Turbo question

I have a piper turbo arrow with a TSIO-360-FB engine. It has the original
waste gate on the turbo, and an after market turbo plus intercooler.
I recently made a long trip, and got the plane up to 14000 for the first
time in a long time. I was having trouble keeping the exhaust temp down. I
had the mixture full rich, and the engine was only using 14 gph. It seemed I
could not get the mixture rich enough.

I don't remember this happening on any of my previous flights at high
altitude, but the previous flights were a while back. The plane behaves
perfectly normal at altitudes up to 10000 which is were most of my flying
is.

Does this imply something wrong with the fuel system or fuel pump or is this
normal behavior for these planes?

On Sun, 04 Jun 2006 23:48:02 GMT, "soxinbox" wrote:

The first step would be to make sure that your fuel system has been
setup IAW

http://www.tcmlink.com/pdf2/SID97-3C.pdf

It should really be done on a regular basis whether or not you think
you have fuel delivery problems.

Was the 14 GPH a mechanical fuel flow (which is actually a pressure
gage BTW) indication, or from a flow/totalizer indicator?

Your engine really doesn't have a wastegate/controller, it essentially
has a fixed bolt screwed into the exhaust stream. The bolt is adjusted
in or out to match requirements called out in the aircraft maintenance
manual.

Turbo plus used to offer a variable replacement unit that essentially
used a diaphragm to move the bolt in/out according to demand. Only
ever worked on a couple of aircraft that had them installed, and never
had the opportunity to take one up to altitude.

Maybe some Mooney people can jump in here, I'm thinking that the
Mooney's with similar engine installations had a CDT (compressor
discharge temp) gage, with a redline/max temperature. Again, never had
the chance to get one so equipped up to altitude to see what effect
altitude had on the numbers.

TC

I have a piper turbo arrow with a TSIO-360-FB engine. It has the original
waste gate on the turbo, and an after market turbo plus intercooler.
I recently made a long trip, and got the plane up to 14000 for the first
time in a long time. I was having trouble keeping the exhaust temp down. I
had the mixture full rich, and the engine was only using 14 gph. It seemed I
could not get the mixture rich enough.

I don't remember this happening on any of my previous flights at high
altitude, but the previous flights were a while back. The plane behaves
perfectly normal at altitudes up to 10000 which is were most of my flying
is.

Does this imply something wrong with the fuel system or fuel pump or is this
normal behavior for these planes?

You are right, my engine has the fixed wastegate ( Bolt in the waste tube ).
The flow was read from both the piper differential gage and a fuel flow
sensor/computer. They both had the same reading.
Thanks for the service directions link. I will go over it in detail.

wrote in message
...
On Sun, 04 Jun 2006 23:48:02 GMT, "soxinbox" wrote:

The first step would be to make sure that your fuel system has been
setup IAW

http://www.tcmlink.com/pdf2/SID97-3C.pdf

It should really be done on a regular basis whether or not you think
you have fuel delivery problems.

Was the 14 GPH a mechanical fuel flow (which is actually a pressure
gage BTW) indication, or from a flow/totalizer indicator?

Your engine really doesn't have a wastegate/controller, it essentially
has a fixed bolt screwed into the exhaust stream. The bolt is adjusted
in or out to match requirements called out in the aircraft maintenance
manual.

Turbo plus used to offer a variable replacement unit that essentially
used a diaphragm to move the bolt in/out according to demand. Only
ever worked on a couple of aircraft that had them installed, and never
had the opportunity to take one up to altitude.

Maybe some Mooney people can jump in here, I'm thinking that the
Mooney's with similar engine installations had a CDT (compressor
discharge temp) gage, with a redline/max temperature. Again, never had
the chance to get one so equipped up to altitude to see what effect
altitude had on the numbers.

TC

I have a piper turbo arrow with a TSIO-360-FB engine. It has the original
waste gate on the turbo, and an after market turbo plus intercooler.
I recently made a long trip, and got the plane up to 14000 for the first
time in a long time. I was having trouble keeping the exhaust temp down. I
had the mixture full rich, and the engine was only using 14 gph. It seemed
I
could not get the mixture rich enough.

I don't remember this happening on any of my previous flights at high
altitude, but the previous flights were a while back. The plane behaves
perfectly normal at altitudes up to 10000 which is were most of my flying
is.

Does this imply something wrong with the fuel system or fuel pump or is
this
normal behavior for these planes?

If the TIT is too high, there is not enough fuel flow.

High TIT at high power when the engine is working
hard is very destructive. Should be 1350 or so.
To get that, you will have to set the pressures at the
absolute top end of what Continental recommends.

The electronic fuel flow restricts the flow a bit, requiring
even higher pressure, which is not widely recoginzed as
a problem.

Bill Hale BPPP instructor

If the TIT is too high, there is not enough fuel flow.
High TIT at high power when the engine is working
hard is very destructive. Should be 1350 or so.

Are you talking about a specific installation in a specific airplane ?
The red line for my TIT is 1750ºF. 1350ºF is way cold on my airplane. I
don't think I could possibly put that much fuel through it.
---
Ken Reed
M20M, N9124X

On Wed, 07 Jun 2006 00:24:02 GMT, Ken Reed wrote:

Just curious. Is the M20M the one equipped with the
turbo-supercharged Lycoming that was retrofitted with external oil
lines to cool the exhaust valve guides a la the TIGO-541?

If this is indeed the case, 1350 is only slightly cool on your
airplane, 1750 is way too darn hot.

TC

If the TIT is too high, there is not enough fuel flow.
High TIT at high power when the engine is working
hard is very destructive. Should be 1350 or so.

Are you talking about a specific installation in a specific airplane ?
The red line for my TIT is 1750ºF. 1350ºF is way cold on my airplane. I
don't think I could possibly put that much fuel through it.
---
Ken Reed
M20M, N9124X

wrote:
Are you talking about a specific installation in a specific airplane ?
The red line for my TIT is 1750ºF. 1350ºF is way cold on my airplane.. I
don't think I could possibly put that much fuel through it.

I believe recommended on the turbo Arrow is 1650F. [I could be off on
that, but that's memory.] Some systems do allow 1750 - but they have a
different metal for the exhaust.

For the problem itself - first off, as was said, make sure the fuel
system is set up correctly. You should be over 20 gph on takeoff
power. For cruise, do you have the cowling cooling mod? [I'm guessing
yours is an Arrow III.] That's the set of side vents (one on each
side) that were added. Most older turbo Arrows have had them added by
now, but not all.

The Merlyn Automatic Wastegate is a popular mod for that aircraft.
It's not a true automatic controller, but it is a durn site better than
the screw-in bolt that Piper installed. Having said that, the main
heat advantage it gives is down low. Up high it allows more power
(much more), but doesn't help with heat (with one exception below).
Some folks have installed an intercooler, but it really shouldn't be
necessary.

Now for that exception: If you *really* want the temps to come down,
reduce engine RPM. I cruise about 2300 or so, no more than that
certainly, at any altitude. However, without the Merlyn, you may have
trouble getting adequate power up into the flight levels.

Another option - run LOP. Then you can pretty much put the temps
wherever you want them. Again, though, with the fixed wastegate at
high altitude, you may not be able to produce the power you want.

And lastly, the most absolutely obvious (that is frequently
overlooked). Have your engine baffle system looked at by someone who
knows what he is doing. Very small leaks can make a huge difference.

The red line for my TIT is 1750ºF. 1350ºF is way cold on my
airplane. I don't think I could possibly put that much fuel
through it.

Just curious. Is the M20M the one equipped with the
turbo-supercharged Lycoming that was retrofitted with external oil
lines to cool the exhaust valve guides a la the TIGO-541?

Yes.

If this is indeed the case, 1350 is only slightly cool on your
airplane, 1750 is way too darn hot.

I don't run it anywhere near 1750º, but that is the red line for that
installation. I cruise at 1600º TIT and climb around 1450º. I don't
think I can get it down to 1350º.

At 1600º, at typical altitudes, RPM and MP, I get just under 210 KTAS.
---
Ken Reed
M20M, N9124X

For the problem itself - first off, as was said, make sure the fuel
system is set up correctly. You should be over 20 gph on takeoff
power.

I'm burning 27 GPH in take-off and climb.

For cruise, do you have the cowling cooling mod? [I'm guessing
yours is an Arrow III.]

No, I fly a Mooney Bravo. Sounds like you may have been discussing a
different (and specific) airplane and engine combination ?

Another option - run LOP.

Unfortunately, that isn't an option in the Mooney Bravo. I know about a
dozen owners and no one can run LOP. I ran LOP regularly in my previous
airplane, but this airplane/engine combination simply won't run LOP
smoothly and with reasonable temperatures.
---
Ken Reed
M20M, N9124X

It could be your high end fuel flow is not sufficient. (Yes there is
also a low end setting also.)

When you do a normal take off at full rich, does the FF needle go to
just about the redline?

John

soxinbox wrote:
I have a piper turbo arrow with a TSIO-360-FB engine. It has the original
waste gate on the turbo, and an after market turbo plus intercooler.
I recently made a long trip, and got the plane up to 14000 for the first
time in a long time. I was having trouble keeping the exhaust temp down. I
had the mixture full rich, and the engine was only using 14 gph. It seemed I
could not get the mixture rich enough.

I don't remember this happening on any of my previous flights at high
altitude, but the previous flights were a while back. The plane behaves
perfectly normal at altitudes up to 10000 which is were most of my flying
is.

Does this imply something wrong with the fuel system or fuel pump or is this
normal behavior for these planes?