X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 27 Nov 2010 15:43:33 -0500 Message-ID: X-Original-Return-Path: Received: from elasmtp-junco.atl.sa.earthlink.net ([209.86.89.63] verified) by logan.com (CommuniGate Pro SMTP 5.3.10) with ESMTP id 4593873 for lml@lancaironline.net; Sat, 27 Nov 2010 10:39:54 -0500 Received-SPF: none receiver=logan.com; client-ip=209.86.89.63; envelope-from=colyncase@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=WD+UHLZnjHtIJ2J25YM5m2mF/LifBDK1KBa7KzkLtnFao+PY58knPJx6BWoj5HYJ; h=Received:From:Mime-Version:Content-Type:Subject:Date:In-Reply-To:To:References:Message-Id:X-Mailer:X-ELNK-Trace:X-Originating-IP; Received: from [216.57.118.85] (helo=[192.168.1.103]) by elasmtp-junco.atl.sa.earthlink.net with esmtpa (Exim 4.67) (envelope-from ) id 1PMMrt-0007SL-MY for lml@lancaironline.net; Sat, 27 Nov 2010 10:39:18 -0500 From: Colyn Case Mime-Version: 1.0 (Apple Message framework v1081) Content-Type: multipart/alternative; boundary=Apple-Mail-14--967456010 Subject: Re: [LML] Re: Inquiry: Critical Turbo Altitude (LIVP) with TSIO550E? X-Original-Date: Sat, 27 Nov 2010 10:39:16 -0500 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: X-Mailer: Apple Mail (2.1081) X-ELNK-Trace: 63d5d3452847f8b1d6dd28457998182d7e972de0d01da94035737b2e2f8c0d44a6fc9d42de2233e3350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 216.57.118.85 --Apple-Mail-14--967456010 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Brent, say more about the turbo stall issue? Is it the turbine that stalls or the compressor? I'm assuming the = latter. I swapped my compressors out for the larger ones (I think they are the = stock Malibu ones) keeping the same turbines. Does that represent the "right turbos" solution? I also cut out the restrictor on the co-pilot side because I couldn't = get anyone to say what it was for. What are the symptoms of "turbo stall". Would that by any chance cause the Fuel/Air ratio to go rich and cause = backfiring? Colyn TSIO-550B with 7.5:1 cylinders and pressurized slick mags. On Nov 27, 2010, at 3:26 AM, Brent Regan wrote: > Jim Writes: > << They were from Brazil and they told me that they flew their IV-P's = at 33,000 feet with no problems.>>> >=20 > FL330? Really? Maybe after having your wings waxed. >=20 > My IV-P has a TIO540 Lyc with 8.7:1 pistons and max MAP of 35" (360 Hp = on the Barrett dyno @ 2700 RPM). Measured critical altitude is FL280. = Back during the flight test period, pre RVSM, I took the old girl to = FL300 but she was not happy. Flight controls were very sensitive, engine = was hot, mags were starting to misfire, cabin altitude was in the O2 = needed range, and this was one occupant, half fuel and no baggage with a = 2,188 Lb empty weight. Note to self FL280 is operational max. With the = RVSM requirements, anything above FL270 does not matter as you cant get = there from here.=20 >=20 > If you have a low critical altitude then here are some things you may = wan to check: >=20 > Air cleaner. Is it rated for the volumetric flow you are asking? As = you climb the air cleaner flow increases and the delta P across it rises = causing the compressor inlet pressure to drop below ambient. Full power = air demand is ~500 CFM at sea level. You need ~2.4 times that at FL280. = I use a pair of K&Ns that are rated to 800 CFM each. >=20 > Right turbos. Early TSIO550 had turbos that tended to stall. The fix = was a restrictor on the turbine outlet. The real fix was the right size = turbos. >=20 > Leaky Wastegate (or controller out of adjustment). >=20 > Exhaust leak. >=20 > Pop-off valve leak. >=20 > Poor cooling flow through intercooler. >=20 > There are others but that is where I would start. >=20 > FYI, typical performance numbers for N170BR are 275KTAS @ FL240 & 75% = power (2,500 RPM, 28" MAP, 21.5 GPH, 1,500 TIT, 385 CHT, 195 Oil Temp). = Yes, I run ROP with a BSFC of .49 BUT I just logged 1,000 hours on the = Lycoming with all original parts. Cylinders, rings, valves and = compression is still 72 -75 PSI. Pay for fuel or pay for cylinders. >=20 > Regards > Brent Regan --Apple-Mail-14--967456010 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii
I also cut out the restrictor on the co-pilot side = because I couldn't get anyone to say what it was = for.

What are the symptoms of "turbo = stall".
Would that by any chance cause the Fuel/Air ratio to = go rich and cause = backfiring?

Colyn
TSIO-550B with = 7.5:1 cylinders and pressurized slick = mags.


On Nov 27, 2010, at 3:26 = AM, Brent Regan wrote:

 Jim Writes:
<< They were from Brazil and they told me that they flew their IV-P's at 33,000 feet with no problems.>>>

FL330? Really? Maybe after having your wings waxed.

My IV-P has a TIO540 Lyc with 8.7:1 pistons and max MAP of 35" (360 Hp on the Barrett dyno @ 2700 RPM).  Measured critical altitude is = FL280. Back during the flight test period, pre RVSM, I took the old girl to FL300 but she was not happy. Flight controls were very sensitive, engine was hot, mags were starting to misfire, cabin altitude was in the O2 needed range, and this was one occupant, half fuel and no baggage with a 2,188 Lb empty weight. Note to self FL280 is operational max. With the RVSM requirements, anything above FL270 does not matter as you cant get there from here.

If you have a low critical altitude then here are some things you may wan to check:

Air cleaner. Is it rated for the volumetric flow you are asking? As you climb the air cleaner flow increases and the delta P across it rises causing the compressor inlet pressure to drop below ambient. Full power air demand is ~500 CFM at sea level. You need ~2.4 times that at FL280. I use a pair of K&Ns that are rated to 800 CFM each.

Right turbos. Early TSIO550  had turbos that tended to stall. The = fix was a restrictor on the turbine outlet. The real fix was the right size turbos.

Leaky Wastegate (or controller out of adjustment).

Exhaust leak.

Pop-off valve leak.

Poor cooling flow through intercooler.

There are others but that is where I would start.

FYI, typical performance numbers for N170BR are 275KTAS @ FL240 & 75% power (2,500 RPM, 28" MAP, 21.5 GPH, 1,500 TIT, 385 CHT, 195 Oil Temp). Yes, I run ROP with a BSFC of .49 BUT I just logged 1,000 hours on the Lycoming with all original parts. Cylinders, rings, valves and compression is still 72 -75 PSI. Pay for fuel or pay for cylinders.

Regards
Brent Regan

= --Apple-Mail-14--967456010--