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View Full Version : Wheres the best place for the egt probe?



GT4SOM
02-02-2005, 01:14 AM
Yeah I was just wondering what the majority of you guys would think where the best place would be. The instructions says to drill the hole 2 inches below the turbo exhaust manifold. Would it be too hot there? What do you guys think? I'll take a picture of my setup tomarrow so I can pin point a spot.

I have another question. The kit explains how to install the probe in three different ways. 1 would be weld fitting which is probably the best. 2 would be a pre existing 1/8"npt threaded hole and 3 would be stainless steel clamp. Do we have a npt hole in the stock down pipe? I haven't checked for one b/c I got home late today. I'll see if I can snap some pics tomarrow.

Hooligan
02-02-2005, 01:36 AM
I doubt there is already a hole in the downpipe. You will have to drill one. I would suggest following the manufacturer's instructions for locating the hole.

I would suggest a center punch, then center drill, then drill a small pilot hole, and finally drill your desired size. After that, you weld the bung on and install the probe. You could probably even get the bung welded on first as long as you are super careful not to damage the threads while drilling the hole.

GT4SOM
02-02-2005, 03:13 AM
Yeah I'll probably end up welding it on but I asking wheres the best spot for me to make the hole for the sensor to go in?I don't want to make it too far down or too far up the down pipe.

ChrisD
02-02-2005, 03:39 AM
The *best* place is as close to the cylinder head as possible. Typically, the closest you can do is about 1" away on the exhaust manifold. People usually choose cylinder #3, because of the air flow properties of the stock intake manifold and the coolant distribution throughout the engine. So in short, on the #3 runner of the exhaust manifold is usually regarded as *best*.

Some argue that the tip could break off and damage your turbo...true, although the only car I've ever heard of was a restrictor plate Group N rally car running antilag and very high boost...but hey, it is possible I suppose. I've never heard of this happening to anyone running a street car.

Here are some pics of where mine is.

http://www.gtfour.ca/DSC01289-1.JPG

http://www.gtfour.ca/DSC01290-1.JPG

Usually you would have to remove the exhaust manfiold to install this. Some people say that it is possible to drill in *if* you do it with the engine running, so that metal shavings dont get sucked in the engine. I'm not sure on how this could affect the turbo, although it *should* be okay...

fyi i did mine with the exhaust manifold out of the car.

Hooligan
02-02-2005, 08:23 AM
Just curious...but why do you install the probe close to the engine when the directions say otherwise? Is it because you will get a hotter temperature (earlier warning) closer to combustion?

ChrisD
02-02-2005, 03:46 PM
Just curious...but why do you install the probe close to the engine when the directions say otherwise? Is it because you will get a hotter temperature (earlier warning) closer to combustion?

Yep, thats it essentially. As you move away from the head, the temps get cooler and cooler. So it is harder to determine the actual temperature of the exhaust gases, becomes more of an average from all cylinders too. After the turbo you can loose several hundred degrees from the reading.

The directions say to add it to the downpipe so that it is easier to install. People don't want to have to remove their complicated turbo set up just to install a gauge. It's probably also to protect their ass if the tip did break off somehow.

:)

GT4SOM
02-02-2005, 11:50 PM
Hmm...Its a very hard decision...Chris what does your guage usually sit at after boosting? Whats the hottests you've seen it get? The only thing I'm worried about would be the tip breaking off, that would suck. Let me know on what kind of numbers your guage reads so I could have an idea of what to expect. If its not too much trouble do you have any pics of the manifold on with the heat shield?