X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 29 May 2012 11:09:08 -0400 Message-ID: X-Original-Return-Path: Received: from mail.grobsystems.com ([74.218.59.19] verified) by logan.com (CommuniGate Pro SMTP 5.4.5) with ESMTP id 5565197 for lml@lancaironline.net; Tue, 29 May 2012 07:31:27 -0400 Received-SPF: none receiver=logan.com; client-ip=74.218.59.19; envelope-from=btv1==496f7803451==bronnenmeier@grobsystems.com X-ASG-Debug-ID: 1338291051-03e9c30e41552a0001-yPXFKn Received: from bluexch01.grob.local ([10.10.0.103]) by mail.grobsystems.com with ESMTP id 9FpRM0Pcz7DVaMYh for ; Tue, 29 May 2012 07:30:51 -0400 (EDT) X-Barracuda-Envelope-From: bronnenmeier@GROBSYSTEMS.COM X-ASG-Whitelist: Client X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01CD3D8E.71FBC5F0" Subject: RE: [LML] boost pump for engine cooling 4P X-Original-Date: Tue, 29 May 2012 07:30:27 -0400 X-ASG-Orig-Subj: RE: [LML] boost pump for engine cooling 4P X-Original-Message-ID: <03E004EAF5B4DC4186EDF0995C9FE57102F98F37@bluexch01.grob.local> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [LML] boost pump for engine cooling 4P Thread-Index: Ac09je7RGSqoIjYzRjeYW4tRhrRf0Q== From: X-Original-To: X-Barracuda-Connect: UNKNOWN[10.10.0.103] X-Barracuda-Start-Time: 1338291051 X-Barracuda-URL: http://74.218.59.19:80/cgi-mod/mark.cgi X-Virus-Scanned: by bsmtpd at grobsystems.com This is a multi-part message in MIME format. ------_=_NextPart_001_01CD3D8E.71FBC5F0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Thank you for your input Bob - I usually took action at 380 because I noticed before that once the cylinders went to 380 they kept climbing to 400+=20 =20 From: Robert R Pastusek [mailto:rpastusek@htii.com]=20 Sent: Friday, May 25, 2012 1:18 PM To: lml@lancaironline.net Subject: RE: [LML] boost pump for engine cooling 4P =20 Ralf wrote: =20 Dear subscribers, =20 A while back I reported a warmer cylinder 4 during climb at 32 MAP and 2500 rpm. Lynn recommended I could test high boost during climb and see if it makes a difference. =20 In the mean time I cranked up my fuel pump by approx. 1 GPH. At take-off I see now 42.5 GPH at 38.4 MAP 2680 rpm (on a TSIO550 B which is rated for 38 MAP at 41...43GPH according to my manual).=20 =20 In climb under full rpm/MAP engine stays very nice and cool. =20 Climb 2500 rpm with 32MAP: all EGTs show the same, after increasing the fuel flow all CHTs stay generally a bit cooler but CHT 4 is still the one that runs a little warmer. During climb when CHT4 approached 380 I turned the high boost on - the CHT went down by approx. 10 degrees back into the 360's. During the climb to 18000 I had the boost pump on 3 times for may be 2 min each time. The Fuel flow increased from 30.5 to 33 GPH. I climbed with +-170 kts at 1000 fpm. This is new: usually I was never able to get the CHT down in climb unless I decreased the climb rate. =20 Question: is it a reasonable practice to use the high boost for engine cooling? How long can it run in high boost without getting damaged? =20 Craig reported earlier that he had his fuel pump modified to feed more fuel under partial power - this sounds complicated and expensive and if I don't have to I would rather not go there. =20 Thanks for you input =20 =20 =20 Ralf, You are still at the lower level of recommended WOT fuel flow for the big Continental. I have increased my WOT fuel flow to 44 GPH and the engine runs very cool all the way up. BTW, cylinder head temps of 380 are not worrisome; start being concerned/taking action at 400+. Still, keeping the engine cool lengthens its life.=20 =20 It's surprising how much cooling just a little extra fuel provides...and that's what you are seeing. The boost pump used on the IV-P is rated for continuous operation at low or high boost, but again, it will wear out sooner if used a lot...and it's quite expensive. Better to open the fuel flow a bit more and use the mixture control to moderate it...with one exception/note: It is possible to feed too much fuel to the engine, which will cause it to choke/stall (as opposed to flooding-a ground operation issue). You want to be sure the engine will take full throttle on takeoff without choking/loading up. With that caveat, the main problems with feeding it too much fuel are fouling the plugs over time, and the cost of extra fuel used. For my money, the extra gas is cheap insurance for the engine during climb; you can economize when you get the power back in cruise. Hope this helps. Bob =20 ------_=_NextPart_001_01CD3D8E.71FBC5F0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Thank you for your input Bob – I usually = took action at 380 because I noticed before that once the cylinders went = to 380 they kept climbing to 400+

 

From:= = Robert R Pastusek [mailto:rpastusek@htii.com]
Sent: Friday, = May 25, 2012 1:18 PM
To: = lml@lancaironline.net
Subject: RE: [LML] boost pump for engine = cooling 4P

 

Ralf wrote:

 

Dear = subscribers,

 

A while back I reported a warmer cylinder 4 during = climb at 32 MAP and 2500 rpm. Lynn recommended I could test high boost = during climb and see if it makes a difference.

 

In the mean = time I cranked up my fuel pump by approx. 1 GPH. At take-off I see now = 42.5 GPH at 38.4 MAP 2680 rpm (on a TSIO550 B which is rated for 38 MAP = at 41…43GPH according to my manual).

 

In climb = under full rpm/MAP engine stays very nice and cool.

 

Climb 2500 = rpm with 32MAP: all EGTs show the same, after increasing the fuel flow = all CHTs stay generally a bit cooler but CHT 4 is still the one that = runs a little warmer. During climb when CHT4 approached 380 I turned the = high boost on – the CHT went down by approx. 10 degrees back into = the 360’s. During the climb to 18000 I had the boost pump on 3 = times for may be 2 min each time. The Fuel flow increased from 30.5 to = 33 GPH. I climbed with +-170 kts at 1000 fpm.  This is new: usually = I was never able to get the CHT down in climb unless I decreased the = climb rate.

 

Question: is it a reasonable practice to use the high = boost for engine cooling? How long can it run in high boost without = getting damaged?

 

Craig = reported earlier that he had his fuel pump modified to feed more fuel = under partial power – this sounds complicated and expensive and if = I don’t have to I would rather not go there.

 

Thanks for = you input

 =

 

 

Ralf,
You are still = at the lower level of recommended WOT fuel flow for the big Continental. = I have increased my WOT fuel flow to 44 GPH and the engine runs very = cool all the way up. BTW, cylinder head temps of 380 are not worrisome; = start being concerned/taking action at 400+. Still, keeping the engine = cool lengthens its life.

 

It’s surprising = how much cooling just a little extra fuel provides…and = that’s what you are seeing. The boost pump used on the IV-P is = rated for continuous operation at low or high boost, but again, it will = wear out sooner if used a lot…and it’s quite expensive. = Better to open the fuel flow a bit more and use the mixture control to = moderate it…with one exception/note: It is possible to feed too = much fuel to the engine, which will cause it to choke/stall (as opposed = to flooding—a ground operation issue). You want to be sure the = engine will take full throttle on takeoff without choking/loading up. = With that caveat, the main problems with feeding it too much fuel are = fouling the plugs over time, and the cost of extra fuel used. For my = money, the extra gas is cheap insurance for the engine during climb; you = can economize when you get the power back in = cruise.


Hope this helps.


Bob

 

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