REFLECTOR: More leaning learning.
Scott Derrick
scott at tnstaafl.net
Tue Sep 1 08:16:19 CDT 2009
Ken,
I didn't know about the AIrflow option! I may have to take
advantage of that for my IO520. I'm 99% sure it won't run LOP as is.
Scott
KMis178813 at aol.com wrote:
> 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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