REFLECTOR: engine tuning ... was Project Updates

[Ron Brown]

Brian, good luck on your tuning.  You have taken on a challenging task for 
certain.

One precaution - Lycomings are not run lean of peak until 8000' elevation or 
with a limit of 75% power.

Running lean of peak at 27" MAP may cause detonation and damage to your 
engine.  I know you have a Franklin, but I would think this applies to your 
engine too.

I got this from the RV list and have used it with very good success - clean 
burning, good results from oil sample analysis, and clean oil filter at 
changes.

RPM / 100 + Manifold pressure = 48 is roughly 75% power
RPM / 100 + Manifold pressure = 47 is roughly 65% power
RPM / 100 + Manifold pressure = 46 is roughly 55% power
RPM / 100 + Manifold pressure = 44 is roughly 45% power

I have an IO360 and Air Flow Performance injectors which have very balanced 
flows.


----- Original Message ----- 
From: "Brian Michalk" <michalk at awpi.com>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Sent: Saturday, June 30, 2007 12:29 PM
Subject: REFLECTOR: engine tuning ... was Project Updates


> Kurt,
>
> I'm still trying to tune in my engine as well.  I've never tuned an
> engine with electronics so this is new to me.  I had been messing around
> with the flow table, jiggling a little here and there, and determined
> that my #4 injector was not flowing correctly.  I now have a new #4, and
> am going to tune again today.
>
> I have half a mind to set the tables back to default and start over.  My
> plan is this:
> 1) Use average EGT (turbine inlet temperature) to find the peak and
> 50ROP for at least two, hopefully three cells on the table.
> 2) Now go back to the data for individual EGT's and trim those values to
> get them to peak at the same time.  I have one bulk table, and six
> individual tables.  The per-cylinder tables can go from 40% to 160%
> range of what's in the bulk table.
>
> Is there a better methodology I'm not aware of?
>
> Once I am more comfortable with the operating fuel flows, I am going to
> mark out an area on the fuel table for running lean of peak.  Perhaps
> the area defined by RPM greater than 2500, and manifold pressure less
> than 27 inches.  I'll have to collect more data to see where this area
> should be.
>
> My backup EFI still needs tweaking.  The good news is that the engine
> does run on my completely homebrew setup.  I'm trimming my spool for the
> barrel valve and will see how that works today.
>
>
> NMFlyer1 at aol.com wrote:
> ...
>
>>
>> I ran the engine again yesterday and all seems well. Now IM on to
>> cutting some exit ports in the cowl.
>>
>> Keep us informed,
>>
>> Kurt
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