X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 12 May 2005 14:10:34 -0400 Message-ID: X-Original-Return-Path: Received: from secure5.liveoakhosting.com ([64.49.254.21] verified) by logan.com (CommuniGate Pro SMTP 4.3c5) with ESMTPS id 941523 for lml@lancaironline.net; Thu, 12 May 2005 13:13:25 -0400 Received-SPF: none receiver=logan.com; client-ip=64.49.254.21; envelope-from=walter@advancedpilot.com Received: (qmail 20246 invoked by uid 2520); 12 May 2005 17:12:39 -0000 Received: from 216.107.97.170 by secure5.liveoakhosting.com (envelope-from , uid 2020) with qmail-scanner-1.25st (clamdscan: 0.84/871. perlscan: 1.25st. Clear:RC:0(216.107.97.170):. Processed in 0.273084 secs); 12 May 2005 17:12:39 -0000 Received: from 216-107-97-170.wan.networktel.net (HELO ?10.0.1.2?) (216.107.97.170) by secure5.liveoakhosting.com with SMTP; 12 May 2005 17:12:39 -0000 Mime-Version: 1.0 (Apple Message framework v622) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-4-171804940 X-Original-Message-Id: <5df80c46792498cf805f5743cf176298@advancedpilot.com> From: Walter Atkinson Subject: Re: [LML] Re: Plasma III on Hi Compression Engines X-Original-Date: Thu, 12 May 2005 12:12:38 -0500 X-Original-To: "Lancair Mailing List" X-Mailer: Apple Mail (2.622) --Apple-Mail-4-171804940 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=WINDOWS-1252; format=flowed Colyn: You've got a lot of that right. The big issue is that the detonation=20 margin is so much narrower as the CR goes up. Walter On May 12, 2005, at 11:16 AM, colyncase on earthlink wrote: If I got my APS stuff right, the only really bad thing about a higher=20 CR is that your engine will last even less long if you mismanage it.=A0=A0= =20 However, it seems that if you are rigorously keeping your peak=20 pressures way beyond TDC (e.g. 16 or more degrees) then high CR isn't=20 going to hurt you.=A0=A0=A0 The pressure difference between correctly = manage=20 high CR and correctly managed standard CR should be at most (high=20 CR/low CR) or 20%.=A0 =A0=A0 But the (peak) pressure difference between = 50 df=20 LOP and 25 df ROP is 100%=A0or more? =A0 Colyn =A0 > ----- Original Message ----- > From: Craig Berland > To: Lancair Mailing List > Sent: Thursday, May 12, 2005 8:24 AM > Subject: [LML] Re: Plasma III on Hi Compression Engines > > > > "I put those two pieces of information together and reach the=20 > conclusion that if there are ways to operate the engine at high power=20= > but minimize the peak torsionals,=A0 then that method ought to be=20 > used.=A0I=92m not sure I answered your question.=A0 If not, let me try=20= > again. Regards,=A0 George" > > Yes you did answer my question...thanks.=A0 One more.=A0 How much of a=20= > tight rope are we walking with the TSIO550 trying to balance peak=20 > pressure and TIT?=A0 Well, two questions.=A0 I have discussed with = some=20 > the advisability of raising the compression ratio on the TSIO550 and I=20= > advised against it. The quest for efficiency is outweighed by the=20 > quest for durability. What do you think?=A0 A similar question.=A0 = Would=20 > you advise retarding the timing if Scot's engine was stock CR?=A0 = Retard=20 > 2 to 3 deg's more=A0at 9 to 1 and 5 to 7 deg's more=A0at 10 to 1???=A0 = If=20 > this is so, then stock CR is the way to go. Finally let me say I=20 > believe there are lots of variables that affect engine durability like=20= > oil type and viscosity, engine component balance and prop balance to=20= > name a few. So this is not a discussion on whether or not Scott or=20 > someone else should run a given CR. I'm trying to isolate and=20 > understand a given engine calibration feature and I'm most interested=20= > in the TSIO550. > > Craig Berland= --Apple-Mail-4-171804940 Content-Transfer-Encoding: quoted-printable Content-Type: text/enriched; charset=WINDOWS-1252 Colyn: You've got a lot of that right. The big issue is that the detonation margin is so much narrower as the CR goes up. Walter =20 On May 12, 2005, at 11:16 AM, colyncase on earthlink wrote: ArialIf I got my APS stuff right, the only really bad thing about a higher CR is that your engine will last even less long if you mismanage it.=A0=A0 However, it seems that if you are rigorously keeping your peak pressures way beyond TDC (e.g. 16 or more degrees) then high CR isn't going to hurt you.=A0=A0=A0 The = pressure difference between correctly manage high CR and correctly managed standard CR should be at most (high CR/low CR) or 20%.=A0 =A0=A0 But the (peak) pressure difference between 50 df LOP and 25 df ROP is 100%=A0or more? =A0 ArialColyn =A0 Arial----- Original Message ----- = ArialFrom:Arial 0000,0000,EEEECraig Berland = = ArialTo:Arial 0000,0000,EEEELancair Mailing List = = ArialSent:Arial Thursday, May 12, 2005 8:24 AM = ArialSubject:Arial [LML] Re: Plasma III on Hi Compression = Engines = Arial0000,0000,8080"I put those two pieces of information together and reach the conclusion that if there are ways to operate the engine at high power but minimize the peak torsionals,=A0 then that method ought to be used.=A0I=92= m not sure I answered your question.=A0 If not, let me try again. Regards,=A0 George" = Arial0000,0000,8080Yes you did answer my question...thanks.=A0 One more.=A0 How much of a tight rope are we walking with the TSIO550 trying to balance peak pressure and TIT?=A0 Well, two questions.=A0 I have discussed with some the advisability of raising the compression ratio on the TSIO550 and I advised against it. The quest for efficiency is outweighed by the quest for durability. What do you think?=A0 A similar question.=A0 Would you advise retarding the timing if Scot's engine was stock CR?=A0 Retard 2 to 3 deg's more=A0at 9 to 1 and 5 to 7 deg's more=A0at 10 to 1???=A0 = If this is so, then stock CR is the way to go. Finally let me say I believe there are lots of variables that affect engine durability like oil type and viscosity, engine component balance and prop balance to name a few. So this is not a discussion on whether or not Scott or someone else should run a given CR. I'm trying to isolate and understand a given engine calibration feature and I'm most interested in the TSIO550. = Arial0000,0000,8080Craig Berland= --Apple-Mail-4-171804940--