DIY_EFI Digest Sunday, 4 February 1996 Volume 01 : Number 031 In this issue: Still more Questions .... Re: Still more Questions .... RE: Still more Questions .... See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: marchil@xxx.net Date: Sat, 03 Feb 96 11:36:38 Subject: Still more Questions .... I have more question on MAF sensors The MAF on OEM's is always plaed very fare from the throtle body by doing this we have to reaslise that we have the intake + the air hose that act as a resevoir after the metered air has passed the MAF, would it not be better placed as close as posible to the intake ??? And also why not just put it after the T-Body and calculate the real air density, since usulay wy have coulant heating the the T-Body. And just to srew things around on super/torbo charged engins the T-Body is after the compressor by placing it there we have to add a bypass valve on the intaketo reduce the chance of over boost when the trotle plates close sudenly. By putting the T-Body beafore the compressor we do not nead the bypass valve but the compressor must have sealedbearing shafts to keep from sucking the oil from them when the intake is at a vacum, Would there be any other ploblems ???? //---------------------------------------------------------------------------- // Marchil@xxx.NET // Alain Marchildon // 1271 Bernard West // Outremont, Quebec Canada // H2V 1V8 ------------------------------ From: pjwales@xxx.net (Peter Wales) Date: Sat, 03 Feb 1996 22:27:17 -0500 Subject: Re: Still more Questions .... At 11:36 AM 2/3/96, diy_efi@xxx.edu wrote: >I have more question on MAF sensors > >The MAF on OEM's is always plaed very fare from the throtle body by doing this we have to >reaslise that we have the intake + the air hose that act as a resevoir after the metered >air has passed the MAF, would it not be better placed as close as posible to the intake >??? >And also why not just put it after the T-Body and calculate the real air density, since >usulay wy have coulant heating the the T-Body. > >And just to srew things around on super/torbo charged engins the T-Body is after the >compressor by placing it there we have to add a bypass valve on the intaketo reduce the >chance of over boost when the trotle plates close sudenly. >By putting the T-Body beafore the compressor we do not nead the bypass valve but the >compressor must have sealedbearing shafts to keep from sucking the oil from them when the >intake is at a vacum, Would there be any other ploblems ???? > > >//---------------------------------------------------------------------------- >// Marchil@xxx.NET >// Alain Marchildon >// 1271 Bernard West >// Outremont, Quebec Canada >// H2V 1V8 > > Do they have spell checkers up there? Peter Wales President Superchips Inc Chairman Superchips Ltd "Timing is everything" Superchips home page with all the answers http://www.superchips.com ------------------------------ From: "Clinton L. Corbin" Date: Sat, 3 Feb 96 19:31:47 PST Subject: RE: Still more Questions .... >I have more question on MAF sensors > >The MAF on OEM's is always placed very fare from the throtle body by doing >this we have to realiase that we have the intake + the air hose that act as >a resevoir after the metered air has passed the MAF, would it not be better >placed as close as posible to the intake ??? And also why not just put it >after the T-Body and calculate the real air density, since usually we have >coulant heating the the T-Body. One of the Mustang magagazines did a bit of hopping up on a 95 Mustang GT. They added a Paxten type supercharger (exactly like a Turbo on the compressor side, only driven from the crankshaft instead of the exhaust). After the hop-up, the car had a very rough idle and just didn't run as smoothly as it did before. They played with the fuel pressure (to richen the mixture), but nothing really helped. Until they moved the MAF sensor back to were it originally was (about 30cm infront of the throttle body). With the kit they had used, the MAF was placed infront of the supercharger. This was almost two meters (about six feet for the U.S.A.!) from the throttle body. After they changed it back, the motor ran great (and made serious HP due to the blower!). >And just to screw things around on super/turbo charged engins the T-Body is >after the compressor by placing it there we have to add a bypass valve on >the intaketo reduce the chance of over boost when the trotle plates close >sudenly. By putting the T-Body beafore the compressor we do not nead the >bypass valve but the compressor must have sealedbearing shafts to keep from >sucking the oil from them when the intake is at a vacum, Would there be any >other ploblems ???? > >//-------------------------------------------------------------------------- >// Marchil@xxx.NET >// Alain Marchildon >// 1271 Bernard West >// Outremont, Quebec Canada >// H2V 1V8 Basically, a little bit of air storage after the MAF doesn't hurt drivablitly. A lot does. Due to resonant frequencies, it would also appear that a small diameter, but long, tube would be worse that a large diameter, but short, one. The reason being the resonant frequencies of the long, thin tube being lower than for the short, large diameter tube. Need more experimentation on this. Clint ccorbin@xxx.com ------------------------------ End of DIY_EFI Digest V1 #31 **************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".