320 Degrees! How high is too high?
Road Master
Joined: Feb 2016
Posts: 858
Likes: 140
From: USA
A bit on the nomenclature-
Head Temperature as displayed on the PV is NOT CHT. Head Temperature is an algorithm derived number.
This algorithm is based partially on the ET sensor, partially on the IAT (Intake Air Temperature) sensor, partially on the MAP (manifold air pressure) and some other factors which HD-Delphi uses.
ET as displayed on the PV is a direct readout of the sensor located on the back left of the front cylinder head. This is a hard number.
What is confusing is that it is reading the cylinder head temperature, but it is called ET (engine temperature). The reading that is call a head temperature is NOT the head temperature, but an algorithm based number.
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,939
Likes: 8,036
From: poway
What do you think about the second log I posted? I figured the HT reading on the PV was the actual temp at the head and the ET was some sort of calculation. I know the new tuner software indicates the reverse, but it doesn't look like that from that log I ran. It looks like my HT decreased when I was stopped due to the LJ fans. I wonder why my ET didn't also decrease. If I have time tomorrow, I am going to run a log without the fans on to see what happens at idle at a stoplight. I will post.
If you look at Tmax, they call the temp sensor in the head, head temp but then they are a complete replacement ECU. Nothing is from Delphi.. This is probably the main reason why I found out it was different. 2 Temp on the Delphi system where Tmax only uses 1.
CHT temps will change first because they are calculated.
The LJ fans are not being given enough time. Really need to see more time..Still the engine temp may not do anything. Switch the fans off. Chamber temps will change faster than engine temps. It's where the source of the heat is coming from. Stall /stop the motor with and without the fans and log the temps. You'll find some interesting things.
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,939
Likes: 8,036
From: poway
I'm more confused now. I have attached a log that I ran with my PV. I have the LJ fans on my bike. While I was sitting at traffic light, my HT dropped from 340 degrees to 329 degrees. My ET didn't move at all. It stayed at 253 degrees. I'm guessing that my HT dropped because the fans blow directly through the head channel and on the sensor. If the temp sensor is a ET "hard reading" as you indicate, how come my my ET didn't decrease.
BTW This is a good thing.. I've thermocoupled up big carbed motors. Roll too a stop and temps jump up..
I'm more confused now. I have attached a log that I ran with my PV. I have the LJ fans on my bike. While I was sitting at traffic light, my HT dropped from 340 degrees to 329 degrees. My ET didn't move at all. It stayed at 253 degrees. I'm guessing that my HT dropped because the fans blow directly through the head channel and on the sensor. If the temp sensor is a ET "hard reading" as you indicate, how come my my ET didn't decrease.
If you are stopped long enough, it is likely the HT number will get very close to the ET number.
Your ET did not drop when you stopped because the actual temperature of the left rear part of the front cylinder head (where the sensor is located) did not drop. If you did not have your fans on, likely it would have increased.
As I noted in my previous post, the HT number varies quite a bit, based on a variety of factors...ET and load on the engine are two of the biggest. So as you are riding, especially if you are accelerating, that number will move quite a bit, and quite quickly.
The ET number is much more stable and slowly moves up and down as the actual temp of the part of the cylinder head where the sensor is located changes.
One thing you can do to get a better feel for how it works-
Have the display of the PV set to show the ET
Start the engine and let it set (fans off) and watch the ET go up
(Don't let it go over 260*)
Around 240* turn the fans on.
You will either see the temp start dropping a little, or at least slow down in how fast the temp is rising.
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Road Master
Joined: Feb 2016
Posts: 858
Likes: 140
From: USA
Your HT (which is not a hard number, but an algorithm derived number) dropped because you were stopped, no longer putting a load on the engine. Even without the fans, that HT number will drop when you come to a stop.
If you are stopped long enough, it is likely the HT number will get very close to the ET number.
Your ET did not drop when you stopped because the actual temperature of the left rear part of the front cylinder head (where the sensor is located) did not drop. If you did not have your fans on, likely it would have increased.
As I noted in my previous post, the HT number varies quite a bit, based on a variety of factors...ET and load on the engine are two of the biggest. So as you are riding, especially if you are accelerating, that number will move quite a bit, and quite quickly.
The ET number is much more stable and slowly moves up and down as the actual temp of the part of the cylinder head where the sensor is located changes.
One thing you can do to get a better feel for how it works-
Have the display of the PV set to show the ET
Start the engine and let it set (fans off) and watch the ET go up
(Don't let it go over 260*)
Around 240* turn the fans on.
You will either see the temp start dropping a little, or at least slow down in how fast the temp is rising.
If you are stopped long enough, it is likely the HT number will get very close to the ET number.
Your ET did not drop when you stopped because the actual temperature of the left rear part of the front cylinder head (where the sensor is located) did not drop. If you did not have your fans on, likely it would have increased.
As I noted in my previous post, the HT number varies quite a bit, based on a variety of factors...ET and load on the engine are two of the biggest. So as you are riding, especially if you are accelerating, that number will move quite a bit, and quite quickly.
The ET number is much more stable and slowly moves up and down as the actual temp of the part of the cylinder head where the sensor is located changes.
One thing you can do to get a better feel for how it works-
Have the display of the PV set to show the ET
Start the engine and let it set (fans off) and watch the ET go up
(Don't let it go over 260*)
Around 240* turn the fans on.
You will either see the temp start dropping a little, or at least slow down in how fast the temp is rising.
One more question/comment. My oil temps generally run 220 - 240. At the same time I am seeing ET on my PV at 230 - 260 and HT on my PV at 320 -330. Are you saying that the actual temperature of the sending unit screwed into the front head is what is being reported as ET on the PV? How can that sending unit's temperature be the same or similar to the oil temperature that I'm seeing? I would think it would be much hotter since it is screwed into the hottest part of the engine?
I would think the temperature of the head sending unit would be the actual HT and the PV would report such as HT. Then the ECM does whatever it does with "load and algorithms and what not" to report a calculated ET. I cannot believe my oil temperature measured in the oil pan is the same or very close to the sending unit temperature in the head. What do you think?
Road Master
Joined: Feb 2016
Posts: 858
Likes: 140
From: USA
I don't buy it.. The head and engine temps of PV are the same head and engine temps for TTS and the HD tuners. Why? When you get right down to it. The aftermarket tuners are nothing more than an interface to modify the ECM (IIRC Cole adds some code).. Core ECM code that the unit runs is the same across all flash tuners. Why change naming / function? The flash tuners still rely the core code to run the motor. The algorithms are pretty sophisticated.
If you look at Tmax, they call the temp sensor in the head, head temp but then they are a complete replacement ECU. Nothing is from Delphi.. This is probably the main reason why I found out it was different. 2 Temp on the Delphi system where Tmax only uses 1.
CHT temps will change first because they are calculated.
The LJ fans are not being given enough time. Really need to see more time..Still the engine temp may not do anything. Switch the fans off. Chamber temps will change faster than engine temps. It's where the source of the heat is coming from. Stall /stop the motor with and without the fans and log the temps. You'll find some interesting things.
If you look at Tmax, they call the temp sensor in the head, head temp but then they are a complete replacement ECU. Nothing is from Delphi.. This is probably the main reason why I found out it was different. 2 Temp on the Delphi system where Tmax only uses 1.
CHT temps will change first because they are calculated.
The LJ fans are not being given enough time. Really need to see more time..Still the engine temp may not do anything. Switch the fans off. Chamber temps will change faster than engine temps. It's where the source of the heat is coming from. Stall /stop the motor with and without the fans and log the temps. You'll find some interesting things.
I don't understand why the HT's dropped 10 degrees and the ET's didn't move at all. If the HT's are calculated, they are calculated from something right. DK indicated that they are calculated from the ET. So how did the HT's drop when the ET's stayed the same?
Road Warrior
Joined: Jul 2013
Posts: 1,725
Likes: 193
From: South
Why would the HT's change first because they are calculated? Wouldn't whatever the HT's were calculated from change as well?
I don't understand why the HT's dropped 10 degrees and the ET's didn't move at all. If the HT's are calculated, they are calculated from something right. DK indicated that they are calculated from the ET. So how did the HT's drop when the ET's stayed the same?
I don't understand why the HT's dropped 10 degrees and the ET's didn't move at all. If the HT's are calculated, they are calculated from something right. DK indicated that they are calculated from the ET. So how did the HT's drop when the ET's stayed the same?
CHT went down because your fan blew on it. Your ET didnt go down because it was supposed to go up after you stopped, so all the fan did was preventing it from going higher.
Did u try to wait for a longer period of time and see if it drops or not?
Road Master
Joined: Feb 2016
Posts: 858
Likes: 140
From: USA
CHT is directly from the sensor, I dont think it's calculated from anything.
CHT went down because your fan blew on it. Your ET didnt go down because it was supposed to go up after you stopped, so all the fan did was preventing it from going higher.
Did u try to wait for a longer period of time and see if it drops or not?
CHT went down because your fan blew on it. Your ET didnt go down because it was supposed to go up after you stopped, so all the fan did was preventing it from going higher.
Did u try to wait for a longer period of time and see if it drops or not?
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Joe Kucinski
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,939
Likes: 8,036
From: poway
I'll give that a try.
One more question/comment. My oil temps generally run 220 - 240. At the same time I am seeing ET on my PV at 230 - 260 and HT on my PV at 320 -330. Are you saying that the actual temperature of the sending unit screwed into the front head is what is being reported as ET on the PV? How can that sending unit's temperature be the same or similar to the oil temperature that I'm seeing? I would think it would be much hotter since it is screwed into the hottest part of the engine?
I would think the temperature of the head sending unit would be the actual HT and the PV would report such as HT. Then the ECM does whatever it does with "load and algorithms and what not" to report a calculated ET. I cannot believe my oil temperature measured in the oil pan is the same or very close to the sending unit temperature in the head. What do you think?
One more question/comment. My oil temps generally run 220 - 240. At the same time I am seeing ET on my PV at 230 - 260 and HT on my PV at 320 -330. Are you saying that the actual temperature of the sending unit screwed into the front head is what is being reported as ET on the PV? How can that sending unit's temperature be the same or similar to the oil temperature that I'm seeing? I would think it would be much hotter since it is screwed into the hottest part of the engine?
I would think the temperature of the head sending unit would be the actual HT and the PV would report such as HT. Then the ECM does whatever it does with "load and algorithms and what not" to report a calculated ET. I cannot believe my oil temperature measured in the oil pan is the same or very close to the sending unit temperature in the head. What do you think?
ET is the heat temp sensor.. They can track within 0 -20 easy. Some of it depends on the lifter flow to the heads..
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,939
Likes: 8,036
From: poway
Why would the HT's change first because they are calculated? Wouldn't whatever the HT's were calculated from change as well?
I don't understand why the HT's dropped 10 degrees and the ET's didn't move at all. If the HT's are calculated, they are calculated from something right. DK indicated that they are calculated from the ET. So how did the HT's drop when the ET's stayed the same?
I don't understand why the HT's dropped 10 degrees and the ET's didn't move at all. If the HT's are calculated, they are calculated from something right. DK indicated that they are calculated from the ET. So how did the HT's drop when the ET's stayed the same?