Pyrometer vs Air Fuel ratio?
 

Anyone out there using EGT gauge or Oxygen sensors to adjust their Carb or EFI? What works best for detecting engine problems?

Re: Pyrometer vs Air Fuel ratio?
 

I use 2 egt probes and plug readings. Works well to avoid over lean situation at WOT and partial throttle. In my boat I look for 1150-1200 max, which seems to be good safe temp for a boat motor with iron heads.

Re: Pyrometer vs Air Fuel ratio?
 

O2 is going to be more accurate than EGT. You can have a high EGT being rich or lean. With Lambda it's giving you accurate A/F ratio.

Re: Pyrometer vs Air Fuel ratio?
 

Be careful there, a dual stage lambda sensor is only accurate from lambda= .9 to 1.0 out of that range it falls off. Now a wide band sensor (controlled sensor) it is very accurate for monitoring Air fuel mixtures. There is a lot of companies out there making stand alone systems with the wide band o2’s
Mike

Re: Pyrometer vs Air Fuel ratio?
 

If you use O2 you need to go Wide Band.

Re: Pyrometer vs Air Fuel ratio?
 

I have bungs for o2 sensors in both headers in dry jacketed area, but the sensors corrode and fail in short order.

Re: Pyrometer vs Air Fuel ratio?
 

I was just looking at the LC-1 from Inovative Motorsports today. It is a controller in a cable and puts out an analog or digital signal. Pretty cool! I think I will have to have one for the new fuel injection I am building..

Anyway, there is a video clip on that model and it says that the Bosch 4.2 is good for 1300* gas temp and 900* pipe temp. If you have more than that.. they sell an insulator that prevents eat from eating them up.. I know that leaded gas and oil and other things can contaminate them, but I didnt realize they had heat limits. You would think something in the exhaust pipe would handle what ever you could throw at it.. So I learned something today.. It was a good day!!

I ran thermocouples a few years back and drill a hole right at the exhaust flange. I would see some pretty high temps, but I know placement was an issue. If it runs too rich it can go hot and lean well the pistons tell you that after they go mush... But it is all relative! If you gauge tells you the upper limit accurately then you can go by that..

Best way to figure it all out is burn down a couple of motors and then you will know the limits.. *S*.. just kidding.. I am hoping the WB O2 is the way to go. Problem I might have is CMI welded the bung in the colletor right next to the four incoming pipes, instead of down steam a bit. I have no idea how that may effect the readings. I have been running narrow band sensors, one in each pipe and with Cutler self tunning EFI would see one side go lean a bit every now and then. But never burned a piston.. We'll see what happens when I get the laptop out and try it myself...

Good luck with your project Jeff.. I think the O2 is the easier way to go..

Dick

Re: Pyrometer vs Air Fuel ratio?
 

I currently have Eddie Marine Exhaust with the long stainless risers. I had them put oxygen sensor bungs 19mm right before the elbow in the risers. I have a Holley MPI kit with their laptop programmable ECU. I have never been able to calibrate it correctly with the O2 sensor. They have always read low. Before switching to the EMI's I had a oxygen sensor mounted about 3 inches away from an exhaust port on the stock manifolds. Could this have damaged the sensors? This was the location Holley recommended to put them on the stock manifolds. When I called to inquire about my O2 readings not reading correctly they wanted to sell me the wide band kit for additional $$. I was thinking about installing EGT's and setting it off of the gauge. Any suggestions?
Thanks,
Jeff

Re: Pyrometer vs Air Fuel ratio?
 

Regular O2 sensors are only accurate at 14.7, past that their readings are NOT very accurate. Wide band is the way to go. At my work we sometimes dyno motors with a wide band sensor in each header tube. (try tuning that)

Re: Pyrometer vs Air Fuel ratio?
 

jeff.
I would imagine that you could have damaged your NB sensor, but I dont know that for sure. But Phughes is right.. the NB acts as a switch that turns off and on at the 14.7 point. I used analog gauges and considered them as not accurate and not the best indicator of what is going on. The WB is much more accurate if the contoroller maintains the proper heat and is calibrated, at least that is what Inovative implies and their unit does this. How much did Holley want for the WB conversion? The LC-1 is $200 and includes the sensor and will connect to various inputs on ECU's.. I think Holley is on thier list.. Take a look at it.. http://www.innovatemotorsports.com/products.php
They have a wide range of products used to get a handle on whats happening in the motor.. I am leaning toward the LC-1 to add to my Megasquirt ECU, where I have the option to run in closed loop or not. I think I may tune it and either leave it in and keep an eye on it with my guages or use it to tune my buddies boats..
Another route to go, is a thermocouple and a hand held meter. I have seen the two input hand held meters as cheep as $90.. So if you did want to check your temps, that would give you some idea of temp, but I think the money is better spent on the WB O2...
Hope this helps...

Dick

Re: Pyrometer vs Air Fuel ratio?
 

As inexpensive as the Innovate stuff is now, there is no reason not to run O2. Back when we ran the Delphi stuff, or Horiba we were spending well over $1100 per cylinder. By the time you put one in each hole, and had backups it got really pricey especially since they wouldn't last long. I use a lot of the Innovate stuff for drivability testing, and have had great results with it.

Re: Pyrometer vs Air Fuel ratio?
 

The O2 sensors sound great but I don't see the value if you go with the wide band. If you want to monitor both manifolds, you need two gouges and 2 sensors. Looks like about $800. I can get a dual pyrometer for less than $250. Can you mount the probes in the same location as the O2's. It will obviously need some sort of reducer to go from 19mm to 1/4".
Thanks,
Jeff

Re: Pyrometer vs Air Fuel ratio?
 

EGT's need to be as close to the exhaust port as possible, so if your O2 fittings are 30 or so inches away from the exhaust port, EGT's will NOT work. the heat lost will give you an inaccurate reading. Jeff are you wanting to put this on one motor or two?

Re: Pyrometer vs Air Fuel ratio?
 

Thats good to hear Rum,, I am hoping for good things with this new setup.. The Cutler I am running now is hard to fool..

Re: Pyrometer vs Air Fuel ratio?
 

You're generally just going to use the O2 for testing, and dial-in, so really one unit is all you need. You can then switch it from side to side if you have multiple bungs in place. An EGT probe should be between 2.5" and 3.5" from the head.

Re: Pyrometer vs Air Fuel ratio?
 

I am wanting to calibrate my PCM correctly, but I would also like to monitor the engine for problems. I recently had a intake cam lobe go down after only 75 hours on a fresh motor. I would have like to have known I was running lean on #5 before I melted a piston. I have a single engine but if you don't monitor both sides you are not getting all the information you need. My sensor bungs are about 14" from the heads. Is this to far away? I think this is where Eddie Marine also puts their K probes.
Thanks
Jeff

Re: Pyrometer vs Air Fuel ratio?
 

I wouldn't mount a K type probe that far away from the cylinder head.

Re: Pyrometer vs Air Fuel ratio?
 

It's been awhile since I built an engine, but in my experience the T couple is only useful once you have the engine tuned. There is no absolute number that means good. Detonation will cause EGT to drop. A blower & a lot of overlap will give you scary EGT's. Once you get really out there on a blower motor (1400 - 1500 HP) a good portion of the fuel is cooling the piston, so conventional wisdom on FA is also out the window. We tuned the last big engine i did with a bore-scope, if there was soot on the piston it was good to go. Otherwise it would melt.

I will say all this was abut 10 years ago (how time flys) and we did not have piston oilers.