X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from oproxy13-pub.unifiedlayer.com ([69.89.16.30] verified) by logan.com (CommuniGate Pro SMTP 6.0.5) with SMTP id 6365958 for flyrotary@lancaironline.net; Tue, 09 Jul 2013 10:24:32 -0400 Received-SPF: unknown receiver=logan.com; client-ip=69.89.16.30; envelope-from=jslade@canardaviation.com Received: (qmail 4205 invoked by uid 0); 9 Jul 2013 14:23:54 -0000 Received: from unknown (HELO host296.hostmonster.com) (66.147.240.96) by oproxy13.unifiedlayer.com with SMTP; 9 Jul 2013 14:23:54 -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=NPayLFoLumUJOAx4XteWEPKK4eC/FNvWGTYPYRS2xr4=; b=GwmBYekC1p571wRVbHHSk3G9xbIWoqu94DCJ7tWrQg9fjVDAsptLJxpUAPUjQflERybsrpZSZqhCcg82reAHosxPnIR8NlTjcUkdm4N5UrJVNkRftnobA3eOe1bRziDg; Received: from [75.69.3.204] (port=51664 helo=[192.168.1.108]) by host296.hostmonster.com with esmtpa (Exim 4.80) (envelope-from ) id 1UwYpc-0001fY-Et for flyrotary@lancaironline.net; Tue, 09 Jul 2013 08:23:52 -0600 Message-ID: <51DC1CF3.1040203@canardaviation.com> Date: Tue, 09 Jul 2013 10:23:47 -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="------------020801090403010407010103" 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. --------------020801090403010407010103 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sorry. I meant 44hg. On 7/9/2013 9:36 AM, Scott Emery wrote: > Wow! 44psi seems very high to me. In tethered ground testing I could > only get about 44"Hg. > You do have me thinking about a Blow Off Valve. I didn't want to add > the complexity of waste gates & BOVs but my recent experience was > somewhat predicted on this forum in the past. > A turbo corvair powered RV-3 just went up for sale on the Vansairforce > site due to 3 deadstick landings in a row, caused by prop drive > failure. The intrepid builder did not seem to have sought help from > experienced builders & operators of the type. This forum does a good > job in that regard. > Sent from my iPhone > > On Jul 8, 2013, at 10:06 AM, John Slade > wrote: > >> 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 >> --------------020801090403010407010103 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit
Sorry. I meant 44hg.

On 7/9/2013 9:36 AM, Scott Emery wrote:
Wow! 44psi seems very high to me. In tethered ground testing I could only get about 44"Hg. 
You do have me thinking about a Blow Off Valve. I didn't want to add the complexity of waste gates & BOVs but my recent experience was somewhat predicted on this forum in the past. 
A turbo corvair powered RV-3 just went up for sale on the Vansairforce site due to 3 deadstick landings in a row, caused by prop drive failure. The intrepid builder did not seem to have sought help from experienced builders & operators of the type. This forum does a good job in that regard.
Sent from my iPhone

On Jul 8, 2013, at 10:06 AM, John Slade <jslade@canardaviation.com> wrote:

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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