V35B upgrade from IO-520-BA to IO-520-BB

After that, I'd like to hang a turbonormalizer on it and no one seems to
recommend putting TN on the 520.

I agree, although TN on a 550 isn't necessarily a cake walk either. The big
Lyc seems to take to turbos better, prehaps because of the sodium valves.
In any event, you may find that 550 performs enough better at altitude that
the need for the turbo will be marginalized.

- Mark

Tom Sixkiller ) wrote:

After that, I'd like to hang a turbonormalizer on it and no one seems to
recommend putting TN on the 520.

Really? The Bonanza V35B I am now flying is equipped with the Tornado
Alley TN on an IO-520 engine. The previous owner had it installed about
600 hours ago and, based on last week's annual inspection, the engine is
still in excellent shape.

With the TN, this aircraft cruises around 190 kts true airspeed at about
19,000 feet MSL, all while burning about 15.5 gallons per hour during the
summer months.



--
Peter

"markjen" wrote in message
news:6EXqc.81041$536.13507539@attbi_s03...
After that, I'd like to hang a turbonormalizer on it and no one seems to
recommend putting TN on the 520.

I agree, although TN on a 550 isn't necessarily a cake walk either. The
big
Lyc seems to take to turbos better, prehaps because of the sodium valves.
In any event, you may find that 550 performs enough better at altitude
that
the need for the turbo will be marginalized.

The airport I'll be operating out of, after May or June, is 6900 feet in
elevation.

Not quite marginal! :~)

"Peter R." wrote in message
...
Tom Sixkiller ) wrote:

After that, I'd like to hang a turbonormalizer on it and no one seems to
recommend putting TN on the 520.

Really? The Bonanza V35B I am now flying is equipped with the Tornado
Alley TN on an IO-520 engine. The previous owner had it installed about
600 hours ago and, based on last week's annual inspection, the engine is
still in excellent shape.

With the TN, this aircraft cruises around 190 kts true airspeed at about
19,000 feet MSL, all while burning about 15.5 gallons per hour during the
summer months.

I should clarify my misstatement: It's not that they don't recommend TN for
the 520, but given the cost of a Millennium overhaul of the 520 or
replacement with M's 550 reman ($27K vs. $23K +/-), for an F33A, they
(TATurbo) said the difference was like night and day.

Really? The Bonanza V35B I am now flying is equipped with the Tornado
Alley TN on an IO-520 engine. The previous owner had it installed about
600 hours ago and, based on last week's annual inspection, the engine is
still in excellent shape.

Great. Most are getting excellent service. But there have been quite a few
owners with problems too.

- Mark

markjen ) wrote:

Great. Most are getting excellent service. But there have been quite a few
owners with problems too.

Ok, you hooked me. What type of problems?

--
Peter












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Well, a friend had a complete and total TN IO-520BB engine failure in Texas,
fortunately able to glide to an airport from altitude. Lost all engine
oil - something to do with the turbo system install. I also flew with him
several times at altitude and he was always jugggling CHTs, TITs, and EGTs
to stay within limits.

Lots and lots of folks have reported premature barrel wear and cylinder head
issues leading to early top overhauls. The 520 factory turbos in a variety
of airplanes (e.g., 425s) are considered relatively problematic and
tempermental. On the early A36TCs, there were some gruesome engine fires,
although I realize this installation is different from the TN systems. (The
550s in the B36TCs are noticeably more reliable.)

I'm not saying that a TN'd 520 or 550 can't be a fine airplane. But I think
you're kidding yourself if you don't accept some reduction in reliability
and much reduced expectation of making normal TBO. It's simple physics -
you're force-feeding the engine to a much higher level of engine power than
it normally makes in normally aspirated form, and you're doing it at high
altitudes when cooling is at its worst. Good instrumentation, careful
operation, and keeping the cooling system in tip-top shape mitigates, but
does not eliminate the factors here.

- Mark