DIY_EFI Digest Sunday, 10 March 1996 Volume 01 : Number 072 In this issue: Re: volumetric efficiency Re: Fuel injector optimum location Re: Info on Code or EPROM for 93 16V Eclipse RE: Encoder Re: Copy of: CD Ignition SMPS? Re: CO sensor for Leaded ? Re: CO sensor for Leaded ? See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: matny@xxx.se (Mattias Nyberg) Date: Sat, 9 Mar 1996 14:28:06 +0100 Subject: Re: volumetric efficiency Measuring the real air flow is not easy. The air flow meter is sensitive to swirl turbulent flow. Also the flow in an engine is pulsating. To measure corectly, the air flow meter must have laminar, steady flow, which is never the case in an engine. To overcome the proplem the air flow meter has to be calibrated in the position where it is going to be used. For example, in our lab we have a hot film air mass flow meter, which was sent away for calibration ($150). After the calibration we mounted the MAF in our lab and it measured the air mass flow with an error of about 25%. We concluded this when we got an volumetric efficiency of 1.1 ! Mattias Nyberg ------------------------------ From: CHarris233@xxx.com Date: Sat, 9 Mar 1996 13:05:23 -0500 Subject: Re: Fuel injector optimum location Mike- Placement of the fuel injector always seems to generate a lot of "discussion". Unfortunately, there isn't always an easy answer, even in similar conditions. As an example, I'd like to point out the difference in injector location on two Indy car engines. The Ford-Cosworth variety places the injector low in the port, just above the inlet valve. This should enable more precise distribution between cylinders, though at some loss in fuel evaporation due to the slightly shorter travel. The Mercedes Benz-Ilmor (my job, BTW) places the injectors high above the trumpets. This gives slightly more time for fuel vaporization, but gives slightly less control over where the fuel ends up. In the end, it alls seems to be a toss-up for WOT running. If you run into problems with fuel distribution, moving the injectors downstream tends to help. If you want to try for a *minor* decrease in fuel consumption, move the injector upstream. At low rpms, placing the injector near the inlet valve can still give good fuel vaporization by timing the fuel delivery to strike the valve when closed. At WOT, pulse width and duty cycle conspire to reduce the usefuleness of worrying about when the injector opens. I wish there was a pre-packaged answer to your question. It would make life easier for a lot of us. As all the above tends to lead toward the dreaded cut-and-try method of development, could you consider molding you intake system with two injector locations? The unused locations could be plugged. This would give you the opportunity to try different locations without starting over. Good luck, and let us know how it goes. Charlie Harris ------------------------------ From: Land Shark Date: Sat, 09 Mar 1996 11:18:32 -0700 Subject: Re: Info on Code or EPROM for 93 16V Eclipse At 23:40 3/8/96 -0500, you wrote: >Anyone know where I can get a chip for a 93 16 valve Eclipse? Or possibly >where I can get the source code, and possibly any other mods I can make to >the stock EFI: Thanks in advance! Well, how about starting by reading the STOCK EPROM to a file, and telling me what the processor is (or looks like) and the xtal speed ... You gotta start somewhere :) Jim C. ------------------------------ From: dn Date: Sat, 9 Mar 96 12:22:23 MDT Subject: RE: Encoder Andrew Dalgleish wrote: > Photo reduction isn't that expensive. I've done it by taking a shot with > a 120 camera and using the negative. Most wedding photographers could do > it for you, probably for a few beers. You can't just use ordinary film for this type of work. It's way too grainy and imprecise for precision photo reduction. The film must be an ultra slow very high contrast film, used to be used a lot for printed circuit board artwork and photolithography. Also, to get precise reduction of the artwork, a very expensive and accurate bellows type camera with precision dolly is necessary. You need exactly X:1 reduction if the finished product is going to have the exact line widths and precise, sharp edges you need for an encoder. Just not the type of stuff Weddings'R'Us is going to have lying around. > I've also seen a sticky metalic (so it doesn't stretch) tape with > light/dark bands on it. You just wrap this around a shaft a few times > until the stripes line up. This would be ok for low res (a few pulses per revolution), but it would be nearly impossible to get it synched up exactly with the camshaft position, which you'd need for an engine controller. > That's less than 28 hours at 6000 rpm. Are you sure there isn't another > 1000 in there? When was the last time you saw a Briggs + Stratton doing 6000 RPM? > Sounds a *lot* better than using separate led/phototransistor. Still doesn't beat someone else doing all the hard stuff, + you just go down to your local supplier and pick one up. The pickup is the easy part, the optical disk is the black art... regards dn - -- - --------------------------------------------------------------------- Darrell A. Norquay Internet: dn@xxx.ca Datalog Technology Inc. Bang: calgary!debug!dlogtech!darrell Calgary, Alberta, Canada Voice: +1 (403) 243-2220 Fax: +1 (403) 243-2872 @ + < __/ "Absolutum Obsoletum" - If it works, it's obsolete -------------------------------------------------------------------- ------------------------------ From: Ryan A Erickson Date: Sat, 9 Mar 1996 17:28:39 -0600 (CST) Subject: Re: Copy of: CD Ignition SMPS? On 21 Feb 1996, George J. Murdoch wrote: > From: George J. Murdoch, 100517,2176 > TO: DIY_EFI, INTERNET:coulomb.eng.ohio-state.edu > DATE: 22/02/96 12:45 > > RE: Copy of: CD Ignition SMPS? > > I am interested in building CD ignition for driving 1 H.T. coil per cylinder > using small coils similar to that used on the SAAB 9000 DI 16V engine > I would be interested to know if anyone has any info on building a switch mode > P.S. for the above and any comments on CD ignition in general . > > Thanks > > George. > > > > Go to your local Saab dealer and ask for the Saab Trionic ignition management manual. I bought it about 2 years ago for some research I did for Honeywell on OBDII. It was $50 US at that time. I don't remember the exact name of the manual so you'll need a helpful tech person. It is written for Saab technicians. later, Ryan ------------------------------ From: MTaylorfi@xxx.com Date: Sat, 9 Mar 1996 21:12:22 -0500 Subject: Re: CO sensor for Leaded ? Measure your exhaust gas temp... See ya, Mike ------------------------------ From: arthurok@xxx.com (ARTHUR OKUN ) Date: Sat, 9 Mar 1996 22:29:05 -0800 Subject: Re: CO sensor for Leaded ? You wrote: > >Measure your exhaust gas temp... > >See ya, > >Mike > i dont think it's an equilivent measurement; . egt s are common on light aircraft for setting mixture but they dont have to pass emmission tests"yet" ie peak egt- 25 to 50 deg rich for power lean to peak for economy thats what my instructor told me and never lean below 3000 ft or at maximum power only at cruise. ------------------------------ End of DIY_EFI Digest V1 #72 **************************** 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".