Exhaust gas temp sensors worth recommending.

[Esteban]

Good post Stewie :-)

I'm in a similar boat looking for recommendations on EGT sensors

I'm not looking to tune the aristo (or the others) with EGT, but I think it's a valuable tool I'd like to have. I certainly cant afford a sensor on each cylinder anyway.

Thanks for the link cptsideways, I'll look into the VEMS units. The other sensors I've been looking at these stinger units but I can't decide...

So anyone have any further recommendations?

[JP]

if you do consider adding a wideband o2 sensor to the car I can recommend an innovative LC-1. I've got that unit in a couple of my cars now (one with autronic SM4 and the other wtih a powerfc/datalogit). Pretty simple to install and the last one I got with an XD16 gauge was $350AUD landed. Very handy to have with an aftermarket ECU.

[jezza323]

if you just want an EGT gauge..........then you need the correct sensor to match the gauge

EGT can be a good tuning tool in some circumstances, but generally a Wideband O2 sensor is all that is needed.

Any dyno tuner (or road tuner) worth using will have a wideband o2 meter/gauge which they will use up the tailpipe while tuning.

[Esteban]

Yep, already got a dual channel WBO2, that's a given. I plan on using one gauge w/ appropriate EGT sensor post turbo, and two EGT thermocouple probes in no.1 and no.6 exhaust runners (space permitting) into the logging inputs on the WBO2. Just can't decide on which EGT gear to get...

[EldarO]

the long and short of it is, unless your after the asthetic value of an EGT guage, you dont need one.

unless you willing to spend bulk on several guages/senders (a nightmare), one for each cylinder, its pretty much useless, and by that stage a wideband meter will be cheaper, and a shite sight better.

[oldcorollas]

EGT's are almost always K type thermocouples, as they have good response in the range you will look at. and they are cheap.
a bare bead with bare leads will always have fastest response, but we are still talking seconds for the thermal mass of the bead.

you can make your own EGT by buying some K type wire, twsiting and welding a bead (use hydrogen or oxy torch or similar), get alumina sheath and slip thru hole in exhaust
may not last long, but will give you numbers to work with, and should be fine for tuning (if you can stop them being blown out the holes )

for example, a bead welded to a sample of metal 1x10x10mm, and placed into a 1000deg furnace, will take minutes to reach 1000deg. but you will get to 900 within maybe 20 seconds?
even the alumina wire spacer sheaths (3mm diameter with 2 1mm holes in it) will slow down response.

next step is a stainless steel sheathed. these have slow response. the thinner the sheath is the better it will be for response, but also reduces lifetime.

in air at 1000-1100deg, we get from thousands to tens of thousands of hours life from high chromium nickel stainless sheaths...

in an exhaust, the way it attaches to the pipe, and the way the wires are attached will also have an ffect on it's "lifetime".. melted wires or broken wires are.. not good..
this looks half decent (and has correct extension wires)


this is stock audi one... slower response but longer life.


this looks a bit cheap as far as the wire goes, but sensor is probably fine and good enough for car use (and $30)
http://www.eagletreesystems.com/uav/.../egt-probe.jpg
(nice logger too http://www.eagletreesystems.com/Boat/boat.html)

this pic shows a thermocouple bead (for those that don't know ).. it is very small.. like 1mm diameter or so... any EGT is just this.. in a fancy sheath
http://www.eagletreesystems.com/uav/images/cht-tc.jpg

R-type couples would not be used i think, as they are platinum based...
i can't imagine N type being used either...
if you want to check pre-turbo or turbo temp, and you suspect the gas temp is over 1000C, then R type couple might be worth lookign at.... K type should last long enough if you are just checking etc..

edit: as shown here.. if you get a simple sheathed probe.. you can use a swagelok fitting to moutn it.. as shown in this pic... i'd be going this way if it was cheaper..
http://www.powerbetter.com/goods/sen...-2-640wp-g.jpg


edit2:.. here is an open tip thermocouple... you can see the bead protruding past the end.
great for tuning... not so bad to change when they break.. if you can make the beads yourself, and the setup allows easy changing of the wires



EDIT AGAIN.... i checked lab supplies catalogues.. for a 1.6 or 3.2(?)mm diameter x 50-100mm long K type thermocouple, with either 304 or 316 stainless sheath, and a 2m cable... is around $30-40 each..

[Esteban]

Stuart! You are a god among insects!

[XR Pilot]

Haven't read the full thread, but if you want to do a wideband oxygen sensor on the cheap with a gauge readout it can be done for around $170, including the sensor...

[oldcorollas]

Stuart! You are a god among insects!

nah thats crap

i've just had the chance to use a lot of these things..

[Howieau]

imho, it is much better for you to get water and oil temp, and oil pressure gauges first, and then get EGT after....

are you tuning it yourself?

Nah I won't be tuning it myself.

In regards to blocked injectors/fuel pump dying etc as a cause of leaning -> engine failure, would a fuel pressure gauge to good to start with also? I'm now looking at oil pressure, fuel pressure, (cant decide on water temp or EGT for the third). As you say water temp should come first before an EGT gauge but i've already got a water temp gauge stock. Are these not accurate or something?

Thanks again, ill get around to repping everyone when I get some more time

[oldcorollas]

not sure what you will get from fuel pressure?
it shcanges constantly depending on how much load you have, thanks to the manifold pressure referenced fuel pressure regulator.
chances are, you will nto be able to see the difference between usual, and 20% bad, which will have already farked th eengine.. or it stops firing from being too lean?...
oil pressure is a must. oil temp is good maybe?

does your stock water temp have degrees or just a couple of lines?
you can easily check the accuracy of the stock gauge.. so you may as well

[oldcorollas]

.......... dbl post

[rogue-vl]

Haven't read the full thread, but if you want to do a wideband oxygen sensor on the cheap with a gauge readout it can be done for around $170, including the sensor...

Please tell us where to find !!!!

[Howieau]

Water temp gauge only has a couple of lines.

How do you check the accuracy of the stock gauge?

[oldcorollas]

How do you check the accuracy of the stock gauge?

get an EGT and test the water temp at the water temp sensor

have to remember that K-type TC's are only as good as their calibration.. but for this purpose they will be enough.

you can use just a "normal" cheap K-type that you get with multimeters.
if your multimeter does not have a thermocouple input, don't despair ... just measure the voltage and use a voltage/temp lookup table
here is hard way http://www.home.agilent.com/upload/c...1-040107_2.htm
general info (inneresting about different types) http://www.picotech.com/applications/thermocouple.html

here is easy lookup table
http://instrumentation-central.com/T...ypeKTableC.pdf

you need an accurate multimeter, because the difference in TC voltage between say 70C and 120C, is 2.851mV vs 4.92mV ... millivolts are small

alternatively, you can use a "precision temp sensor"... part number something like LM35DZ.
http://www.national.com/mpf/LM/LM35.html
it produces 10mV per degree, and is highly calibrated in celcius... ie, 10 deg C = 100mV.
it is only good for 0-150C tho. (i would use this for coolant myself... but i can't help but to try and have accurate measurements )


you will probably find that the gauge in the car is non-linear. ie little action until maybe 80 degrees, and then fast action after that?

edit:, you can test the temp of the sensor and gauge out of the car also.. just use a pot of warm water. if you want to test temps higher than about 90, use something like vegetable oil
12V power for gauge can come from old computer power supply.
5V power for the LM35DZ can also come from the power supply (or from a USB port)