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Date: Wed, 07 Oct 2009 19:16:28 -0400
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Subject: Re: [LML] Re: LNC2 O-320D1F 1" Pull Back
From: paul miller <paul@tbm700.com>
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Lorn: I'm not an expert on the LOP for carb engines but it looks like =20=

you are operating at peak EGT at 6.3 gph.  That's probably the worst =20
place if I read the GAMI folks correctly.    By closing the throttle 1 =20=

inch you might be moving the peaks around a bit but the idea they =20
promote for carb engines is to operate WOT (wide open throttle) and =20
then LOP, say 50d LOP, to get the best efficiency.  =46rom your iwork =20=

graph, I would suggest that if you can adjust the fuel flows on that =20
hot cylinder then it appears to might be able to run down to the 5.9 =20
gph area (or lower) and hopefully smooth operation or with limited =20
vibration.   The vibration at 6.3 gph doesn't surprise me because that =20=

is peak on three cylinders and lean on the #3 cylinder.   I would send =20=

that into GAMI and see if they can add any useful information.   But, =20=

I think the main issue to resolve is running at 6.3 because I think =20
that is peak EGT according to your graph.    If you can get down to =20
5.9 gph later without a lot of vibration I might look at extending =20
that graph by a small amount by reducing FF slightly to get a good =20
picture of where the speed and FF come out.  good luck.

Paul Miller
Calgary
On 2009-10-07, at 10:26 AM, Lorn H Olsen wrote:

> Terrance,
>
> 1" manifold pressure less than full throttle. I wanted to see if on =20=

> my carbureted engine, less than full throttle, would even out the =20
> EGTs. As you can see in the graph it did.
>
> In the past, when I ran the test at full throttle, cyls 1,2 & 3 are =20=

> 50=B0F LOP by the time cyl 4 reaches peak. The engine is running so =20=

> lean at this setting that I can't stand the vibration.
>
> With the throttle pulled back 1", all cyls are very close to peak at =20=

> 6.3 GPH and the engine is still running smoothly. I am 5 KTS slower =20=

> than at full throttle but have gone from 8.0 to 6.3 GPH. This is a =20
> 21% fuel savings for a 3% speed loss.
>
> In a 4 hour (676 NM) trip, it would take 7 minutes longer and save =20
> 6.8 GAL or about $28.
>
> You pays your money, you takes your choices.
>
> Lorn
>
> On Oct 7, 2009, at 10:21 AM, <troneill@charter.net> =
<troneill@charter.net=20
> > wrote:
>
>> Good.
>> What does " 1" Pull Back" mean?
>>
>> I'm presently tuning my injectors to ... or tryign to.
>
> Download the GAMI Flight Test Data Form from:
>
>     http://www.gami.com/gamijectors/leantest.php
>
>> Terrence
>> L235/320 N211AL
>
> --
> Lorn H. 'Feathers' Olsen, MAA, ASMEL, ASES, Comm, Inst
> DynaComm, Corp., 248-345-0500, mailto:lorn@dynacomm.us
> LNC2, FB90/92, O-320-D1F, 1,635 hrs, N31161, Y47, SE Michigan
>
>
> --
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