Tossing factory EGT, replacing with JPI or similar

"Ben Jackson" wrote in message
news:eA3cc.182477$1p.2161124@attbi_s54...
In article ,
Tom Sixkiller wrote:
Right now I'm trying to figure out if I can put it where I want: Right
where the stock EGT is now.

That's usually where they go. I'd suspect that (??) some of the wiring
would
already be in place.

I don't think I'd want to re-use one mis-matched EGT probe with the other
five. I dug up a picture of a 'stock' 260 panel (mine is far from stock
on the left side) and lo and behold, no EGT at all. My EGT is where the
stock suction gauge was.

I wasn't thinking of the probe wires, but now that you mention it that's
makes sense.

In a Bonanza, it fits into the standard EGT readout slot.


How about the GAMI's?

I need the multi-channel EGT to know if I need those!

(Oh believe me, if you have Fuel Injection, you NEED them. :~)

From what I gather, you can't get a proper reading from a multi-channel EG
with stock injectors. Check of John Deakin's articles in AvWeb about that.
What's more, better CHT's, fuel savings, SMOOTHER running...

Tom
--
Life is not a journey to the grave with the intention of arriving
safely in a pretty and well preserved body, but rather to skid
in broadside, thoroughly used up, totally worn out, and loudly
proclaiming - - WOW - - WHAT A RIDE!"

Bravo to Ben---the EDM 700 is the best $1800 we ever spent: $1500 for
the unit plus 6 hrs installation, but we had the engine out anyway.
Expect 8 hrs at your local shop rate. We just have Volts, EGT, and CHT,
didn't opt (yet) for OAT, fuel flow, or the other possibilities.

How about the GAMI's?

I need the multi-channel EGT to know if I need those!

(Oh believe me, if you have Fuel Injection, you NEED them. :~)

Lycoming already uses tuned injectors on the 4-bangers. Our Lyco IO-360
(in a Beech C24R) maintains CHT within 15 degrees for all cylinders, and
LOP is smooth as silk. Correct this last to read "if you have a
Continental engine, or a Lycoming 6-cylinder, you NEED them!"

best of luck

"Musky" wrote in message
...
Bravo to Ben---the EDM 700 is the best $1800 we ever spent: $1500 for
the unit plus 6 hrs installation, but we had the engine out anyway.
Expect 8 hrs at your local shop rate. We just have Volts, EGT, and CHT,
didn't opt (yet) for OAT, fuel flow, or the other possibilities.

How about the GAMI's?

I need the multi-channel EGT to know if I need those!

(Oh believe me, if you have Fuel Injection, you NEED them. :~)

Lycoming already uses tuned injectors on the 4-bangers.

CMIIW but Lycoming's have tuned INDUCTION, not tuned injectors.

Our Lyco IO-360
(in a Beech C24R) maintains CHT within 15 degrees for all cylinders, and
LOP is smooth as silk.

How about EGT's?

Correct this last to read "if you have a
Continental engine, or a Lycoming 6-cylinder, you NEED them!"

Tom Sixkiller wrote:

CMIIW but Lycoming's have tuned INDUCTION, not tuned injectors.

If that's the case, you should be able to use Deakin's trick on a carburetted
Lycoming too.

George Patterson
This marriage is off to a shaky start. The groom just asked the band to
play "Your cheatin' heart", and the bride just requested "Don't come home
a'drinkin' with lovin' on your mind".

"G.R. Patterson III" wrote in message
...


Tom Sixkiller wrote:

CMIIW but Lycoming's have tuned INDUCTION, not tuned injectors.

If that's the case, you should be able to use Deakin's trick on a
carburetted
Lycoming too.


Elaborate, please, for those of us that are not 100% mechanically inclined.
:~)

Tom Sixkiller wrote:

If that's the case, you should be able to use Deakin's trick on a
carburetted
Lycoming too.

Elaborate, please, for those of us that are not 100% mechanically inclined.

There are a couple of interesting things that Deakin recommends. One is running
substantially lean of peak EGT. Running about 50 degrees rich of peak is generally
recommended by other people. Another trick is leaving the throttle wide open and
controlling rpm with the mixture. I've seen both discussed here. I've also seen
running lean of peak discussed elsewhere.

In all of these discussions, everyone seems to agree that this can only be done with
a set of GAMI injectors because the mixture and the distribution of fuel to the
cylinders is uneven with every other system. Well, the entire purpose of a tuned
induction system is to ensure even distribution and mixture of the fuel charges to
the cylinders. It doesn't matter whether you have injectors or not, if you have a
tuned induction system, the fuel charge distribution and mixture will be the same at
every cylinder.

So. If Lycoming has tuned the induction on their engines half as well as Holley or
Shelby used to do for V-8s in the 70s, you should be able to run consistently lean of
peak with, for example, the basic O-360.

George Patterson
This marriage is off to a shaky start. The groom just asked the band to
play "Your cheatin' heart", and the bride just requested "Don't come home
a'drinkin' with lovin' on your mind".

G.R. Patterson III wrote:

So. If Lycoming has tuned the induction on their engines half as well
as Holley or
Shelby used to do for V-8s in the 70s, you should be able to run
consistently lean of
peak with, for example, the basic O-360.

I don't know jack about Holleys or Shelby, but I do know that while I
can run 50 degrees LOP with my COZY MKIV with an O-360 A2A and Ellison
throttle body, that's about the extent of it. If I try to lean it out
more than that, it starts running pretty rough, and the vibration is
annoying as hell.

Still better than ROP, but I don't think that Lycoming's got a perfect
induction system tuning going :-). If I ever have a few thousand $$
fall on my head, I'll install injection and GAMI's. But that's after
the Lightspeed electronic ignition.

--
Marc J. Zeitlin
http://marc.zeitlin.home.comcast.net/
http://www.cozybuilders.org/
Copyright (c) 2004

"G.R. Patterson III" wrote in message
...


Tom Sixkiller wrote:

If that's the case, you should be able to use Deakin's trick on a
carburetted
Lycoming too.

Elaborate, please, for those of us that are not 100% mechanically
inclined.

There are a couple of interesting things that Deakin recommends. One is
running
substantially lean of peak EGT. Running about 50 degrees rich of peak is
generally
recommended by other people.

From what I remember (am am too lazy to look up at 10:30 at night) is that
running that rich is a good way to wind up with lead fouling and other
disasters that lead to a premature top overhaul. What's intersting is the
data the the folks at GAMI got from their test bed contradicts so much
"conventional wisdom".

Another trick is leaving the throttle wide open and
controlling rpm with the mixture. I've seen both discussed here. I've also
seen
running lean of peak discussed elsewhere.


In all of these discussions, everyone seems to agree that this can only be
done with
a set of GAMI injectors because the mixture and the distribution of fuel
to the
cylinders is uneven with every other system. Well, the entire purpose of a
tuned
induction system is to ensure even distribution and mixture of the fuel
charges to
the cylinders.

CMIIW, but a good induction system can be wasted if the QC on the injectors
sucks?

It doesn't matter whether you have injectors or not, if you have a
tuned induction system, the fuel charge distribution and mixture will be
the same at
every cylinder.

See above question.


So. If Lycoming has tuned the induction on their engines half as well as
Holley or
Shelby used to do for V-8s in the 70s, you should be able to run
consistently lean of
peak with, for example, the basic O-360.

In the 70's...or the 60's? By 72' all the pollution equipment threw it all
in the dumper, TMWOT.

How about EGT's?

One cylinder typically reads 40 degrees hot, otherwise they are all very
close. I'll get some data next time I'm up and post.

Tom Sixkiller wrote:

[snip]

CMIIW but Lycoming's have tuned INDUCTION, not tuned injectors.

This is manifestly not true with _all_ Lycomings, but it may be true for
four bangers (but even then perhaps more as a function of marketing spin
than concerted engineering effort).

Tuning an intake system usually implies two goals: Near identical
mixture distribution and tweaks to manipulate the torque curve. For
engines that do not use port or direct injection the former more or less
requires identical runner lengths, something that may be a happy
accident on four bangers but certainly isn't the case on my O-540.
Manipulating the torque curve consists of futzing with the length and
diameter of the runners such that one of the pressure peaks in the gas
column (the gas column has inertia but is perpetually being asked to
stop and start as the intake valve opens and closes, resulting in
standing waves in the gas column) coincides with the intake valve at the
time the valve is open for a particular engine speed, such that there is
a relative overpressure during some portion of the intake valve being
open. I _might_ believe some of that was done, but lacking intake
balance pipes and other weird juju I'd be skeptical of the efficacy of
same -- and even then it wouldn't contribute to mixture distribution.

Don't even get me started on Lycoming plumbing the intake runners
through the oil pan to "improve" the mixture. If the runner design is
so bad that the intake manifold needs to be heated to assure that the
mixture from the carb remains vaporized the only reasonable conclusion
is that the runners are too long or have too many kinks and that the
overall intake system blows hairy goats. It's the mechanical
engineering answer to documenting a bug and calling it a feature.