Return-Path: Received: from [65.33.163.227] (account marv@lancaironline.net) by logan.com (CommuniGate Pro WebUser 4.3c3) with HTTP id 811653 for lml@lancaironline.net; Sat, 19 Mar 2005 14:22:24 -0500 From: "Marvin Kaye" Subject: Re: [LML] Re: superchargers To: lml X-Mailer: CommuniGate Pro WebUser Interface v.4.3c3 Date: Sat, 19 Mar 2005 14:22:24 -0500 Message-ID: In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format="flowed" Content-Transfer-Encoding: 8bit Posted for "George Braly" : Rob, Nice analysis. But there is a lot more to it. I’m in the middle of teaching an APS weekend class and have the FAA coming by for a visit, so I am not going to try to re-run the numbers. But you might try to go back and re-do the numbers and consider some of the following. 1) The centrifugal compressor efficiency will not likely be anywhere near 80%. Many are as poor as 55 to 65% unless you happen to be at just the right mass flow and the right RPM. 2) The belt drive has a significant penalty in lost horsepower. 3) The gear drive in the compressor has another significant drop in efficiency. 4) To get the air temperature back down to tolerable (detonation margins) ranges requires an intercooler 5) The losses across the intercooler and through the induction plumbing to accommodate the twists and turns to make the intercooler fit in the system extract a substantial further penalty requiring still more boost - - but at the penalty of all of the efficiencies noted in 1-3, above. And consider the engine I was referring to was a 400 hp engine, not a 300 hp. Regards, George