REFLECTOR: Egt

[Mike Dawson]

Kurt,

The exhaust are light grey perfect but I suspect that is from the TCP changing lead to white powder. Like I said, the plugs are carbon ed so you are right more lean will clean them up. Wish Dave would pipe in but I'll give it a try!

Mike



________________________________
 From: "nmflyer1 at aol.com" <nmflyer1 at aol.com>
To: reflector at tvbf.org 
Sent: Saturday, May 12, 2012 7:23 AM
Subject: Re: REFLECTOR: Egt
 

Michael,  

Seems to me like you are running rich. If the plugs and exhaust are sooty, that would confirm it. Not sure what altitude you cruise at, but 15GPH sounds high at cruise as well. 
All engines have a "sweet spot" where they make power at an acceptable fuel burn (relatively speaking). Go above that, and sure they run fine and will make more power, but the fuel burn curve steepens (sometimes dramatically). Chevys are no different and that sweet spot is very fine. 

3500 and 21" sounds pretty good, but the 1300 sounds like you are just wasting fuel. Specially considering that you are using 100LL. That fuel should not make a difference in your richness setting, but it will provide a higher safety margin against detonation at higher temps. 
IF the spec sheet or cylinder head numbers say that 1400 is good, I would go with that. 

You can clean the plugs and exhaust tips, then go for a flight at 1400 and recheck. As long as the plugs do not show signs of running to hot or lean, you should be fine. I would bet that your fuel burn goes down noticeably as well. 

Hopefully Dave will pipe in with his experience. Mine is based on my years of engine building and work, but not actually flying my V-6 yet. 
I usually fly my other aircraft at 1400, but it is an old Lyco 540. 

Kurt 



-----Original Message-----
From: Mike Dawson <medawson250 at yahoo.com>
To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
Sent: Sat, May 12, 2012 12:49 am
Subject: Re: REFLECTOR: Egt


They are a little black but I am running 100 LL cuz of the auto gas thing. I hope Dave sees this.
Everything I have found online, although it is about racing, says 1400 is hot if if left too long.
I do have iconel valves so they are ok. 

Michael E Dawson 
ATCI CFII


On May 11, 2012, at 9:33 PM, nmflyer1 at aol.com wrote:


1400 sounds about right for cruise to me. I'd like to hear what Dave says. 1300 sounds like you are running too rich (What do your plugs look like after that?). 
>
>
>Kurt
>
>
>Alum. V-6
>
>
>
>
>-----Original Message-----
>From: Mike Dawson <medawson250 at yahoo.com>
>To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
>Sent: Fri, May 11, 2012 10:07 pm
>Subject: REFLECTOR: Egt
>
>
>David Bertram,
Since we have the same engine, I was wondering if you could give me an idea what 
egt you lean to. Len's spec sheet show 1350F for max power and 1400F for cruise. 
Seems a little hot!
So far 3500 engine RPM, 21.5 manifold and 1300F EGT seems to be about 62% power 
and around 15 Gph. You concur?
Thanks, Michael E Dawson
ATCI CFII _______________________________________________
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