Triumphrat

PaulBx

The question was not what rev range, but what engine load.

bigbofo

I am not an expert by any means, but dont you want to achieve a 14:1 air/fuel ratio (or close to) under all conditions for ideal performance? At least that is how I understand it...

So you got main/pilot jets, shims, fuel screw and more to achieve that and play with.

The whole purpose of this thread was to ascertain the best procedure on WHERE and HOW to install the O2 sensor for BEST results.

I believe consensus is to get the best reading from the header pipe about 6-12 inches from the head. Which means you would need a bung in each header pipe for most accurate tuning. If you just put a bung in the collector or the muffler you will achieve a composite reading from all three cylinders - which could be close enough if you are happy with an approximate reading.

Could be completely wrong here, but this is the outcome of my research. Happy to be challenged any given time.

IrlMike

After having a read thru' the Innovate site, it looks like the sensor could be much further back. The accessory item on the far left of this picture:



is a device they offer to fit/clamp the sensor in the end of the tail pipe. That suggests to me that any point, say, on the header side of the muffler should give reliable readings? Innovate also seem to say that the sensor is best in a cooler area of the the exhaust flow so that it's own heater control works better to keep it at the correct temperature.

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98 Tbird tank/seat, Sprint fairing, ZX7R forks+Racetech Gold Valves, 08 ZX6R shock, Alcon 6-pot, Ignitech+TPS, T'bike 3-1+Beowolf can, airbox mods/rejet, tubeless wheels, lots :) per mile.

WSC

Yeah, the adapter pictured above snags a bit of the exhaust from several inches up the pipe and feeds it to the dirty side of the sensor, allowing the clean side to stay in the atmosphere. Should work fine unless it's a 500CC single.

And, yes, you have to load the engine. CV carbs move the slides in response to air flow, so without a load you won't get much past the pilot transition circuits. A dyno is ideal, but you can do it on the road, too, especially if you can capture the data stream and somehow correlate it to RPM and throttle position.

I'm pretty sure all wideband sensors have integral heaters.

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John
2004 Thunderbird Sport
1975 T150V
1968 BSA Thunderbolt

PaulBx

Yeah, that makes sense. Probably get on a long straight road (without cops), sit up straight in top gear for max wind resistance and set the tach at each thousand rpm and take a reading, maybe speaking into a voice recorder. Not sure how to figure out what the throttle position is, though. I happen to have a throttle lock so maybe I could make some marks on it or something.

I was thinking of putting together some kind of logger with one of those Arduino boards, since the guage does outputs for a logger, but this project just keeps getting more and more complex so I may just try some simple-minded manual method as I just described.

WSC

Actually, if you could correlate it to manifold pressure and RPM, that'd probably work better. The slides react to airflow, not throttle position.

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John
2004 Thunderbird Sport
1975 T150V
1968 BSA Thunderbolt

PaulBx

I was looking at MikeIrl's thread on adding a throttle position sensor. That would be ideal for logging, since it is just a voltage from a resistor or similar. I like that idea too although hooking into the throttle shaft is a pain and I'm not yet buying a new ignitor so it would be kinda pointless. I don't know about manifold vacuum, maybe I can find some pressure sensor somewhere. Of course hooking that in would be trivial, just use the sync ports. Thanks for the suggestion.

BTW what lifts the slide higher, high manifold vacuum or low vacuum? I need to re-read about CVK carbs too...

Just got my new first-attempt jets. Put the needles up two washers and put in 115 mains. That should do for a start. I'll be able to play a little with idle mixture but with winter I probably won't be doing much full throttle testing for months. Also it's about 2 hours drive to the other side of the Cascades to find a nice safe place for testing. Maybe I'll spend the winter messing with my logger.

I think I figured out a simple/cheap device to get the wideband sensor sampling exhaust. I'll give that a try too and post here when I try it out to see if it works.

<later>
Ouch! MAP sensors are expensive! Maybe I can find a junkyard sensor. Or maybe I should just go to get a dyno test done!

IrlMike

Paul, if you go for a MAP sensor, be sure to get a an analog one (giving a 0 to 5V dc output). Some of them give a frequency output. A 5V regulated power supply would be needed to power it too. One of those auto USB power supply (5V) converters would do I think. Here's a handy info link:

http://www.crxsi.com/info/driveabili...AP-Sensors.htm

And a data sheet on some common Bosch analog sensors:

http://www.bosch.com.au/content/lang...cification.pdf

I think some sort of damping arrangement in the connecting vacuum pipe might be needed also to damp out the intake oscillations. I suppose something like the constrictor tube that carbtune fit in their vacuum gauges might be the thing?

Oh, and you obviously want one suitable for a naturally aspirated engine. Turbos etc. use much wider range MAP sensors as they need to cover a few bar positive pressure as well. It would still give a signal but smaller with lower resolution.

I must say I'm a bit tempted by this Innovate kit, esp already having the TPS signal that would make logging easy at various rpms & throttle positions. But the signal interface & logger boxes double the cost to over $430 + shipping. It's a bit hard to justify the cost for me, as my bike seems to run well & get very good economy too.

If a temporary tail pipe O2 sensor works reliably on our bikes that might make the difference for me as it would then make it easier to use on other bikes too.

Be interesting to hear how you get on with your exhaust sampling set up Paul?

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98 Tbird tank/seat, Sprint fairing, ZX7R forks+Racetech Gold Valves, 08 ZX6R shock, Alcon 6-pot, Ignitech+TPS, T'bike 3-1+Beowolf can, airbox mods/rejet, tubeless wheels, lots :) per mile.

WSC

CV stands for constant velocity. The slides rise in response to the drop in pressure caused by an increase in the speed of the air passing through the throat of the carb. The rising slide causes the air to slow, until a new equilibrium is reached between the low pressure (above the diaphragm) and the spring pressure. High manifold vacuum (low pressure) correlates to a low volume of flow and lower velocity, so less slide lift.

Junk yard MAP sensors should be easy to find. They are also used to monitor vacuum control on emission controls, like EGR valves.

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John
2004 Thunderbird Sport
1975 T150V
1968 BSA Thunderbolt

IrlMike

Just been looking at this small co. that offer a Lambda / AFR kit:

http://www.ecotrons.com/Accurate_Lambda_Meter.html

Also this kit, which has some extra data logging inputs (eg for a MAP or TPS) which would enable logging to a laptop:

http://www.ecotrons.com/Accurate_Lambda_Meter_old.html

Some interesting info on their site too concerning the Bosch sensors used by them (& oems) vs other aftermarket kits, and sensor controller performance/accuracy.

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98 Tbird tank/seat, Sprint fairing, ZX7R forks+Racetech Gold Valves, 08 ZX6R shock, Alcon 6-pot, Ignitech+TPS, T'bike 3-1+Beowolf can, airbox mods/rejet, tubeless wheels, lots :) per mile.