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1. 06:34 AM - Re: Jetting Stratus Bing Carbureters (Don Walker)
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| Subject: | Re: Jetting Stratus Bing Carbureters |
Seal-Send-Time: Sat, 18 Dec 2004 08:30:37 -0600
--> Stratus-List message posted by: "Don Walker" <d3dw@msn.com>
Jim, You might check your jet size compared to this report. Mine came from Stratus
with smaller main jets...162 rather than the 164 reported here. Mine ran smooth
as a sewing machine until this week when I changed the jetting. I put in
a 165 main, which seems to do well, and enriched the mid-range two notches. Now
I am going to do what you did...bring the mid-range back up to the third notch.
Also remember that some here are getting more air flow with the Ram heads.
don walker----- Original Message -----
From: Weston, Jim<mailto:Jim.Weston@delta.com>
To: stratus-list@matronics.com<mailto:stratus-list@matronics.com>
Sent: Friday, December 17, 2004 12:55 PM
Subject: RE: Stratus-List: Jetting Stratus Bing Carbureters
--> Stratus-List message posted by: "Weston, Jim" <Jim.Weston@delta.com<mailto:Jim.Weston@delta.com>>
So am I to take it that everyone has been finding that the jets are too
lean at cruise, as the engine comes from Stratus? I don't have EGT
gauges. This might explain why I've never been able to run at high RPM
for long before the temps (engine & oil) start to climb. I changed my
mid-range needle to the 3rd ring, some time back, and this helped some.
Jim Weston
601HDS, Stratus
Concord, Ga.
-----Original Message-----
From: owner-stratus-list-server@matronics.com<mailto:owner-stratus-list-server@matronics.com>
[mailto:owner-stratus-list-server@matronics.com] On Behalf Of Hinde,
Frank George (Corvallis)
To: stratus-list@matronics.com<mailto:stratus-list@matronics.com>
Subject: RE: Stratus-List: Jetting Stratus Bing Carbureters
--> Stratus-List message posted by: "Hinde, Frank George (Corvallis)"
--> <frank.hinde@hp.com<mailto:frank.hinde@hp.com>>
Your experience pretty much mirros mine Larry, the only difference is I
ended up with a cruise EGT of 1450. The mixture were confirmed correct
by the exhaust gas analyser.
I can't remember what jets I ended up with finally.
Thanks
Frank
-----Original Message-----
From: owner-stratus-list-server@matronics.com<mailto:owner-stratus-list-server@matronics.com>
[mailto:owner-stratus-list-server@matronics.com] On Behalf Of Larry
McFarland
To: stratus-list@matronics.com<mailto:stratus-list@matronics.com>
Subject: Stratus-List: Jetting Stratus Bing Carbureters
--> Stratus-List message posted by: "Larry McFarland"
--> <larrymc@qconline.com<mailto:larrymc@qconline.com>>
Hi guys, (fellow Stratus EA-81 users)
I think it's time to put the experience of re-jetting Stratus-Bing carbs
into the archives. Perhaps it'll reduce your time and expense of
"discovery". The "Bing Carburettors Aircraft Tuning & Parts Manual" is
needed to fully visualize this information. Bing can be reached at
1-800-309-2464 weekdays and it's only $8.00. (Yes, the spelling is
correct) The manual is a good parts-identifier and primer for getting
correct mixture, but you have to do the guesswork till it's right, so
for the Stratus, that's what this piece is about.
My Stratus engine with Bing carburetor's initially came with No.40 idle
mixture-jets adjusted 2-turns from closed, 164 main jets and 2.72
mid-range jets. (Note; all jets have the number stamped on each one.)
The mid-range jet-needles came with 2 scribed rings on their diameters
for identification and on the jet-needle 4 snap-ring notches, the
circlips were set at the #2 position or second notch from the top.
Ram Performance installed new S.S. valves, springs and guides. The
rework also provides more airflow, so increased jet sizes are
recommended by Ron at Ram to get a target cruise EGT of 1350-degrees.
Mykal at Stratus says 1400 to 1500 degrees is fine with an upper limit
short duration 1600-degrees.
With high EGTs, I changed to 170 main jets. EGTs came down, but were
too high for takeoff rpms. 180 main jets were tried but the engine ran
rough with these.
With 174 mains, the plane flew well. EGTs reached 1400 degrees at 4200
rpm. (Still too high for higher rpms) The mid-range jet-needle was set
higher to enrich fuel mixture by moving the circlip from #2 notch down
to the #3 notch. This made a serious difference and I could cruise at
4600 rpm all day at 1390 degrees EGT. At full 5100, the EGT would still
slowly climb above 1450-degrees, which I felt might be high for
continuous running.
Without initially knowing, I changed out the air filters to K&N types
because of concern for the foam. This reduced air resistance into the
carburetors, provided more air, leaner mixture and increased EGTs. Cool
weather also seemed to increase EGTs.
On a Bing phone inquiry/discussion, the technical rep was surprised I
had not yet increased mid-range jetting and suggested I replace 2.72
with 2.76 jets and lower the needles one notch to see if the equivalent
of a one-jet change would work. 174 mains were also changed to 176
jets. A 3500-rpm run-up with brakes brought EGTs to 1400-degrees rather
quickly. The needle jet was then raised by re-setting the circlip down
to #3 notch and the EGTs climbed to 1290 at 3500-rpm, but no higher.
Quite a difference!
Was anxious to fly these jet and needle settings to see what happens at
higher rpms. Today, at 40-degrees, winds at 10, I taxied to 31 and
holding short, watched pre-heated oil reach 240 until clearance was
given for takeoff. Climb out was impressive, and EGTs were slow to
climb to 1450 at 5100, so I reduced rpms to 4400 and turned south to the
practice area and EGTs came down to 1435. Rpms were lowered to a
comfortable 4300 and EGTs stabilized at 1420. The largest change from
increasing jet sizes was the slow mid range climb through 1400 on
takeoff. I flew an hour and then returned to land on 27. All other
temps were normal throughout the flight.
Back at the hangar, the K&N type air filters were removed and replaced
with the original foam types to see if they would make a difference.
Went home for lunch. Afterward, I refueled the plane and taxied out in
16 mph winds to lift off very quickly from 31. The EGT rise was slower
and never got past 1420 on takeoff. After leveling the plane, I headed
south for 15 minutes. Rpms were set back to 4350 and EGTs settled in at
1375. There's still about a 40-degree difference from the right to left
sides. I tried raising the rpms to 5000 and the EGTs would level out at
1425. The old foam filters had a much greater impact on mixture than
I'd have thought. EGTs are satisfactory to this point as I can cruise
at 115 to 120 without getting much beyond a 1400-degree limit.
My Engine timing is set to 30-degrees at 4500 rpm. I haven't seen
evidence that re-timing 1 or 2 degrees either way helped it run better.
Plugs soot up at idle and plug color doesn't offer exact information, so
I purchased a high-compression Colortune plug from Bing. This will
permit actually seeing the mixture and rpms from idle to 4000, but no
further. Haven't used it yet as focus has been on the high end and
getting Horsepower at lower EGTs. I expect to install an O2 sensor to
confirm running mixtures when the jet settings have been flown.
EGT sensors are installed 3-1/2" from the exhaust flange in the top of
the first straight after the bend. They are a probe-type secured by a
hose-clamp that also grips a belting heat wrap on the exhaust pipes to
protect the cowling.
All engine data is displayed on a Grand Rapids Technologies E I S. This
thing is indispensable for showing all real-time engine parameters and
immediately displaying an alarm-light while pointing out any
out-of-limit condition. It's an easy set-up too!
Earlier this season, the radiator was moved back as a P51,
to where it was and it works very well.
Please forgive the lengthy diatribe, but the archives needed specific
jet and needle setting information for this engine. That's as much as I
know at this time. If you've been there done that, have a comment or
objection, please do, so we can all compare notes and learn from the
collective experience.
Thanks guys,
Larry McFarland - 601HDS with Stratus Subaru and Ram Performance heads
at www.macsmachine.com<http://www.macsmachine.com/>
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