---------------------------------------------------------- RV-List Digest Archive --- Total Messages Posted Thu 12/16/10: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:00 AM - Re: typical peak EGT ? (Gene Lee) 2. 10:01 AM - Re: typical peak EGT ? (Linn Walters) 3. 10:55 AM - Re: typical peak EGT ? (Greg young) ________________________________ Message 1 _____________________________________ Time: 07:00:55 AM PST US From: "Gene Lee" Subject: RE: RV-List: typical peak EGT ? After reading all the comments about CHT , EGT, and Leaning I can't help but ask. If an engine has temperature probes for both CHT and EGT, why not find the 'peak' using CHT rather than EGT? Especially since it's been pointed out how inaccurate CHT temperature readings are. Gene RV-7a N247DE From: owner-rv-list-server@matronics.com [mailto:owner-rv-list-server@matronics.com] On Behalf Of Richard Martin Sent: Wednesday, December 15, 2010 8:18 AM Subject: Re: RV-List: typical peak EGT ? I have been opperating both the IO-360 and now the IO390 in my rv8 for the last ten years and found that the operating temps are the same in each engine. I find that the CHT should operate in the 360 range not to exceed 400. The EGT should operate in the 1400 to 1440. range. Another method is to lean until the engine peaks and then enrich until temps reduce 100 degrees. This is general proceedure, you will have to tweak it to reach optimum performance with your airplane/engine combination. Note, you will note small variation from winter (0 degrees in Wisconsin) to summer temps 60 to 90 degrees. Dick Martin RV8 N233m the fast one On Tue, Dec 14, 2010 at 2:28 PM, thomas sargent wrote: I have an Lyc. IO-360-B2B from Aerosport on my 6A. It has about 23 hours on it now and after talking to Bart, he says it can be considered brokeDickn in. So I started experimenting with leaning it. I had been keeping the exhaust gas temps below 1300 F. (I have a VM1000 so I have EGT and CHT on each cylinder.) I should mention I've never done this before - this is the only plane I've flown with all these temp. probes. At 6500 ft and 2400 rpm I started leaning it out a quarter of a turn at a time and then wait 30 seconds or so watching the exhaust gas temp and cyl. head temp. The exhaust gas temp responds quickly. By the time I was at about EGT 1430 F and CHT 395 F with the fuel flow down to around 7.5gph, the engine started missing. The more I leaned the more it missed, so it must have been in the too-lean range at that point. I never saw the temperature peak. Admittedly, was kind of hard to tell with the vm1000 displaying a different probe every second. I guess I should pick one EGT probe and watch that, but I was expecting a more pronounced peak. (I wasn't using the vm1000 "leaning mode" display.) >From what I read in the Lycoming manual, I was expecting to see peak temperatures well over 1500 F. I have the Vetterman exhaust and I placed the e.g.t. probes right where Larry V. said to put them. Larry does a lot of experimenting and I'm pretty sure that he has found the optimal place to measure e.g.t. What are typical peak EGT temperatures for this engine? -- Tom Sargent, RV-6A "_blank">www.aeroelectric.com .com/" target="_blank">www.buildersbooks.com ="_blank">www.homebuilthelp.com _blank">http://www.matronics.com/contribution t="_blank">http://www.matronics.com/Navigator?RV-List ttp://forums.matronics.com ________________________________ Message 2 _____________________________________ Time: 10:01:37 AM PST US From: Linn Walters Subject: Re: RV-List: typical peak EGT ? Gene, EGTs are the ones that don't have a specific value, mostly due to the variable distance from the valve, the exhaust flow pattern, and the thickness of the exhaust pipe material. Typically used for leaning because EGTs change more rapidly than CHTs. From anecdotal experience, it seems that the old 'lean by ear' method works almost as good as that expensive engine monitor, but the ear can't tell you how far from peak you are. Also, your EGTs will change with altitude and throttle setting, so the 'peak' will change. Linn On 12/16/2010 9:56 AM, Gene Lee wrote: > > After reading all the comments about CHT , EGT, and Leaning I can't > help but ask... > > If an engine has temperature probes for both CHT and EGT, why not find > the 'peak' using CHT rather than EGT? Especially since it's been > pointed out how inaccurate CHT temperature readings are. > > Gene > > RV-7a > > N247DE > > *From:*owner-rv-list-server@matronics.com > [mailto:owner-rv-list-server@matronics.com] *On Behalf Of *Richard Martin > *Sent:* Wednesday, December 15, 2010 8:18 AM > *To:* rv-list@matronics.com > *Subject:* Re: RV-List: typical peak EGT ? > > I have been opperating both the IO-360 and now the IO390 in my rv8 for > the last ten years and found that the operating temps are the same in > each engine. I find that the CHT should operate in the 360 range not > to exceed 400. The EGT should operate in the 1400 to 1440. range. > Another method is to lean until the engine peaks and then enrich until > temps reduce 100 degrees. This is general proceedure, you will have > to tweak it to reach optimum performance with your airplane/engine > combination. Note, you will note small variation from winter (0 > degrees in Wisconsin) to summer temps 60 to 90 degrees. > > Dick Martin > > RV8 > > N233m > > the fast one > > On Tue, Dec 14, 2010 at 2:28 PM, thomas sargent > wrote: > > I have an Lyc. IO-360-B2B from Aerosport on my 6A. It has about > 23 hours on it now and after talking to Bart, he says it can be > considered brokeDickn in. So I started experimenting with leaning > it. I had been keeping the exhaust gas temps below 1300 F. (I > have a VM1000 so I have EGT and CHT on each cylinder.) I should > mention I've never done this before - this is the only plane I've > flown with all these temp. probes. > > At 6500 ft and 2400 rpm I started leaning it out a quarter of a > turn at a time and then wait 30 seconds or so watching the exhaust > gas temp and cyl. head temp. The exhaust gas temp responds > quickly. By the time I was at about EGT 1430 F and CHT 395 F > with the fuel flow down to around 7.5gph, the engine started > missing. The more I leaned the more it missed, so it must have > been in the too-lean range at that point. I never saw the > temperature peak. Admittedly, was kind of hard to tell with the > vm1000 displaying a different probe every second. I guess I > should pick one EGT probe and watch that, but I was expecting a > more pronounced peak. (I wasn't using the vm1000 "leaning mode" > display.) > > From what I read in the Lycoming manual, I was expecting to see > peak temperatures well over 1500 F. I have the Vetterman exhaust > and I placed the e.g.t. probes right where Larry V. said to put > them. Larry does a lot of experimenting and I'm pretty sure that > he has found the optimal place to measure e.g.t. > > What are typical peak EGT temperatures for this engine? > > > -- > Tom Sargent, RV-6A > > * * > > * * > > *"_blank">www.aeroelectric.com* > > *.com/" target="_blank">www.buildersbooks.com* > > *="_blank">www.homebuilthelp.com* > > *_blank">http://www.matronics.com/contribution* > > *t="_blank">http://www.matronics.com/Navigator?RV-List* > > *ttp://forums.matronics.com* > > * * > * * > ** > ** > ** > ** > ** > ** > ** > ** > *www.aeroelectric.com* > *www.buildersbooks.com * > *www.homebuilthelp.com* > ** > *http://www.matronics.com/contribution* > ** > ** > ** > ** > ** > ** > ** > *http://www.matronics.com/Navigator?RV-List* > ** > ** > *http://forums.matronics.com* > ** > * > > * ________________________________ Message 3 _____________________________________ Time: 10:55:05 AM PST US From: "Greg young" Subject: RE: RV-List: typical peak EGT ? Peak EGT is supposed to indicate when the mixture is at the exact stoichiometric ratio for combustion. EGT response time is fast limited only by the reaction time of the probe. CHT is slow having to contend with the mass of the head and the probe's location. By the time you locate each cylinder's peak with CHT you might have melted the heads. Greg Young Phoenix project - N6GY From: owner-rv-list-server@matronics.com [mailto:owner-rv-list-server@matronics.com] On Behalf Of Gene Lee Sent: Thursday, December 16, 2010 8:57 AM Subject: RE: RV-List: typical peak EGT ? After reading all the comments about CHT , EGT, and Leaning I can't help but ask. If an engine has temperature probes for both CHT and EGT, why not find the 'peak' using CHT rather than EGT? Especially since it's been pointed out how inaccurate CHT temperature readings are. Gene RV-7a N247DE ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rv-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RV-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/rv-list Browse Digests http://www.matronics.com/digest/rv-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.