DIY_EFI Digest Tuesday, September 14 1999 Volume 04 : Number 523 In this issue: Bailey AFM-1 wide band O2 system for tuning (SpeedBrain) Re: Low impedance waste spark coils? Re: Vapor Pressure of Water Re: Vapour Pressure Perpetual motion machines See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Mon, 13 Sep 1999 13:49:21 -0600 From: Scott Beltz Subject: Bailey AFM-1 wide band O2 system for tuning (SpeedBrain) Sorry for the cross post but I need input from anyone who has experience with wide band 02 systems especially the Bailey AFM-1. I am thinking about buying one because here in Denver the Dyno shops do not have a wide band systems. They only use the dynos to check for horsepower improvements. I have recently purchased a Speedbrain to fine tune my supercharged 5.8 SN95. I have been using Chris Johnson's chips for awhile but wanted more control of the system without having to re-burn and change chips. I have heard that there are some private individuals here in Denver that have wide bands for tuning there own cars but have not been able to talk with them yet. My question is with the quality of the Bailey AFM-1. This product is selling for about $1100 while the Lambda Meter and others are over $5000. Some information on the Bailey can be found on APE's WEB site. If anyone has experience with these Wide band systems please let me know what your thought are. I do not want to spend $5000+ for a system that with be used for my private use but also do not want to spend $1100 for a POS. Any help will be appreciated, Thanks Scott Beltz ------------------------------ Date: Mon, 13 Sep 1999 13:55:22 -0700 From: "John Dammeyer" Subject: Re: Low impedance waste spark coils? >From: "Clay Buccellato (Anthony)" >Subject: Low impedance waste spark coils? >As far as I can tell, the only coil packs currently available are the >factory units from Ford and Chevy. I've been told that they suffer from >insulation breakdown on the secondary side, if you try and drive them >very hard. I'm looking for the waste-spark equivalent of the Crane >PS-92, or MSD pro-power. I want lightning bolts :) We're currently using the Ford units for aircraft applications and haven't yet had problem that we are aware of. Where did you hear that the insulation breaks down on the secondary side? I'm currently dumping a 1.5uFd Cap sitting at 225V into it through a triac. Works great. Regards, John ------------------------------ Date: Mon, 13 Sep 1999 17:45:46 EDT From: A70Duster@xxx.com Subject: Re: Vapor Pressure of Water << Does anyone have the formulae for Vapor Pressure? If I assume RH is 75% and can measure the Air Temperature inside the intake manifold what is the calculation for vp? >> I feel I have a good contribution for this one. >From steam tables, I calculated a forth order polynomial fitted curve for the pressures of saturated water vapor between 40 °F and 100 °F at 14.7 PSI. Partial Pressure of Water Vapor = (0.0672 - 0.0022175 * TEMP + 1.1065E-04 * TEMP ^ 2 - 8.7841E-07 * TEMP ^ 3 + 8.7671E-09 * TEMP ^ 4) To find the partial pressure (in PSI) of water vapor with known relative humidity, put in the temperature (°F) and multiply by the relative humidity value. Vapor pressure of water (below 100 °F) should never be over 1 PSI at STP. I have an executable program that determines relative humidity and oxygen to water ratio. The user needs to input a dry bulb temperature, wet bulb temperature, and atmospheric pressure. If interested, please email me back. ------------------------------ Date: Tue, 14 Sep 1999 11:55:50 +1000 From: Stuart Baly Subject: Re: Vapour Pressure >Date: Sat, 11 Sep 1999 07:40:49 -0600 >From: bearbvd@xxx.net (Greg Hermann) >Subject: Re: DIY_EFI Digest V4 #518 > >>Date: Fri, 10 Sep 1999 15:24:29 -0700 >>From: "John Dammeyer" >>Subject: Vapour Pressure >> >>Hi All, >> >>Does anyone have the formulae for Vapor Pressure? If I assume RH is 75% >>and can >>measure the Air Temperature inside the intake manifold what is the calculation >>for vp? >> >>Thanks, >> >>John > >You need some combination of psychrometric charts or GOOD steam tables. A >good steam table will include a section giving the equations upon which the >values stated in the tables are based. > >If RH is 75%, the VP will be 75% of the VP (partial pressure of H2O vapor) >at saturated conditions for that temp. > >Greg > John, To calculate the saturation vapor pressure, you need the Goff-Gratch formula, which is: log10(Ew)= -7.90298(Ts/T-1) + 5.02808*log10(Ts/T) - 1.3816*10^-7*(10^(11.334(1-T/Ts))-1) + 8.1328*(10^(-3.49149(Ts/T-1))-1) + log10(Ews) where Ew = saturation vapor pressure in millibar T = abs. temp. (in K) Ts = steam point temp (=373.16K) Ews = saturation pressure of water @xxx.246 millibar) There's a handwritten correction to this formula in my reference book - 8.1328 has been marked as 'should be 0.0081328'. To check this, you should get the following results T (C) pressure (mb) 10 12.272 15 17.044 20 23.373 This was from the Smithsonian Meteorological Tables, 1951 edition. Relative humidity = Vapor Pressure/Saturation Vapor Pressure I take it 75% RH refers to ambient conditions - the RH will change drastically as the air passes through the throttle body. There's a whole mess of if, buts and empirical corrections in this area of meteorology. You'll probably need to get a hold of a good reference and check it out. Cheers, Stuart Baly. 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M`````````!X`0X (( 8``````, ```````!&`````#B%```!`````0`````` <```>`#T``0````$``````````P`--/TW```::P`` ` end ------------------------------ Date: Tue, 14 Sep 1999 09:44:49 +0200 From: Nic van der Walt Subject: Perpetual motion machines >conversion to energy of another variety the problem remains with >exactly where the low energy state is to be found. If within the >rotating >machine there is a zone of infinite negative pressure or lower temp >the "flow" will be unidirectional. A perfect perpetual motion machine. Simple... All you need is a micro black hole and a way to control it! I think Heinlein described it in the fifties, so they can't even patent it. N. ;-) ------------------------------ End of DIY_EFI Digest V4 #523 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. 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