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+--- Thread: Oxygen Sensors (/showthread.php?tid=1656)
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Oxygen Sensors - Bob Culver - 02-09-2018
A few years ago the topic of oxygen sensors arose. Someone was tinkering with and going to report but nothing further. Economy is not really the concern of Seven owners nowadays but observation could be interesting.
I am curious to monitor another car. Is there an inexpensive simple early non heated (single wire) sensor readily available? Can volts easily be monitored with a digital voltmeter or is interference impossible ? Does a shielded wire suffice to avoid?
Presumably the racer fraternity have extensively explored. Or with Sevens is it impossible to read a meter and stay on the road?
RE: Oxygen Sensors - jansens - 02-09-2018
I was recently wondering about getting one of these: http://www.nzperformance.co.nz/mtx-l-plus-wideband-air-fuel-ratio-gauge-kit
Not for permanent fitment but for setting the car up. You can download some (dated looking!) software for it that allows you to log to a laptop in real time it seems so you can actually get an idea of the ratios under actual driving conditions.
The sensors are finicky. You do need some sort of smart interface to connect to and drive them.
Simon
RE: Oxygen Sensors - Bob Culver - 02-09-2018
Hi Simon
I guess the data logger stuff is applicable to moderns where there is other data to coordinate with. For a simple older car just knowing which side of the knee on could be useful, and that just requires the voltage output. Not much concerned about the cold engine condition.
I dunno what resistance load they typically operate into but an unmodified digital voltmeter would seem to invite ignition volt troubles.
Someone must have some NOS single wire units going for $50 or so!
RE: Oxygen Sensors - Ruairidh Dunford - 02-09-2018
Andrew Goodfellow has a lambda connection built into his Ulster silencer box - he uses it to set the engine and it appears to work rather well.
RE: Oxygen Sensors - Charles P - 02-09-2018
(02-09-2018, 07:41 AM)Ruairidh Dunford Wrote: Andrew Goodfellow has a lambda connection built into his Ulster silencer box - he uses it to set the engine and it appears to work rather well.
I have a boss welded into the exhaust just before the silencer and a pair of connections for the 12v feed hidden under the dash. The meter is one of these http://www.dtmpower.com/fuelmeter
Very handy for ensuring that the mixture is acceptable. When not in use the whole lot is unplugged and the threaded boss is blanked off. It's handy that Lambda sensors use an 18mm spark plug thread so a cut down spark plug with a 1931 half penny soldered on provides blanking. Sadly I didn't have a vintage coin to hand
C
RE: Oxygen Sensors - Ruairidh Dunford - 02-09-2018
I think Andrew's connection is an identical set up Charles.
RE: Oxygen Sensors - A Goodfellow - 02-09-2018
Charles / Ruairidh
I use a LM2 Innovate to monitor and set up that fuel mixture. Along with that I connect a throttle positioning sensor and also take a reading of the rpm and road speed. That way you can set up the mixture to the way you drive the car(important if your using it for different uses). All the data is read through the LM2 and graphs it out back to the laptop allowing you to analyse the date and make changes accordingly. A good guide would be for road use 13.4 - 13.6% approx. although while i was running the car in the Monte Carlo rally I had it set to 14.1- 14.3% but my air temperature was around -4C. When I'm running an engine on the dyno I set to approx 13.6%.
Hope that's of some help
Andrew
RE: Oxygen Sensors - Charles P - 02-09-2018
(02-09-2018, 02:29 PM)A Goodfellow Wrote: Charles / Ruairidh
I use a LM2 Innovate to monitor and set up that fuel mixture. Along with that I connect a throttle positioning sensor and also take a reading of the rpm and road speed. That way you can set up the mixture to the way you drive the car(important if your using it for different uses). All the data is read through the LM2 and graphs it out back to the laptop allowing you to analyse the date and make changes accordingly. A good guide would be for road use 13.4 - 13.6% approx. although while i was running the car in the Monte Carlo rally I had it set to 14.1- 14.3% but my air temperature was around -4C. When I'm running an engine on the dyno I set to approx 13.6%.
Hope that's of some help
Andrew
Blimey Andrew. That's very posh. Way ahead of my simple set up combined with a known road route containing a long uphill drag.
I'd be interested to see how the throttle position sensor is fitted.
C
RE: Oxygen Sensors - Ruairidh Dunford - 02-09-2018
I have absolutely no idea what Andrew is talking about but he clearly does and I can vouch for that - his car is a rocket!
RE: Oxygen Sensors - Bob Culver - 03-09-2018
Thanks fellahs. If it can be persuaded to read reliably a digital voltmeter would detect the knee much as Charle’s device. If anyone can acquire a known good sensor it could cost nothing to experiment.
Sorry to bore most on this forum but books reckon mixture distribution esp with carbs usually differs by one ratio or so between cyls. (which is presumably why some valve seats in my 1960s car recess faster than others). With a four each discharge is more or less independent. With a detector in the manifold any exhaust with free oxygen would have little chance to combine with CO from other cyls. The reading is an average of some sort but with the very non linear response just what the very precise readings really mean I dunno.
(I referred to single wire but now gather some unheated units have two wires.)