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I agree with the point that operating a peak can be dangerous, but you should also consider the % of power that the engine is producing. If less than 65% power (say at altitude with WOT), then according to the info I got from GAMI, you will not do any damage due to peak cylinder pressure.
As I mentioned on the LML about a month ago, my (injected io360) runs rough before I can get to LOP on all cylinders (even with GAMI injectors). GAMI told me that if I am < 65% power I should not worry about internal cylinder pressures even if some of the cylinders are at peak. Or at least that is what I took away from the conversation with 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 like you are operating at peak EGT at 6.3 gph. That's probably the worst place if I read the GAMI folks correctly. By closing the throttle 1 inch you might be moving the peaks around a bit but the idea they promote for carb engines is to operate WOT (wide open throttle) and then LOP, say 50d LOP, to get the best efficiency. From your iwork graph, I would suggest that if you can adjust the fuel flows on that hot cylinder then it appears to might be able to run down to the 5.9 gph area (or lower) and hopefully smooth operation or with limited vibration. The vibration at 6.3 gph doesn't surprise me because that is peak on three cylinders and lean on the #3 cylinder. I would send that into GAMI and see if they can add any useful information. But, I think the main issue to resolve is running at 6.3 because I think that is peak EGT according to your graph. If you can get down to 5.9 gph later without a lot of vibration I might look at extending that graph by a small amount by reducing FF slightly to get a good 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 my carbureted engine, less than full throttle, would even out the 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 50°F LOP by the time cyl 4 reaches peak. The engine is running so 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 6.3 GPH and the engine is still running smoothly. I am 5 KTS slower than at full throttle but have gone from 8.0 to 6.3 GPH. 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 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> 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
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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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