DIY_EFI Digest Saturday, 17 August 1996 Volume 01 : Number 233 In this issue: Re: 80552, Air core meter Truck parts Dynamometer. Re: Heads Up Display Re: CD Ignition re: speaking of displays & DPM re: Leaded Fuel and Lambda Sensors Re: Electric vehicle Re: Electric vehicle Re: Electric vehicle Re: hego Re: My DIY EFI Re: Electric vehicle Re: CD Ignition Re: Setting Mixture with Nitrous Re: CD Ignition Re: My DIY EFI Re: 80552, Air core meter Re: Truck parts Dynamometer. Re: Electric vehicle , wrong list for this discussion, but I must Re: Electric vehicle Re: Setting Mixture with Nitrous Re: Truck parts Dynamometer. Re: Truck parts Dynamometer. Re: CD Ignition Re: My DIY EFI Re: CD Ignition See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Kalle Pihlajasaari Date: Fri, 16 Aug 1996 13:10:41 +0200 (sat) Subject: Re: 80552, Air core meter Hi, > In an old Philips 8051 databook I have, it describes a meter movement > called an air core meter - two coils are fixed at right angles to each > other, and a permanent magnet moves the needle. To move the needle to a > desired angle, the coil currents are set so that one coil current is > proportional to the sine of the required angle, and the other is the > cosine. The big question is, are there any cars available in Australia (or > more to the point, in Australian wrecking yards) which use this movement? > It looks like a fun thing to play with. I think the Peugeot 305 petrol gague was of this type, used to compensate for obattery voltage changes as the one coil has Bbat and the other has a current limited version throug the sender unit. Cheers - -- Kalle Pihlajasaari kalle@xxx.za Interface Products Box 15775, Doornfontein, 2028, South Africa +27 (11) 402-7750 Fax: +27 (11) 402-7751 ------------------------------ From: einarp@xxx.no (einarp) Date: Fri, 16 Aug 96 13:40:34 CET Subject: Truck parts Dynamometer. >Other stupid ideas...... >Build a back yard dyno out of a truck axle..... Not so stupid... Know what a Telma is? It's an electromagnetic brake system used on trucks & buses. They are normally mounted inline with the propeller shaft. If you've noticed the bus driver activate braking through a multiposition stalk near the steering wheel, that's the control stick. They should be fairly easy to find at appropriate breakers yards. The nice thing about them is that the braking effect is current controlled. So they should need only (very) high current drivers to be directly controlled from a micro. They are also small and light in proportion to their braking effect. Einar - -- einarp@xxx.no ( Maserati Biturbo Spyder ) ------------------------------ From: Alexander.M.Lichstein@xxx. Lichstein) Date: 16 Aug 96 08:33:41 EDT Subject: Re: Heads Up Display Head's up Displays use a complex set of optics to get the focal point of the image to appear at the end of the hood or beyond. Trying to build one is not for the weak minded. They are certinly NOT monitors reflected off the windscreen. Aircraft HUD's have the ability to project images at programmable distances. I have seen the former and it's REAL complex... I'll never see the latter. - - Z ------------------------------ From: Terry Sare Date: 16 Aug 96 08:37 CDT Subject: Re: CD Ignition There have been several articles on building your own in Radio Electronics, Electronics Today (I think that is the name -- its English). That is all I can remember off the top of my head, I am at work. The basic theory is simple, take 12VDC and chop it into pulses, feed it into a step-up transformer, rectify it, and charge a 0.1uF cap. To trigger, use a SCR in series with a coil primary. Then the SCR is triggered by the points, whatever, then the cap dumps it charge into the coil, about 300 volts or so. Also, MSD has a system that does multple sparks using a cap. system. There are a lot of practical consideration that I skipped. If you need the articles referenced I can try to look them up this weekend and post them. I tried building one in 81 but it didn't work very well, course I really didn't have a clue back then but that is another story. Terry Sare EMAIL: Terry_Sare@xxx.com ______________________________ Reply Separator _________________________________ Subject: CD Ignition Author: owner-diy_efi-outgoing@xxx.edu at dell_unix Date: 8/15/96 1:55 PM Hi, Has anyone have an article on the theory or even a schematic of a Capacitive Discharge Ignition. In particular are they just stepping up battery voltage to about 300V and then switching that with a shorter dwell time or is there more to it? Got to be able to crank my Briggs&Stratton Lawnmower engine down to -40 degrees you know and at that temperature the batter is much less efficient. Thanks, John. Pioneers are the ones, face down in the mud, with arrows in their backs. Automation Artisans Inc. Ph. 604-544-4950 6468 Loganberry Place Fax 604-544-4954 Victoria BC CANADA V8Z 7E6 ------------------------------ From: SRavet@xxx.com Date: Fri, 16 Aug 96 9:43:34 CDT Subject: re: speaking of displays & DPM "George M. Dailey" Wrote: | | At 10:37 AM 8/1/96 -0500, you wrote: | >>> A simple and effective indicator for O2 sensor is a DPM (digital | >>> panel meter) from Hosfelt Electronics. It is $14.95, their part | >>> number 39-165 (the part no. on the data says PM-128). It uses an | >>> Intersil ICL7106 DMM chip with a fairly standard wiring. There is | >>> one problem -- they have connected the supply voltage common with | >>> the input common, which can cause ground loop problems | | I'd like to install a heads up display in a car. Several years ago I | disected a LCD display and noticed that the silver background could be | easily removed. To my surprise, the LCD was clear. Could a lap top | computer LCD be used as a heads up display with the silver background | removed? Does any company market such a device? | | Thanks, GMD | | Some cars have HUDs right now. Pontiac Bonneville comes to mind. It has some sort of display (vacuum fluorescent?) embedded flat in the top of the dash, so that it reflects off the windshield and you can see it. It might be hard to mount a laptop LCD in the appropriate place with the raked windshields that most cars have. HUD=heads up display Steve Ravet sravet@xxx.com Baby you're a genius when it comes to cooking up some chili sauce... ------------------------------ From: Matthew Lamari Date: Fri, 16 Aug 1996 11:15:19 -0500 Subject: re: Leaded Fuel and Lambda Sensors > >Valve seat recession is a long term problem, and it certainly doesn't >preclude the use of ULP in pre-ULP engines. It depends on what you >want to acheive. > > What I meant was lubrication, the lead is added to be a lubricant. Bad things are said to happen without it. I didn't know that they dropped Leaded below 96. Guess I've been too far away from home too long. Matt. ------------------------------ From: Todd Knighton Date: Fri, 16 Aug 1996 09:26:49 -0700 Subject: Re: Electric vehicle > > Consider this, 4 off the shelf electric motors. Ridgidly mounted to chassis > > and connected to the wheel via cv joints. No, No, No, you're not getting it. We're trying to eliminate all the possible losses that electric vehicles incur, thus more efficient, thus less battery power required. That's why the motors in the wheel hubs. That way no frictional loss through bearings, nor through CV's which are horrible. > > A battery pack per current electric vehicle standards, and one off the shelf small > > gas engine DC generators. No again, the turbine motor can be made to run at constant rpm and a much higher efficiency that any off the shelf Gas Generator. Remember, we're trying to make something that will work, not practical maybe, but if it does work, high volume manufacturing can make it practical. > > I think you know where I'm going. Generator is sized to propell > > the car at 55mph, stand alone. Generator and battery pack combined might > > give you 0-60 in 3 seconds. Of course, all of this would require > > micro-processor control. Ok experts, what are the real world physical limits? > > Not with a small gas generator you're not going to make it to 0-60 in 3 seconds. Specially with many tons of batteries on board. Todd Knighton Protomototive Engineering ------------------------------ From: Todd Knighton Date: Fri, 16 Aug 1996 09:34:05 -0700 Subject: Re: Electric vehicle > I can speak from experience with electric vehicles. I was the > electrical man for TWO solar electric vehicles for Mankato State Univ, > in MN for Sunrayce '93 and Sunrayce '95 respectively. Battery > technology sucks. So does Solar power. Yes, the best electric holding cells I've seen hold about 10% less energy per unit mass than fuel. > Sure electric is very clean, but > performance is terrible. Well, let's work on that. > In each instance follow the path that the power has to change states. > Remember NOTHING is 100% efficient. Even if the motor and generator > were made form superconducting wire, there is resistance from the > contact points and very very very small ohmic resistance in the wire. > Even just using a belt or chain drive loses about 1-5% due to friction > in the chain or belt. We will eventually have to use someithing other > than fossil fuels, but the technology has to come a long way. We still > have a lot to do with gas engines. With all the refinements made to > engines we only get about twice the gas mileage as compared to a Model A > FORD. That's why the wheel hub Idea. No frictional losses. Kind of like the mag lev trains. where are those things getting their power from, the tracks or the train? > > I don' mean at all to shoot your idea down, I think it is great that > someone else is interested in doing something innovative, these are just > some of my experiences and the hurdles to overcome. > > Any other thoughts?? -Ryan Unfortuately this is the path the government is going to force us to take. Regardless of what we think. They've already implemented all the zero emmissions laws and are trending that way. So rather than fight like we usually do, let's beat them to they're act and blow they're doors off with something that WILL COMPLY as well as be as fun and powerful as some of the stuff we're playing with now. Todd Knighton Protomotive Engineering ------------------------------ From: Digital Boy Date: Fri, 16 Aug 1996 11:14:11 -0700 Subject: Re: Electric vehicle At 09:26 AM 8/16/96 -0700, you wrote: >> > Consider this, 4 off the shelf electric motors. Ridgidly mounted to chassis >> > and connected to the wheel via cv joints. > > No, No, No, you're not getting it. We're trying to eliminate all the >possible losses that electric vehicles incur, thus more efficient, thus >less battery power required. That's why the motors in the wheel hubs. >That way no frictional loss through bearings, nor through CV's which are >horrible. Take a look at the Dodge Intrepid ESX proto HEV. They have 250HP Zytec (Zytek?) electric motors mounted where the brakes would be. >> > A battery pack per current electric vehicle standards, and one off the shelf small >> > gas engine DC generators. > > No again, the turbine motor can be made to run at constant rpm and a >much higher efficiency that any off the shelf Gas Generator. Remember, >we're trying to make something that will work, not practical maybe, but >if it does work, high volume manufacturing can make it practical. Try Capstone Corporation's website at , they build a small, fuel effecient turbogenerator that produces 24kW, and weighs 165 lbs. >> > I think you know where I'm going. Generator is sized to propell >> > the car at 55mph, stand alone. Generator and battery pack combined might >> > give you 0-60 in 3 seconds. Of course, all of this would require >> > micro-processor control. Ok experts, what are the real world physical limits? >> > > Not with a small gas generator you're not going to make it to 0-60 in 3 >seconds. Specially with many tons of batteries on board. I'm not sure how to work the kW to acceleration thing. My general idea on this subject is this, take the Zytec motors, mounted in a small car, with a generator (Capstone's seems ideally suited). Sure, maybe the 250HP Zytec's are a bit much, but why not 4 smaller motors at each wheel? Say, 75 or 100HP each? If I build an HEV, then it's going to have to perform as well, or better than, the car with it's IC powertrain. Terry ------------------------------ From: Todd Knighton Date: Fri, 16 Aug 1996 11:37:21 -0700 Subject: Re: hego Ed, Read a paper once that the O2 sensors will change their reading (indicating leaner) at higher pressures. Thus, upstream of the turbine would give a different reading on boost than off. Todd Knighton Protomotive Engineering Edward C. Hernandez wrote: > > >Put one(HEGO) after a turbo or at the collector of a header > > and you will likely have problems at idle and low rpm light load >running. > > I believe most factory turbo setups have the HEGO downstream of the > turbine. I've owned two cars like this(Chrysler 2.2 and Mitsu 2.0), and > they worked fine. Of course, BOTH of them had O2 sensor recalls that > consisted of merely replacing the sensors(as opposed to relocating > them). I still don't know why they were recalled, and I couldn't tell > any difference in closed loop performance after the change. > > Anyone else seen factory setups with the HEGOs upstream of the turbine? > > -- > Ed Hernandez > Ford Motor Company > ehernan3@xxx.com ------------------------------ From: Todd Knighton Date: Fri, 16 Aug 1996 11:39:11 -0700 Subject: Re: My DIY EFI John, Bosch uses a similar setup, though 8051's are more popular. Later stuff is Siemens 80C515 stuff. Possibly some of the code and layouts of their computers might get you on your way. Todd Knighton Protomotive Engineering DJohn77284@xxx.com wrote: > > Just a quick note on my DIY EFI project. > > Based around an 80c32, programmed via Keil C. To control both ignition and > fuelling via TPS v RPM lookup tables stored in EEPROM, modified by coolant > temp, air temp and battery voltage. Analogue inputs are via an LTC1090 which > is a serial 8-channel 10-bits ADC. For the outputs at the moment I'm thinking > of using MC3334s for the ignition and an MC33298 for the injection. Does > anyone have any views on these chips or experience on equivalents? > > Progress is slow at the moment as I'm learning to program in C - this > pointers business gets confusing sometimes.... The situation at present is > that I have a working mother board to which I intend to add an expansion > board with the necessay signal conditioning for the inputs and the output > drivers for the ignition and injection. I'd also like to add serial > communications to a PC to enable updating of the lookup tables but this is > not a priority at the moment. > > The end application at the moment is a Rover V8 which has no mods on it at > all. The main aim of this project being to improve drivability and economy > with hopefully a bit more power through more accurate setup. > > If anyone has any advice, comments or whatever, they will be gratefully > appriciated. > > Regards, > > Dave Johnson ------------------------------ From: "Mike Fahrion" Date: Fri, 16 Aug 1996 14:42:51 +0000 Subject: Re: Electric vehicle Hi all - I'm new to the list and am coming in the middle of this discussion - but had to through in my $.02. In my opinion - the politicians that came up with zero emissions laws must have had their heads thrust in some dark orifice. Perhaps I'm wrong - but their are *so many* serious problems with the concept that I doubt that any engineer would consider zero emissions vehicles a viable alternative for efficient transportation for the general public. To me it seems obvious that if we must have ultra low emissions vehicles that a hybred is the way to go - although even this seems extreme to me. I think the standard IC engine has a long way to go in its life cycle - Honda's ultra low emissions Accord for example - has managed to exceed the governments emissions schedule greatly, for a reasonable price. I do agree however that sometimes technology can be greatly spurred by such a government mandate - I just think that in this case - at least for the short term, it will be the public that suffers. Sorry for the outburst.... - -mike mfahrion@xxx.com ------------------------------ From: Jonathan Lloyd Date: Fri, 16 Aug 1996 20:46:11 +0100 Subject: Re: CD Ignition In message , John Dammeyer writes >Hi, > >Has anyone have an article on the theory or even a schematic of a Capacitive >Discharge Ignition. In particular are they just stepping up battery voltage >to about 300V and then switching that with a shorter dwell time or is there >more to it? > > Basically the spark energy is held in a capacitor and the coil used as a transformer, i.e. as electrostatic ( whereas a straight coil system stores it as magnetic). I am pretty sure they are not that good for starting as the spark can be high energy but is always very short duration. - -- Jonathan Lloyd john@xxx.uk ------------------------------ From: Jonathan Lloyd Date: Fri, 16 Aug 1996 20:26:07 +0100 Subject: Re: Setting Mixture with Nitrous In message <199608150643.QAA13482@xxx.au>, David Crocombe writes >I wish to know how we can measure the mixture lean/rich on a Drag racing >car that runs leaded petrol and Nitrous Oxide. > >David Crocombe. >Sydney, Australia. I'me sort of lurking out here and trying to learn some electronics before having a real go at things; it is coming slowly -- thanks guys. I've wondered for a while now if it is possible to attach some electronics to the spark plug!!! It needs to be "disconnected" when the spark flies but for the period before and after could it be used as a sensor. Without going into the bumf the dissociation and ionisation going on in the bore should be electronically measurable??? such data should be able to allow investigation of maximum pressures, temps etc and eventually be included in a control system. It seems like the "easiest" way of getting data on the actual behaviour of the power stroke which I guess is the key to max power?? Just thinking out loud!! - -- Jonathan Lloyd john@xxx.uk ------------------------------ From: MSargent@xxx. Sargent) Date: Fri, 16 Aug 1996 16:07:10 -0400 Subject: Re: CD Ignition > I am pretty sure they are not that good for starting ... I'd have to disagree with that. The MSD I have in my boat is *very* good for starting. +--------------------------------------------------------------------------+ | Michael F. Sargent | Net: msargent@xxx.com | Phone: 1(613)721-0902 | | Gallium Software Inc.| | FAX: 1(613)721-1278 | +--------------------------------------------------------------------------+ ------------------------------ From: DJohn77284@xxx.com Date: Fri, 16 Aug 1996 16:20:08 -0400 Subject: Re: My DIY EFI Todd, you say that Bosch used 8051s or derrivatives. I would be interested in seeing anything really - coding, schematics, etc. Can you point me in the right direction so I can get a peak at these? The reason that I'm going for an 80c32 is that I've already got a few. I've also been looking at the Phillips range and the one's with IIC and CAN BUS look interesting. Any thoughts? Regards, Dave. ------------------------------ From: DJohn77284@xxx.com Date: Fri, 16 Aug 1996 16:20:15 -0400 Subject: Re: 80552, Air core meter Warren, I'm playing around with an 80c32 at the moment but I'm not too far down the road to change processors. I think I'm right in that the 80552 is a derrivative of the 8051 so I would be interested in seeing a copy of what you have if that's at all possible. Regards, Dave DJohn77284@xxx.com ------------------------------ From: DJohn77284@xxx.com Date: Fri, 16 Aug 1996 16:20:14 -0400 Subject: Re: Truck parts Dynamometer. What really is involved in putting together a dynamometer - either chassis or engine? Is there a prescribed method as I'd be interested in putting together somesort of engine dynamometer. Regards, Dave. ------------------------------ From: Jerry Wills Date: Fri, 16 Aug 96 13:23:47 PDT Subject: Re: Electric vehicle , wrong list for this discussion, but I must Folks, One person is already doing some of what you would like. good acceleration , 0-60 in the 4 sec. range motors drive all wheels directly regenerative braking for long distance a small trailer , just big enough for a stationary gas generator, which yields 40ish mpg. the battery technology is the problem at the moment The car started out as a honda, and still looks like it on the outside, but not under the hood. The guy name is Alan ?????, our former sunracer my know his last name and company, or I can find out. He was a consultant to GM for a while. Email me directly if you must have more info. My problem with all of the is how many dinosaurs does it take to make the electricity , that you charge your batteries with, from the power company? Hell...how much energy does it take to make the solarcells, that are how efficent? when the solarcells and batteries and current switches all get alot better we will be a lot closer, but until then, shall we go back to the explosive stuff? Jerry Wills I'll have enough POWER when I can spin the tires at the end of the straight! 89 FJ DERSLYR, DoD#500 KotF(Flag) Mark Donahue, about 917's USC/Information Sciences Institute (USC/ISI) SoCal (310) 822-1511 x 236 90's cowboys, ride iron horses, and punch Deer!!! You done violated Physics, BOY! Assume the position..... (Rider 5/92) ------------------------------ From: jwest@xxx.edu (Joe West) Date: Fri, 16 Aug 1996 17:54:08 -0600 Subject: Re: Electric vehicle Hello all: I think that battery power is not the direction that any company or individual should pursue. Take a look at the recent issue of Discover magazine. There is an article about flywheel power that I believe folks would find interesting. On a side note I firmly believe that the only reason the GM Impact HEV is being released for sale is due to Mercedes work with the hydrogen engine. Kind of like, lets make our money back before we loose our shirts! Although the Oil industry is a very powerful influence in Washington. They will make sure that their pockets stay lined. Joseph D. West Electronics Lab. Supervisor College of Mechanical Eng. Ohio State University (614) 292-2845 Fax (614) 292-3163 ------------------------------ From: Kalle Pihlajasaari Date: Fri, 16 Aug 1996 23:33:11 +0200 (sat) Subject: Re: Setting Mixture with Nitrous Hi Jonathan, > >I wish to know how we can measure the mixture lean/rich on a Drag racing > >car that runs leaded petrol and Nitrous Oxide. > > > I'me sort of lurking out here and trying to learn some electronics > before having a real go at things; it is coming slowly -- thanks guys. > I've wondered for a while now if it is possible to attach some > electronics to the spark plug!!! It needs to be "disconnected" when the > spark flies but for the period before and after could it be used as a > sensor. Without going into the bumf the dissociation and ionisation > going on in the bore should be electronically measurable??? such data > should be able to allow investigation of maximum pressures, temps etc > and eventually be included in a control system. > It seems like the "easiest" way of getting data on the actual behaviour > of the power stroke which I guess is the key to max power?? If you are happy with information one spark in the past you could probably (not havin actually tried it) glean something from the current waveform of the actual spark, should be able to indicate spark voltage as well and might give a clue as to the mixture. > Just thinking out loud!! Same here. Cheers - -- Kalle Pihlajasaari kalle@xxx.za Interface Products Box 15775, Doornfontein, 2028, South Africa +27 (11) 402-7750 Fax: +27 (11) 402-7751 ------------------------------ From: rickydik@xxx.com (RD Rick) Date: Fri, 16 Aug 1996 15:11:28 -0700 Subject: Re: Truck parts Dynamometer. Dave asked: > >What really is involved in putting together a dynamometer - either chassis or>engine? > >Is there a prescribed method as I'd be interested in putting together >somesort of engine dynamometer. If the engine is in a car, all you need is a stopwatch, a tach, a tape recorder, and a hill. RD ------------------------------ From: Dave Zug Date: Fri, 16 Aug 1996 23:15:56 -0400 Subject: Re: Truck parts Dynamometer. RD Rick wrote: > > Dave asked: > > > >What really is involved in putting together a dynamometer - either > chassis or>engine? > > > >Is there a prescribed method as I'd be interested in putting together > >somesort of engine dynamometer. > > If the engine is in a car, all you need is a stopwatch, a tach, a tape > recorder, and a hill. > > RD AND A BUDDY who knows the formula! (and so you can concentrate on following the yellow lines) call this the anticipated request for the conversion formula and procedure, again. (look ma, i contributed!) ps. anyone have a pathfinder II or III cartridge for OTC-2000 for sale? ------------------------------ From: Sandy Date: Fri, 16 Aug 1996 20:42:12 -0700 Subject: Re: CD Ignition At 04:07 PM 8/16/96 -0400, you wrote: >> I am pretty sure they are not that good for starting ... > >I'd have to disagree with that. The MSD I have in my boat is *very* good >for starting. MSD will fire may times, vs, once for the Cheeze CDI systems. MSD's are good! ------------------------------ From: John Dammeyer Date: Fri, 16 Aug 96 23:46 PDT Subject: Re: My DIY EFI At 04:20 PM 16/08/1996 -0400, you wrote: >Todd, you say that Bosch used 8051s or derrivatives. > >I would be interested in seeing anything really - coding, schematics, etc. >Can you point me in the right direction so I can get a peak at these? > >The reason that I'm going for an 80c32 is that I've already got a few. I've >also been looking at the Phillips range and the one's with IIC and CAN BUS >look interesting. Any thoughts? > Using the 80C592 (with CAN bus controller) has a lot of advantages if you are putting together an integrated controller for a car. The ignition/EFI controller can broadcast RPM along with manifold pressure onto the CAN bus. With the leftover 10 bit A/D channels you can measure temperatures etc and also broadcast them. This makes diagnostics rather easy as there is a one point connection for all engine inforamtion. Now if you were also controlling the automatic transmission then you can use those parameters for shifting etc. Finally your dash board computer can display the engine stuff on an electronic instrument panel. Signal lights can be turned on/off with CAN bus messages if you use something like a 68HC05X4 as the tail light controller. This means frame gorund, fused +12 volts and a pair of CAN bus wires to the rear of the car rather than an entire harness and the connectors that go with it. Can't see any reason to not use a CAN based engine controller; I am. John Pioneers are the ones, face down in the mud, with arrows in their backs. Automation Artisans Inc. Ph. 604-544-4950 6468 Loganberry Place Fax 604-544-4954 Victoria BC CANADA V8Z 7E6 ------------------------------ From: John Dammeyer Date: Fri, 16 Aug 96 23:45 PDT Subject: Re: CD Ignition At 08:46 PM 16/08/1996 +0100, you wrote: >In message , John Dammeyer > writes >>Hi, >> >>Has anyone have an article on the theory or even a schematic of a Capacitive >>Discharge Ignition. In particular are they just stepping up battery voltage >>to about 300V and then switching that with a shorter dwell time or is there >>more to it? >> >> >Basically the spark energy is held in a capacitor and the coil used as a >transformer, i.e. as electrostatic ( whereas a straight coil system >stores it as magnetic). I am pretty sure they are not that good for >starting as the spark can be high energy but is always very short >duration. >-- Oh contrare. Back when I lived in Edmonton (-40C temps.) I installed a CD ignition into my Datsun 510. Car still had to have the block heater plugged in just to warm up the oil and so the starter could turn the engine over but in situations where the car was cold the difference after the CD ignition was nothing hort of miraculous. It's just this news group is about DIY EFI and that usually also adds ignition since the parameters are there for it. So if I know when to fire the plugs I can program the micro to appy current through the coil for n milliseconds to keep dwell constant and coil heating down. So lets say 5ms dwell at 12 volts and a coil resistance of 12 Ohms. Then we have 1 Amp for 5 ms and when current is broken, fild collapses and ignition occurs. At cold temperatures and a battery voltage of 6 volts during cranking we get only 500ma and much less energy. So.... do I step up the voltage to 24 volts with a switching power supply and decrease dwell by 50% and then still trigger the coil with the FET transistor. In other words, before uComputers was the CD Ignition with the Capacitor and the SCR just an elegant solution to the problem? John. Pioneers are the ones, face down in the mud, with arrows in their backs. Automation Artisans Inc. Ph. 604-544-4950 6468 Loganberry Place Fax 604-544-4954 Victoria BC CANADA V8Z 7E6 ------------------------------ End of DIY_EFI Digest V1 #233 ***************************** 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".