Have you measured the effectiveness with an hydrometer by measuring the difference in air saturation before and after?
No, that is very difficult because hygrometers that work at low relH cost a lot of money. The usual stuff is garbage in the 20% range.
For me it’s very simple: when I open the oil filler cap after a flight, I can see a lot of water vapor escaping. Therefore replacing their air with ambient air that is not too humid, will do good.
This is not the same thing but I found a 0.5kg silica gel bag in the cabin drops the RH by about 10 percentage points. I have a handheld RH meter.
I have both the Engine Saver as well as the Tanis Dehydrator system. Also use Dehydrator plugs for the exhaust.
When I land after a flight I open the oil filler. About 15 min later I install the Tanis inflow only. Leave that on for about 10 mins while I go about my business. Then afterwards plug in the return line.
Im away for this month and have the system set up. In two weeks I have someone check the desiccant if not blue they reactivate it. They check it every 2 weeks.
The only problem is when I fly to other airports where there is no facility for a plug in. There I just hope for the best. But I usually fly after a few days max 2 weeks so its less than optimal but not critical.
At least thats my story and sticking to it.
My club has a homemade dehydrator system. We have a box with the dehydrator stuff and an aquarium pump that feeds dried air down the oil dipstick tube.
My neighbor has engineered the following solar powered solution for hos float airplane, Three hoses: One attached to the breather, one to the muffler, and one to the oil filler:
This issue was raised here and elsewhere.
I think one could prevent engine corrosion simply by pushing dry air up the exhaust.
Eventually, probably within hours, this will fill all of the engine.
I nearly built such a thing – a box with a little battery powered fan and a 0.5kg bag of silica gel – some years ago but never finished it. You won’t get much battery life so a weekly visit to the hangar would be necessary, unless the hangar-political situation is ok for a mains connection.
Maybe, even better, would be forcing dry air up the breather pipe. That would initially fill the crankcase
The notoriously missing @achimha did implement something similar.
Wish he was around to comment ;-p
Lycoming has SL L180B titled “Engine Preservation for Active and Stored Aircraft” and a possibly less relevant SI 1481B titled “Factory Engine Preservation”.
I use the last two years such a device, called “Engine Life Extender”. The 12 V battery will last several weeks, in summer time even longer. 1 kg Silica Gel is dried as requiered at home in the kitchen and is therefore reusable. The humidity of the air can be significantly reduced, according to the constructor.
In combination with Camguard the corrosion protection will probably increase.
tmo wrote:
The notoriously missing @achimha did implement something similar.
I made a Chinese copy of what is described there and apply it as soon as our bird is pushed into the hangar. I use Camguard as well. It’s hard to say what all this is worth, you never know what would be without. At least it gives me the feeling that I do what can be done 
