Joined: Aug 2017 Posts: 2,748 Threads: 31
Reputation:
95
Location: Auckland, NZ
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?
Joined: Aug 2017 Posts: 2,748 Threads: 31
Reputation:
95
Location: Auckland, NZ
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!
Joined: Mar 2015 Posts: 5,467 Threads: 231
Reputation:
67
Location: Scotchland
02-09-2018, 07:41 AM
(This post was last modified: 02-09-2018, 07:42 AM by Ruairidh Dunford.)
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.
Joined: Mar 2015 Posts: 5,467 Threads: 231
Reputation:
67
Location: Scotchland
I think Andrew's connection is an identical set up Charles.
Joined: Aug 2017 Posts: 8 Threads: 0
Reputation:
0
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
Joined: Mar 2015 Posts: 5,467 Threads: 231
Reputation:
67
Location: Scotchland
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!
Joined: Aug 2017 Posts: 2,748 Threads: 31
Reputation:
95
Location: Auckland, NZ
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.)
