EGT GAUGES

[Bulletproof]

Richard, where is your EGT probe located ? those temperatures seem to be very low to me. I know your motor is fitted with an extractor exhaust, is it four into one and is the probe at the collector ?????. My 2LTE ( 2.4 turbo Toyota ) has the probe in the exhaust manifold just before the turbo mounting flange where it can read all four cylinders and where my research told me you should be about 7 to 8 inches from the exhaust valve, in my case it is the head ports. If I was to drive at 450/550deg C I would be idling around, I drive mine up to 650 with the 700 deg C reached for very short duration and cruise with the caravan on the back at 600 deg C all day. I would never own another diesel with out fitting a EGT gauge, like you I drive to it all the time and despite what 2's says about the 2.4 mine just clocked up over 200,000 km and hasn't gone = boom .

KEEP COOL MAN,

FITZY.

Hi Fitzy
The figures of 450-550 would be under normal driving 95% of the time. On a hill or overtaking I will allow it to go to 650 but only for short periods of time. It is easy to control by lifting the foot slightly or changing down.

Mine is fitted in the collector of the four pipes of the extractors and because I don't have a turbo are generally getting a reading less than one fitted before a turbo.

As you say keep it cool.
Cheers Richard

[SMOKEY]

Hi Bushrash, back to your original question all though all this information on EGT is very valid. If you do a forum search, put EGT Gauge as topic and SMOKEY as author you will find a lot of information on the topic, if I had more computer knowledge I would post the links, may be someone else will. As I have stated many times before,

FIT AN EXHAUST TEMPERATURE GAUGE AND DRIVE BY IT,

FITZY.

[DaveM]

viewtopic.php?f=13&t=3678&p=34187&hilit=egt#p34187

[SMOKEY]

Richard, thanks for the reply, with you engine configuration ( Supercharger, Intercooler and Exhaust extractor) along with your probe location your lower readings are on a par with mine. The EGT gauge gives you the confidence to get the best performance out of you engine and still maintain a safety margin, I shudder when I think of the heat generated when I used to tow the caravan from Christchurch to Nelson into a howling northwester with 30deg C ambient temperature with my foot on the floor all the way. After the fitment of my gauge on a drive up Porters Pass I was waved on to pass a vehicle towing a large trailer, half way past the combination the guy must have found another gear and left me stuck along side with no where to go but forward with my foot through the floor and the EGT climbing, after seeing the temp go past the 800 mark I thought F@#$$$$ , jumped on the brakes and sat there on the wrong side of the road and waited till I could get back in behind the line of cars that where behind the Dickhead towing the trailer. With the heat that can be generated no wonder there are so many heads that crack.

Richard on your other topic of your son taking his computer gig's, get some of your Bird Nesting Money out of your pocket and buy some of your own, .

YOU CAN'T TAKE IT WITH YOU,

FITZY.

[Bushrash]

Hi Bushrash, back to your original question all though all this information on EGT is very valid. If you do a forum search, put EGT Gauge as topic and SMOKEY as author you will find a lot of information on the topic, if I had more computer knowledge I would post the links, may be someone else will. As I have stated many times before,

FIT AN EXHAUST TEMPERATURE GAUGE AND DRIVE BY IT,

FITZY.

Hey Smokey
Cheers will be fitting one i see that one from jaycar looks like something you could incorp into your dash which would be good and being able to set it up to alarm would be a bonus ,,,,but the pyro looks like it could be a mission to fit to the manifold??? has anyone fitted one of these??it basically just looks like a probe,,,,,no mounting hardware
cheers
Bushrash

[KiwiBacon]

Hey Smokey
Cheers will be fitting one i see that one from jaycar looks like something you could incorp into your dash which would be good and being able to set it up to alarm would be a bonus ,,,,but the pyro looks like it could be a mission to fit to the manifold??? has anyone fitted one of these??it basically just looks like a probe,,,,,no mounting hardware
cheers
Bushrash

Yeah they're pretty easy to fit.
You'll need:
A steel compression fitting that fits your probe.
A pipe tap with the same thread as your compression fitting.
A drill to suit your pipe tap.

Most manifolds are cast iron and drill very easily. Drill, tap, install the compression fitting then slide the probe in and torque it up till it grips.
Don't use brass compression fittings, they go soft and let the probe move at the temperatures you need it most.

[Bushrash]

hey
Kiwi where do ya get ya compression fitings from??
cheers bushrash

[KiwiBacon]

hey
Kiwi where do ya get ya compression fitings from??
cheers bushrash

I got mine from a local hydraulic shop. But they had to order steel ones in, brass were on the shelf. Stainless would look better.

[wildplumdx]

i paid 128 for my pyrometer off trade me brand new with probe was an auto meter one, seems sweet as i dont understand why you would wanna pay 600 bux for something that does the same thing ? mine does the trick got it off this guy http://www.trademe.co.nz/Members/Listin ... ber=219237 but you have to ask him about it as its not listed as an auction just says he has them under boost gauges etc...

[KiwiBacon]

i paid 128 for my pyrometer off trade me brand new with probe was an auto meter one, seems sweet as i dont understand why you would wanna pay 600 bux for something that does the same thing ? mine does the trick got it off this guy http://www.trademe.co.nz/Members/Listin ... ber=219237 but you have to ask him about it as its not listed as an auction just says he has them under boost gauges etc...

Good score.

Just remember, you can't extend the probe wires with any normal wire or you'll throw it out of calibration. You need K type compensating cable which has the same materials (or compatible) to the probe wires. Normally the gauge will come with a roll of this wire, the polarity of the compensating wire is very important.

To connect the probe I used mini K type plugs because they're extremely convenient and they don't throw it out of calibration.

[wildplumdx]

sweet yeah mine came with more than enough length anyway

[Bulletproof]

Richard, where is your EGT probe located ? those temperatures seem to be very low to me. I know your motor is fitted with an extractor exhaust, is it four into one and is the probe at the collector ?????. My 2LTE ( 2.4 turbo Toyota ) has the probe in the exhaust manifold just before the turbo mounting flange where it can read all four cylinders and where my research told me you should be about 7 to 8 inches from the exhaust valve, in my case it is the head ports. If I was to drive at 450/550deg C I would be idling around, I drive mine up to 650 with the 700 deg C reached for very short duration and cruise with the caravan on the back at 600 deg C all day. I would never own another diesel with out fitting a EGT gauge, like you I drive to it all the time and despite what 2's says about the 2.4 mine just clocked up over 200,000 km and hasn't gone = boom .

KEEP COOL MAN,

FITZY.

Hi Fitzy
The figures of 450-550 would be under normal driving 95% of the time. On a hill or overtaking I will allow it to go to 650 but only for short periods of time. It is easy to control by lifting the foot slightly or changing down.

Mine is fitted in the collector of the four pipes of the extractors and because I don't have a turbo are generally getting a reading less than one fitted before a turbo.

As you say keep it cool.
Cheers Richard

The figures I quoted of 450-500 are on 33inch tyres. When I run the 35x11.5 simex ETs I can add 100 degees more to these figures and do most of my driving in 4th to get back to my 450-500 C.

Richard

[darinz]

i paid 128 for my pyrometer off trade me brand new with probe was an auto meter one, seems sweet as i dont understand why you would wanna pay 600 bux for something that does the same thing ? mine does the trick got it off this guy http://www.trademe.co.nz/Members/Listin ... ber=219237 but you have to ask him about it as its not listed as an auction just says he has them under boost gauges etc...

Good score.

Just remember, you can't extend the probe wires with any normal wire or you'll throw it out of calibration. You need K type compensating cable which has the same materials (or compatible) to the probe wires. Normally the gauge will come with a roll of this wire, the polarity of the compensating wire is very important.

To connect the probe I used mini K type plugs because they're extremely convenient and they don't throw it out of calibration.

Or you just get a gauge that can be calibrated and then is doesn't matter. Mine is a VDO electronic pyro and it can be swutched from *c to *f and have alarms etc. It also only cost $400 complete. With my gauge you wire it in then calibrate it with ice water ie 0*c.

[smurf182]

i paid 128 for my pyrometer off trade me brand new with probe was an auto meter one, seems sweet as i dont understand why you would wanna pay 600 bux for something that does the same thing ? mine does the trick got it off this guy http://www.trademe.co.nz/Members/Listin ... ber=219237 but you have to ask him about it as its not listed as an auction just says he has them under boost gauges etc...

Good score.

Just remember, you can't extend the probe wires with any normal wire or you'll throw it out of calibration. You need K type compensating cable which has the same materials (or compatible) to the probe wires. Normally the gauge will come with a roll of this wire, the polarity of the compensating wire is very important.

To connect the probe I used mini K type plugs because they're extremely convenient and they don't throw it out of calibration.

Or you just get a gauge that can be calibrated and then is doesn't matter. Mine is a VDO electronic pyro and it can be swutched from *c to *f and have alarms etc. It also only cost $400 complete. With my gauge you wire it in then calibrate it with ice water ie 0*c.

So you dip the actual probe itself in ice water, or something else? Usually ice water is used to set the cold junction compensation temp, since thermocouples measure a temperature differential, not an absolute temperature. Though i guess if you're dipping the actual probe itself in ice water to calibrate it, this would take into account any extra resistance introduced by using cable not specifically made for use with a K type thermocouple.

[KiwiBacon]

Or you just get a gauge that can be calibrated and then is doesn't matter. Mine is a VDO electronic pyro and it can be swutched from *c to *f and have alarms etc. It also only cost $400 complete. With my gauge you wire it in then calibrate it with ice water ie 0*c.

No, cold junctions cannot be accurately compensated for.

[KiwiBacon]

So you dip the actual probe itself in ice water, or something else? Usually ice water is used to set the cold junction compensation temp, since thermocouples measure a temperature differential, not an absolute temperature. Though i guess if you're dipping the actual probe itself in ice water to calibrate it, this would take into account any extra resistance introduced by using cable not specifically made for use with a K type thermocouple.

Thermocouples give off a small voltage depending on the temperature of the junction of two dissimilar metals.
If you use the wrong wire and/or connectors, you can get 5 different thermocouples in your system, all adding or subtracting to your intended reading and probably at a very different rate to each other.

This is a bad thing and cannot be tuned out.

You should only use the correct wire and connectors, the only place you can get away with anything different is at the gauge itself, the gauge will have a thermistor in it to pick up the actual temperature of those connections (cold junctions) and compensate for them.

[Bulletproof]

I would like to be corrected if Im wrong ,but talking to ship engineers my understanding is that the optimum temperature for a diesel is mid 400s C and they maintain that 24 hours of the day on every cylinder by altering the fuel mixture.

So 450-500 is the temperature I try to maintain, but I am not in a ship and have drive up hills and down hills therefore my pyrometer will hit nearly 700C going up and 100 C going down.

Why am I telling you this ?

Some of my friends with the Cheaper EGT gauges never get much over 400C and that makes me question whether they are giving a true reading.

Cheer Richard

[KiwiBacon]

Some of my friends with the Cheaper EGT gauges never get much over 400C and that makes me question whether they are giving a true reading.

Cheer Richard

I don't agree with the 400C being the optimum (well covered topic), but a probe that's too short to reach the centre of the air-stream will always give you the wrong reading.
Also use the thinnest probe you can. I have two, a 3mm probe and a 6mm. The 6mm is so laggy that on a 0-100km/h acceleration run it doesn't get within 200C of the 3mm probes reading.

[Bulletproof]

Some of my friends with the Cheaper EGT gauges never get much over 400C and that makes me question whether they are giving a true reading.

Cheer Richard

I don't agree with the 400C being the optimum (well covered topic), but a probe that's too short to reach the centre of the air-stream will always give you the wrong reading.
Also use the thinnest probe you can. I have two, a 3mm probe and a 6mm. The 6mm is so laggy that on a 0-100km/h acceleration run it doesn't get within 200C of the 3mm probes reading.

What do you believe is the optimum temperature for a diesel ?

Cheers Richard

[KiwiBacon]

What do you believe is the optimum temperature for a diesel ?

Cheers Richard

As they get hotter and hotter they get more and more efficient, the limit is of course meltdown.
I happily run mine above 600C for long periods, intermittently up to 750C.

Cruising on a flat road at 100km/h I'm pulling around 430C. At 430C the turbo has 50% more backpressure than boost (i.e. 10psi boost creates 15psi backpressure).
As the temperatures increase, the backpressure drops. Just past 600C and I get as much boost as backpressure (20psi boost, 20psi backpressure).
As it goes hotter still, I get more boost than backpressure.

The big problem with comparing ships is that ships don't often have gearing options, try to load the engine up more (higher EGT's) and you're trying to drive the boat faster which results in a whole lot more wasted energy. The optimum cruising temperature may be based on many factors including hull speed and propellor choice.

[Bulletproof]

What do you believe is the optimum temperature for a diesel ?

Cheers Richard

As they get hotter and hotter they get more and more efficient, the limit is of course meltdown.
I happily run mine above 600C for long periods, intermittently up to 750C.

Cruising on a flat road at 100km/h I'm pulling around 430C. At 430C the turbo has 50% more backpressure than boost (i.e. 10psi boost creates 15psi backpressure).
As the temperatures increase, the backpressure drops. Just past 600C and I get as much boost as backpressure (20psi boost, 20psi backpressure).
As it goes hotter still, I get more boost than backpressure.

The big problem with comparing ships is that ships don't often have gearing options, try to load the engine up more (higher EGT's) and you're trying to drive the boat faster which results in a whole lot more wasted energy. The optimum cruising temperature may be based on many factors including hull speed and propellor choice.

The point Im trying to make is on some of the Cheaper EGTs that dont read much over 400C ,Is it the Gauge giving false readings or is it the position of the probe or is their motor not running to max efficiency ?

Richard

[KiwiBacon]

The point Im trying to make is on some of the Cheaper EGTs that dont read much over 400C ,Is it the Gauge giving false readings or is it the position of the probe or is their motor not running to max efficiency ?

Richard

Easy test.
Take the probe out and stick it into an LPG flame. See how hot it reads.
That'll tell you if the gauge and probe are working, to check it's accurate you need to compare it to another one (I have a handheld k type tester and a couple of probes so it's easy for me).

Whether it penetrates far enough into the gas stream is the big question. It's hottest in the middle.

[Bushrash]

hey
so the general opinion is to mount the probe pre turbo ??kiwi these figures you are giving are for this positon?? cheers
Bushrash

[KiwiBacon]

hey
so the general opinion is to mount the probe pre turbo ??kiwi these figures you are giving are for this positon?? cheers
Bushrash

Yes, upstream of the turbo is best. The turbo extracts a lot of heat from the exhaust, which makes post-turbo measurements not much use.

[Bushrash]

sweet will look at mounting this up before i put engine in ,,,wil be easier to do a nice job

[fishjoe]

This is a very good discussion!!!!

Now my questions are:
I have fitted my EGT and not working, I extended the cable with normal wire and not getting any reading. is this the problem?
Also where I can buy this "K type" compensation cable?
Does it require any special connectors/soldering/or whatever?
Does the cable itself has polarity?


Thanks alot.

[KiwiBacon]

This is a very good discussion!!!!

Now my questions are:
I have fitted my EGT and not working, I extended the cable with normal wire and not getting any reading. is this the problem?
Also where I can buy this "K type" compensation cable?
Does it require any special connectors/soldering/or whatever?
Does the cable itself has polarity?


Thanks alot.

Any electrical trade supplier should be able to get you some K type compensating cable. Ideal electrical, coreys etc.
Yes the cable has polarity. Red is negative, yellow is positive but there are other colour codings too.

Yes it requires special connectors, ask at the above electrical trade suppliers for mini K type plugs and use those to join it.

[Swamped]

If anyones interested
Engine parts ltd just quoted me $349 inc gst for a egt gauge setup.

Email from Engine parts
Nothing on the shelf at the mo, but i can order one in for you ..

AU3344-M $349 inc gst

Part Number: AU3344-M


Air-Core meter movement.

Includes 8 ft. tubing or wiring harness.

Includes type K Thermocouple.
Autometer - Sport-comp 2-1/16" Pyrometer
0 - 900° C (electric)

[Bulletproof]

This is a very good discussion!!!!

Now my questions are:
I have fitted my EGT and not working, I extended the cable with normal wire and not getting any reading. is this the problem?
Also where I can buy this "K type" compensation cable?
Does it require any special connectors/soldering/or whatever?
Does the cable itself has polarity?


Thanks alot.

The instructions that came with my VDO Oceanic said the wires from the Sensor to the guage are not to be altered . They said they were not to be shortened and to coil if needed.
My understanding is that it gives a false reading.

Richard

[dazza85]

The instructions that came with my VDO Oceanic said the wires from the Sensor to the guage are not to be altered . They said they were not to be shortened and to coil if needed.
My understanding is that it gives a false reading.
Richard

I believe that Richard is correct as all our thermocouples at work have the spare cable coiled up and when I asked one of our calibration techs about it he said that all the thermocouples come already calibrated and any damage to the cable results in the thermo getting tossed out.