ZachKarpinski
Member
I preface this with the fact that I have not flown yet.
I have a dual muffler system where it takes the hot air from one muf and then sends it to the other muf before being routed to the cabin for heat. I decided I would remove the second muf, as I live in a warmer climate and would prefer to have less plumbing under the cowl for cooling. I removed the muf on the number 2/4 side (pilot side). I went flying and saw a measurable jump in CHT on number 4, about 15–20, and about a 5–6 rise on number 2. I was surprised by this. However, logically, I guess this makes sense if heat was indeed radiating up from the exhaust and hitting number 4, or if the muffler was trapping heat and not allowing as much heat to stay in the cowl. Obviously, intake air is what does the cooling, so I was surprised by the fact that it raised the CHT that much. I imagine they are associated because that is the only thing that was changed between flights.
With that in mind, I had a few of the Anti-Splat Aero heat shields lying around. I decided to put a few back over the exhaust pipe where the muf was before to validate my theory. Again ,I haven’t flown yet.
While I was there, I got to thinking about it more. If that did indeed radiate heat up to 4/2, then could all the exhaust pipes also be radiating heat to the heads of the cylinders? I still had some more heat shields, so I figured I could put them between the exhaust pipe and the head. My question is, is there any reason not to do this? Has anybody else done this, or is this common practice? Is this definitely a “don’t do this” practice? They are basically where the EGT probes are now, so I would imagine perhaps a bit of an EGT increase might be expected.
I did not wrap the exhaust in any way. I just used the Anti-Splat heat shields. I know the heat shields are usually used to protect the COWL from heat, but I imagine they could be used in this way without harm?
I am curious if somebody could give some insight into whether there is any reason I should not do what I did. I don’t think it would hurt anything, but please let me. know.
Is my thought process all wrong? Correlation does not equal causation?
I have a dual muffler system where it takes the hot air from one muf and then sends it to the other muf before being routed to the cabin for heat. I decided I would remove the second muf, as I live in a warmer climate and would prefer to have less plumbing under the cowl for cooling. I removed the muf on the number 2/4 side (pilot side). I went flying and saw a measurable jump in CHT on number 4, about 15–20, and about a 5–6 rise on number 2. I was surprised by this. However, logically, I guess this makes sense if heat was indeed radiating up from the exhaust and hitting number 4, or if the muffler was trapping heat and not allowing as much heat to stay in the cowl. Obviously, intake air is what does the cooling, so I was surprised by the fact that it raised the CHT that much. I imagine they are associated because that is the only thing that was changed between flights.
With that in mind, I had a few of the Anti-Splat Aero heat shields lying around. I decided to put a few back over the exhaust pipe where the muf was before to validate my theory. Again ,I haven’t flown yet.
While I was there, I got to thinking about it more. If that did indeed radiate heat up to 4/2, then could all the exhaust pipes also be radiating heat to the heads of the cylinders? I still had some more heat shields, so I figured I could put them between the exhaust pipe and the head. My question is, is there any reason not to do this? Has anybody else done this, or is this common practice? Is this definitely a “don’t do this” practice? They are basically where the EGT probes are now, so I would imagine perhaps a bit of an EGT increase might be expected.
I did not wrap the exhaust in any way. I just used the Anti-Splat heat shields. I know the heat shields are usually used to protect the COWL from heat, but I imagine they could be used in this way without harm?
I am curious if somebody could give some insight into whether there is any reason I should not do what I did. I don’t think it would hurt anything, but please let me. know.
Is my thought process all wrong? Correlation does not equal causation?
