EGT temp readings, how hot is to hot?

[RipperXX]

I tried posting this in Tuneing but the damn page wouldn't load, after trying 10 mines I figured id just post it here.


Anyway soon as I get home (first of april) i will be installing a Autometer EGT guage kit. An

Wondering how hot is to hot? The guage reads up to 1600*F if im not mistaken. Which is around the time when the head starts to melt

I did do a search but came up empty just alot of install threads no one was mentioning readings.




Also I KNOW everyone and there mother says to install the probe in the manifold. But it seems the rest of the world says this is a no no. Im just curious of the temp diference betwine the manifold and o2 housing. Also for the people running them in there manifolds how offen do you have to replace the sensor?

 

[evil_eagle]

Well most people tune for around 850-900 degrees celsius top of each gear, 1600 degrees fahrenheit is 870 degrees celsius. SO really it would be a better Idea to get a greddy egt gauge rather then the autometer as the autometer does not read any further then 1600 degrees fahrenheit.

With my car top of 3rd gear I see around 870 degrees celsius.

Also install the probe in the #2 runner about 3-4 inches away from the head, that is going to be the most acurate spot for readings.

 

[RipperXX]

####! I ordered the autometer so it would match my boost guage... it's already in the mail I think... damn it

 

[robs90tsi]

Well most people tune for around 850-900 degrees celsius top of each gear, 1600 degrees fahrenheit is 870 degrees celsius. SO really it would be a better Idea to get a greddy egt gauge rather then the autometer as the autometer does not read any further then 1600 degrees fahrenheit.

With my car top of 3rd gear I see around 870 degrees celsius.

Also install the probe in the #2 runner about 3-4 inches away from the head, that is going to be the most acurate spot for readings.

Right you should go with something higher than a reading of 1600 F just in case, but the reading should be a little different than Eagles here. This should help you out a little, read that and you'll understand it a little better. Also, Im pretty sure that you should use the runner closest to the timing belt, not the second one, about 4 inches or so away from the cylinder head.........
http://www.vfaq.com/mods/wayback/BradBauer/gauges/egt.html

 

[evil_eagle]

Right you should go with something higher than a reading of 1600 F just in case, but the reading should be a little different than Eagles here. This should help you out a little, read that and you'll understand it a little better. Also, Im pretty sure that you should use the runner closest to the timing belt, not the second one, about 4 inches or so away from the cylinder head.........
http://www.vfaq.com/mods/wayback/BradBauer/gauges/egt.html

Well the reason behind the whole puting the probe into #2 runner is that in our cars #2 cylinder is the leanest cylinder in our cars (hense knock sensor behind #2)

For some odd reason #2 is allways the one that gets the most abuse in our cars, that is why we put the egt probe into the #2 runner.

 

[robs90tsi]

Well the reason behind the whole puting the probe into #2 runner is that in our cars #2 cylinder is the leanest cylinder in our cars (hense knock sensor behind #2)

For some odd reason #2 is allways the one that gets the most abuse in our cars, that is why we put the egt probe into the #2 runner.

Really?? Huh, I always was told " #1 cylinder", thats good to know, so when I install mine Ill use the #2 instead of the #1, thanks for letting me know that one. BTW, how big of a difference in temp readings would you get between the two cylinders to make you use the #2 instead of #1???

 

[evil_eagle]

Really?? Huh, I always was told " #1 cylinder", thats good to know, so when I install mine Ill use the #2 instead of the #1, thanks for letting me know that one. BTW, how big of a difference in temp readings would you get between the two cylinders to make you use the #2 instead of #1???

I did some testing back in the day and on an average I would see about a 75-100 degree celsius difference. In fahrenheit that is about 20-40 degrees difference. I allways install probes in the #2 runner. If you read up on peoples compression test threads you will see that #2 cylinder is allways the lowest cylinder. If any pistons are going to melt #2 is going to go 1st. Allthough most people now days don't really tune by EGT's, hell I don't even pay attention to the EGT much anymore. It's mostly timing related that effects EGT. High timing will cause low egt's and really low timing will cause extremely hot egt's, so in return it's nice to have in a way cause if it starts to climb faster then normal, chances are you are pulling timing.

 

[a_scobel]

Right you should go with something higher than a reading of 1600 F just in case, but the reading should be a little different than Eagles here. This should help you out a little, read that and you'll understand it a little better. Also, Im pretty sure that you should use the runner closest to the timing belt, not the second one, about 4 inches or so away from the cylinder head.........
http://www.vfaq.com/mods/wayback/BradBauer/gauges/egt.html

So from the bottom of that page:

Expected Temperature Readings (in F)
Idle after warm-up: 1000
Normal constant speed (~3000 RPM): 1350
Danger: 1700+

Are these accurate? What about WOT?

 

[RipperXX]

well I just contacted someone that has theres mounted in there DP 2" from the flange and he tells me his normaly sees around 1350*

I didn't really want to drill a hole in my new Evo III manifold anyway. I'll just mount it in the O2 houseing.

 

[boostedinaz]

Just some extra info.

Autometer is now making EGT gauges that read upto 2K in fahrenheit. I will be changing my 1600 to a 2K in the near future.

Also as far as placement you might have a hard time comparing numbers with people that have it installed in the exhaust manifold so keep that in mind.

 

[boostedinaz]

Are these accurate? What about WOT?

900C or 1600F are the hotest I would go at WOT. Keep in mind that you should not be tunning with these numbers.

 

[robs90tsi]

Right, you wouldnt want it in the 02 only because of the inaccurate reading?? The O2 would put out lesser temps than what you would actually see if it were in the exhaust manifold.

 

[SpooledGSX98]

I drive about 35 miles a day on the freeway. In 5th, around 3000-3500rpms, I average 1400ºf, steady. I average 75mph on the freeway the whole time, so maybe my rpms may be here nor there, but the temp is 1400ºf. I was also wondering, is this good or bad, normal?

 

[DROOPY209]

pretty soon, I'm buying a TRE EGT probe and hooking it up to my Greddy 60mm EGT gauge....

I'm gunna tap into my #2 runner as well.

 

[DSMJim]

You do not HAVE to install it in the manifold, you can put it in the O2 sensor housing right behind the turbo too.

Here is the thing. All you want to do is make sure your EGT is constant not some magical number. Take all the numbers off the gauge and just look at the little ticks. If you put the probe in your manifold it's going to read the hottest so going up high will be normal, if you put it behind the turbo it will go 3/4 of the way up and be normal. If you put the probe in your muffler it will only go 1/4 of the way up and thats normal.

It really doesn't matter where it is or what the reading is. People are all hung up on this magical number which means nothing.

What matters is that you see the gauge and during your tuning you establish whats normal for your car. If while racing or diriving you exceed that normal marker then you know it's geting hotter. The closer you put it to the engine the less room you have to see if it's going hotter or not because the normal range of operation will be at the top of what the guage is capable of displyaing.

I personally always put the probe right behind the turbo in the O2 snesor housing or if your downpipe comes right off the turbo like normal cars then right there, so it's about 1" behind the wheel or so. This way your average will be 1200-1300 and you wil have 300 more deg on the gauge to see when something is going wrong.

If you insist on putting it in the collector because some how the exhaust gas is magically more accurate or something there, it will read much higher and not leave you much gauge left to see if something gets hotter.

Only DSM guys say the manifold and I have no idea why. Nobody else does that on their cars (Honda, Supra, RX7 etc etc) and they all make as much or more power on average as we do.

 

[RipperXX]

^ Thats what I was trying to figureout, no one else puts it in the manifold so why does it seem like every dsmer is?

But thanks thats pretty much what I wanted to hear.

 

[a_scobel]

You do not HAVE to install it in the manifold, you can put it in the O2 sensor housing right behind the turbo too.

Here is the thing. All you want to do is make sure your EGT is constant not some magical number. Take all the numbers off the gauge and just look at the little ticks. If you put the probe in your manifold it's going to read the hottest so going up high will be normal, if you put it behind the turbo it will go 3/4 of the way up and be normal. If you put the probe in your muffler it will only go 1/4 of the way up and thats normal.

It really doesn't matter where it is or what the reading is. People are all hung up on this magical number which means nothing.

What matters is that you see the gauge and during your tuning you establish whats normal for your car. If while racing or diriving you exceed that normal marker then you know it's geting hotter. The closer you put it to the engine the less room you have to see if it's going hotter or not because the normal range of operation will be at the top of what the guage is capable of displyaing.

I personally always put the probe right behind the turbo in the O2 snesor housing or if your downpipe comes right off the turbo like normal cars then right there, so it's about 1" behind the wheel or so. This way your average will be 1200-1300 and you wil have 300 more deg on the gauge to see when something is going wrong.

If you insist on putting it in the collector because some how the exhaust gas is magically more accurate or something there, it will read much higher and not leave you much gauge left to see if something gets hotter.

Only DSM guys say the manifold and I have no idea why. Nobody else does that on their cars (Honda, Supra, RX7 etc etc) and they all make as much or more power on average as we do.

Awesome. Thanks for clearing that up

 

[boostedinaz]

While I agree on some thing Jim had said I will have to disagree with others.

These are not some magical numbers. These are pertinent numbers that should be looked at to avoid possible damage, just like oil pressure, water temp, or any other monitoring device. While my oil pressure or water temp may be different from the next guy the point at which engine failure might happen should be about the same. It is well know than at above 1600F or 900C the pistons are getting to point of possibly melting. So with that said while my cruising values might be different the max value should be about the same. If my cruising temp is 1000 and the other guy is at 1100 then he at least knows he is in the ballpark, however, if my temp is the same 1000 and his is 1450 then he now knows somthing is not correct and he needs to look at the cause of the problem. So just saying that what ever your normal numbers are will be fine is not a correct statment. While they don't need to be exactly the same something close, given similar probe location, is nice to know. Same with oil pressure and the other gauges I mentioned above.

On the other side of the argument do we know what the critical temp is with the probe in O2 sensor or DP? Is it 1200, 1300, 1350? What about cruising temp? I'm not sure because I am not going to find out on my own and as far as I have seen not many run the probe in that location, DSM wise, so they might not know either. So if they always getting a temp of 1500 in the O2 housing then are they ok becasue that is normal or are they on the verge of blowing shit up? While these may seem like magical numbers I am not going to hope that Harry Potter will replace my motor.

As far as the two most common reason to not place the probe in the manifold both can very easiy avoided. Autometer makes EGT gauges that go to 2K, like I mentioned above
http://www.autometer.com/cat_gaugedetail.aspx?gid=3301&sid=7 ,and other gauge companies do the same on metric units. So running out of gauge is not an issue. If people do regular maintenance on there car then they shouldn't have to worryy about the probe breaking. The probe shoud be replaced every 45K according to TRE, but I will do mine every 30K just be safe, after all I wouldn't want my turbo to get killed. I would also like to see how many threads are out there that show a turbo being trashed due to an EGT probe breaking. I have a good feeling they will all be threads of people being scared of it happening but not one actual event.

Now don't get me wrong I am not anti DP or anti O2 housing, I just want people to know that the manifold option is not some horrible thing that will make the world come to and end. Yes, some people make it sound that way. You can go either way and I really don't care, but know that the numbers may be off from other people around you and with no exact conversion formula it may be hard to find out exactly what is going on inside your motor.

 

[Lordpaxin]

I am mounting Mine In the back side of the collector on a DNP manifold.

just below where runners 1&2 empty out.

 

[Vallary99]

I have my probe in my downpipe. With a/c on and driving it's around 1000. If I'm romping on it, about 1300. If I'm on the highway for like an hour at 80 mph, about 1300. Without a/c and normal driving it's about 900. Idle after driving (cooling off) it's down to 700-800.

I moved it from the manifold because I had a custom manifold made. I saw like a 100 degree drop from moving it.

 

[DROOPY209]

I don't know about you guys but I'd rather have my probe measure the hottest place then measure a cooler place.

Those extra 100 degrees can make a difference.

Whats the point of having an EGT probe mounted in a place that is going to be cooler?
I'd put mine where it's gunna be the hottest, so I can see when stuff is about to melt, etc...

I'm gunna put my EGT probe in the place that is going to get the hottest coming out of the head.....about 3"-4" from the head on the #2 runner.

If you guys want to get "ball park" numbers, go ahead.
It's your money, mount your EGT probe on your muffler if that's what you want to do.

 

[Lordpaxin]

So just because your Mouting it in the manifold, Makes your readings more accurate than His?

Dont you understand. Its Not the fact that its a hundred degres cooler, that doesnt matter.

BIG DEAL say manifold mount normal driving is 1300 DEG and His DP Mount normal driving is 900 DEG

Yours raises to 1650 DEG UHOH better see wtf is going on right?
Same thing, Only his raises to a different number.

it still shows the SAME AMOUT OF TEMP INCREASE how is this ballpark? its just got a differnt refernece temp.

 

[DSMJim]

So just because your Mouting it in the manifold, Makes your readings more accurate than His?

Dont you understand. Its Not the fact that its a hundred degres cooler, that doesnt matter.

BIG DEAL say manifold mount normal driving is 1300 DEG and His DP Mount normal driving is 900 DEG

Yours raises to 1650 DEG UHOH better see wtf is going on right?
Same thing, Only his raises to a different number.

it still shows the SAME AMOUT OF TEMP INCREASE how is this ballpark? its just got a differnt refernece temp.

This is exactly what I said, but buddy obviously did not read my post.

It's about knowing what is normal for your car. If you put the probe in your exhaust tip and it reads 400* at WOT and all the sudden you see 450 then you know there is a problem. It doens't matter where it's put as long as you see consistant reading.

Hell put a bunch of different fruit on the gauge instead of numbers, as long as the gauge always point to the apple it's fine but when it points to the bananna, well you know where I'm going with that.

There is much validity to what boostedinaz says as with everybody running it in the manifodl you have some point of reference from 10,000 other guys as to what normal should be close to. I always do things my own way, and tune my own car my way on the dyno, so I know EXACTLY what my EGT should be with the probe right behind the turbo in all driving conditions and it left some additional room on the guage to go higher if there was a problem.

It's a known fact that guages are most accurate in the middle of their display, at the very top or bottom the margin of error is much higher. If your driving around with 1600deg showing on your 1600deg gauge all the time at WOT and things get hotter, what are you going to see that will tell you there is a problem? Nothing, right exactly .

 

[Vallary99]

Just because a runner #2 is supposed to be the hottest doesn't mean it really is. You could have a problem in another cylinder and not even know it because you are only reading the temperature out of #2.

 

[2-0turbo]

You know, on some machines, an EGT probe is mandatory equipment. It is not used as a simple "piece of mind", but an integral tool to making power safely.

I fly airplanes for a hobby. All airplanes have a manual mixture adjustment in the cockpit so that I can lean the mixture as I climb to make up for the decreasing air density. There are a couple ways to adjust this mixture. On older airplanes, you lean until you get a drop in RPM and then richen it back up to peak, then go rich of peak by about 50-100 RPM. Keep in mind, these engines are developing 75% of their rated power, so they are "fully loaded", much like your car in top gear with the gas pedal down.

Turbocharged airplanes are always equipped with an EGT gauge. It is more accurately labeled TIT, or Turbine Inlet Temperature. This is the temperature of the hot gases as they enter the turbine. Good name, right? Get that number too high through excessive leaning and your turbine will start to melt and molten metal will spinning around at 100K RPM. Not good.

So, I get up to altitude and I know have to adjust my power settings. I have control of: mixture, manifold pressure (your gas pedal) and propellor RPM (think of it as your transmission). I set my RPM to whatever the manual says, usually 2400 RPM and then adjust my manifold pressure to 24". 29.92" of manifold pressure would be atmospheric and equivalent to wide open throttle on a NA car. 38" of manifold pressure would be equivalent to approximately 4-5 lbs of "boost".

So I set my RPM and manifold pressure and then start leaning. You can see the TIT start to climb as you lean and the fuel flow decreases. Keep leaning, keep leaning, slowly. Most planes limit TIT to about 1550-1600, depending on the engine. If I keep leaning the mixture, you will see that TIT sky rocket and bad things will start to happen. Understand, most aviation piston engines have such low compression that knock is not an issue. An, I'm running 100LL fuel which has a lean octane rating of 100 and a rich octane rating of 125. So, knock is not a problem, only keeping the internals of the engine and turbine from liquefying.

So, my argument says that placement is critical. I believe it goes before the turbine. How do you establish what is "right" for your car when a maximum EGt you will see in the downpipe is something like 1200-1300? The turbo is going to consume 200-500*F in enthalpy, depending on how efficient it is. So what is the inlet side really reading?

Those of you who take your cars on the roadcourse will also notice things that your 1/4 mile friends do not. You can tune a car to top out at the top of fourth in the 1/4-mile and just see 1600*F. Take that same car to the road course and stand on it down the back stretch. You will find that you will have to run richer to keep EGT's down.

One more thing. Unless you are watching timing, EGT (or TIT) is worthless. If your engine starts to knock a bit and your ECU pulls timing, you are going to dump a ton of fuel out your exhaust due to that retarded timing. Inside, you engine will stay nice and cool, but your EGT will skyrocket. So, if you are getting real high EGT number, look at what your timing is doing before determining that you have a real big problem. It could be that you just are getting your timing pulled.