DIY_EFI Digest Thursday, December 2 1999 Volume 04 : Number 670 In this issue: RE: Transients Data Acquisition RE: Looking for Steve Parkersons work. Re: Basic electronic stuff 2000 GM Performance Part Lineup Re: Basic electronic stuff KLUTCH!!! See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Thu, 2 Dec 1999 09:43:31 +1300 From: Tony Bryant Subject: RE: Transients > Is this race car, or street car, how much cam?. Lots of > things come into > play. > I'm addressing a street engine, as opposed to streetable or racing. > It is a race car with a biggish cam, but I trying to develop a general understanding of fueling requirements, and the point of this exersize is to develop an ECU that will as much as possible make a hot cam behave less like a dog, when using in street conditions. Race engines bring out the nasties inherent in all engines, so it make sense to consider the worst case first. > | I run across bazillions of different theories, all of which I've > | decided are crap (feel free to correct me though). > > Everyone is entitled to their opinion, weither you call it > crap or not is > immaterial. Wrong choice of words, I'll admit, but I'm interested in facts, just the facts. And I KNOW that some of the opinions ventured to me in the past have no basis in fact. > | 2) The intake runners have columns of air that need to be > | accelerated to the new conditions. > > | Bollocks. That would also make it run rich, and besides the > | flow always tops between intake cycles anyway. > > Why then is cross sectional area so important to throttle response?. Because a smaller diameter runner will have less self-EGR effect, due to the higher velocities. e.g. e.g. Assume 100% VE requires 5ms duration. Engine A: At idle (assume 15" vac) with a small diameter runner assume 30% VE -> 1.33ms Engine B: At idle with a large diameter runner, with more self-EGR effect assume 20% VE -> 1ms So, when the throttle is snapped open, lets say next cycle you've got 50% VE worth of air, but either 40% or 60% of the fuel required for this mixture. Engine A may be able to fire this lean mixture, Engine B probably won't. The same principles applies to changing cams. > | 3) There is a delay getting the fuel in the port to the cylinder. > | Bollocks. Its squirted directly on the back of the valve, at low rpm > | it'll just run in under the influence of gravity, when the valve is > | opened. > > Gravity ain't fast enough for cylinder filling of puddled fuel. > > | 4) Manifold wall wetting effects > | Bollocks. This is port injection, the walls don't ever see fuel. > > Look again, where does the fuel go when sprayed against a > closed valve?. > The back of the valve, and splashs the walls, not the entire > lenght like a > carb set up, but still some. My experience with squirting injectors at things, did not generate any amount of splatter. It just wets what you point it at. There may be some fuel temporary tied up wetting the valve, I can't believe the walls get involved with this story at all. I'll concede a small amount extra may be required for the first post transition cycle due to valve wetting effects. > > | 5) The vapourised fuel in the port condenses because of the pressure > | increase. > | Maybe, but it seems that this would not cause a major > change in fuelling, > | as its hard to see how the fuel in the cylinder will not be burnt. > > If the droplets are large enough it won't.. If the fuel condenses during the first 100% VE cycle, it'll condense during the second,third, and fourth etc too, and it'll run like crap on all WOT cycles. I can't see how this effect would only affect transitions. > > | 6) A richer mixture (i.e. more powerful) is needed to accelerate the > engine. > | Bollocks. Running a seriously rich mixture at say > 1300RPM/0" vac, does not > | help > | the problem. Neither does serious amounts of dMap/dt. > dTPS/dt helps a > | little, > | but not much. > > Then try going very lean, ahh, see, problem gets worse That because on your first 100% VE cycle after the transition, the fuelling will still generally be set-up for the pre-transition conditions. Leaner there, gives much leaner post transition. > | ---------------------- > | Having stated what I think its not, here's what I think it is: > | 1) Fueling delays. The ECU not responding to changes in MAP as > | quickly as the engine. The engine will respond on a cycle by cycle > | basis, whereas an ECU and MAP sensor most likely will not. > > If you've changed cams, or got too much volume in the MAP > sensor line, then > the filtering rate may be off. The ecm can play a chess game between > ignition cycles. Time/response not an issue or no high > performance engine > could run one. It all depends on the compromises you mind making. High performance engine generally run a (very) high idle. Why? 1. Self-EGR at low rpm makes the required mixture hard to predict. 2. Take it out of the low rpm stumble "danger" area. I'm trying to push the boundaries of what possible with a high-performance engine. e.g. Silky smooth, low rpm idle, with instant throttle response everywhere, all with reasonable emissions. Difficult - of course - thats why I'm trying to develop my understanding of the phenomenens involved. > | 2) The fact that the fuel is injected before the IVO > (intake valve open) > | event, but the engine "samples" MAP at IVO. Therefore it may not be > | predictable what the fuel will need to be, when the fuel is > squirted in, > | because the MAP can change significantly then and IVO. > > For vaporization, (ie street) you want the fuel to hit the > back of a closed > valve, > also, the shearing action against the fuel as the valve opens. Obviously there's a trade-off here between vapourisation, and accurate fuelling, by being able to delay your fuelling calculation until the last possible moment. I'm currently modifying my ECU, to allow calculation and updating of injector durations at least every cycle (at <2500RPM). I will post to let you know if this helps. ------------------------------ Date: Wed, 01 Dec 1999 17:08:40 -0500 (EST) From: Andris Subject: Data Acquisition Folks, I'm looking to get a few more gadgets to help me design a better intake, and set up the fuel/timing maps on the Camaro. I would like to make a data acquisition system that can simultaneously record 5 channels at 10 Hz. I figure one K-Type thermocouple before each turbo, one in the intake manifold, one before the throttlebody and one just after a turbo (and before the intercooler). I'd like to know exhaust temps after the turbo for my own knowledge, and would just swap thermocouple inputs for that one... For pressure, I would like to have an exhaust before/after turbo pressure transducer and a before/after transducer to measure pressure drop in the intake system. I'd monitor this at some other point than the temps, hopefully saving some $$$ by buying a less channel DAQ. I've looked at Omega, and I frankly can afford anything there. Are there any cards in the sub $250 range that could accomplish this (w/o the thermocouples or sensors)? If not, what would be the most appropriate card out there? I'd probably just stick the old desktop and an inverter strapped down on the seat, and have the card in a PCI/ISA slot, possibly running through my 2 year old LabView software... Any ideas or suggestions? Thanks :) Andris Skulte Z28tt-89 IROC T56 DFI Twin Turbo ------------------------------ Date: Wed, 1 Dec 1999 19:08:13 -0500 From: jacobss@xxx.com Subject: RE: Looking for Steve Parkersons work. Hello all I am looking for work from a former list member named Steve Parkerson. It has been pointed out he is now passed onto the internal combustion engine intake sky. Darn I should have bought these years ago. Any rate, I am looking for anybody who may have purchased any of his manuals, my main interest is the VW conversion manuals. If anybody has these, I am looking for them to help me with a project, please drop me a note. Stephen Jacobs - -----Original Message----- From: DIY_EFI-Digest-Owner@xxx.edu [mailto:DIY_EFI-Digest-Owner@xxx.edu] Sent: Wednesday, December 01, 1999 3:00 PM To: DIY_EFI-Digest@xxx.edu Subject: DIY_EFI Digest V4 #669 DIY_EFI Digest Wednesday, December 1 1999 Volume 04 : Number 669 In this issue: Basic electronic stuff Haltech data logging question? Sunbird wiring Grand Prix Turbo wiring diagrams See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. - ---------------------------------------------------------------------- Date: Wed, 1 Dec 1999 07:17:40 -0500 From: "Posea, David G, SITS" Subject: Basic electronic stuff Some of you may remember I am working on a boost retard device based on a PIC controller for the Ford DIS ignition. I found a good trigger circuit that goes to logic 1 when the EEC grounds the trigger wire for a coil. My question is how do I handle the "open" state on the output side of the controller? This is the negative side of the coil. If I attach it to an output pin out on the PIC, won't I be feeding Vbat (+13V)into that same pin from the coil side? Can I just set the output pin high until time to fire the coil, then ground it? Or do I need to use the output as the input to a transistor to switch the negative coil wire to ground? Something seems wrong here, and I'm not sure what it is. I'm a programmer by trade with limited electronic knowlegde. Thanks in advance for any help. David Posea - ------------------------------ Date: Wed, 1 Dec 1999 10:50:00 EST From: A70Duster@xxx.com Subject: Haltech data logging question? I have a Haltech F3 series on a Chevy engine. Works fine but I'm trying to view the saved data with the data logging feature. I believed the data is saved in a binary format, and I'm trying to get it into an Excel type of program. Any help converting the file?? Thanks Mike - ------------------------------ Date: Wed, 01 Dec 1999 12:15:35 -0600 From: steve ravet Subject: Sunbird wiring > > Date: Tue, 30 Nov 1999 22:19:58 -0700 > From: cwagner@xxx.net > Subject: Sunbird wiring > > Does anyone have a wiring diagram for a 2.0 Sunbird using the > 7749? Need it for a conversion. Also, does anyone have a list of > where the data tables are located on the chip? You're in luck, I just uploaded this yesterday from Bruce. Sent a note to GMECM I think, which is the better place to ask. Anyway, go to the diy_efi WWW page, (efi332.eng.ohio-state.edu/diy_efi), click on ftp site index, then scroll to the bottom for schematics. As I understand it, this sunbird ECM is the same as syty, in which all tables are known. There's even a shareware program for it for editing bins. check www.syty.org or something like that. - - --steve - - -- Steve Ravet steve.ravet@xxx.com Advanced Risc Machines, Inc. www.arm.com - ------------------------------ Date: Wed, 1 Dec 1999 12:08:26 -0700 From: cwagner@xxx.net Subject: Grand Prix Turbo wiring diagrams I earlier wrote about needing wiring diagrams for the Sunbird. I goofed, I found them on the ftp area. What I needed were from a 89 or 90 turbo Grand Prix. I understand that the computer used is a 7727 which is the sane as the 7730. Does anyone know where the wires go on a 730 computer. I don't have a 727 but I do have a 730. - ------------------------------ End of DIY_EFI Digest V4 #669 ***************************** 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". ------------------------------ Date: Thu, 2 Dec 1999 10:18:12 +0800 From: dzorde@xxx.com Subject: Re: Basic electronic stuff Dave, haven't been following the thread but I wouldn't suggest trying to connect the PIC directly to the coil negative as you'll fry it. As soon as you ground the PIC output the coil will try and charge through your PIC at a rate of 8A or so, basically your PIC will let out all the magical smoke that makes it work. There are two options depending on what you want to do. 1. if you want to use the PIC for actually operating the coil with proper electronic advance and retard, you can use the PIC to drive a nice big transistor (my ignition system uses a BUX80 driven by a smaller 2N3055) or FET to drive the coil. 2. if you just want to cut ignition pulses (rev limiter style), use the PIC to drive a decent size SCR (probably C122E) and just sample boost and revs and short coil negative to ground at the appropriate time. In either case you will need some spike protection on the devices but that's a different matter. Dan dzorde@xxx.com Date: Wed, 1 Dec 1999 07:17:40 -0500 From: "Posea, David G, SITS" Subject: Basic electronic stuff Some of you may remember I am working on a boost retard device based on a PIC controller for the Ford DIS ignition. I found a good trigger circuit that goes to logic 1 when the EEC grounds the trigger wire for a coil. My question is how do I handle the "open" state on the output side of the controller? This is the negative side of the coil. If I attach it to an output pin out on the PIC, won't I be feeding Vbat (+13V)into that same pin from the coil side? Can I just set the output pin high until time to fire the coil, then ground it? Or do I need to use the output as the input to a transistor to switch the negative coil wire to ground? Something seems wrong here, and I'm not sure what it is. I'm a programmer by trade with limited electronic knowlegde. Thanks in advance for any help. David Posea ------------------------------ Date: Wed, 01 Dec 1999 23:52:37 -0600 From: "Chris G. Lucas" Subject: 2000 GM Performance Part Lineup - --------------091C07D38AA6B7DBC35F832E Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Just thought I would send this to you all just in case you haven't seen it yet. The new Chevy crate motor/ parts line up. Including the 383 crate motor. 385hp upgradable to 430hp crate motor and the NEW GM FUEL INJECTION SYSTEM!!!!! http://www.sallee-chevrolet.com/Gm_Performance_Parts_Update/gmnew.html Chris Lucas - --------------091C07D38AA6B7DBC35F832E Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Just thought I would send this to you all just in case you haven't seen it yet.
The new Chevy crate motor/ parts line up. Including the 383 crate motor. 385hp upgradable to 430hp crate motor and the NEW GM FUEL INJECTION SYSTEM!!!!!
            http://www.sallee-chevrolet.com/Gm_Performance_Parts_Update/gmnew.html

Chris Lucas - --------------091C07D38AA6B7DBC35F832E-- ------------------------------ Date: Wed, 1 Dec 1999 22:42:53 -0800 (PST) From: Orin Eman Subject: Re: Basic electronic stuff > There are two options depending on what you want to do. > 1. if you want to use the PIC for actually operating the coil with proper > electronic advance and retard, you can use the PIC to drive a nice big > transistor (my ignition system uses a BUX80 driven by a smaller 2N3055) or FET > to drive the coil. If they are 'real' coils, then he could use the EFI332 driver boards. I suspect there will be a group buy for them in the near future. If they are like the new Corvette coils, the PIC could drive them directly... but I wouldn't want to. I drive the Corvette coils from a PIC via opto-isolators. Orin. ------------------------------ Date: Thu, 2 Dec 1999 01:50:53 EST From: A70Duster@xxx.com Subject: KLUTCH!!! Been thinking about MAD MAX again (turning the blower on/off) when I was looking at a Vortech style blower. The preverbal light came on. Could one use an AC clutch to engage and disengage the impeller. At idle and cruise, the impeller doesn't turn, but for gettin' giggy, fire up the "blower" and blow past the NIGHT RIDER!!!!! Can an AC clutch "hold together" when attached to a blower??? Mike ------------------------------ End of DIY_EFI Digest V4 #670 ***************************** 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".