DIY_EFI Digest Thursday, 22 August 1996 Volume 01 : Number 240 In this issue: Re: EFI musings Re: linear EFI Cylinder Select See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: pantera@xxx.com (David Doddek) Date: Wed, 21 Aug 1996 22:17:33 -0500 Subject: Re: EFI musings >But, in one page or less, what do you need and why not carbs? > >-- >Ed Hernandez >Ford Motor Company >ehernan3@xxx.com > > In one sentence. With a single microcontroller chip ecm, I replaced the 2Barrel carb on a warmed over 69 302 in a Fairlane with a 2 barrel throttle body, I eleminated an anoying throttle lag and flat spot at part throttle, increased gas mileage from 13 to 16 mpg, and increased 0 to 60 from 8.5 to 8 seconds. Yes, I know that I could of bolted on a eddlebrock performer RPM intake and carb, but would it start and idle easily at 10 below 0F!! And it sure is easy to drive and throttle response is increadable. Well that was three sentences, but? David J. Doddek |pantera@xxx.com Owner SGD Electronics & Development Engr for Caterpillar |h 309 685-7965 Formula SAE Team Sidewinder 94-95 |w 309 578-2931 89 T-bird SC, 69 Fairlane w/SGD EFI |fx 217 428-4686 74 Pantera w/Electromotive Tec-II Twin turbos and Nitros | Hey, If you are going to go fast, go REEEAAL FAST. | ------------------------------ From: Darrell Norquay Date: Wed, 21 Aug 1996 22:27:51 -0700 (PDT) Subject: Re: linear EFI At 09:33 AM 8/21/96 -0500, Tom Cloud wrote: >To answer your question, yes, I have such a system. It is the >Holley aftermarket EFI. Here's my $0.02 ($0.015 CDN) worth on the subject, then I'll shut up. The basic Holley system is analog / digital, but no uP chip. As I said, essentially an electronic carburetor. Nothing wrong with this, but not as adaptable as a full blown EFI. Sufficient for most applications, and definitely easier to tune and just as reliable as a carburetor. >I work with an engineer who designed an EFI for racing jet skis >using hybrid analog / digital >He has supported me in thinking that, unless trying to achieve zero >emissions, simplicity (i.e. no micro-controller) is the best. Who says you can't have a simple microcontroller system? This guy sounds like an old school type, knowledgeable about analog but scared of microprocessors. In fact, digital systems can be (and most of the time, are) less complex (hardware wise) than analog systems. Imagine trying to build a completely analog soundblaster card... >I observe that analog, though the building block everything else >is built upon, is not being taught our new engineers. I guess Here, I agree. Unfortunate, but true. >Like most, I love the 'neatness' of digital, but I've learned >from hard knocks that sometimes a relay is preferable to an >SSR (solid state relay) and digital is not necessarily all it's >cracked up to be. To all things, their application... Digital works best for digital type things, and analog works best for analog type things, and microprocessors do both pretty well. Remember, simple analog circuits can only do one simple thing, while simple microcontrollers can do many amazing things. >Analog can be unstable (temp and oscillation), but digital has >sampling, aliasing, etc. errors and loss of resolution in conversion >to and from digital. (Besides if it's too cold or hot for an analog >system, this old boy's staying inside!) Analog electronics' cost, complexity, difficulty of calibration, etc. increase almost exponentially with increasing the amount and type of things that it has to do. Every time you want to change the operation of some circuit 'cause it doesn't do what you expected, you have to drag out the soldering iron and rewire the damn thing. With microprocessors, you basically can design the hardware with enough or excess capability for what you want to do, and it's carved. From then on, changing anything is simply a matter of rewriting a little code. You can rip it all out and start over with a minimum of fuss. You can reinvent it a thousand times at minimal cost. You can use the same hardware for many different applications, by using modular CPU and I/O sections. >The cost of doing a micro- >controller system can be overwhelming, unless you have all the stuff >at work. One needs a computer, assemblers, dis-assemblers, high speed >oscilloscopes, maybe logic analyzers and ICE's, logic probes, and >lots and lots of printer paper. (Programmers get rusty zippers and >yellow sneakers, I hear -- just gotta compile one more time.) Not true. There are lots of developement systems for just about any microcontroller flavor, for under $100, including software. Lots more are available for under $300, with more features and better software. Lots of free, shareware, or low cost software is also out there. Up until a few months ago, I did all my development with freeware tools and a serial port. I did get an ICE, but only because it saves a little time, which is necessary in the professional environment, but not for the hobbyist. I still prefer my $50 assembler to the $1000+ professional tools that I have at work, except for the most complex of jobs. >One can do the analog design with a 20 MHz scope, a triple output >power supply, and a proto board. Of course, a copy of Electronic >Workbench or such to do a computer simulation would be helpful. Hmmm, using a computer to design an analog system... Ironic, wouldn't you say? >An advantage of the digital: it can do data logging and can even >be taught to 'learn' standard system conditions, thereby sort of >self calibrating or adjusting itself -- but this becomes a serious >programming effort. Been there, done that! I'm getting old enough >where I'd like to use it in this life. Think of it as a hobby. Get a basic system working and tweek it or add to it as necessary afterwards. I agree, the self learning and adaptive algorithms are tough, and probably aren't worth it for the DIY'er. >The digital system could be wire wrapped. The analog system >could be soldered. Else one would need to lay out a PCB and get >it etched, drilled and plated. I've found that a PCB is absolutely necessary for analog circuits. Think about the cost of several iterations of pcb's before you get it right... >help but believe that the simple hybrid or pure analog path is 98% as >effective as the pure digital with probably 10% the development time >and cost! Possibly the former, but definitely not the latter. Have you checked out the cost of good analog chips lately? An instrumentation amp costs $8, while I can get a micro for $2. I design both analog and microprocessor systems for a living, and believe me, the hair pulling, nailbiting, [expletive deleted] problems that you end up with in analog circuits sometimes are a real pain. The same can be said for programming, of course, but IMHO it's easier + faster in the long run. regards dn dnorquay@xxx.com ------------------------------ From: peter paul fenske Date: Wed, 21 Aug 1996 21:40:29 -0700 Subject: Cylinder Select Hi Folks Just to update you all. Finally got my test L98 running on a test stand in my garage. After three tries managed to find the Vats disable bit. So starts up without using Sig generator at 30 Hz(tnx). Fyi the GM eprom in the 730 Calpak reprograms well. The only reason for a zif socket is rapid change of parameters for testing. Now to a problem. The calpak I used is from a V6. The one error I am getting is a cylinder select error. Unlike the earlier P4 the 165 ECM there doesn't appear to be an external Cylinder select jumper. So it must be in the Calpak. I am wondering if anyone has info on which pins to change in the resistor pak. Not a great hassle. Just have to dig up a V8 calpak. Well tnx everybody GL: peter ------------------------------ End of DIY_EFI Digest V1 #240 ***************************** 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".