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Date: Thu, 08 Oct 2009 20:13:29 -0400
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From: mmcmanus@grandecom.net
Subject: Re: [LML] Re: LNC2 O-320D1F 1" Pull Back
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I agree with the point that operating a peak can be dangerous, but you =20
should also consider the % of power that the engine is producing.  If =20
less than 65% power (say at altitude with WOT), then according to the =20
info I got from GAMI, you will not do any damage due to peak cylinder =20
pressure.

As I mentioned on the LML about a month ago, my (injected io360) runs =20
rough before I can get to LOP on all cylinders (even with GAMI =20
injectors).  GAMI told me that if I am < 65% power I should not worry =20
about internal cylinder pressures even if some of the cylinders are at =20
peak.  Or at least that is what I took away from the conversation with =20
them.

Matt McManus
LNC2


Quoting paul miller <paul@tbm700.com>:

> Lorn: I'm not an expert on the LOP for carb engines but it looks =20
> like you are operating at peak EGT at 6.3 gph.  That's probably the =20
> worst place if I read the GAMI folks correctly.    By closing the =20
> throttle 1 inch you might be moving the peaks around a bit but the =20
> idea they promote for carb engines is to operate WOT (wide open =20
> throttle) and then LOP, say 50d LOP, to get the best efficiency.  =20
> From your iwork graph, I would suggest that if you can adjust the =20
> fuel flows on that hot cylinder then it appears to might be able to =20
> run down to the 5.9 gph area (or lower) and hopefully smooth =20
> operation or with limited vibration.   The vibration at 6.3 gph =20
> doesn't surprise me because that is peak on three cylinders and lean =20
> on the #3 cylinder.   I would send that into GAMI and see if they =20
> can add any useful information.   But, I think the main issue to =20
> resolve is running at 6.3 because I think that is peak EGT according =20
> to your graph.    If you can get down to 5.9 gph later without a lot =20
> of vibration I might look at extending that graph by a small amount =20
> by reducing FF slightly to get a good picture of where the speed and =20
> 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 =20
>> at 6.3 GPH and the engine is still running smoothly. I am 5 KTS =20
>> slower than at full throttle but have gone from 8.0 to 6.3 GPH. =20
>> This is a 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> =20
>> <troneill@charter.net> 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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