REFLECTOR:INTAKE COMBUSTION AIR

[Chuck Jensen]

Well, I'm not speaking for GAMI, but I believe they are not looking at the
absolute values of either EGT or CHT.  Which is wise since they have no way
of assessing the accuracy of each sensor, sensor location, whether they are
properly calibrated or any of the other miscellanies that can affect
readings from cylinder to cylinder.  What they are looking at is
trends/peaks. 

In other words, they care little what your absolute values are compared to
at what GPH that each cylinder reaches peak temp.  I suspect they look at
CHT since they suggest waiting a minute or two between changes in the fuel
adjustments for everything to settle down.  If they were looking at EGT,
that response would be nearly instantaneous.  

Before installing the first set of GAMIs, my cylinders started peaking at
about 15.8 and the last cylinder peaked at 13.7.  As a result, I had to run
the 540 at about 15 gph to lean some of the cylinders while others were
still ROP.  If I tried to go to LOP for all the cylinders, the ones that
initially peaked, would then be so starved for fuel they would get very
rough.

In the end, the goal is to get all the cylinder to reach peak temp over as
small a fuel flow range as possible; ideally less than 0.3 gph across all
cylinders, though 0.5 is considered good.  I'm down under 1 gph (previously
2+) and my fuel flow at cruise setting, to get smooth engine ops, has
dropped from 15 gph to low 14s, sometimes to 13.7.

Chuck Jensen
Diversified Technologies
2680 Westcott Blvd
Knoxville, TN  37931
Phn:     865-539-9000 x25
Cell:     865-406-9001
Fax:     865-539-9001
cjensen@dts9000.com


-----Original Message-----
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
Behalf Of Jerry.Brainard@anthem.com
Sent: Monday, September 15, 2003 8:31 AM
To: reflector@tvbf.org
Subject: Re: REFLECTOR:INTAKE COMBUSTION AIR



OK, I give up.  I have to ask.  Since cylinder head temp reflects mixture
and cooling, why is GAMI looking at CHT instead of EGT?  Why tune to CHT
when mixture is quickly reflected in the EGT?  What am I missing here?  Is
the GAMI approach compensating for the uneven cooling by running a rich
mixture on the hot CHT?

Just my wondering, no engineering here.

-jerry


 

                      Jack Sheehan

                      <j.f.sheehan@issmail.lar        To:
reflector@tvbf.org

                      c.nasa.gov>                     cc:

                      Sent by:                        Subject:  Re:
REFLECTOR:INTAKE COMBUSTION AIR                                            
                      reflector-admin@tvbf.org

 

 

                      09/15/2003 09:01 AM

                      Please respond to

                      reflector

 

 





Bob,
I will be very interested in the results of the closing up of the ends on
the plenum. I presume you have added some metal to the plenum and wrapped
it down around the end cylinders?
My IO-540 has been running high cylinder head temps thereby preventing me
from leaning as much as I would like. I need to run a little rich about 15
gal/hr to keep the temps on the high cylinders at about 410-420. I have
played with the moving of the VG's and sealed the plenum with silicone Not
much change.
Jack




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