Anybody watch EGT's?
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TECH Senior Member
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From: Waco, TX
Anybody watch EGT's? Got the AutoMeter Pyrometer installed last week. The AIR fitting on my driver's side Grot header is about 1 1/2" from the head... So, I lopped it off with the sawzall, whipped out a 1/8" NPT tap, and easily installed the EGT probe right there.
Been watching the gauge, and at idle the temps are pretty low... Say 800 degrees. But as the RPMs increase, they go up. For example, at about 3000 RPM, the gauge goes to a little over 1300 degrees.
So, my question is - this sound about right? I think the probe is installed correctly, and in a good spot.
Just trying to get a baseline of how it's supposed to look.
-Andrew
Been watching the gauge, and at idle the temps are pretty low... Say 800 degrees. But as the RPMs increase, they go up. For example, at about 3000 RPM, the gauge goes to a little over 1300 degrees.
So, my question is - this sound about right? I think the probe is installed correctly, and in a good spot.
Just trying to get a baseline of how it's supposed to look.
-Andrew
Re: Anybody watch EGT's? Airplane motor guys use this as a primary tuning
indicator, I know I've found charts of mixture
vs EGT on those kind of sites. But non-steady-
state and low-exhaust-flow, you might have the
headers' cooling effect embedded in your data
and might want to do stuff like wrap the leg that
has the sensor etc. to get better readings.
indicator, I know I've found charts of mixture
vs EGT on those kind of sites. But non-steady-
state and low-exhaust-flow, you might have the
headers' cooling effect embedded in your data
and might want to do stuff like wrap the leg that
has the sensor etc. to get better readings.
On The Tree
Joined: May 2003
Posts: 106
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From: Apache Junc, Az
Re: Anybody watch EGT's? EGT probes, regardless of the application, should be installed at a location which would be 1/2 of the primary tube diameter from the head surface. So if the ID of your primary tubes is 3", the hole or bung should be located 1.5" from the head side of the flange. You may place it at any angle to allow access to header bolts, etc. This is a position that's considered a "standard" for location in the automotive world.
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From: USA
Re: Anybody watch EGT's? I would place the sensor at the point all pipes of 1 head converge so your seeing the total combined temp and not on the output of just 1 cyclinder.
If the pipes are heat coated it would have an effect on exhaust gas temps.
The AIR inlet would be colder then what O2s are measuring. Max temp if I recall is like around 1,700 degrees.
If the pipes are heat coated it would have an effect on exhaust gas temps.
The AIR inlet would be colder then what O2s are measuring. Max temp if I recall is like around 1,700 degrees.
TECH Fanatic
Joined: Nov 2001
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From: Las Cruces, NM
Re: Anybody watch EGT's? Putting the egt probe were all the exhuast gas from each cylinder combines would yield temperature considerably hotter (up to 500 deg F due to turbulance) than at each cylinder. You should also have the tip of the probe in the center (roughly) of the flow path (header primary). If have it just barely poking through the header you will be a stagnate portion of the flow and temperature will also be off.
I dont have baseline for a LS1 but does not appear to high.
Gary
I dont have baseline for a LS1 but does not appear to high.
Gary
Thread Starter
TECH Senior Member
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From: Waco, TX
Re: Anybody watch EGT's? Thanks for the replies, guys.
Here is the instruction manual for the AutoMeter pyrometer that I have:
http://www.autometer.com/hp/instruct...ctions/514.pdf
It does say to install the probe 1"-2" from the head. That's exactly where my AIR tube inlet went. And since the AIR system is in a box in my garage...
I did cut down the AIR tube inlet pipe. There is at least 1/2" (my estimation) of probe tip sticking directly in to the exhaust stream, in the center of the pipe (the AIR pipe does protrude down in to the header a tad). I could probably cut the AIR pipe upwards to expose more probe, but the probe almost looks like it's made from 2 pieces - a small section, about 3/8" long, at the very very tip - and then the rest of the metal on the probe. I've got the small section completely exposed in the exhaust stream.
It'd be nice (pipe dreams) to have 8 probes and a data acquisition system monitoring them, but that's not financially feasible for me.
I guess I was just surprised by seeing 1300+ when driving in 5th at about 65 mph. Drop it in to 6th and the temp comes down some. (I have 4.56 gears ). And at idle it goes down to a reasonably low temp.
Thanks,
Andrew
Here is the instruction manual for the AutoMeter pyrometer that I have:
http://www.autometer.com/hp/instruct...ctions/514.pdf
It does say to install the probe 1"-2" from the head. That's exactly where my AIR tube inlet went. And since the AIR system is in a box in my garage...
I did cut down the AIR tube inlet pipe. There is at least 1/2" (my estimation) of probe tip sticking directly in to the exhaust stream, in the center of the pipe (the AIR pipe does protrude down in to the header a tad). I could probably cut the AIR pipe upwards to expose more probe, but the probe almost looks like it's made from 2 pieces - a small section, about 3/8" long, at the very very tip - and then the rest of the metal on the probe. I've got the small section completely exposed in the exhaust stream.
It'd be nice (pipe dreams) to have 8 probes and a data acquisition system monitoring them, but that's not financially feasible for me.
I guess I was just surprised by seeing 1300+ when driving in 5th at about 65 mph. Drop it in to 6th and the temp comes down some. (I have 4.56 gears
). And at idle it goes down to a reasonably low temp.Thanks,
Andrew
On The Tree
Joined: May 2003
Posts: 106
Likes: 1
From: Apache Junc, Az
Re: Anybody watch EGT's?
I would place the sensor at the point all pipes of 1 head converge so your seeing the total combined temp and not on the output of just 1 cyclinder.
If the pipes are heat coated it would have an effect on exhaust gas temps.
The AIR inlet would be colder then what O2s are measuring. Max temp if I recall is like around 1,700 degrees.
If the pipes are heat coated it would have an effect on exhaust gas temps.
The AIR inlet would be colder then what O2s are measuring. Max temp if I recall is like around 1,700 degrees.
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Thread Starter
TECH Senior Member
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From: Waco, TX
Re: Anybody watch EGT's? Found this on the Pro-Flow (MAF people) web site. Thought it was interesting, so I thought I'd share. Looks like my readings are within spec.
-Andrew
Exhaust Gas Temperature
One of the best indications of how an engine is being fueled is the temperature of the exhaust. The usual set up is to put an "K" type thermocouple on the exhaust header of the hottest cylinder and monitor the temperature while doing various tests.
Idle: while the engine is idling for a long period of time the EGT should not exceed 1000 degrees F. and should be no lower than 500 degrees F. Adjusting the low speed (0) potentiometer on the calibrator the temperature should be regulated……if temperature is hot turn voltage up……if temperature is cold turn voltage down.
Road Load: 1800 to 2200 RPM flat road steady speed for 2 min. EGT should not exceed 1400 and be more than 1000 degrees F.
WOT: Full throttle accels at high speed EGT should never exceed 1440 degrees F. and should normally in the 1100 to 1250 degree range. Adjusting the high speed potentiometer on the calibrator the temperature at WOT should be controlled…If the temperature is too high richen the mixture by increasing the voltage…if the temperature is too low lean out the mixture by decreasing the voltage.
Note: Our experience says that the most logical tube to measure is the no. 7 cylinder. This especially if the system is supercharged and larger than 24 #….injectors are used.
-Andrew
Exhaust Gas Temperature
One of the best indications of how an engine is being fueled is the temperature of the exhaust. The usual set up is to put an "K" type thermocouple on the exhaust header of the hottest cylinder and monitor the temperature while doing various tests.
Idle: while the engine is idling for a long period of time the EGT should not exceed 1000 degrees F. and should be no lower than 500 degrees F. Adjusting the low speed (0) potentiometer on the calibrator the temperature should be regulated……if temperature is hot turn voltage up……if temperature is cold turn voltage down.
Road Load: 1800 to 2200 RPM flat road steady speed for 2 min. EGT should not exceed 1400 and be more than 1000 degrees F.
WOT: Full throttle accels at high speed EGT should never exceed 1440 degrees F. and should normally in the 1100 to 1250 degree range. Adjusting the high speed potentiometer on the calibrator the temperature at WOT should be controlled…If the temperature is too high richen the mixture by increasing the voltage…if the temperature is too low lean out the mixture by decreasing the voltage.
Note: Our experience says that the most logical tube to measure is the no. 7 cylinder. This especially if the system is supercharged and larger than 24 #….injectors are used.
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