X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from omr-m10.mx.aol.com ([64.12.143.86] verified) by logan.com (CommuniGate Pro SMTP 6.0.5) with ESMTPS id 6365892 for flyrotary@lancaironline.net; Tue, 09 Jul 2013 09:36:50 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.143.86; envelope-from=shipchief@aol.com Received: from mtaout-mb01.r1000.mx.aol.com (mtaout-mb01.r1000.mx.aol.com [172.29.41.65]) by omr-m10.mx.aol.com (Outbound Mail Relay) with ESMTP id B0DEB700BAF74 for ; Tue, 9 Jul 2013 09:36:14 -0400 (EDT) Received: from [10.244.185.36] (227.sub-174-233-194.myvzw.com [174.233.194.227]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by mtaout-mb01.r1000.mx.aol.com (MUA/Third Party Client Interface) with ESMTPSA id 407EFE0000EC for ; Tue, 9 Jul 2013 09:36:13 -0400 (EDT) Subject: Re: [FlyRotary] Re: Turbo boost indication References: From: Scott Emery Content-Type: multipart/alternative; boundary=Apple-Mail-3--67221685 X-Mailer: iPhone Mail (8E600) In-Reply-To: Message-Id: <4B43E55E-5294-4780-8810-EA0565617F85@aol.com> Date: Tue, 9 Jul 2013 06:36:05 -0700 To: Rotary motors in aircraft Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (iPhone Mail 8E600) x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20121107; t=1373376974; bh=MxHMZLsFyxljtV1UOUwMvjTl4ytr5hr8/wsjUkHZrWc=; h=From:To:Subject:Message-Id:Date:Mime-Version:Content-Type; b=t3nEl/xCIGI2vXIUHsHGhs/PFKyTH8LiYgIJMT7LAelojNQb2g6jE6Q9B1iGfZJYm aT2RJ6FZzqjHpSjLHZ3tVofd+jXcBhQjLgQbXi9gp8FSD3hQSX34IDxl7uU4VXqZA1 264PqewX9Gx5miOStq8BWRdrbLiKSwPe/Mc0pkpc= X-AOL-SCOLL-SCORE: 0:2:446645248:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d294151dc11cb14e1 X-AOL-IP: 174.233.194.227 --Apple-Mail-3--67221685 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Wow! 44psi seems very high to me. In tethered ground testing I could only ge= t about 44"Hg.=20 You do have me thinking about a Blow Off Valve. I didn't want to add the com= plexity of waste gates & BOVs but my recent experience was somewhat predicte= d on this forum in the past.=20 A turbo corvair powered RV-3 just went up for sale on the Vansairforce site d= ue to 3 deadstick landings in a row, caused by prop drive failure. The intre= pid builder did not seem to have sought help from experienced builders & ope= rators 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 >=20 >=20 > On 7/8/2013 11:23 AM, Scott Emery wrote: >> Last night (from epay) I bought a manifold pressure gauge for a twin Cess= na. The two needles are labelled Front & Rear. It's marked 10 to 50 inches o= f mercury absolute. I intend to use it to read turbo boost before the thrott= le body, and manifold pressure after the throttle body.=20 >> I'm having a hard time finding an intercooler that fits the available spa= ce plus has a usable configuration of inlet/outlet tubes. The stock rx7 inte= rcooler I have in hand seems the best so far, but it's a bit small compared t= o aftermarket offerings. >>=20 >> Sent from my iPhone >>=20 >> On Jul 7, 2013, at 2:17 PM, Scott Emery wrote: >>=20 >>> I'm thinking my "Blown Engine" experience might be avoidable in the futu= re 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 a= dd an intercooler.=20 >>> In that order. >>> I got an engine hoist yesterday so now I can put the repaired engine bac= k on. Getting it off didn't require as much precision... >>> After I get some experience, I'll try different grades of mogas @ define= d manifold pressure limits. >>>=20 >>> Sent from my iPhone >>>=20 >>> On Jul 6, 2013, at 12:36 PM, David Leonard wrote: >>>=20 >>>> OK, so the more accurate conversion is=20 >>>> 20psi=3D40.7 in Hg >>>> so in your example >>>> 20psi boost =3D 70.6 in MAP (Manifold Absolute Pressure) >>>>=20 >>>> It help in your article, turbos work as a boost ratio. So this turbo i= t then making a boost ratio of: >>>> 70.6 / 29.9 =3D 2.36 >>>>=20 >>>> So as you go up in altitude you multiply the ambient pressure by 2.36 >>>>=20 >>>> So at 17,500 ft the pressure is half, and so is the MAP, or, 35.3 " MAP= >>>>=20 >>>> Losses are not porportunately reduced, and the turbo may be less effici= ent in that range so actual MAP may be less. >>>>=20 >>>>=20 >>>>=20 >>>>=20 >>>> On Sat, Jul 6, 2013 at 11:57 AM, Patrick Panzera wrote: >>>> I'm editing an article about a bone stock, turbocharged direct injectio= n car engine that boasts 20 lbs of boost.=20 >>>>=20 >>>> I want to convert that to MP so us airplane junkies can wrap our heads a= round it. >>>>=20 >>>> Thanks! >>>>=20 >>>> Pat=20 >>>>=20 >>>>=20 >>>> On Sat, Jul 6, 2013 at 11:44 AM, David Leonard wr= ote: >>>> 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. >>>>=20 >>>> I keep my plane less that 45 inches MP. You have to be more rich and s= killed than me to go higher without detonation. >>>>=20 >>>>=20 >>>> On Sat, Jul 6, 2013 at 11:14 AM, Patrick Panzera wrote: >>>> Friends, >>>>=20 >>>> Hypothetical question.=20 >>>> 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 automob= ile turbo boost gauge, along with my traditional manifold pressure gauge. >>>>=20 >>>> I ground-run the engine to full throttle (where the MP would normally b= e reading 29.92- minus some efficiency loss) and the boost gauge is reading 2= 0 psi. >>>>=20 >>>> What should the MP indicator be reading? >>>>=20 >>>> Thanks! >>>>=20 >>>> Pat >>>>=20 >>>>=20 >>>>=20 >>>>=20 >>>> --=20 >>>> David Leonard >>>>=20 >>>> Turbo Rotary RV-6 N4VY >>>> http://N4VY.RotaryRoster.net >>>> http://RotaryRoster.net >>>>=20 >>>>=20 >>>>=20 >>>>=20 >>>> --=20 >>>> David Leonard >>>>=20 >>>> Turbo Rotary RV-6 N4VY >>>> http://N4VY.RotaryRoster.net >>>> http://RotaryRoster.net >>>=20 >>=20 >=20 --Apple-Mail-3--67221685 Content-Transfer-Encoding: 7bit Content-Type: text/html; charset=utf-8
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

--Apple-Mail-3--67221685--