X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from oproxy12-pub.bluehost.com ([50.87.16.10] verified) by logan.com (CommuniGate Pro SMTP 6.0.5) with SMTP id 6364875 for flyrotary@lancaironline.net; Mon, 08 Jul 2013 13:06:42 -0400 Received-SPF: unknown receiver=logan.com; client-ip=50.87.16.10; envelope-from=jslade@canardaviation.com Received: (qmail 19699 invoked by uid 0); 8 Jul 2013 17:06:07 -0000 Received: from unknown (HELO host296.hostmonster.com) (66.147.240.96) by oproxy12.bluehost.com with SMTP; 8 Jul 2013 17:06:07 -0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=canardaviation.com; s=default; h=Content-Type:In-Reply-To:References:Subject:To:MIME-Version:From:Date:Message-ID; bh=oMMS0ccVuJ4E4WhFevFzi1VsBWke/kGkeBpyeqLNDrw=; b=ny90TOhK0t37Lw2psjbpYJT50iXx70EhMXeV5EOs28jcWtKrAJqK9fO4S9POVqhtq3XXjMmSbgNTY0xK1tdQmzhIhycjOLb66dsRZ1vD3/T2zRL5hAjkbrOgrOcxCfUO; Received: from [75.69.3.204] (port=63588 helo=[192.168.1.108]) by host296.hostmonster.com with esmtpa (Exim 4.80) (envelope-from ) id 1UwEt5-00045s-8t for flyrotary@lancaironline.net; Mon, 08 Jul 2013 11:06:07 -0600 Message-ID: <51DAF17B.60905@canardaviation.com> Date: Mon, 08 Jul 2013 13:06:03 -0400 From: John Slade User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130509 Thunderbird/17.0.6 MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Turbo boost indication References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------060405080903090303000502" X-Identified-User: {3339:host296.hostmonster.com:instanu1:trickysites.com} {sentby:smtp auth 75.69.3.204 authed with jslade@trickysites.com} This is a multi-part message in MIME format. --------------060405080903090303000502 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Scott, I have the stock 3rd gen intercooler. I also have a blow-off valve set at 44psi to avoid overboost. Regards, John On 7/8/2013 11:23 AM, Scott Emery wrote: > Last night (from epay) I bought a manifold pressure gauge for a twin > Cessna. The two needles are labelled Front & Rear. It's marked 10 to > 50 inches of mercury absolute. I intend to use it to read turbo boost > before the throttle body, and manifold pressure after the throttle body. > I'm having a hard time finding an intercooler that fits the available > space plus has a usable configuration of inlet/outlet tubes. The stock > rx7 intercooler I have in hand seems the best so far, but it's a bit > small compared to aftermarket offerings. > > Sent from my iPhone > > On Jul 7, 2013, at 2:17 PM, Scott Emery > wrote: > >> I'm thinking my "Blown Engine" experience might be avoidable in the >> future if I add a large manifold pressure gauge in plain sight, >> install a 1.30 A/R exhaust housing, retard the timing, run 100 LL >> blue gas, and add an intercooler. >> In that order. >> I got an engine hoist yesterday so now I can put the repaired engine >> back on. Getting it off didn't require as much precision... >> After I get some experience, I'll try different grades of mogas @ >> defined manifold pressure limits. >> >> Sent from my iPhone >> >> On Jul 6, 2013, at 12:36 PM, David Leonard > > wrote: >> >>> OK, so the more accurate conversion is >>> 20psi=40.7 in Hg >>> so in your example >>> 20psi boost = 70.6 in MAP (Manifold Absolute Pressure) >>> >>> It help in your article, turbos work as a boost ratio. So this >>> turbo it then making a boost ratio of: >>> 70.6 / 29.9 = 2.36 >>> >>> So as you go up in altitude you multiply the ambient pressure by 2.36 >>> >>> So at 17,500 ft the pressure is half, and so is the MAP, or, 35.3 " MAP >>> >>> Losses are not porportunately reduced, and the turbo may be less >>> efficient in that range so actual MAP may be less. >>> >>> >>> >>> >>> On Sat, Jul 6, 2013 at 11:57 AM, Patrick Panzera >>> > wrote: >>> >>> I'm editing an article about a bone stock, turbocharged direct >>> injection car engine that boasts 20 lbs of boost. >>> >>> I want to convert that to MP so us airplane junkies can wrap our >>> heads around it. >>> >>> Thanks! >>> >>> Pat >>> >>> >>> On Sat, Jul 6, 2013 at 11:44 AM, David Leonard >>> > wrote: >>> >>> Simply convert 20 psi to Inches of Hg (its about 2 to 1 but >>> not exactly) and add it to 29.9. So the MP should be about >>> 69 inches, give or take depending on losses and where in the >>> system you measure. >>> >>> I keep my plane less that 45 inches MP. You have to be more >>> rich and skilled than me to go higher without detonation. >>> >>> >>> On Sat, Jul 6, 2013 at 11:14 AM, Patrick Panzera >>> >> > wrote: >>> >>> Friends, >>> >>> Hypothetical question. >>> Let's say it's a standard day and I'm at sea level. >>> I've installed a turbocharger and have also connected >>> the stock automobile turbo boost gauge, along with my >>> traditional manifold pressure gauge. >>> >>> I ground-run the engine to full throttle (where the MP >>> would normally be reading 29.92- minus some efficiency >>> loss) and the boost gauge is reading 20 psi. >>> >>> What should the MP indicator be reading? >>> >>> Thanks! >>> >>> Pat >>> >>> >>> >>> >>> -- >>> David Leonard >>> >>> Turbo Rotary RV-6 N4VY >>> http://N4VY.RotaryRoster.net >>> http://RotaryRoster.net >>> >>> >>> >>> >>> >>> -- >>> David Leonard >>> >>> Turbo Rotary RV-6 N4VY >>> http://N4VY.RotaryRoster.net >>> http://RotaryRoster.net --------------060405080903090303000502 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit
Scott,
I have the stock 3rd gen intercooler.
I also have a blow-off valve set at 44psi to avoid overboost.
Regards,
John


On 7/8/2013 11:23 AM, Scott Emery wrote:
Last night (from epay) I bought a manifold pressure gauge for a twin Cessna. The two needles are labelled Front & Rear. It's marked 10 to 50 inches of mercury absolute. I intend to use it to read turbo boost before the throttle body, and manifold pressure after the throttle body. 
I'm having a hard time finding an intercooler that fits the available space plus has a usable configuration of inlet/outlet tubes. The stock rx7 intercooler I have in hand seems the best so far, but it's a bit small compared to aftermarket offerings.

Sent from my iPhone

On Jul 7, 2013, at 2:17 PM, Scott Emery <shipchief@aol.com> wrote:

I'm thinking my "Blown Engine" experience might be avoidable in the future if I add a large manifold pressure gauge in plain sight, install a 1.30 A/R exhaust housing, retard the timing, run 100 LL blue gas, and add an intercooler. 
In that order.
I got an engine hoist yesterday so now I can put the repaired engine back on. Getting it off didn't require as much precision...
After I get some experience, I'll try different grades of mogas @ defined manifold pressure limits.

Sent from my iPhone

On Jul 6, 2013, at 12:36 PM, David Leonard <wdleonard@gmail.com> wrote:

OK, so the more accurate conversion is 
20psi=40.7 in Hg
so in your example
20psi boost = 70.6 in MAP (Manifold Absolute Pressure)

It help in your article, turbos work as a boost ratio.  So this turbo it then making a boost ratio of:
70.6 / 29.9  = 2.36

So as you go up in altitude you multiply the ambient pressure by 2.36

So at 17,500 ft the pressure is half, and so is the MAP, or, 35.3 " MAP

Losses are not porportunately reduced, and the turbo may be less efficient in that range so actual MAP may be less.




On Sat, Jul 6, 2013 at 11:57 AM, Patrick Panzera <editor@contactmagazine.com> wrote:
I'm editing an article about a bone stock, turbocharged direct injection car engine that boasts 20 lbs of boost.

I want to convert that to MP so us airplane junkies can wrap our heads around it.

Thanks!

Pat 


On Sat, Jul 6, 2013 at 11:44 AM, David Leonard <wdleonard@gmail.com> wrote:
Simply convert 20 psi to Inches of Hg (its about 2 to 1 but not exactly) and add it to 29.9.  So the MP should be about 69 inches, give or take depending on losses and where in the system you measure.

I keep my plane less that 45 inches MP.  You have to be more rich and skilled than me to go higher without detonation.


On Sat, Jul 6, 2013 at 11:14 AM, Patrick Panzera <editor@contactmagazine.com> wrote:
Friends,

Hypothetical question. 
Let's say it's a standard day and I'm at sea level.
I've installed a turbocharger and have also connected the stock automobile turbo boost gauge, along with my traditional manifold pressure gauge.

I ground-run the engine to full throttle (where the MP would normally be reading 29.92- minus some efficiency loss) and the boost gauge is reading 20 psi.

What should the MP indicator be reading?

Thanks!

Pat




--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net




--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net

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