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EGT Gauge reading.


SMW

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Had an EGT gauge fitted recently and was just wondering what sort of readings others who have one get.

I was told to a reading of 850+ was the starting point for concern and that if it went up towards 950 then I'd have real problems!

 

However I've not seen it get above about 720 even on a fairly long high speed run.

Is this normal or should I be seeing higher figures?

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I'm under the impression it should be as close to the exhaust port as possible.

 

That's where CW mouted mine. (Thanks again Chris, wouldn't want to try that myself!).

 

I get readings of about 600-650 around town runs, 750 on a high speed cruise and 900 when at WOT at ~1.2 - 1.3 bar boost.

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Guest Terry S

Right after seeing my GReddy EGT probe fail, I would not install pre turbo. I know post turbo is not as accurate but I wouldn't take the risk. My reading Post turbo were 200 degrees c less than Pre turbo.

 

I know Chris won't agree with me, but these are my findings.

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Originally posted by Matt Harwood

I'm under the impression it should be as close to the exhaust port as possible.

 

That's where CW mouted mine. (Thanks again Chris, wouldn't want to try that myself!).

 

I get readings of about 600-650 around town runs, 750 on a high speed cruise and 900 when at WOT at ~1.2 - 1.3 bar boost.

 

Did mine aswell mine has shown 980 for a brief second when pressing the loud pedal at 1.4 Bar but typically stays under 900 when giving some stick.

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Originally posted by Matt Harwood

I'm under the impression it should be as close to the exhaust port as possible.

 

That's where CW mouted mine. (Thanks again Chris, wouldn't want to try that myself!).

 

I get readings of about 600-650 around town runs, 750 on a high speed cruise and 900 when at WOT at ~1.2 - 1.3 bar boost.

 

Same as you Matt but, at WOT (1.2bar)I see around 800-850 C

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Guest Martin F
Originally posted by Barry

Martin,

 

Where is the best place for the probe.?

 

:)

 

 

Must resist........................ :baa:

 

Well (disagreeing with Terry) it has to be pre-turbo, preferably on the outlet of chamber No6. They respond slow enough as it is, putting them too far away from a chamber exit is just making things worse.

 

Also it's so hard to come up with a true value for the exhaust gas temps on the other side of the turbo as the difference can vary from car to car, turbo to turbo, jap spec to UK spec, etc.

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Originally posted by Matt Harwood

I hit 950 on Saturday afternoon on the M25 when holding full throttle for about 20 seconds starting at 70mph at 1.33 - Do the maths...

 

Ouch! - Backed off when I noticed!

 

Mmmm, 70MPH + 20 seconds at 1.33 bar must be about.......

 

 

 

 

 

 

 

 

.....mmmmmm, 70 leptons :p

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Originally posted by Matt Harwood

I hit 950 on Saturday afternoon on the M25 when holding full throttle for about 20 seconds starting at 70mph at 1.33 - Do the maths...

 

Ouch! - Backed off when I noticed!

 

Have never really tried to test the calibration on these things, but even on totally stock cars the readings seem to vary. I can't help wondering just how accurate they are... I suppose they all use K type thermocouples and as such a connector change would mean they could be connected to a lab standard readout. I have the latter, maybe I should check a new kit against a calibrated probe and meter sometime.

 

980 is getting pretty hot, although something with forged pistons and decent fuel should stand longish periods at 1000

Wouldn't recommend sustained over 950 usage in a MKIV though. Be interesting to monitor plenum air temps at the same time.

 

Looks like the EGT stuff saved damage there Matt...:eek:

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Chris fitted my EGT probe, I guess in the same location as Matt and Peter. I also get a max of about 850 at around 1.2 on WOT sustained. Most of the time I get 600 to 750. . The gauge does appear to respond quite quickly to temperature change with the probe in this position..

 

Anyone ( Terry ) know at what temperature the probe melts?

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Guest Terry S
Originally posted by Martin F

Well (disagreeing with Terry) it has to be pre-turbo, preferably on the outlet of chamber No6. They respond slow enough as it is, putting them too far away from a chamber exit is just making things worse.

 

 

Martin I know technically they should go pre turbo but I have heard so many horror stories from turbo builders, that I would now be reluctant, although I must say I am the only person with a MKIV that has lost a probe.

 

Phil, the Greddy one give up at 1100c.

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Terry, I was thinking about getting mine moved to pre turbo, as mine is post turbo, dont ask me why, Whiffin fitted it. Anyway I can see your point and can understand how gutted you'd be if you knackard a turbo, becuase your probe came off. But like you said, your the only one SO FAR with a MKIV that we know off that this has happened to.:(

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Originally posted by Ashley Willis

Terry, I was thinking about getting mine moved to pre turbo, as mine is post turbo, dont ask me why, Whiffin fitted it. Anyway I can see your point and can understand how gutted you'd be if you knackard a turbo, becuase your probe came off. But like you said, your the only one SO FAR with a MKIV that we know off that this has happened to.:(

 

I think the safety trick is to just have the very tip of the probe (which is the bit that contains the thermocouple junction) sticking into the ehaust gas strem, the heat sink effect of manifold and olive union and its mechanical support help to then prevent mechanical or temp related failure. Obviously extreme EGT temps are going to melt something anyway, probably piston tops :D

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Originally posted by Ashley Willis

There's a little round ring that holds the probe into the drilled hole, I have lost mine, can I get hold of these, do you know what Im on about......???

 

Do you mean the olive? Like a tiny version of those used in compression type plumbing fittings? Or the actual threaded adaptor the probe pokes through, male thread either end, with a cap nut and olive on the atmospheric side? Olives and fittings complete may be available from RS Components, and certainly from a good hydraulics or pneumatics company. 1/8 BSP is the normal size, but if you have already drilled the hole yu need to be quite sure...

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Originally posted by Chris Wilson

Do you mean the olive? Like a tiny version of those used in compression type plumbing fittings? Or the actual threaded adaptor the probe pokes through, male thread either end, with a cap nut and olive on the atmospheric side? Olives and fittings complete may be available from RS Components, and certainly from a good hydraulics or pneumatics company. 1/8 BSP is the normal size, but if you have already drilled the hole yu need to be quite sure...

 

Chris, It was my Apexi gauge that P Whiffin, he drilled the hole, and then there was a little round thing missing that the probe should be fed through into the hole, this little round thing as far I know holds or screws the probe tight into the hole. Im not sure about everything you said, but will give that place a go....

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