to handle-bar mount it for the short term and have an EGO sensor stuffed down the end of the pipe with some way of strapping it in place so I can ride with it in place.

I realise plug chops can be done, but most of my riding at the moment is going somewhere to do something (eg. work), so plug chops really aren't an option.

If I use a setup like this and mark my throttle for the various tuning positions, it should give me a greater amount of flexibility in terms of times I can get an idea of the AFR while riding so I can really get the carbs tuned a lot better than they are now.

There are also another three kits for this sort of thing, but they just get more expensive and I think this basic one will be all I really need for what I want.

Does anyone have any thoughts or ideas on this? I know it's not the ideal way, and there are ready made devices to do this, but they're not going to be cheap, and this is the only way I can really see getting into the tuning properly with the time I have available at present.

I believe this kit uses a narrow band EGO sensor, so the trick will be finding one... I haven't started Googling for that yet but will be soon...

[koolaid_kid]

Let me see if I can help you, Pete. First, let's clarify the terminology so we can be on the same page. Here in the states we call it a wideband meter (some call it a sniffer). It is a system consisting of the display, which you posted a link to, and the O2 sensor, which comes in narrowband (normal for emission control) and wideband (used for tuning). The narrowband sensors are relatively inexpensive as they are used in all vehicles here per Federal law. The on-board computer uses these narrowband sensors to make fueling adjustments and determine if there is a cat converter issue.
The wideband sensors are expensive and are used by tuners to dial in the AFR. You can't use a narrowband because it only measures from 15.0 to 14.2. A wideband measures from 20.0 to 10.0. The numbers you will be looking at whilst you tune with be from around 11.5 to 18.0, which is why a narrowband will not be suitable.
O.K. The display you pointed to is:
a) For automobiles. Cars, because they are watercooled, can run leaner (AFR number is higher, roughly 14.7). An air-cooled bike uses the fuel mixture to help cool the combustion chamber, so you want the AFR number to be a bit smaller (richer). Thus, what they consider the "sweet spot" will be different because you have an air-cooled bike.
b) Displays led lights rather than a number. You will need to convert the lights into numbers so you can dial in your AFR much closer. The more precise the better. You could also use a voltmeter when you know what number equates to what AFR, btw.
For your bike, you will want an AFR of around 13.8 at steady state cruising. It will rise when you chop the throttle since you won't be sending any fuel to the combustion chamber. At WOT, you want your AFR to be around 12.8. This will make it rich enough to cool the chamber to prevent holing a piston.
To fix your sensor in your pipe, fashion a clamp that clamps on your pipe. It should be threaded so you can thread the sensor into the clamp. The clamp goes on the pipe itself, and the sensor is shoved up the arse of the pipe, directly into the exhaust flow.

I use an LM-1, the predecessor to the LM-2: Innovate LM-2
Scroll down to the bottom. Top left item is the clamp. It has a couple of nice touches. See the long screw on the left top part of the clamp? That clamps onto the pipe (I use a cloth to keep from scratching my pipe). Just to the left of the clamp is where the sensor is mounted. Far right is a tube with a hole in the center. This is what fits into the pipe. They call it a venturi tube. It allows the exhaust gasses to be channeled to the sensor at a calculated rate.
Bottom right is the wideband sensor with the communication wires.

Which leads me to the biggest rub. Your sensor needs to be calibrated. You will have to figure out a way to do that with your system.

Here is an example of a wideband sensor with a connector: Wideband Sensor
Here is an example of a ready to go gauge: AFR Gauge

I apologize for the length of this post, but it is an involved subject, as you can see.

[spchips]

I did a low tech version of this. First, very impotant you get a heated 4 wire O2 sensor or your rwadings won't make sense. Second, for just tuning carbs you may be okau with a narrow band and this will save you $$. Thee wide band will work better.

Hook up the two heating wires to your battery.
Hook up the two signal wires to a cheap ass volt meter (harbor freight...), and stuff the voltmeter into the clear top of a tank bag.
Make a small bracket out of flat steel with 2 holes, a small one on one end to hook to something on the frame, and a large one on the other to mount the O2 sensor through. Bend as needed to get the sensor tip right at the exhaust outlet, preferably sticking in a little. The back needs to be exposed to clean air.
Set the meter to read 1 volt.

Readings:
0.2 - lean
0.45 - automobile perfect/very slightly lean
0.8 rich


Realistically, you'll never get it perfect, but since you only need to know which way to adjust anyway, this should help. 0.6 to 0.8 is fine as long as it isn't smoking rich (depending on your preference)

[koolaid_kid]

Yes, you can use a voltmeter. After all, the output of an O2 sensor is in voltage, the meter merely changes it to a reading that makes sense, be it Lamda or AFR.
I thought it went without saying that it needs a heater, even narrowbands use heaters. My bad for making an assumption.
No, you cannot use a narrowband for reasons I outlined above. A narrowband will allow you to dial in steady-state cruising. That is it.
Not trying to be argumentative, merely stating the facts.

[spchips]

I see, so the "rich" 0.8 reading on a narrowband corresponds to appx 14.2, which is still technically lean?

And definitely lean for bikes.

[salty_monk]

So...how do you calibrate the sensor? Also I thought that the further up the pipe (closer to the collector) you could get the sensor the better...

Posplayr has done this with an Innovate LM2...

[koolaid_kid]

I see, so the "rich" 0.8 reading on a narrowband corresponds to appx 14.2, which is still technically lean?

And definitely lean for bikes.

Correct. It is a water-cooled engine sensor. It would probably work for a water-cooled bike (haven't tuned one yet) but not an air-cooled bike.

[koolaid_kid]

So...how do you calibrate the sensor? Also I thought that the further up the pipe (closer to the collector) you could get the sensor the better...

Posplayr has done this with an Innovate LM2...

Yes. On a bike, the collector is the perfect place to put it. It requires welding in an O2 bung, which may be what Jim did. I have not asked him. I was not willing to do that to my Kerker, which has been ceramic coated.
The Innovate clamp I use is for moving the O2 sensor from vehicle to vehicle. I have yet to find an automobile it would not fit in. My Kerker has a cap on the end so I can remove the baffle and re-pack it. I remove the cap, place a modified tuna can on the end and clamp on the sensor. I use the tuna can because it blows out all the packing if I do not. This not only makes it annoyingly loud, it also changes the airflow, negating the readings for that run.
However, the clamp was too large to fit in TCK's Zrex aftermarket pipe.
If you go to a tuner, the clamp is what he will use, so it works "good enough".
My LM-1 automatically calibrates the sensor the moment I plug it in. It also has a calibrate button on the meter itself. Not sure how you would do it on a home-made unit such as discussed in this thread.

Here's the kicker, which I have not discussed yet. If you do not have a recording device, you will have to look at the display, whatever it may be, while doing your runs. On a highly modified 750 which is supposedly putting out close to 100 hp. at the output sprocket, I was not willing to do that while doing my WOT runs.

[salty_monk]

Jim's is on a clamp but the sensor sits on the end of a long rod which you can pass down the exhaust to get close to the collector....

[twotimeGSr]

I just finished rebuilding the carbs on my 79 850 and need to dial them in. So how do you know which carb to adjust when using this?

[salty_monk]

You adjust them as a group...

[pete]

Thanks for the input and feedback guys, very valuable information KK!

Let's start with the simple stuff, mounting the sensor.

My thoughts were exactly what Jim has done according to Dan, which was mount on a rod to get in as far as it could.

SPChips suggestion is how I was thinking of mounting it, I don't want to damage my awesome ceramic coated pipe!

KK, I get it in terms of the inaccuracy of the cheap kit I linked to and needing a wide band. That makes sense, and I wasn't sure on the difference between narrow and wide but am now, so thanks for the clarification!

I think this would be a better option for the tuning. It's a bit dearer but still nearly $300 less than an LM-2

http://jaycar.com.au/productView.asp?ID=KC5300&form=CAT2&SUBCATID=965#11

So the missing bit would be locating a heated wideband EGO sensor right?

It looks like they're all around the same price as the one posted earlier, which would still make the total cost around a third of the LM-2 kit.

I realise it would be much easier just to get an LM-2 kit, but that is going to be out of budget for quite a long time...

So, the real remaining question is the calibration... how does one go about that?

And yes I still need to read the details on the linked kit above to make sure it's suitable.

[pete]

I just finished rebuilding the carbs on my 79 850 and need to dial them in. So how do you know which carb to adjust when using this?

You adjust them as a group...

What Dan said ^

My plan is to do the mains and needles with this setup, then use the Colortune to get the mixture screws dialed in. That should get me as close as I can without expensive stuff...

If I get the opportunity after doing all this, I'd love to get an AFR run done on a dyno to see how it works out... overkill for a 450 but I love my 450... hahaha

[pete]

Hmmmm this is looking less and less "budget" all the time...

It seems that kit is designed for use with a Bosch LSM11 wideband sensor which is apparently "pseudo" wideband, and they're in the $200 - $300 price range just for the sensor

Jaycar also have this kit:

http://www.jaycar.com.au/productView.asp?ID=KC5485

But it needs to marry with a wideband sensor controller as well as the sensor (makes sense due to the heating/calibrating requirement).

They have one:

http://www.jaycar.com.au/productView.asp?ID=KC5486

At least the sensor comes back to the $70 - 80 mark as it appears to be the same one used in the Innovate stuff.

This setup would end up costing me $220 or thereabouts in total...

There goes the budget idea

I'll keep searching...

[koolaid_kid]

A proper wideband setup is not a budget item. That is why you will mostly find them in the hands of tuners, mechanics and racers. I am a bit of all 3, unfortunately.
How much is an LM-2 over there?