EGT Probe Thread Size

[Rusty]

Is there a standard thread size for egt probes? I'm looking to get a bung welded into the DP.

[Jonnybravo]

I believe my fitting was 1/8 npt.

Just checked and the one in the manifold and downpipe are both 1/8npt

[driftin jo]

The short answer is no.
some are NPT some are BSP and some are metric fine, you need to buy one then sort it out, usually they have for sale a weld in or screw in bung to go with it when you buy them.

[driftin jo]

There are also some clamp on ones, that are just like a hose clamp, a bit **** IMHO.

See here. http://www.auberins.com/index.php?ma...dex&cPath=5_22

[G60Rallye]

Mine is 1/8" NPT. I have mine in a lambda boss using an adapter that you can get off ebay.

[Rusty]

So I could just get a 3rd Lambda boss welded on...

[Jonnybravo]

Just get a weld on 1/8 npt fitting with a bung, I found sensors in that size ranging from £20 to £100+, seems a very common size that people use.

We used 4 of them in a mates manifold and got the sensors and logger from a aviation parts supplier, was only about £250 for everything and was a very impressive bit of kit if not ofcourse a little on the large side.

[Rusty]

Another question - zeitronix recommend that the EGT probe is before the turbo. I don't really want to go drilling and tapping my new EM, so do people bother with this or just put it in the DP and lower the upper limit that's acceptable? Obviously, expanding the exhaust gas through the turbine will cool it somewhat...

[Jonnybravo]

For prolonged use I wouldn't run it before the turbo, mine was done that way but I've moved it to the downpipe as I don't want a probe breaking and going through my turbo ! If your using ALS or LC then the probes can easily break I'm told, even if your not I still wouldn't risk it, depends how much money your rolling around in I guess

I have always been curious of the readings from the downpipe but I'd imagine anything over 850 and you might want to be getting concerned, I've been in a few vehicles that have reached close that though and they haven't had any troubles as far as I'm aware.

[K Simmonds]

Likewise, I didn't want to fit mine before the turbo, the idea of the tip coming adrift and going through the turbine put me off. I welded in a boss as close to the turbo as poss, figured it would still warn me of impending doom. I used a brake line union as it was the right thread.

[Jonas_R]

I'm running mine just after the turbo and think the "rule" is to subtract 100 degrees celcius.

[prj]

I'm running mine just after the turbo and think the "rule" is to subtract 100 degrees celcius.

That is optimistic. Realistic is 150.

Yes, 850-860 is the max you should be seeing, and that with a very long pull.
5th from 3000 to 7000 rpm for example.

[A80Avant]

Another question - zeitronix recommend that the EGT probe is before the turbo. I don't really want to go drilling and tapping my new EM, so do people bother with this or just put it in the DP and lower the upper limit that's acceptable? Obviously, expanding the exhaust gas through the turbine will cool it somewhat...

we have drilled and tapped the SQ EM, at the collector. no problems!

I would go to the solution of before the turbo if i had to redo it and wouldnt mind drilling the EM.

i dont use ALS, and i have never heard of a before turbo break of an EGT sensor which was a good quality one. I use the thick one that vems has and it stopped working once. I had to replace it and once taken out, it was looking pretty good. No signs of chipping due to temps.

[AndyP]

That is optimistic. Realistic is 150.

Yes, 850-860 is the max you should be seeing, and that with a very long pull.
5th from 3000 to 7000 rpm for example.

Just to confirm, 850-860°C with the probe after the turbo?

[Jonnybravo]

we have drilled and tapped the SQ EM, at the collector. no problems!

I would go to the solution of before the turbo if i had to redo it and wouldnt mind drilling the EM.

i dont use ALS, and i have never heard of a before turbo break of an EGT sensor which was a good quality one. I use the thick one that vems has and it stopped working once. I had to replace it and once taken out, it was looking pretty good. No signs of chipping due to temps.

I know people that have had them fail due to probably ALS use, luckily they were situated in the downpipe not the manifold. They were not cheap probes either but that depends what you class as cheap ?

Certainly interesting info, just not sure I'd fancy keeping one before the turbo for any length of time but as you say you you don't use ALS that could well be why you haven't had a problem.

Mine is situated in the elbow that connects the manifold to the turbo, its used when the engine goes on the dyno but I have decided to keep one fitted at all times but chose the downpipe just to be on the safe side !