Re: [LML] High #2 CHT on a IVP
How much does the red hot turbo sitting underneath the Cyl 2 (and
Cyl 1) effect the CHT reading through adjacent heat source and even
directly via infrared heat on the probe hub itself? The air flow
behind/through Cyl 2 is not a generous (due to oil cooler siphon)
compared with Cyl 1, but would a turbo heat shield help?
Cylinders are cooler LOP, so I'm lean of peak via Big Mixture
Pull (BMP) after throttle reduction and RPM adjust, usually by 600'
AGL. My fuel flow is identical to recently posted
34"/2500/18gph climb.
Jeff L
LIVP
I am getting
the 43.5 at wide open throttle at 38.5 inches. I will check the
32 gallons at 31.5" and 2500.
I have the
standard TCM injectors which are all the same
size.
After
testing today I found that #2, #4, and #6 all peak about the same
time. Number 1, 3, and 5 seem to peak at about the same time.
The fuel flow difference from first to peak and last to peak looks to
be about .6 gallons per hour. (this is at 23" and 2500 rpm)
It seems strange that all on the left side peak first but then I don't
know a lot about the workings of this engine.
The air
flowing around #2 is well managed. It flows properly around the
back and is directed well around the bottom.
I don't know
the answer to the "degrees the hottest egt is below
peak when at full rich".
I think I am
about to the point of investigating the setting lean of peak that
will give good tit's and good cht's. I sure can't get any speed
while running rich of peak and I know the heat is not good for the
engine.
I really
really appreciate the input to this problem.
Dan
Reagan
----- Original Message -----
From: Colyn Case at
earthlink
To: lml@lancaironline.net
Sent: Sunday, October 04, 2009 5:07 AM
Subject: Re: [LML] High #2 CHT on a
IVP
Dan,
There's no reason you can't
get a non-fadec engine to have reasonable cooling. I think you
got some other change along with this engine.
- I agree with Craig on fuel
flow. Do you get the 43.5 wide open? If not, I would fix
that first. Then are you getting the 32 at
31.5?
- 375 for the other cylinders
is also high which is another reason to suspect FF is too
low.
- you really don't want #2 to
be first to peak so you want more flow on that injector.
Do you have gami jectors?
- You didn't mention the gami
spread between #2 and the others. (gph fuel flow between when #2 peaks
and the others).
- re: the oil cooler, is the
air actually flowing through the fins on #2 or escaping around the
back. you also want flow guides
under the back of #2 to force
the air to flow through the bottom fins
- 400 in cruise is
extreme. how many degrees is your hottest egt below peak
when you are full rich? you should be able to get 150-200
dF rich of peak if you want it. When you lean
it, tit will go past 1700 dF near peak. you have to go to
the other side of peak. to get it to come back down. it
would be worth knowing if there is a mixture setting on the lean side
that will get your tit down and your cht's e.g. in the < 350
range.
Colyn
----- Original Message -----
From: Craig
Berland
To: lml@lancaironline.net
Sent: Saturday, October 03, 2009 8:36
PM
Subject: [LML] High #2 CHT on a IVP
Dan, my engine is doing the same thing. One thing to
try is putting your "last" to peak injector in #2 cylinder.
#2 is the hardest cylinder to cool in my plane as well. This may
cause you to fly quite lean if you cruise "lean of peak. Two,
check your fuel rate at 2500 rpm and 31.5 inHg. I think at full rich
it should be approx 32 gph and mine is way below that. I have
43.5 gph at 2700 rpm and 38.4 inHg. It appears I may need to
pull the fuel pump and check the calibration. I'm trying to find
fuel flow rate data for the TSIO550 right now.
Craig
Berland
IV-P N7VG
The current engine I have is
brand new with approximately 20 hours on it. It has a standard
mixture control and replaced the previous FADEC controlled
engine.
I can not seem to correct my
number 2 CHT problem. The previous engine did not seem to have
the problem to this extent. The mod of building a recess in the
oil cooler plenum was done long ago.
I cannot climb with
31.5" MP, full rich without #2 hitting 400F at about 11,000
feet. Climb speed is 165 knots. Today's ground temp was
70F. I have made a clear path for the air by relocating hoses,
spark plug leads, brackets and anything that might disturb the cooling
air. The only thing left to move is the air conditioning hoses
which are right in the way of the air as it enters the
cowling.
All the baffling is very
tight and everything is the same as was on the other
engine.
Has any one had to use a
larger injector to keep number 2 cool. Number 2 EGT is the first
to peak. All the other 5 CHT's run within 3 degrees of each
other with number 2 being about 25 degrees higher. EGT's are
running in the 1450 range with #2 being the
hottest.
Straight and level at 17,000
feet indicating over 200 knots the #2 CHT will stay just under 400
degrees 31.5" and full rich. When I try to lean it
out the TIT's start above 1650.
Has anyone got any
suggestions?
I will be looking at the
injectors tomorrow.
I wonder what the trade in
value of a slightly used red knob control cable
is?
Dan
Reagan
IVP 670 hours and wishing I
had my FADEC back
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