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EGT Placement
- Thread starter Adam
- Start date
what works best?
gmcjetpilot
Well Known Member
Fast-slow, Long-short
From what I understand the closer (to exhaust port) the better, but your probe life will be very very short. Put it down stream too far, response is much slower but you get best probe life. Remember absolute EGT temp value is not important but peaks and deltas (difference between cylinders) is important. (Alcor EGT gages don't even put numbers on there analog gages).
The most important is equal or equivalent position on all cylinders. My opinion is no closer than 3" and no further than 6". I tend to go towards the further out position for probe life. Also bends and the shape of you exhaust stack may come into play. If you get too far down you may get into a bend or have interference issue, so you would default towards the closer position for installation issues.
Not super critical and try to get even or equivalent position on exhaust all stacks. Split the diff of the ranges above, the position would be around 4.5" - 5.0".
Cheers George
From what I understand the closer (to exhaust port) the better, but your probe life will be very very short. Put it down stream too far, response is much slower but you get best probe life. Remember absolute EGT temp value is not important but peaks and deltas (difference between cylinders) is important. (Alcor EGT gages don't even put numbers on there analog gages).
The most important is equal or equivalent position on all cylinders. My opinion is no closer than 3" and no further than 6". I tend to go towards the further out position for probe life. Also bends and the shape of you exhaust stack may come into play. If you get too far down you may get into a bend or have interference issue, so you would default towards the closer position for installation issues.
Not super critical and try to get even or equivalent position on exhaust all stacks. Split the diff of the ranges above, the position would be around 4.5" - 5.0".
Cheers George
Last edited:
vlittle
Well Known Member
EGT Location
EGT probe specs 2" to 4" from exhaust flange. With a Vetterman exhaust, you want to be above the slip joint, limiting you to about 3".
I chose 2.75" all around. Apparently, the flame front extends about 1.5", so this seems like a good compromise.
Vern Little, RV-9A
EGT probe specs 2" to 4" from exhaust flange. With a Vetterman exhaust, you want to be above the slip joint, limiting you to about 3".
I chose 2.75" all around. Apparently, the flame front extends about 1.5", so this seems like a good compromise.
Vern Little, RV-9A
Bob Martin
Well Known Member
EGT probe placement
I just installed a JPInstruments EDM 700c...and love it..
on a RV-6 0-360 vetterman exhaust.
the book said 2 to 4 inches from the cylinder head....
but stressed all 4 equal distance for accurate readings
If you look all all 4 cylinders, the #1 cylinder has the quickest bend.
I didn't want the probe in the bend, possible affecting the readings on that cylinder, I'm almost sure I used 2 3/8 inches from the bottom of the exhaust flange....that would make about 2 5/8 to 2 3/4 from the cylinder head.
Like others said, stay away from the slip joints and make all the same distance down. Think ahead with the placement location around the pipe...as to not interfere with the plug wires, primer lines etc.
I routed my probe leads around to the inside of the intake tubes and mounted them with tywraps....neatly bundled. Maintain some amount of give in the mounting as the engine shakes, rattles and rolls and you want the probe wires to hang in there with it.
Also, I used a EPM firewall penetration
http://www.epm-avcorp.com/tubeseal.html
for the probe leads and engine ground wire for this install and Loved it...I highly recommend it, simple and clean, but not cheap. Also I purchased hardware store clear flexable tubing, 1/4 or 5/16 ID I think, and routed the 4 left wires and 4 right wires thru them from the firewall penetration to the point they split apart. this makes the routing and attaching easier and a cleaner looking job. IMHO
Bob Martin
Louisa, Virginia
I just installed a JPInstruments EDM 700c...and love it..
on a RV-6 0-360 vetterman exhaust.
the book said 2 to 4 inches from the cylinder head....
but stressed all 4 equal distance for accurate readings
If you look all all 4 cylinders, the #1 cylinder has the quickest bend.
I didn't want the probe in the bend, possible affecting the readings on that cylinder, I'm almost sure I used 2 3/8 inches from the bottom of the exhaust flange....that would make about 2 5/8 to 2 3/4 from the cylinder head.
Like others said, stay away from the slip joints and make all the same distance down. Think ahead with the placement location around the pipe...as to not interfere with the plug wires, primer lines etc.
I routed my probe leads around to the inside of the intake tubes and mounted them with tywraps....neatly bundled. Maintain some amount of give in the mounting as the engine shakes, rattles and rolls and you want the probe wires to hang in there with it.
Also, I used a EPM firewall penetration
http://www.epm-avcorp.com/tubeseal.html
for the probe leads and engine ground wire for this install and Loved it...I highly recommend it, simple and clean, but not cheap. Also I purchased hardware store clear flexable tubing, 1/4 or 5/16 ID I think, and routed the 4 left wires and 4 right wires thru them from the firewall penetration to the point they split apart. this makes the routing and attaching easier and a cleaner looking job. IMHO
Bob Martin
Louisa, Virginia
