Mailing List Message #65353
From: Bobby J. Hughes <>
Subject: RE: [FlyRotary] Re: EGT Probe location in stock manifold
Date: Mon, 18 Nov 2019 10:20:01 -0600
To: Rotary motors in aircraft <>



You should be able to locate the EGT probe about 0.75-1" out for Rotor 2. Bottom or prop side of the tube. Match Rotor 1 location to rotor 2. Adjust mixture to keep EGT’s below 1650F. I target below 1600F but see 1650F if I’m not paying attention. Formula renesis race engines are running below 1600F with F/A in the 13’s. I have not been able to achieve EGT’s that low in the 13’s. I have to run richer at high power to keep EGT’s around 1600F.





From: Rotary motors in aircraft []
Sent: Monday, November 18, 2019 9:36 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: EGT Probe location in stock manifold


Engine builders like different locations. The object of the probe is to collect data on the combustion process inside the chamber. So, the ideal power mixture is the highest temperature in general the same as a piston engine. (It was running great just before the piston melted) So, more fuel or less fuel than best power can both lower exhaust temps. So, one way or the other (pick one) keep EGTs below 1650 and the probes last a long time. Stock apex seals last longer as well. So the EGT gauge is nice to have rather than trying to get chunks of apex seal out of a muffler. Even if you run ceramic apex seals which will stand up to anything, however the exhaust system (even stainless) will have a short life above 1700 degrees. I melted everything there is to melt on the racer. I was a slow learner.

3 inches out from the port, on the outside of any curve...................Lynn E. Hanover





In a message dated 11/17/2019 8:49:32 PM Eastern Standard Time, writes:


Finn,  Not a stock manifold, made from 321 S/S.  Drilled in and welded

boss for probes.  One each end as it came out from exhaust port each

end.  Neil.


On 11/18/2019 9:31 AM, Finn Lassen wrote:

> Curious how you could place them 4" from the port(s).


> The Renesis manifold has at least two layers. Center ports? Outer ports?


> Finn


> On 11/17/2019 3:16 PM, Neil Unger wrote:

>> finn,


>> ?????????????????????????????????????? I put 2 EGT's in the standard

>> position of 4 inches from the port, and really there was no

>> difference except that I kept burning both off.?? Their usefulness,

>> and one will do, is to regulate high temps with either revs (lower)

>> or a richer mix to lower the high EGT. 1800 degrees F is quite warm

>> and will test the exhaust system.?? The probe just lets you know if

>> you are wasting your time or actually achieving something.?? Once set

>> up they are just another thing to worry about in my case, so

>> currently running without.


>> Neil


>> On 11/18/2019 4:16 AM, Finn Lassen wrote:

>>> For those of you that are using the stock manifold, where/how did

>>> you locate the EGT probes?


>>> With an O2 sensor, I'm not sure that a single EGT probe has much

>>> usefulness. However, one for each rotor would give indication of

>>> mixture imbalance between the two rotors.


>>> Finn



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