REFLECTOR: More leaning learning.
KMis178813 at aol.com
KMis178813 at aol.com
Mon Aug 31 21:29:54 CDT 2009
Terry
Airflow Performance in Spartanburg SC. (864-576-4512) If you give them
a call they will sell you the injector pills so you can richen the lean one
and lean the rich ones. On my IO-360 the stock size was .029 and I went to
.0295 on 2 of them and to .0285 on another. The change brought then all
within 6 degrees of each other at 50 LOP. (Not 6 Degrees in actual
temperature because that does not matter). They charged me $25 each plus shipping.
You might not get it perfect the first time, but that is the same thing Gami
does. I run 70-80 LOP with no problems and cool!!!
Ken
In a message dated 8/31/2009 10:05:25 P.M. Eastern Daylight Time,
scott at tnstaafl.net writes:
Terry,
Glad to hear you are cognizant of the issues. Sounds like you are tuned
in to LOP.
as long as you lean as you described below, above 8,000 ft, that should
be perfectly acceptable. Because the engine is making less than 75%
power at full throttle, and leaned to your described settings probably
closer to 50% power.
But that is not leaning to LOP, that is leaning to best run. I did that
all the time in my Bonanza above 8,000 ft because my engine like yours
couldn't run LOP, the mixture spread was to poor. It was carburated.
I believe you have three alternatives to being able to truly run LOP. At
low altitude, even in a cruise climb.
1.) Expensive but guaranteed to work is to order GAMIjectors from GAMI
http://www.gami.com/ Looks like it would be $800
2.) Play swap the injectors. Swap the leanest cylinder(first to peak)
with the richest cylinder(last to peak). See if it improves.
Re-evaluate. Sometimes you have to do a few swaps with different cyls.
It all trial and error. Cheap, relatively easy and perfectly legal in
an experimental. Sometimes it works sometimes not. It didn't for my
IO360.
3.) My Io360 would not run LOP, even after playing swap the injectors. I
then installed a Lightspeed Ignition system. It improved the fuel burn
so much I could then just barely lean to 50-60 LOP. I couldn't get
below 10-20 LOP before the Lightspeed.
Maybe somebody else knows of another method to improve your fuel spread.
Scott
Terry Miles wrote:
> Bernard,
>
> Thanks for the thoughts. I was indeed sweet spot oriented.
>
> Someone posted that power point that was provided at OSH. Slide six of
that
> presentation might be one to consider so we are all on the same page with
> the same data.
>
> In my Ly IO-540, there is a 60 degree spread from the coolest to the
hotest
> cylinder, and about a 60 to 80 degree spread in peaks temps when leaning.
> Here is a question for the group. You look at your engine analizer and
see
> this: -61, -91, -36, -71, -31, -61. I didn't make this up. It is out
of
> my engine log. Taking cylinder #5 another 19 degrees cooler and will
have
> the power stroke on cylinder #2 signifcantly out of the balance. Look
at
> that PP presentation and look how power drops off when a given cyl is
past
> 100 LOP.
>
> I understand what Scott is saying. Believe me. I would never ignore
you,
> man. Every fool and his dog is making presentations on this LOP issue
like
> it is some new discovery, with the usual crap about OWT that were sound
> advice for carburated engines. Several of write ups--due maybe to
editoral
> demands for not too much detail--do not provide "big picture"
explanations,
> let alone adress EGT spreads within a single power plant and how they
should
> be addressed in practice. As Scott has mentioned when you are at
altitude,
> when full throttle is below 65% the concern with "over pressure" within
the
> given cylinders is greatly reduced.
>
> When it sounds and feels the best to me in this airplane with this
engine,
> #2 is about -60 LOP and #3 and #5 are right near peak. If I pull #3 and
#5
> to -50 LOP and let it sit and then enrich again it is clear the mixture
was
> too lean. This is sitting in a cruise situation on a 3 hour cross
country
> at a constant speed making small adjustments and waiting for things to
> stabilize.
>
> Terry
>
>
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of Scott Derrick
> Sent: Sunday, August 30, 2009 21:58
> To: Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: Fuel Consumption Performance
>
> But Bernard, to have all the cylinders Lean of 50 LOP, you have to lean
to
> the "Last to Peak", not the first. The first is the leanest cylinder,
all
> the rest are richer.
>
> You use the "First to Peak" for ROP operations.
>
> Scott
>
>
> Bernard Despins wrote:
>
>> I think Terry may be arriving at the same "sweet spot of leaning" as
>> you are Scott. He is just making all of his cylinders leaner than the
>> sweet spot, and adding fuel until the FIRST cylinder reaches it. The
>> rest of the cylinders are cooler than the sweet spot. The only
>> problem with this is that when all the cylinders go leaner than the
>> "sweet spot" (lets say 50 LOP) you may go a little too far on the
>> lean side and the engine could run a little rough depending on how
>> well balance the injectors are. No harm done.
>>
>> Scott just skips the step of making all the cylinders leaner than the
>> sweet spot and leans starting on the ROP side of things until the LAST
>> cylinder gets to 50 LOP. The rest of the cylinders are cooler than
>> the sweet spot. Just like Terry's method. The only problem would be
>> leaning too slow and lingering in the "danger zone". But once you get
>> use to the "big pull", it is absolutely not a problem.
>>
>> Hope this helps.
>>
>> Bernard Despins
>>
>>
>>
>> Terry Miles wrote:
>>
>>> Al,
>>>
>>> Here is my cruz engine log to include this last IN to CO trip.
>>> Westbound was full power. 10,000 will get me mid 180 Kts TAS and
>>> 12,000 gets mid 190 kts TAS. That runs about 11.5 at full throttle
>>> and leaning 50 LOP. Thanks to Scott I did it right and pulled the
>>> mixture out until they were all LOP and enriched back on the first to
>>> peak so to get 50 LOP.
>>>
>>>
>> ----------------------------------------------------------------------
>> --
>>
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>
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