Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Tue, 19 Apr 2005 08:07:51 -0400 Message-ID: X-Original-Return-Path: Received: from systems3.net ([68.14.236.16] verified) by logan.com (CommuniGate Pro SMTP 4.3c3) with ESMTP-TLS id 882667 for lml@lancaironline.net; Mon, 18 Apr 2005 18:47:53 -0400 Received-SPF: none receiver=logan.com; client-ip=68.14.236.16; envelope-from=cberland@systems3.net Received: from systems0d3b724 ([192.168.1.81]) by systems3.net (8.13.4/8.13.4/Debian-1) with SMTP id j3IMl4QT027640 for ; Mon, 18 Apr 2005 15:47:06 -0700 X-Original-Message-ID: <021f01c54467$85a8ce40$5101a8c0@systems0d3b724> From: "Craig Berland" X-Original-To: "Lancair Mail List" Subject: [LML] Re: supershargers X-Original-Date: Mon, 18 Apr 2005 15:39:39 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_021C_01C5442C.D5087C00" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 X-Virus-Scanned: ClamAV 0.84rc1/839/Mon Apr 18 07:53:43 2005 on systems3.net X-Virus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_021C_01C5442C.D5087C00 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Wish I'd had a dyno for some better data. The B&M book charts for this = engine with my mods showed (estimated) about 380 HP, up from unblown = about 270. Any other comments on engine HP needed to drive a = centrifugal supercharger? T "Terrence, I do not have any 1st hand data...I sent out a feeler to an = old General Motors engineering buddy...I'll let you know if I get any = real data. Craig Berland" Well it wasn't fast, but here is some general info. First, if you are = running high pressure ratios with a roots type supercharger, then the = parasitic losses get very high. With that said, GM is introducing a = "roots type" supercharged V8 with peak HP occurring at 5400 RPM. The = parasitic loss for that engine with a pressure ratio of less than 2 to 1 = is 60 to 85 hp depending on the inlet air temperature. For higher = pressure ratios they would go with a screw type supercharger due to the = increasing parasitic losses. The problem with a screw type in autos is = the losses during part throttle operation. This requires a clutch to = overcome. The benefits for a supercharger over a turbo are response, = packaging and emission converter light off. Packaging could be of = interest to us, the others are not. Another tidbit....if you disconnect = the supercharger belt at 65 mph, the fuel economy goes up 6 mpg. This = vehicle is a 4.5 second 0-60 car. To put parasitic losses, blower size = and pressure ratio in perspective...I was told by the engineer who = designed and built the screw type superchargers for top fuel cars that = 20 years ago it took over 500 hp to spin the roots type blower in a top = fuel car. Not exactly new data but still relevant. Craig Berland ------=_NextPart_000_021C_01C5442C.D5087C00 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Wish I'd had a = dyno for some=20 better data.  The B&M book charts for this engine with my mods = showed=20 (estimated) about 380 HP, up from unblown about 270.  Any other = comments on=20 engine HP needed to drive a centrifugal supercharger? =20 T
"Terrence, I do not have = any 1st hand=20 data...I sent out a feeler to an old General Motors engineering = buddy...I'll let=20 you know if I get any real data. Craig Berland"
 
Well it wasn't fast, but here is some general info. = First, if=20 you are running high pressure ratios with a roots type supercharger, = then the=20 parasitic losses get very high. With that said, GM is introducing a = "roots type"=20 supercharged V8 with peak HP occurring at 5400 RPM. The parasitic loss = for that=20 engine with a pressure ratio of less than 2 to 1 is 60 to 85 hp = depending on the=20 inlet air temperature.  For higher pressure ratios they would go = with a=20 screw type supercharger due to the increasing parasitic losses.  = The=20 problem with a screw type in autos is the losses during = part throttle=20 operation. This requires a clutch to overcome.  The benefits for a=20 supercharger over a turbo are response, packaging and emission = converter light off. Packaging could be of interest to us, the others = are not.=20 Another tidbit....if you disconnect the supercharger belt at 65 mph, the = fuel=20 economy goes up 6 mpg. This vehicle is a 4.5 second 0-60 car. To put = parasitic=20 losses, blower size and pressure ratio in perspective...I was told  = by the=20 engineer who designed and built the screw type superchargers for = top fuel=20 cars that 20 years ago it took over 500 hp to spin the roots type = blower in=20 a top fuel car. Not exactly new data but still relevant.
Craig Berland
 
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