DIY_EFI Digest Thursday, 4 July 1996 Volume 01 : Number 189 In this issue: Re: G-Force Measurement Re: G-Force Measurement 6811 Disassembler Re: G-Force Measurement G-TECH Header insulation MAF output signal Re: Header insulation Forwarded: Header insulation Re: Forwarded: Header insulation Re: MAF output signal GM ECM IO Re[2]: Forwarded: Header insulation Re: MAF output signal 68HC11 See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Alexander.M.Lichstein@xxx. Lichstein) Date: 03 Jul 96 05:50:23 EDT Subject: Re: G-Force Measurement I believe that AD makes an adxl02 now (+-2 g's) which might give you even more accuracy. I studied MEMS (Microelectro-mechanical systems) for a while here at school and learned a lot about the adxl50 (+-50 g... +-8%) which is used for airbags now. the adxl05 was brand new at that time, and allowed for +-3% or so. I would bet that they've got the adcl02 down about 1% by now. I'm buried under my own adaptive algorithm for the moment, but would love to hear what you find out about accelerometers. Please keep me up to speed. If you search Alta Vista advanced query with 3-axis AND accelerometer, you should be able to find lots of cool stuff. I saw a couple just now, but have no info on any of them. If you have the time to contact those people, and could tell me what you find, it would be much appreciated. thanks _ zander ------------------------------ From: "Al Grippo" Date: Wed, 03 Jul 96 20:30:47 EST Subject: Re: G-Force Measurement >Hi to all, >I have been lurking on this list for quite awhile. Although a G-meter is not >strictly diy efi material, I know that many in the group may have an interest or >information regarding my inquiry. >To the point, I wish to either purchase or design an instrument for measuring >the G-forces generated during cornering of a vehicle. If anyone knows of a >unit >made for this purpose, please reply and let me know. >If I have to make one, maybe the ADXL05 from Analog Devices would be the most >suitable place to start, however I have not yet managed to get a hold of a >databook/spec sheet. What does anybody else think? >Regards, >Brian Davies You can get the specs on the ADXL05 from http://www.analog.com/products/sheets. I ordered 1 from Newark Electronics for $38US - expect delivery in August. I plan to hook up an ADXL05 to the cpu332 sensor board. I will pivot mount it so that when it is straight ahead it will measure accel g's, then by simply turning it 90 degrees, it will measure lateral g's. I plan to display the output continuously on an led display. Al Grippo ------------------------------ From: Donald Whisnant Date: Wed, 03 Jul 1996 10:26:53 -0400 Subject: 6811 Disassembler Since the requests for my 68HC11 disassembler have tapered off, I'm assuming that most everyone wanting a copy has requested it -- I've sent out a copy to all who have requested it, so if you requested it and didn't receive it then something happened to the emails somewhere and you need to resend your request... I also will be gone on July 4th vacation starting this afternoon and won't return till next monday -- so any emails to me concerning ECM reverse engineering (which is what this disassembler is all about), or the disassembler itself, etc, won't get answered until I return next week... For those who are also wanting the as6811 (and other asxxxx) assemblers, I'm still hunting for the FTP site address that has these. When I return (and can find them) I will post it to the list as well... Later... Donald Whisnant dewhisna@xxx.com ------------------------------ From: Paul.J.Timmerman@xxx.gov Date: Wed, 3 Jul 1996 08:19:00 -0700 Subject: Re: G-Force Measurement I have purchased a G-Tek unit, mainly for engine developement because it will do 0-60, 1/4 mile, and instantaneous HP. It also does lateral acceleration. It is still in the box, but I will report on it, hopefully monday. It was $139.00. paul timmerman ------------------------------ From: pfenske@xxx.ca (peter paul fenske) Date: Wed, 03 Jul 1996 09:06:18 -0700 Subject: G-TECH Hi Guys While this goes against the spirit of DIY A accelerometer performance meter is available from Ecklers 1-800-327-4868. Yes they are on the web. The PN for the gizmo is 32208. 1/100 sec 1/100 G accuracy. GL all: peter PS wondering if anybody has any info on C3 6801 rom they want to share. ------------------------------ From: michael glidewell Date: Wed, 03 Jul 1996 18:00:11 -0400 Subject: Header insulation I'd like too insulate my exhaust header down to the O2 sensor so it won't cool off and get better gas mileage( that's my theory anyway) Does annyone have a simple recommendation for something effective? I've thoght of the asbestos muffler wrap stuff but I don't think it will retain the heat in very well. This for an 81 528i BMW. - ---------------------------------------------- Michael Glidewell Boston, Massachusetts glide@xxx.net KE1CP BMW 528i BMWCCA http://www.shore.net/~glide/ ------------------------------ From: mjos@xxx.com (mjos) Date: Wed, 3 Jul 1996 15:56:55 -0600 Subject: MAF output signal Hi all, I am working on a frequency limiting circuit that will intercept the output of my MAF sensor and pass the original freq as long as it falls at or below a set limit. If it goes above the limit freq, the circuit will pass only the limit freq. regardless of how high the input freq. goes beyond it. What is the typical freq. output range vs. air flow for these sensors. The car is a Dodge Steath Turbo and uses a Mitsubishi MAF device. I haven't had a chance to put it on a scope yet. Also, does this MAF type put out a pulse, sine, square, ? type of wave? I am aware that HKS makes such a unit in two forms. One for voltage output type MAF's and one for freq. output MAF's. I don't want to use just a low pass filter design but rather a frequency peak limit\hold circuit. Has anyone else made such a circuit? I am open to various ideas. Thanks in advance, Mark Josewski Applications Eng. ------------------------------ From: dzorde@xxx.au Date: Thu, 04 Jul 96 08:24:33 Subject: Re: Header insulation I have found asbestor wrapping tape to be the best. However, don't buy it from a performance shop as they will charge a fortune for it. I usually get it from a good hardware store, because this stuff is also used for insulating water pipes in buildings to stop them freezing up. Dan dzorde@xxx.au ______________________________ Reply Separator _________________________________ Subject: Header insulation Author: diy_efi@xxx.edu at INTERNET Date: 7/4/96 6:46 AM I'd like too insulate my exhaust header down to the O2 sensor so it won't cool off and get better gas mileage( that's my theory anyway) Does annyone have a simple recommendation for something effective? I've thoght of the asbestos muffler wrap stuff but I don't think it will retain the heat in very well. This for an 81 528i BMW. - ---------------------------------------------- Michael Glidewell Boston, Massachusetts glide@xxx.net KE1CP BMW 528i BMWCCA http://www.shore.net/~glide/ ------------------------------ From: RABBITT_Andrew@xxx.au Date: Thu, 4 Jul 1996 09:59:50 est Subject: Forwarded: Header insulation I can't imagine you'll get too many mpg's out of this exercise, since once the exhaust heat is out of the combustion chamber it can do no further useful work, whatever its temperature (unless you have a turbocharger). It's just waste heat from the exhaust port onwards! If you're concerned with the EGO sensor losing temperature, I can't see how it would except maybe after a prolonged idle period. If you do gain anything in your BSFC, then you'll lose it from carrying the extra inertia of the insulation! From: (michael glidewell) glide@xxx.net:smtp Date: ## 07/03/96 18:00 ## I'd like too insulate my exhaust header down to the O2 sensor so it won't cool off and get better gas mileage( that's my theory anyway) Does annyone have a simple recommendation for something effective? I've thoght of the asbestos muffler wrap stuff but I don't think it will retain the heat in very well. This for an 81 528i BMW. - ---------------------------------------------- Michael Glidewell Boston, Massachusetts glide@xxx.net KE1CP BMW 528i BMWCCA http://www.shore.net/~glide/ ------------------------------ From: Sandy Date: Wed, 03 Jul 1996 23:40:46 -0700 Subject: Re: Forwarded: Header insulation At 09:59 AM 7/4/96 est, you wrote: > >I can't imagine you'll get too many mpg's out of this exercise, since >once the exhaust heat is out of the combustion chamber it can do no >further useful work, whatever its temperature (unless you have a >turbocharger). It's just waste heat from the exhaust port onwards! I don't think that this is really true, I recall that the density of the hot gasses tend to expand when exchanging heat with the header causing a kind'a clogging effect. Also, wrapping the exhaust with some heat preserving wrap will most definitely change the engines mixture to be on the lean side. I think that this is again related to the better efficiency in the exhaust system. I'll let some of the experts follow up with the scientific explanations...You wont get dramatic changes in MPG in any case. I have done this to a 372 chevy, and it allowed me to move up a couple of jet sizes, thus allowing more fuel to be burn and more power. [chomp] Sandy ------------------------------ From: pfenske@xxx.ca (peter paul fenske) Date: Wed, 03 Jul 1996 23:28:48 -0700 Subject: Re: MAF output signal >Hi all, > >I am working on a frequency limiting circuit that will intercept the output chomp......... >the limit freq. regardless of how high the input freq. goes beyond it. >> >>Well first off use am LM2907 to convert the freq to a voltage. >>The 2907 is scalable to freq. Use the voltage that corresponds >>to wot max load to switch a comparator. Use the comparator to >>switch to signal output to a 555 with you steady state freq >>signal. >>Of course if you are one of the gurus the HC11 can be >>easily programmed to do the JOB. A EVB could do it. >>Of course EVB costs bucks so analog ok. >> >What is the typical freq. output range vs. air flow for these sensors. The muunnnchhheee......... >>Best way to do this is with a freq cntr DVM wired up so your >>co pilot can take measurements while you torture car. You explain >>to the genedarme what are you up to.. IN the name of science and EFI. >> >Thanks in advance, > >Mark Josewski >Applications Eng. > >Have a nice day: the peter > ------------------------------ From: pfenske@xxx.ca (peter paul fenske) Date: Wed, 03 Jul 1996 23:40:33 -0700 Subject: GM ECM IO Hi GUYs (and gals) sori Been playing with IO on 730 ECM. Well there is this monstrous block of IO from about 3FC0 to 401F. Trying to untangle this mess is interesting. In the 730 the GMP-4 communicates with the ECU directly. This is probably some of the IO. Also via a High Speed internal serial buss with the A.D and FMD. This explains some of the two byte io instructions. The one around 3FFC and 3FFA seem to be of this order. The high byte is the serial address and the low byte the data. FB1A means don't use backup. FB12 means use backup. Stuff like that. There appear to be general Io from 4000H to 4007. 4001 to 4004 appear to be simple outputs. Things like PN switch ect. 4007 has multiple commands. Could be stepper control for all I know. All the interchanges around 3FCX seem to be counter timers. A/D around 3FEA with A/D control at 3FDA??????? Now comes the clincher. I am not sure but I am beginning to suspect the low ram of the co-processor the ECU is mapped into the IO of the GMP-4. By alternating E clocks such an arrangement could be possible. Anyways If someone wants to tell me I am on drugs I would appreciate the criticism. Also if someone wished to reveal this fudge caramel puzzle well please. Tnx all: peter PS yes still working at it. ------------------------------ From: dzorde@xxx.au Date: Thu, 04 Jul 96 15:50:16 Subject: Re[2]: Forwarded: Header insulation The hotter the exhaust is, the less dense the air in the exhaust system, thus on the exhaust stroke the air can escape the engine faster due to the lower resistivity towards the air coming out of the engine. Ideally the whole exhaust system should be red hot so that air gets sucked out of the engine. ______________________________ Reply Separator _________________________________ Subject: Re: Forwarded: Header insulation Author: diy_efi@xxx.edu at INTERNET Date: 7/4/96 3:40 PM At 09:59 AM 7/4/96 est, you wrote: > >I can't imagine you'll get too many mpg's out of this exercise, since >once the exhaust heat is out of the combustion chamber it can do no >further useful work, whatever its temperature (unless you have a >turbocharger). It's just waste heat from the exhaust port onwards! I don't think that this is really true, I recall that the density of the hot gasses tend to expand when exchanging heat with the header causing a kind'a clogging effect. Also, wrapping the exhaust with some heat preserving wrap will most definitely change the engines mixture to be on the lean side. I think that this is again related to the better efficiency in the exhaust system. I'll let some of the experts follow up with the scientific explanations...You wont get dramatic changes in MPG in any case. I have done this to a 372 chevy, and it allowed me to move up a couple of jet sizes, thus allowing more fuel to be burn and more power. [chomp] Sandy ------------------------------ From: arthurok@xxx.com (ARTHUR OKUN) Date: Thu, 4 Jul 1996 00:48:14 -0700 Subject: Re: MAF output signal You wrote: > >Hi all, > >I am working on a frequency limiting circuit that will intercept the output >of my MAF sensor and pass the original freq as long as it falls at or >below a set limit. If it goes above the limit freq, the circuit will pass only >the limit freq. regardless of how high the input freq. goes beyond it. > >What is the typical freq. output range vs. air flow for these sensors. The >car is a Dodge Steath Turbo and uses a Mitsubishi MAF device. I haven't >had a chance to put it on a scope yet. Also, does this MAF type put out >a pulse, sine, square, ? type of wave? > >I am aware that HKS makes such a unit in two forms. One for voltage >output type MAF's and one for freq. output MAF's. I don't want to use >just a low pass filter design but rather a frequency peak limit\hold circuit. > >Has anyone else made such a circuit? I am open to various ideas. > >Thanks in advance, > >Mark Josewski >Applications Eng. > seems like a good application for a pic 16 ; my gm car has a frequency output maf maybe i'll try building a signal translator for it right now it has a speed density chip in it ------------------------------ From: walter.kaufmann@xxx.ch (Walter Kaufmann) Date: Thu, 4 Jul 1996 09:50:34 +0200 Subject: 68HC11 Does anyone have a program for an ECU on a HC11 (I prefer Assembler)? ------------------------------ End of DIY_EFI Digest V1 #189 ***************************** 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".