clamp style egt probe?

[tonyz2897]

Anybody have any pictures of where they drilled their exhaust manifold to install a clamp on egt probe (thermocouple)? A pic of the probe installed with the manifold on the engine would really come in handy. Also, is it 100% necessary to install the thermocouple in the manifold or would it be ok in the downpipe? I know you'd lose some heat through the turbo, but if you took that into account would it still be accurate?
Thanks,
Tony

[OmniGuy123]

Quote:

Originally Posted by tonyz2897 Anybody have any pictures of where they drilled their exhaust manifold to install a clamp on egt probe (thermocouple)? A pic of the probe installed with the manifold on the engine would really come in handy. Also, is it 100% necessary to install the thermocouple in the manifold or would it be ok in the downpipe? I know you'd lose some heat through the turbo, but if you took that into account would it still be accurate? Thanks, Tony

Lots of people run them in the DP. My grandfater was astounded when I told him what EGTs we run in our cars until he realized that we put it in the runners of the manifold. The biggest disadvantage to puting it after the turbo, is that the response would be much slower, and there are only vauge guidlines of what to shoot for that way, as most run it in the manifold.

I tried to figure out a way to clamp mine into the 3rd cyl. runner, but I could not figure out a way to do it.

Why not just drill and tap it?

[tonyz2897]

Well, the egt gauge I'm looking at comes with a clamp style probe and the price is right(85$) I have heard that some people run and even prefer the clamp style. I'm just curious to see one installed so that I can get an idea of where to drill the manifold.
Thanks,
Tony

[OmniGuy123]

Quote:

Originally Posted by tonyz2897 Well, the egt gauge I'm looking at comes with a clamp style probe and the price is right(85$) I have heard that some people run and even prefer the clamp style. I'm just curious to see one installed so that I can get an idea of where to drill the manifold. Thanks, Tony

Are all of the probes compression type, or just some of them? You might be able to get the fittings for it , and make it work for cheap?

[tonyz2897]

Not sure what you mean. The probe that comes with the gauge is the clamp in type. At least the picture in the ad shows it attached to a radiator hose type clamp.
This will be the first TD I've installed an EGT gauge on, so I'm flying blind.
Tony

[tonyz2897]

Here is the ebay item # if the pics would help clarify anything.
8020360740

Thanks,
Tony

[russ jerome]

They work fine, those 4 probes are going on there 3rd manifold
and 5th or 6th differnt combo overall

[OmniGuy123]

Quote:

Originally Posted by tonyz2897 Here is the ebay item # if the pics would help clarify anything. 8020360740 Thanks, Tony

It sure looks like the autometer style probe that I use in my cars. I would think that you would be able to use the screw in fitting by looking at the pic.

I wonder how it is self powered. As stated the autometer gauge requirs 12v power and a very good ground.

[tonyz2897]

Quote:

Originally Posted by russ jerome They work fine, those 4 probes are going on there 3rd manifold and 5th or 6th differnt combo overall

Thanks Russ!
I was kind of hoping for a shot with a stock manifold though. The way the stocker is made, it's going to be interesting to get the probe in the #4 runner and still be able to get a good straight pull with the clamp.
Thanks Again,
Tony

[tonyz2897]

Quote:

Originally Posted by cordes It sure looks like the autometer style probe that I use in my cars. I would think that you would be able to use the screw in fitting by looking at the pic. I wonder how it is self powered. As stated the autometer gauge requirs 12v power and a very good ground.

That's a good question. Not knowing how they work I just assumed they generated voltage based on heat and the gauge translated the voltage into a temperature reading.
Tony

[minimopar]

To display it with any real accuracy, it needs to be powered so that it can compensate for the local junction at the guage and drive the guage needle. The Autometer I took apart does it with a diode a dual op-amp and some feedback networks to linearize the signal for the guage driver.

[tonyz2897]

Good information!
So one that is "self powered" is likely going to be a waste of money and dangerously inaccurate?
Thanks,
Tony

[minimopar]

Well, I suppose a 40-degree sweep self-powered guage could be done, but the output of a thermocouple is very non-linear so it would be a tough to do it accurately. Would have to compensate mechanically, or with some other tricks.

A full 270-degree sweep guage has to be externally powered.

[tonyz2897]

I just found a neat article that compares different gauges and thermocouples.
I was kind of surprised to see that the self-powered Westberg (Westach) was just as accurate as the autometer and has a significantly quicker response time.
Anyhow, here's a link to the article (it's in PDF format) if anybody wants to read it.
EGT thermocouple and gauge test

Another thing I ran into that falls into the category of neat stuff is this:
EGT Gauge with thermocouple

It's a 2" EGT gauge that comes with a thermocouple for $57!
They also have a 2 1/4" model for $1.00 more but it's the square faced aircraft style. If these things are as accurate as the Westach gauge in the test (pretty sure these are made by Westach) then it looks like they'd be a great bargain for somebody wanting to add an egt on a budget.
I'll probably start another thread specifically about these to get the word out.
Maybe it's just me, but they seem like a great deal.
Tony

[tonyz2897]

Almost forgot, here's a couple links to pages that give a discription of the thermocouples based on the part#.
Clamp type thermocouples
Screw in type thermocouples
The list of thermocouples you have to choose from with the gauges was a little confusing since they are listed by part# only, but these links will let you match the part# to a discription.
While I'm thinking about it, any good advice as to what length probe would be best for a stock 8v manifold?
Thanks,
Tony