Probe placement egt difference.

RonA

RonA

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Joined
Feb 26, 2008
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How much egt difference should one see between having the probe about 2 inches from the turbo mount surface in the manifold where #2 and #3 come together verses where number 5 and 6 come together.
 
Never measured it Ron, I have been told the rear cylinders run a bit hotter and to mount said probe in the rear part of the manifold. That's what I based mine on anyway, pretty sure somebody out here has done both and can chime in.
 
Ron I have used both placements. I've seen a 50-80 difference on mid-range bursts and on a 1/4 mile WO run seen 100.

I usually keep it located on the 5-6.
 
Wow! 50-100 deg difference? The rear being hotter, correct? Is this due to less water flow at the rear of the engine? That is crazy. I've always had mine mounted in the back and never thought the difference would be that much.
 
4x4dually said:
Wow! 50-100 deg difference? The rear being hotter, correct? Is this due to less water flow at the rear of the engine? That is crazy. I've always had mine mounted in the back and never thought the difference would be that much.
Click to expand...

Nope, less air at the back intake valves;) Water temp has almost nothing to do with EGT's

Chris
 
I'm seeing about 75deg higher egt's than before. I changed a number of things, but the probe position is what I suspect is causing it. It even idles hotter. I was secretely hoping to see a slight reduction with the new intercooler, but I was told that wasn't always the case. I am hoping to start tuning the wastegates this weekend and i will be able to rule the manifold wastegate out then. It doesn't feel like it's opening early, but I will add a bit more spring to it and make sure. With the weakest spring and no air to either side it doesn't seem to be opening with drive pressure. But then drive pressure is under the valve and hot pipe pressure(slightly less) is on top of the valve, so it may never open on its own. Or it may only open enough to be a headache.
 
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