O2 Sensor Questions

[BlackoutSteve]

Re: O2 Sensor Questions

By the way.. I threw the question to Autometer and they agree with your advice.. Thanks guys.

"Hello.
I assume it is normal to fit an O2 sensor in each collector of a V8 engine's exhaust system. Does this mean that I need two A/F ratio gauges for each sensor, or can one gauge read off them both (averaging the results), or is one of the sensors to be left redundant?
I am considering A/F ratio gauge #3878.
Thanks for your help."

"Hi Steve,

You'll be fine with only one sending unit. If there was anything going on that would cause one side of the engine to run any leaner/richer than the other, there would be major drivability issues present. In all but the most highly tuned race vehicles I find a second wideband to be redundant. Hope this helps, please let me know if I can be of further assistance.

Best regards,

Joseph Mills
Auto Meter Products, Inc."

[SpiderGearsMan]

Re: O2 Sensor Questions

if he government is so serious about cleaning the air
why do they restrict the drilling of clean burning natural gas in AMERICA ?
political , it ain't about cars and dirty air - it is about power and control - after 1968 , the government has all power over the car companies
we lost our edge in the world worrying about moonbat theories that turn out to be wrong
look at ddt - some fool thinks it make bird eggs too thin [it doesn't ] and they[ WHO'S THEY ?] ban the stuff
tens of millions of poor children worldwide die of malaria because of a discredited book
fight the power

[TheSilverBuick]

Re: O2 Sensor Questions

my conclsion is since the "ir is so much dirtier now " the epa failed
the price of lost revenue , lost wages and lost liberty has been overwhelming
epa obviously did nothing but add to the bloated unelected ass holes to tell us what to do
the diesel population of big ass trucks grew
not much done on those emissions until a few years ago
pollution was a hoax , just like global warming is now
because all of this overregulation wrecked our competitivness in the world

Sorry Spidey, but anyone who has lived in LA for the last 30 years can tell you that since emission testing, etc. had started the air in and around LA has actually become more transparent! Growing up I remember going weeks with out seeing the mountains ten miles to the north of where I lived because the smog. The last several years I lived in and around LA it was a rare time the smog haze hid the mountains. No more chewable air. And I'm sure it's not just LA, but that's where I've seen the changes. I'm not going to say any more about this on this hi-jacked thread.

[SpiderGearsMan]

Re: O2 Sensor Questions

california is now bankrupt
are you sure it wasn't things like the furnace in kaiser steel , the huge GM , Ford plants running three shifts
all of the aircraft manufacturing - the air is cleaner cause the commerce is all gone
I have years of training as an emissions inspector from GM and the state
all this regulation has destroyed the American economy


GM had to design all the emission controls for everybody
you think they could have fought the foreign invaders head on ? without the mandates to slow em down
why didn't they get real and require bbq natural gas in trucks and trains ? the technology was around then
I say BULL - it was to hobble America
the germans didn't go to emissions until the green party took over a significant portion of parliaments all over europe in the late 80s
green party was the red party in the 50s
now all the factories are in red china - we are an overcrowded debtor nation borrowing money from despot regimes like red china

[SpiderGearsMan]

Re: O2 Sensor Questions

be a sceptic and don't believe all the crap the unelcted scum tels you

[chevy3100]

Re: O2 Sensor Questions

As someone who actually sells IR Thermometers, unless you are spending $3000 & up, you won't get an accurate enough reading to differentiate air/fuel ratios, but you can easily find if a cylinder is misfiring. They cheapies are great for general usage, but don't expect accuracy. Many of the mid range units have adjustable emmissivity levels, but without knowing what emmissivity to set the unit to it won't do any good (ie. if your headers aren't flat black (100% flat - no shine) you need to adjust the emmissivity, but do you know what the emmissivity is for slightly dull headers? or ceramic coated?

The best way to get temperatures for each cylinder is to use a Type K Thermocouple in each header tube. As far as reading the temps, you can use a mutimeter to get the millivolt signal & a chart to give you the corresponding temp or just buy a cheap TC reader and plug the thermocouple in to get a direct reading. It won't do you much good if you are trying to get all of the temps at the same time, but will give you an accurate reading one cylinder at a time. (Just make sure that any extension wire and plugs you use from the thermocouple are made with THERMOCOUPLE EXTENSION WIRE - not regular copper wire - if you use copper you can throw any accuracy out the window.....

[BOWTIE6872]

Re: O2 Sensor Questions

As someone who actually sells IR Thermometers, unless you are spending $3000 & up, you won't get an accurate enough reading to differentiate air/fuel ratios, but you can easily find if a cylinder is misfiring. They cheapies are great for general usage, but don't expect accuracy. Many of the mid range units have adjustable emmissivity levels, but without knowing what emmissivity to set the unit to it won't do any good (ie. if your headers aren't flat black (100% flat - no shine) you need to adjust the emmissivity, but do you know what the emmissivity is for slightly dull headers? or ceramic coated?

The best way to get temperatures for each cylinder is to use a Type K Thermocouple in each header tube. As far as reading the temps, you can use a mutimeter to get the millivolt signal & a chart to give you the corresponding temp or just buy a cheap TC reader and plug the thermocouple in to get a direct reading. It won't do you much good if you are trying to get all of the temps at the same time, but will give you an accurate reading one cylinder at a time. (Just make sure that any extension wire and plugs you use from the thermocouple are made with THERMOCOUPLE EXTENSION WIRE - not regular copper wire - if you use copper you can throw any accuracy out the window.....

THE ONE i'VE BEEN ABLE TO USE IS A 9K TOOL..
IT ACCURATE

[chevy3100]

Re: O2 Sensor Questions

It's probably going to be fairly accurate then, as long as the user knows the correct emissivity settings. Still, nothing beats a gold old temp probe in the actuall process (preferably an RTD, but for most mid temp stuff up to 2300F a type K Thermocouple is the least expensive option)

[BlackoutSteve]

Re: O2 Sensor Questions

An accurate IR tool is one thing..
Finding a spot on a header tube that is receiving and dissapating heat exactly like the other seven is something else..

[DanStokes]

Re: O2 Sensor Questions

We generally used K type T/Cs for high temps and T's for lower temps (our instrumentation can read either). We found RTDs to be too fragile and T/Cs are indestructo unless you break a wire. Using SS shielded, I don't think we ever melted one, even in exhaust where you could see the gasses move (THAT'S HOT!). As pointed out, they're cheap, too. They can be read with a volt meter but are not linear. Omega and others sell a little linearizer for a volt meter that works pretty well. We had a couple but generally used LabView for our dyno cell instrumentation. Of course, we regularly calibrated the T/Cs against ice water and boiling water (corrected for sea level). Really, you're calibrating the readouts as the accuracy of the T/C is a result of the metallurgy. Thank Whomever for Peltier!

Now I bet you all know WAY more about this than you wanted to!

Dan

[CTX-SLPR]

Re: O2 Sensor Questions

Not me! I'm a lab monkey who's been forced to live outside.

[chevy3100]

Re: O2 Sensor Questions

RTD's definitely are more fragile than thermocouples (and ones that are more rugged and designed for higher temps are definitely more expensive than thermocouples)

Type K's do tend to drift after they have been used for a while (green rot if the tip is exposed), but relly there is no simpler way of reading temps (weld or twist 2 wires together and you have an instant temp sensor)

Now to go out to the shop and build 6 RTD's & 12 thermocouples for another customer......

[BOWTIE6872]

Re: O2 Sensor Questions

ok will do ;D

[DanStokes]

Re: O2 Sensor Questions

We usually bought the SS sheathed ones from Thermo Electron, so the ends don't get funky. I know what you mean, though - the copper wire gets nasty after a while if exposed. Note to others - Type J uses iron/constantan wire, while Type J uses copper/constantan, if my old brain is remembering correctly. Can't remember what's in Type T (chromel/alumel?) as we didn't use them.

Dan

[chevy3100]

Re: O2 Sensor Questions

Type K = Chromel + / Alumel - 32-2300F
Type J = Iron + / Constantan - 32-1400F
Type T = Copper + / Constantan - -328-700F

On Type J the copper wire will get kind of nasty, but on Type K it is actually the junction that will get green rot & loose calibration over time (typically negative drop & normally in low oxygen atmospheres). Basically old thermocouples tend to register lower temps than new thermocouples.