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Tagged: High Compression Upgrade, Propeller
- This topic has 4 replies, 4 voices, and was last updated 6 years, 1 month ago by Wes Sears.
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April 3, 2018 at 00:05 #8702Vern SchulzeParticipant
We are looking at upgrading our Cheetah’s O320-E2G with the High Compression STC from Precision Engine, LLC. We are wondering if our existing McCauley 1C172/SBTM7359 propellor would be sufficient for the additional power available from the upgrade. Some have suggested that a Sensenich 61″ pitch prop. would be a better fit than the McCauley 59″ pitched prop. I would appreciate any thoughts of the GPA concerning this situation.
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April 13, 2018 at 21:24 #8748Wes SearsParticipant
No one has answered so I will jump in with my first post. I am far from an expert, I just bought a 74 traveler in November. It has the Precision STC and the 7359 propeller. It has done some sitting prior to me and the compression is not that great. 74/68/73/71. I bought a digital tach so I am confident in the RPM numbers. 40 degree days in Seattle I get about 2330 RPM static. At 100 mph climb I get a bit over 2500. With stronger compression I would consider a 61 but I am more interested in getting off the runway than I am in going fast.
I hope using fly therapy the compression will get a bit better…
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April 13, 2018 at 23:08 #8749Roscoe RoschéKeymaster
If history is any guide it should. I have seen many engine come up in compression over the years when they had a dormant stretch, but not all. You an try switching to W100 straight weight oil to help some say.
Fly it hard and often.
Cheers
Roscoe
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April 15, 2018 at 13:24 #8755Dan VoegeliParticipant
I just had my Cheetah go through Fletchair and did the 160 hp STC and the Powerflow exhaust. I went with the 61″ prop and can really tell the difference. The climb is considerably better. I did it because it seemed like a waste of HP to get an upgraded engine and then not use it.
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April 16, 2018 at 14:01 #8772Wes SearsParticipant
Thank you Roscoe, next oil change I will check the compression and if still low give the oil a try.
Powerflow exhaust should ship later this month. Will try to get as specific as possible on my before/after numbers.
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