DIY_EFI Digest Monday, 29 January 1996 Volume 01 : Number 025 In this issue: Re: efi555 Re: Engine Reversal and EFI Re: efi555 Finding out Fuel Consumption. Re: Finding out Fuel Consumption. Re: efi555 Re: efi555 See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Bill Lewis Date: Sun, 28 Jan 1996 11:05:08 -0500 Subject: Re: efi555 > Lastly, some questions on the MAF sensor you recommended. I am > not familiar with a Starion, They may not sell the model under > that name here in Canada. (Then again, I don't follow the new > car lines much, I'm a 60's +70's vintage kinda guy). Some details > on what other models, makes, and years used this MAF would be > helpful in a junket to the local boneyard. Will this thing handle > the required airflow for a V8 making 400+ HP? The MAF sensor used on the Chevy 305 and 350 Tuned Port system will probably handle a 400 HP V8 as-is, and its output is a 0 to 5 volt analog signal. It seems like an op-amp or two would let you connect the output of the MAF directly to the 555 control voltage pin. Bill ------------------------------ From: dave.williams@xxx.us (Dave Williams) Date: Sun, 28 Jan 1996 10:03:00 +0000 Subject: Re: Engine Reversal and EFI - -> A marine mechanic I spoke to said the only difference between a CW - -> and a CCW motor was the cam and the starter - makes sense. He also - -> mentioned that the reverse motors usually had a hotter cam since they - -> didn't make as much power as their normal rotation cousins. The distributor drive gear will have to be changed to maintain oil pump direction. We ran into that with an Isky two-gear cam drive on a small block Chevy. For reverse rotation, you'll have to do something about the direction of the water pump rotation. Nowadays it'd be easy to use a serpentine pump on most engines; I don't know how they did it in the old days. Engines with offset piston pins would work okay, though you'd probably want to swap left for right to have both engines the same. Reverse rotation engines were a common question in Smokey Yunick's column in Circle Track. He claimed everything from "not a good idea" to "can't be done", though it's interesting you can actually get reverse rotation Chevys, Fords, and Chryslers from the manufacturer for marine purposes. Yunick also had a problem with the oilway drilling locations "not bring right" for reverse rotation on the small block Chevy. Considering every one of the crank oilways is drilled as non-optimally as possible to start with, reverse rotation ought to be a big help for oiling. For a real high performance application you'd want to take a close look at the intake manifolding and windage tray, but it shouldn't be a big deal. ------------------------------ From: dn Date: Sun, 28 Jan 96 13:08:06 MDT Subject: Re: efi555 George M. Dailey wrote: > I started having the same questions that are circulating around now about > the 555. > If I were still interested in building an EFI control unit from scratch. I > would seriously consider the Basic Stamp microcontroller by Parallax. With > 8 i/o's, you would have a lot more flexibility than the 555. Imagine: I have some reservations about the Basic Stamp type processor. Firstly, with a BASIC interpreter running, you are burning up a lot of processor time just running the interpreter, thus leaving much less for your application. I don't think the thing would be fast enough to get microsecond timing resolution for the injector. Secondly, you will need several analog inputs for things such as temp, MAP, etc, and you would need an A/D converter for this. True, the Basic stamp has some Pseudo analog inputs in the form of R/C timing on some of the pins, which would work for say, temp inputs which are strictly resisitive, but not for MAP. If I was going to design a processor based system, I would use an 68HC11, since it has all the nifty timers, A/D, etc necessary for an electronic engine control (as a matter of fact, that's what the thing was originally designed for...) However, this would entail possibly hundreds of hours of writing code, testing, and debugging. The major advantage of the 555 type system is that it will run just fine with no processor at all... thus your limp-home mode is built right in to the system. You can later add the processor with advanced functions, and debug with impunity, and save a lot of towing bills if it doesn't work first time around. Also, you can add, test, and debug one feature at a time, thus building the sysem into an advanced engine management unit as time and money permits. The hardware approach doesn't bother me, since, as Steve Ciarcia (Circuit Cellar Ink founder) says, "solder is my favorite programming language". I am, however, a reasonable HC11 programmer, but a complete fuel injection system is a major undertaking. GM spends billions on R+D for their systems, with hundreds of programmers and engineers, along with all the necessary toys to test it along the way. I'm talking about spending a few hundred on my daily driver and still being able to drive it to work every day during the development cycle... 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: Gerry Date: Sun, 28 Jan 1996 19:12:48 -0500 Subject: Finding out Fuel Consumption. I dont know if anyone can help me, but Ill give it a shot. I am currently doing a microprocessor project using an 8051. What I am building is a simple Fuel / Trip computer. I have a 1993 Ford Thunderbird with a 5.0H.O. engine. Someone told me = that Pin 34 on the EEC computer relates to how long the fuel injector is = open. This in turn relates to the instantaneous fuel consumption.=20 Does anyone know of how I can find out more about the EEC-IV engine = computer? I know ford is tight lipped about these type of things. Can anyone out there suggest a book that would help me out with this = subject?? Any help would be greatly appreciated. - ---gerry ------------------------------ From: Bruce Bowling Date: Sun, 28 Jan 1996 20:36:09 EST Subject: Re: Finding out Fuel Consumption. ~ ~ ~ ~ I dont know if anyone can help me, but Ill give it a shot. ~ ~ I am currently doing a microprocessor project using an 8051. ~ What I am building is a simple Fuel / Trip computer. ~ ~ I have a 1993 Ford Thunderbird with a 5.0H.O. engine. Someone told me = ~ that Pin 34 on the EEC computer relates to how long the fuel injector is = ~ open. This in turn relates to the instantaneous fuel consumption.=20 ~ Does anyone know of how I can find out more about the EEC-IV engine = ~ computer? I know ford is tight lipped about these type of things. ~ ~ Can anyone out there suggest a book that would help me out with this = ~ subject?? ~ ~ Any help would be greatly appreciated. ~ ~ ---gerry ~ ~ I know that the trip computer on Series III Jaguars tap right off one of the injectors. All it does is keep a running sum of how long the injector is open, and, knowing the Lbs/hr rating of the injector (times the number of cylinders), the computer generates a guess of fuel consumption and mileage (distance is derived from the speedo transducer). - - Bruce - -- - ----------------------------------------------------- <<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> - ----------------------------------------------------- Bruce A. Bowling Staff Scientist - Instrumentation and Controls The Continuous Electron Beam Accelerator Facility 12000 Jefferson Ave - Newport News, VA 23602 (804) 249-7240 bowling@xxx.gov http://devserve.cebaf.gov/~bowling - ----------------------------------------------------- <<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> - ----------------------------------------------------- ------------------------------ From: pjwales@xxx.net (Peter Wales) Date: Sun, 28 Jan 1996 22:55:26 -0500 Subject: Re: efi555 At 11:05 AM 1/28/96 -0500, >Bill wrote: >The MAF sensor used on the Chevy 305 and 350 Tuned Port system will >probably handle a 400 HP V8 as-is, and its output is a 0 to 5 volt >analog signal. It seems like an op-amp or two would let you connect the >output of the MAF directly to the 555 control voltage pin. Bill, you are completely missing the point of this. The idea is that the Mitsubishi MAF measures the airflow and generates a pulse rate. The GM system needs a pulse generator (which is probably going to be engine speed) and then needs to be calibrated for 1 liter to 7 liter engines. The Mitsubishi system is self contained and needs no electronic mods to work on any car. Peter Wales President Superchips Inc Chairman Superchips Ltd "Timing is everything" Superchips home page with all the answers http://www.superchips.com ------------------------------ From: pantera@xxx.com (David Doddek) Date: Mon, 29 Jan 1996 00:09:52 -0600 (CST) Subject: Re: efi555 >Darrell wrote: >The hardware approach doesn't bother me, since, as Steve Ciarcia >(Circuit Cellar Ink founder) says, "solder is my favorite >programming language". I am, however, a reasonable HC11 >programmer, but a complete fuel injection system is a major >undertaking. GM spends billions on R+D for their systems, >with hundreds of programmers and engineers, along with all the >necessary toys to test it along the way. I'm talking about >spending a few hundred on my daily driver and still being able to >drive it to work every day during the development cycle... > >Regards >dn > I would not say that a EFI system using a micro is that hard. When knowing nothing about EFI I designed a system using an 8085 and all descrete hardware timers. This project was done in only one semester in college and worked well. I now work for Caterpillar and like the auto companies, yes it does take a while to develop an EFI system. The moral is the big companies take time to develop a system that is sold to the public and has to be warrantied. When you develop one for yourself there are a lot of areas that you do not have to address, like reducing cost to the abosolute minimum and passing corporate fuel econemy and emissions. My second design of a system was done, hardware and software in two weeks. And it is still on my car. As a matter of fact, I am currently in the process of making it for sale to the public. I have also made a analog system like the one being discussed with the 555. It used op amps and had a map sensor and fired one injection per ignition event. It worked well and it was the basis for the program model for my current micro EFI system. The one problem with an analog system is that there is a large change in volumetric effeciency at low rpm causing a rich mixture at idle in gear (automatic) and lean at low speed cruse (30 mph) However, something like this is not a concern on a race engine that spends a lot of time at wide open throttle. This is probably why the race engine that the gentleman at superchips ran well. An analog system is possible and even possible to add a VE offset by using a couple of a to d converters, an eprom and a d to a converter added into the main voltage signal as an offset. The inputs would be the map or maf signal and the rpm from a frequency to voltage converter and the output would be the data signal from the eprom through the d to a. The rev limiter could even be added by using a comparitor on the analog signal from the freq to voltage converter. You can do almost anything you want if you try hard enough. Just a few silver pieces worth 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/Electromitive Tec-II Twin turbos and Nitros | Hey, If you are going to go fast, go REEEAAL FAST. | ------------------------------ End of DIY_EFI Digest V1 #25 **************************** 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".