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egt probe

B

BrApple

No Life But CEG
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is it ok to install a pyrometer guage probe in the exhuast and not have it connected to the guage? I know for heated O2 sensors I have read it isn't good for the sensor to be in the exhaust and not have the heater powered. I am getting a pyrometer guage today and want to install the sensor while the turbo pipes are out of the car, I'm placing the sensor at the turbo exit, and before I reinstall them tonight. I might not have time before tomorrow to wire up the guage and move my boost guage to the change holder in the dash.



actually where would I be better off placing the probe? before or after the turbo. the autometer instructions comment about putting it after the turbo exit. If I place it before the turbo I would put it just after the headers in the up-pipe.
 
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Accurate EGT's would be about 2-3" away from the head exhaust port.

EGT's don't need to be hooked up to anything while installed. It won't hurt anything... just keep the leads covered to prevent any stray voltages from the EGT... as minute as they are.
 
Barge said:
Accurate EGT's would be about 2-3" away from the head exhaust port.

EGT's don't need to be hooked up to anything while installed. It won't hurt anything... just keep the leads covered to prevent any stray voltages from the EGT... as minute as they are.
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yeah I have heard that they are most accurate that close to the exhaust port. I wanted to monitor the egts the best that I could either for a whole bank for the whole enigne after the turbo. I would prefer not to drill my msds headers, although I dont think I could get in there with a drill anyway.

so bearing that in mind what would be the better place? at the header collector or after the turbo? I check the down pipe all the time with a inferred thermometer so that is why I was also partly thinking about putting it there.
 
Somewhere before the turbo would be better in my mind. The temps post turbo would be mostly meaningless.

If your headers are well insulated (coated, wrapped or both) the egt in the turbo collector may be fairly close to accurate.
 
Barge said:
If your headers are well insulated (coated, wrapped or both) the egt in the turbo collector may be fairly close to accurate.
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headers where jet hot coated. so I think I will now go pre-turbo in the up-pipe which is painted with high temp paint and wrapped.
 
I am so happy those Jet-hot coated headers have made it into such a worthy application!!!

I have mine ~ 2 inches from the head on my setup. I know you don't want to drill your headers, but just wanted to let you know where I plumb mine in.

My EGTs from that location hang around 1200 when driving with mild aggression, and get up to ~1300 when I give it a little more gusto.

Worst case scenario if you do not like the results you get you could always cap off the bung and have another one welded in the header at at later date.
 
which side and what runner? I got the 0 to 1600 degree guage. If I can reasonable get in there to drill the header to install the probe then I will. I follow that the furthur away the cooler the exhaust gas will be. I am thinking maybe into the collector of the rear manifold at this point in time.
 
Mine is on the rear bank, middle runner. I did it mostly because there is some space back there for the probe to stick out. No specific reason why I choose the middle runner. The hole was drilled just above the apex of the curve in the header.

I was fortunate enough to have the header off the car when I drilled and installed the bung. I thought that the front was too crowded with the coolant crossover tube.

Not sure how best to go about it with the headers on the car....I guess if your crossover pipe and uppipe are off you wouldnt have to worry about shavings. There might be enough room back there with the coilpack removed to get a drill in.

Does your bung thread in or have to be welded?
 
up pipe is off the car so I don't have to worry about metal shavings. I still have to get under the car to see where I can place the sensor. I can either weld in a bung, use a band clamp or just thread the fitting in.
 
I would weld a bung in, you can get them cheap from mcmaster-carr.

If you do it off of a port you want to pick what would be the hottest one. I'm not aware that anyone's done any testing on the duratec to see if there's a hottest cylinder though.

Although my banks always ran different fuel trims... i just can't remember which... but i'd put it on the leaner bank and pick a cylinder.

Or you can just do the up-pipe and knock 1-200 degrees off as a "safe" temp. Compare what you're running cruising to Shogo and use that as a rough compensation.
 
About the bung, check to see if it's a standard thread pitch. o2 sensor bungs are just std M18 nuts. I can get 100 of them for less than (1) o2 bung from Summit. I don't know if you actually need one I just saw something about it and figured I'd throw it out there. Barge mentioned this, any fastener shop should have one.
 
2000ZxT said:
About the bung, check to see if it's a standard thread pitch. o2 sensor bungs are just std M18 nuts. I can get 100 of them for less than (1) o2 bung from Summit. I don't know if you actually need one I just saw something about it and figured I'd throw it out there. Barge mentioned this, any fastener shop should have one.
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it came with a weld in bung but I don't have a welder. so for now I used the band clamp method to install the sensor.

so what I am seeing at the exit of the rear header is 900~1000 sitting at idle at a light. its more like 800 when I just start the car. cruise is ~1200 on the highway and ~1100 or maybe a bit less cruising on secondary roads.

on the highway under full boost it will hit 1400~1500 depending how long I run in boost. then when I closs the throttle is drops way back to 900~1000.
 
Sounds like your retaining good heat to that point. Those numbers look to be pretty close to what i would expect near the head. The runners on the msds headers aren't too long.
 
Barge is right that you should run the sensor in a single runner, about 2" from the flange to get your most accurate temps. Without testing back to back in both locations, you really can't know for sure exactly how much temp drop you are seeing from the port to the turbo.

Fwiw, Running too much temp WILL destroy the exhaust valves. I'd imagine though, that if you're hitting 1500 at the end of the header, you're probably closer to 1600F in the port. The exhaust valves are an austenitic steel, that can't withstand those temps for a long period of time. You will wear the valve faces badly, and possibly stretch the valves. The lash adjusters will keep up for awhile, but not forever. And a dropped exhaust valve will eat both the engine and the turbo.
 
yeah that high temp was flat out on the highway and it was only there for a few seconds.


how much would tuning the car help with the exhaust temps? meaning if it was alittle richer would that help the temps?
 
Running richer will typically lower your exhaust temps... unless you get unburnt fuel combusting in the manifolds themselves.

Timing also has an effect on your exhaust temps. Typically they will get higher as you approach your highest power and then drop off after that. You don't wanna be on that side of the peak though because power will go down and chance of detonation and pre-ignition go way up.

Edit: On another note, which EGT probe did you get? If you're actually going to use it for modifying a tune I would recommend getting the more "race" oriented quick reacting probes. The only problem with them is they don't last nearly as long.

You could always switch to the slower reacting for long term monitoring and use the fast reacting one for tuning/datalogging.
 
Barge said:
Edit: On another note, which EGT probe did you get? If you're actually going to use it for modifying a tune I would recommend getting the more "race" oriented quick reacting probes. The only problem with them is they don't last nearly as long.
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Autometer. it seems to respond pretty fast. I am not specifically going to use it for tuning, I installed it because I have heard its a good thing to monitor. I do want to get a fine tune done at some point on a dyno.

Barge said:
Timing also has an effect on your exhaust temps. Typically they will get higher as you approach your highest power and then drop off after that. You don't wanna be on that side of the peak though because power will go down and chance of detonation and pre-ignition go way up.
Click to expand...

from what I have observed over the weekend the temp goes up with the rpm. I haven't see it jump around or anything, its pretty stable while cruising. get on it and it shoots right up.
 
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Not real sure which probe that comes with, but if you look in their accessories section you will find several different probes rated street, sportsman, pro.

Anyway, if you get serious about using it as a tuning tool I'd recommend contacting autometer and figuring out what is the fastest response thermocouple you can use with your gauge.
 
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