DIY_EFI Digest Thursday, 29 August 1996 Volume 01 : Number 251 In this issue: re: switching EPROMs Re: switching between EPROMS EPROM Switch Manifold conversions. Re: Re[2]: real time dyno? Re: switching between EPROMS Re: My DIY EFI Re: switching between EPROMS Re: switching between EPROMS RE: Manifold conversions. FW: *&**&^%$&^ Maths! Re: switching between EPROMS Re: Newer VATS Vehicles Hello Re: switching between EPROMS Re: switching between EPROMS Re: switching between EPROMS TPIS Big Ram? Re: real time dyno? [none] FORD EEC-xx [none] [none] [none] [none] Re: TPIS Big Ram? Bosch MAF to Hitachi MAF Re: EFI Conv. Re: speaking of displays & DPM Manifold conversions. Re: Real time dyno Re: Bosch MAF to Hitachi MAF Re: TPIS Big Ram? Re: switching between EPROMS Re: Real time dyno Re: switching between EPROMS Re: Re[2]: real time dyno? See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Krister Wikstrom Date: Wed, 28 Aug 1996 13:12:08 +0200 Subject: re: switching EPROMs >I'd prefer to do it with the engine ON!!! I don't see any reason why it >cannot be done, provided the switch over is not done at a critical time, and >that the only difference between the EPROMS is the data: ie. the fuelling, >ignition timing, etc. Also it should be done quick enough so that the micro >does not miss an external data fetch (anyone know what the micro will do in >this case?? will it hang or retry? ). > >Warren Most systems have no indication on failing data fetch, they just read in an incorrect value, propably FF or 00, and just do what that value suggests. If a code fetch fails, anything can happen. Remember that the same chip has also the code, so you'll get code fetches on it all the time. There might be some unexpected problems, if the software expects some previously read values - for example if it fetches a 16-bit value, and you happen to make the change just after the first byte... I've been also thinking of swithing EPROMs on the fly, and I made a simple circuit (that is not tested yet...), which uses a latch to do the switch at the rising edge of CE. This way it will have some time before the next fetch can happen. I have OR-gated the CE of the EPROMs, and this will put some delay on the signal, but in my case it was of no importance, and you can always compensate by using a bit faster EPROM! Note, that on some microcontroller systems CE could be directly connected to ground. On these you could use the OE instead. Krister Wikstrom kwi@xxx.fi ------------------------------ From: Kalle Pihlajasaari Date: Wed, 28 Aug 1996 12:32:59 +0200 (sat) Subject: Re: switching between EPROMS Hi Warren, Long post about ROM switching > > If you switch it with the engine turned OFF, I don't think you'd have > > a problem. > > This is a simple solution, and will work, but.. > > I'd prefer to do it with the engine ON!!! I don't see any reason why it > cannot be done, provided the switch over is not done at a critical time, and > that the only difference between the EPROMS is the data: ie. the fuelling, > ignition timing, etc. Also it should be done quick enough so that the micro > does not miss an external data fetch (anyone know what the micro will do in > this case?? will it hang or retry? ). Hardware do not expect code memory fetches to be faulty, if this occurs you will execute garbage. Data fetches that are corrupt will be more transitory as the next time it checks it will get the right value, it may store the wrong value for a long time though so it is also a very bad idea. You cannot allow this to happen as you could get any number of fault conditions to occur, a hand would be relatively benign and the watchdog (if any) would reset it again but you would have to be ready for a boot sequence. You can use multiple EPROMS in parallel or as was mentioned you can use a larger EPROM and bank switch within it, either method is sound but having a 'known good' EPROM and then switching between 3 test units would be a nice thing in your application I think. For the single EPROM setup youcan get away with just one extra IC basically any type of latch with a width of however many address lines you want to change (8 programs would only need 3 lines) and you then use an external thumbwheel switch to load the latch inputs and feed the latch outputs to the high address lines of your EPROM. You would then use either the _OE or _CS line to latch the new selection onto the address lines. The latch will be fast enough to set the address lines for the current transfer if you have the correct edge in use but it will be easier to use the trailing edge of the last fetch to load in the new selection. You may be able to use either _SIGNAL in a rising edge latch or have to use _CS inverted on a falling edge latch this does depend some on how they select the ROM so you may have 4 combinations to try out _CS, _OE, CS or OE in a rising edge latch (DO NOT USE A LEVEL SENSITIVE LATCH) edge sensitive latches are often referred to as D-Flip-Flops. To use multiple ICs that you wish to gate the _CS signal you would be able to do it with 2 ICs by having a latch and a 3-to-8 line decoder chip with the 3 inputs from your latch and the _CS into one of the _EN inputs of the decoder. Cheers ,have fun, don't do this to someone elses car without warning them, you may still have occasional glitches if you get the latch enable polarity wrong, also if you change the latch with the wrong signal midway in a address fetch, CS is safer than OE in norma useage. > >has anyone made a device that you can plugs lots of EPROMs into, plug into > >your car ECU, and switch between them with a switch?? > > > >I want to make one for only 2 EPROMs, and was thinking of using a simple > >switch to switch the chip enable between the EPROMs. Will this work?? or > >will the time gap when neither of the EPROMs are enabled be enough to > >confuse the micro, and go into some unknown state? > > > >I could use latches and some simple logic chips to get around this I guess. You dont need to latch any of the common signals, just your extra ones. 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: Wed, 28 Aug 96 12:50:07 CET Subject: EPROM Switch >EX for to switch two 27128 chip you must have a 27256 and controll the pin >for the MSB Should be synchronized with MPU clock to avoid switching in the middle of an instruction or data transfer. And as someone said: the program must be exactly the same. >ignition timing, etc. Also it should be done quick enough so that the micro >does not miss an external data fetch (anyone know what the micro will do in >this case?? will it hang or retry? ). Quick enough _and_ outside an access cycle. If the access is to data, it would probably result in a tiny hiccup at worst. If it happens within a code fetch, it will with great probability set the MPU off track resulting in a hangup. For most sensibly designed controllers that again will trigger a watchdog and a total restart of the controller. Not the nice way to do it however. What signal you will need to synchronize with depends on the MPU used, and the hardware design of the system. For a Motorola 6800 family MPU the E clock should be suitable. In many designs you can use the OE or CS of the EPROM. Just a switch won't do. The switch noise if nothing else will stop that from working in a running system. Other problems may occur with an adaptive system that bases it's control upon previous experience. It may need to "go to scool" for a while after switching. It may even counteract your changes. Talking about hangup of controller: I had a car that often experienced a hiccup. It felt like the ignition cut totally for less than a second. But it always happened at the same place (within appx. 100m)! I blamed everything from a bad connector to my mobile phone until I found that it was connected with this specific location. Einar - -- einarp@xxx.no ( Maserati Biturbo Spyder ) ------------------------------ From: Chris Morriss Date: Thu, 22 Aug 1996 19:17:05 +0100 Subject: Manifold conversions. Does anyone have any experience in modifying manifolds to take EFI injectors? I wonder if anyone tell me if there is any source in the UK for adaptors to weld into a carb type manifold so that EFI injectors can be fitted. I do have the dimensions from Weber Alpha, so I could have some machined up and TIG welded into the manifold, but it would be less hassle to be able to buy them ready made. I know that such things are available in the US, having seen them in the book by Jeff Hartman. The manifold I want to modify isn't a carb one, but the one that is normally used with the Bosch mechanical injection (K-jetronic) on the Renault V6. (on this version of the engine, the mechanical injectors are in the head, not the manifold as on the EFI versions of the engine.) The manifold has two plenum chambers and cross-over inlet runners. I am informed that the flow on this is much better than on the normal Renault/Volvo/Peugot EFI manifold. (I would use two throttle bodies, one at the end of each plenum chamber. It's to convert an Alpine- Renault GTA to fuel injection). I know where the injectors should be fitted on the manifold, it's just the adapter bits I need. Thanks for any advice, - - Chris Morriss - -- Chris Morriss ------------------------------ From: "David M Parrish" Date: Wed, 28 Aug 1996 08:24:21 +0000 Subject: Re: Re[2]: real time dyno? > From: "John Faubion" > >2) You do not want to suck away 200 HP, only enough to cause an > >RPM drop. Yes, at higher torque, you need to suck away more torque > >to get a reliable RPM drop. > > I was told a few days ago that if you applied a known load to an engine you > could calculate engine torque using the know load and the amount of rpm > drop. Got any ideas on what the formula would be? Ah! So that's were that question came from! This is the first I've heard of such a method. - --- David Parrish Actually, my reply was rather tongue-in-cheek. ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Wed, 28 Aug 1996 07:48:58 -0500 Subject: Re: switching between EPROMS >> If you switch it with the engine turned OFF, I don't think you'd have >> a problem. >I'd prefer to do it with the engine ON!!! If you blew the EPROM, why don't you just code different sections, look for a logic input (read selection switch) and branch to the appropriate code?? Changing a computer's brain in mid-sentence is not a wise thing to do. tom ------------------------------ From: sebring@xxx.net (Jim Santoro) Date: Wed, 28 Aug 1996 12:42:36 GMT Subject: Re: My DIY EFI On Wed, 28 Aug 1996 08:51:08 +1000, you wrote: >Date sent: Wed, 21 Aug 1996 10:15:08 -0500 (CDT) >From: Robert Van Zant >To: diy_efi@xxx.edu >Subject: Re: My DIY EFI >Send reply to: diy_efi@xxx.edu > > >> >Could you give me more info about your system, and the cost of it? >> Ditto > > Me three. > >bob >rvanzant@xxx.net > > That makes me Four. > > Simon Tippett > Tippy@xxx.au > > Me too tdata@xxx.net ------------------------------ From: Thor Johnson Date: Wed, 28 Aug 1996 09:14:46 -0400 (EDT) Subject: Re: switching between EPROMS On Wed, 28 Aug 1996, Warren Crowther wrote: > > If you switch it with the engine turned OFF, I don't think you'd have > > a problem. > > This is a simple solution, and will work, but.. > > I'd prefer to do it with the engine ON!!! I don't see any reason why it > cannot be done, provided the switch over is not done at a critical time, and > that the only difference between the EPROMS is the data: ie. the fuelling, > ignition timing, etc. Also it should be done quick enough so that the micro > does not miss an external data fetch (anyone know what the micro will do in > this case?? will it hang or retry? ). If you switch when the uP is not reading or writing (look at uP docs), AND the uP doesn't copy the tables into another RAM chip (for speed..?), there shouldn't be any problems. Thor Johnson johnsont@xxx.edu http://falcon.mercer.peachnet.edu/~johnsont Have you seen the WarpMap lately? http://falcon.mercer.peachnet.edu/~johnsont/warpmap ------------------------------ From: Jody Shapiro Date: Wed, 28 Aug 1996 09:54:04 -0400 (EDT) Subject: Re: switching between EPROMS There was a company (Adaptive _______ ???) that used to make a product called the PROMPaq (I think) for the GM ECM's that would allow you to switch between up to 5 EPROM's using a rotary keyswitch. I believe that you could even do it while driving. There were articles (and a few installs) in magazines like Hot Rod, Car Craft, and Popular Hot Rodding a few years ago (1990 - 1993) - -Jody ------------------------------ From: Mark Pitts Date: Wed, 28 Aug 1996 16:34:46 +-200 Subject: RE: Manifold conversions. Chris, When fitting injectors, the collars need to be trimmed inside so that = its all flush (wouldn't want anything lowering the VE by putting a lump = in the flow now would we?) You aint going to believe this but, on a semi permanent basis, you can = epoxy (slow epoxy, overnight stuff) the adapters into the recesses of = the manifold! No the heat doesn't do too much damage. Works fine. = And.... Here is the good bit, point a blow torch down the hole in the = middle for a few seconds (till the epoxy smokes... dont breath the = fumes, they are harmful... and mores the point they STINK) and you will = find the epoxy has gone soft, and you can twist the injector seat back = out of the head. Dont try this trick with your EGOs guys.... The epoxy might just not = hold in that application! (You can do it with body filler as well! (Isopon, plastic padding etc)) Mark - ---------- From: Chris Morriss[SMTP:crsm@xxx.uk] Sent: Thursday, August 22, 1996 8:17 PM To: diy_efi@xxx.edu Subject: Manifold conversions. Does anyone have any experience in modifying manifolds to take EFI injectors? I wonder if anyone tell me if there is any source in the UK for adaptors to weld into a carb type manifold so that EFI injectors can be fitted. I do have the dimensions from Weber Alpha, so I could have some machined up and TIG welded into the manifold, but it would be less hassle to be able to buy them ready made. I know that such things are available in the US, having seen them in the book by Jeff Hartman. The manifold I want to modify isn't a carb one, but the one that is normally used with the Bosch mechanical injection (K-jetronic) on the Renault V6. (on this version of the engine, the mechanical injectors are in the head, not the manifold as on the EFI versions of the engine.) The manifold has two plenum chambers and cross-over inlet runners. I am informed that the flow on this is much better than on the normal Renault/Volvo/Peugot EFI manifold. (I would use two throttle bodies, one at the end of each plenum chamber. It's to convert an Alpine- Renault GTA to fuel injection). I know where the injectors should be fitted on the manifold, it's just the adapter bits I need. Thanks for any advice, - -=20 Chris Morriss - --=20 Chris Morriss ------------------------------ From: Mark Pitts Date: Wed, 28 Aug 1996 16:42:49 +-200 Subject: FW: *&**&^%$&^ Maths! Ok guys... sorry about the repost, but no one answered a desperate plea = for help. PS sorrry about the style, I was a little tiddly whaen I wrote it (half = a bottle of Jack Daniels tiddly!) Mark - ---------- From: Mark Pitts[SMTP:saxon@xxx.org] Sent: Saturday, August 17, 1996 4:50 PM To: 'DIY EFI' Subject: *&**&^%$&^ Maths! OK guys.. getting back to the nitty gritty here: I got a father with flare for mech eng. He has built some very nice, and = some serious cars. I'm nearly at the point of adding the I/O bits to the = uP core system, and I realy need to know what the formula for working = out Ignition times, and Injection pulse widths, based on any data = needed. What I'm after is the *BEST* control algo' that anybody knows = of, regardless of what sensors are needed (Either I'll implement them, = or just cut them out for now :-)). I've got a GOOD tame programmer, who = works for beer, so complexity no problem (I can even implement some = stuff in hardware, timers and such) I just dont care, all I want is the = MATH! Arrrrrggggghhhh. There I've said it! I've been reding bl**dy books = for 4 whole years now, and still cant decide for myself!=20 Please help before I give up, and go back to simple amps and curtain = closers, go mad, drink my self silly, and die dreaming of 11000 RPM and = 0-60 times in the low 4s. Sax. When all is said and done, RTFM. When the reply comes "WFM?", SHOUT = LOUD, AND ASK! TTFN! ------------------------------ From: korn@xxx. Korn) Date: Wed, 28 Aug 1996 10:18:16 -0400 (EDT) Subject: Re: switching between EPROMS I simply used a larger eprom and switched the extra address line. If the progran data is the same it shouldn't crash. to be completely safe use a latch to to pass the select bits only when ce is disabled ------------------------------ From: Wayne Braun Date: Wed, 28 Aug 1996 09:29:35 -0600 Subject: Re: Newer VATS Vehicles At 09:16 PM 8/27/96 -0500, you wrote: >At 07:49 AM 8/27/96 -0500, you wrote: >>>More and more GM vehicles are using VATS. The newer units are still a >> >>Okay, time for me to ask the dumb question: what's VATS ? >> >>tom cloud > >Vehicle Anti Theft System. Uses resister coded key and matched module to >inform the ECM if the original key is used. A fail signal causes the ecm to >not fire the injectors. Bottom line... this system make the car less >attractive to the novice thief. Any one out there with statistics on Vette >thiefts before and after Vats?? > >gmd > I donm't know about vettes, but I recently watched a program on A&E about stolen vehicles. The year that GM started putting the VATS stuff into the camero/firebird theft dropped something like 75%. This same program re-stated a couple of things; 1 - If you make it difficult or inconvenient for the thief to steal the vehicle, many times they will go somewhere else. Using items like " The Club " actually do in many cases cause the thief to go find an easier target. 2 - If the thief is REALLY intent on stealing your car, he/she will. No matter what you do to try to stop the thief, if they are that intent on getting this particular vehicle they WILL find a way to do so. Regards Wayne Braun ------------------------------ From: Bob_Tillman@xxx.com Date: Wed, 28 Aug 96 11:38:18 -0400 Subject: Hello Hi all - I've newly subscribed to this list, so I thought I'd introduce myself. I'm Bob Tillman, a software engineer by trade, and an auto enthusiast. My interest in DIY EFI came about after my recent purchase of a '96 VW GTI-VR6. I am interested in the challenge of trying to figure out what its Motronic code looks like. I have no big plans to hack it (yet!) but I may if I can figure out what's going on in there. I am able to get a dump from a '95 rom, but I don't feel like voiding my warranty to get at the rom in my car. As I'm sure you all know, the '95 and '96 systems differ in that '96 has OBD-II... I also have experience in disassembly and writing disassemblers, so I'm not totally in the dark as far as that goes. Hopefully this is the right forum for these questions. If not, my apologies... :) My questions: 1) Am I re-inventing the wheel? Has anyone out there already disassembled modern Motronic code, and are the results freely available? 2) How different is the Motronic code between manufacturers? Will my VW's code be markedly different from, say, a contemporary BMW's (excepting fuel/ignition tables, of course)? 2.5) Are the Motronic ECU's similar (or identical?) in hardware design between manufacturers (VW vs BMW, for example)? 3) Is there an easy (and cheap;) way to get a dump of a '96 GTI-VR6 ROM without having to dig into my own ECU? 4) Does anyone know what processor my car's ECU has? I'm guessing MCS-96, from a BMW FAQ I found... 5) I don't think I'd doing anything illegal, am I (copyright infringement, etc.)? Thanks for your input... Cheers, - - Bob T. ------------------------------ From: Donald Whisnant Date: Wed, 28 Aug 1996 11:55:07 -0400 Subject: Re: switching between EPROMS > From: Warren Crowther > Date: Wed, 28 Aug 1996 21:06:11 +1200 > Subject: Re: switching between EPROMS > > > If you switch it with the engine turned OFF, I don't think you'd have > > a problem. > > This is a simple solution, and will work, but.. > > I'd prefer to do it with the engine ON!!! I don't see any reason why it > cannot be done, provided the switch over is not done at a critical time, and > that the only difference between the EPROMS is the data: ie. the fuelling, > ignition timing, etc. Also it should be done quick enough so that the micro > does not miss an external data fetch (anyone know what the micro will do in > this case?? will it hang or retry? ). > > Warren > Warren... It will hang... The micro doesn't have any way of knowing what is "supposed" to be out there... So during the switch, if it is in the middle of a cycle, if the data values going to the micro get goofy, the micro will end up executing the "goofy code" and not what it should... If you are real lucky and happen to hit it on a "inconsequental" instruction, nothing will happen except maybe a slight glitch... At worst case, it will lockup and totally stop... What I'm planning to do (eventually) is to use a couple of EEPROMs that I can program with my PC --- one EEPROM just has a "selector" byte telling the little bit of logic I have weither to take the values from EPROM or EEPROM. With a little bit of addition, a switch could be added along with a small circuit that would synchronize the micro's access to the rom so that the switch won't cause a problem... The logic could be as simple as a flip/flop. i.e. the "switch" goes into the data input on the flip/flop. The flip/flop is clocked by the end of the E-clock cycle of the micro. And the output of the flip/flop is sent to the enable of the rom's (i.e. either a upper bit if you are using a 2x sized rom or to a circuit that will "and" the enables with the CPU enables) ... Sounds simple enough to implement... Good luck... Donald Whisnant dewhisna@xxx.com ------------------------------ From: Sandy Date: Wed, 28 Aug 1996 09:04:43 -0700 Subject: Re: switching between EPROMS You could also buy a ROM simulator, and just change the needed values. I have the DATAMAN S3, and it is a bit overkill, but you can plug it into a byte wide rom socket, and change blocks of memory if needed. You could also get a low cost plug in simulator, and use a laptop to change much of what you need. Sandy ------------------------------ From: Kalle Pihlajasaari Date: Wed, 28 Aug 1996 17:57:02 +0200 (sat) Subject: Re: switching between EPROMS Hi, > If you switch when the uP is not reading or writing (look at uP docs), > AND the uP doesn't copy the tables into another RAM chip (for speed..?), > there shouldn't be any problems. In addition to the simple switching I described you would have to be very carefull if there are word constants stored in the area that will change between versions as you may switch between the two byte reads and read a number that is way out of bounds. old number 0123 = 291 dec new number 00e8 = 232 dec one old byte and one new byte 01e8 = 488 dec 0023 = 35 dec These may be out of bounds and cause a jump table to do the wrong thing (code dependant) and only if the change is between the two bytes in a word. There may obviously be congruency problems with the rest of the data unless the changes are kept small. You could improve the hardware I described by gating one of the low address lines with the latch signal so you will only switch when fetching in low memory (processor dependant). This will add another IC at least to the one or two. Switch debouncing will not be a significant problem if the data is allowed to be a mix of more than one version during the time the switch bounces, every read will be a good read but from a indeterminate version for a few read cycles. Cheers. - -- Kalle Pihlajasaari kalle@xxx.za Interface Products Box 15775, Doornfontein, 2028, South Africa +27 (11) 402-7750 Fax: +27 (11) 402-7751 ------------------------------ From: Chuck Tomlinson Date: Wed, 28 Aug 1996 12:42:21 -0400 Subject: TPIS Big Ram? Hi folks, Tuned Port Injection Specialties (TPIS) makes the LT1-like MiniRam manifold for pre-LT1 small block Chevys, and they also make a "Big Ram" for big block Chevys. Does anyone know what the Big Ram looks like? I am looking for a low-profile EFI manifold for a big block (it needs to fit under a stock late-model Corvette hood). Does the Big Ram fit the bill? Thanks, Chuck Tomlinson. ------------------------------ From: "George Najarian" Date: Wed, 28 Aug 96 10:14:45 -0800 Subject: Re: real time dyno? Instead of some sort of strain gauge attached somewhere to a driveshaft or axle, can't you just measure driveshaft twist? It makes the sensors and attachment much simpler, but I am unsure of the resolution. George Najarian | '95 Ford Mustang GTS E/SP (14.21/100.81) najay@xxx.0/93) http://users.deltanet.com/~najay/ Team.Net Team OS/2 ------------------------------ From: cloud@xxx.edu (Tom Cloud) Date: Wed, 28 Aug 1996 12:59:20 -0500 Subject: [none] ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Wed, 28 Aug 1996 13:10:32 -0500 Subject: FORD EEC-xx Okay, the EEC thread seems to have died and I'd like to revive it. I've heard from the following people: "James V. Pearl/QSI" <@xxx._Pearl/QSI@QSI> ***** [I am unable to respond to this address -- any clues?] **** Jonathan Lloyd Sven Pruett Tom Cloud Mike Wesley To: tom cloud Subject: Re: EEC control On Mon, 19 Aug 1996, tom cloud wrote: > Mike, > > A member of the DYI_EFI group gave me your name as developing a > controller for Ford EEC. If so, please let me know. Well, I doing calibration hardware for them. I make 'chips' and I'm finishing up a device called the Calibrator which allows you to hook at laptop to the EEC-IV/V and change whatever you want. Mike... = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Surely someone has tackled -- and probably even solved -- this riddle, so please, let's hear from you. What's "FordNatics" list ? Someone mentioned it and I'd like to find it. Thanks, Tom Cloud ------------------------------ From: cloud@xxx.edu (Tom Cloud) Date: Wed, 28 Aug 1996 12:01:03 -0500 Subject: [none] ------------------------------ From: cloud@xxx.edu (Tom Cloud) Date: Wed, 28 Aug 1996 12:48:27 -0500 Subject: [none] ------------------------------ From: cloud@xxx.edu (Tom Cloud) Date: Wed, 28 Aug 1996 12:36:20 -0500 Subject: [none] ------------------------------ From: cloud@xxx.edu (Tom Cloud) Date: Wed, 28 Aug 1996 12:37:31 -0500 Subject: [none] ------------------------------ From: Rick Lindstedt Date: Wed, 28 Aug 1996 13:47:56 -0500 Subject: Re: TPIS Big Ram? Chuck Tomlinson wrote: >Does anyone know what the Big Ram looks like? I am looking for a Yep ...just like the "Mini" Ram for the small blocks but taller >low-profile EFI manifold for a big block (it needs to fit under a >stock late-model Corvette hood). Does the Big Ram fit the bill? I dont think it would fit...they are pretty tall. but I bet you can call TPIS and get a height dimension [to know for sure] to see if it would fit...but my guess is it will not fit under the hood. =( >Thanks, >Chuck Tomlinson. Rick ------------------------------ From: "Terry McLane 312.630.0533" Date: Wed, 28 Aug 1996 14:27:41 CDT Subject: Bosch MAF to Hitachi MAF I am wondering if anyone can help me. I have a car with a Bosch style MAF on it using the velocity meter approach of the L-Jetronic. Since the MAF is on a Turbo car, I would like to replace the restrictive velocity meter with one of the new non-restrictive Hitachi units like those that are used on the new 3800 Series II. Both use a 5V reference, but the Bosch reads low when maxed out, the Hitach reads high when maxed out. My questions are : Is there an easy way to invert the voltage signal from the Hitachi to the ECU? Is there any way to also adjust the low/hi voltage signals, and interpolate between them? If I could get the voltage of both units at a set of RPM (idle, max torque), it would be nice to get a smooth interpolation. Being a software engineer (without a background in electronics), I am turning to this group for help. Thanks :-) e-mail: tm8@xxx.com ------------------------------ From: Todd Knighton Date: Mon, 26 Aug 1996 09:53:44 -0700 Subject: Re: EFI Conv. > >From what I understand, the ECM designed for the peak and hold type can use > the saturated injectors with out problems but not vice versa. However from > the looks of it should be a simple process to design a board to use a peak > and hold injector driver to take the signal from the ECM and fire the > injectors. This way we won't hurt the ECM and you could use either injector > type. > Yeah, we've had to do that. Good injectors beyond 36#/hr arent available in 15 ohm. As well as at high pressure (above 5 bar) they stick close because of the limited driver type. They're slower, not repeatable, etc etc etc. We had to make drivers that would invert the output of the computer, then drive a typical peak and hold circuit. The trick was, on late model OBD I and II cars, they look for faulty injectors, so you need to place a load resistor on the output. Not much, but just enough that the computer still thinks theres an injector out there. Otherwise the drivers work great. Todd Knighton Protomotive Engineering ------------------------------ From: Corey Stup Date: Mon, 26 Aug 1996 12:46:12 -0400 Subject: Re: speaking of displays & DPM Fred Miranda wrote: > > Maybe I have an odd LCD pannel (2x20, I doubt it). Mine turns black when the > car warms up in the sun. Sounds more like the components used for adjusting contrast are changing values due to the heat... ------------------------------ From: dave.williams@xxx.us (Dave Williams) Date: Wed, 28 Aug 1996 15:05:00 +0000 Subject: Manifold conversions. - -> I wonder if anyone tell me if there is any source in the UK for - -> adaptors to weld into a carb type manifold so that EFI injectors can - -> be fitted. MSD and Kinsler sell the injector holders for around US $5 each. ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Wed, 28 Aug 1996 15:50:36 -0500 Subject: Re: Real time dyno >So, the acceleration thing, is not only not practical for on the road >use, but doesn't really give much results either. >An EGO sensor and a knock sensor from J&S with a monitor will get you >calibrated 10 times faster. Don't worry about the changes till you're >done then record the results and get a graph or something. The basic >engine combination is more of a factor to record changes, the tuning is >just set up for a specific engine combo. > Todd, My specific requirement has been to tune my current (Holley) EFI. The Idle, Midrange, Accelerator Pump, and Choke adjustments are simple enough. It's the Power adjustment that's too darned subjective for me. I used my EGO (but it's probably deteriorated with age -- ~ 14 years and 150,000 miles), and, of course, it tells me I'm either rich or richer. And frankly, I'm not one to want to do a bunch of timed runs to find the optimum setting. Seems to me being able to adjust acceleration for a peak would be a good way to adjust operation at WOT (understand I have a little more than 4 or 5 seconds to work with here). So, what's a J&S knock sensor? Tom Cloud ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Wed, 28 Aug 1996 17:04:35 -0500 Subject: Re: Bosch MAF to Hitachi MAF > Is there an easy way to invert the voltage signal from the Hitachi to > the ECU? +------R2----+ | |\ | in --- R1 -+-|- \ | | \_____|____ out | / +--|+ / | |/ R3 | (gnd)--pot--(max offset) Maybe simple op-amp inverter (LF-351, LF-356, uA-741). For single supply (i.e. if running too close to 0 or plus 12) use one of LM-324. Adjust the (inverting) gain with R2. Z-in is set with R1. R3 can be zero. The pot will allow for an offset, if needed. For example, if present app output is 0 to 4 volt, and want 4 to 0, feed output of sensor into R1 and set gain = -1 by making R1 = R2. Consider that the output/input are like a see-saw centered on the offset voltage set at the pot. So, since you want 4 in to make 0 out, set the offset at 2 volts. Then, 4v in = 0 v out, 2 v in = 2 volts out, and 0 volts in = 4 volts out. Voila'. tom ------------------------------ From: Chuck Tomlinson Date: Wed, 28 Aug 1996 19:24:01 -0400 Subject: Re: TPIS Big Ram? At 01:47 PM 8/28/96 -0500, you wrote: >Chuck Tomlinson wrote: >>Does anyone know what the Big Ram looks like? I am looking for a > >Yep ...just like the "Mini" Ram for the small blocks but taller > >>low-profile EFI manifold for a big block (it needs to fit under a >>stock late-model Corvette hood). Does the Big Ram fit the bill? > >I dont think it would fit...they are pretty tall. but I bet you can call >TPIS and get a height dimension [to know for sure] to see if it would >fit...but my guess is it will not fit under the hood. =( Thanks for the info. I'll give them a call and get some dimensions. I'm still a bit hopeful because the big block is less than an inch taller than the small block at the top of the block. No doubt the Big Ram is taller than the Mini Ram/LT1 manifold, but late model Vettes have room for the older TPI manifold, which I think is at least 2" taller than the LT1 manifold. Later. Chuck Tomlinson [fingers crossed] ------------------------------ From: Todd Knighton Date: Wed, 28 Aug 1996 17:47:01 -0700 Subject: Re: switching between EPROMS Sandy wrote: > > You could also buy a ROM simulator, and just change the needed values. I > have the DATAMAN S3, and it is a bit overkill, but you can plug it into a > byte wide rom socket, and change blocks of memory if needed. You could also > get a low cost plug in simulator, and use a laptop to change much of what > you need. > > Sandy Or even better is the Unirom, by Tech Tools, it will allow code changes on the fly. I've also got a Dataman, but S4 not S3, and it's a great tool, but to make changes, you need to shut the engine down. Todd Knighton Protomotive Engineering ------------------------------ From: Todd Knighton Date: Wed, 28 Aug 1996 17:45:41 -0700 Subject: Re: Real time dyno tom cloud wrote: > > My specific requirement has been to tune my current (Holley) EFI. > The Idle, Midrange, Accelerator Pump, and Choke adjustments are > simple enough. It's the Power adjustment that's too darned > subjective for me. I used my EGO (but it's probably deteriorated > with age -- ~ 14 years and 150,000 miles), and, of course, it tells > me I'm either rich or richer. And frankly, I'm not one to want to > do a bunch of timed runs to find the optimum setting. Seems to me > being able to adjust acceleration for a peak would be a good way > to adjust operation at WOT (understand I have a little more than > 4 or 5 seconds to work with here). > > So, what's a J&S knock sensor? > > Tom Cloud Get a good EGO sensor firts, then something that will tell you when you're in the 12.8 to 13.3 range, if you're running on Normal Gasoline and normally aspirated. That will be you're peak power range. Have never found a resource to tell me differently. If you calibrate for acceleration, you might burn the motor up before you find it. Most engines like leaner settings to produce peak power, but they don't last long there. A J&S knock sensor is an aftermarket knock sensor unit that will intercept the ignition signal and alter it according to individual cylinder knock. He's also got a monitor that will tell you how much each cylinder, or group, is retarding so you can go back and adjust your timing till no lights come on. Works great for a calibration tool. Listed his phone and address for someone else in a previous post today. Todd Knighton Protomotive Engineering ------------------------------ From: Todd Knighton Date: Wed, 28 Aug 1996 17:48:44 -0700 Subject: Re: switching between EPROMS Jody Shapiro wrote: > > There was a company (Adaptive _______ ???) that used to make a product > called the PROMPaq (I think) for the GM ECM's that would allow you to > switch between up to 5 EPROM's using a rotary keyswitch. I believe that > you could even do it while driving. > > There were articles (and a few installs) in magazines like Hot Rod, Car > Craft, and Popular Hot Rodding a few years ago (1990 - 1993) > > -Jody Give Autothority Performance Engineering a call, they've distributed that PromPaq for a couple of years. They're in Virginia, as well as every magazing known to man. You're code changing will work fine if all you're changing is maps between chips. If you're changing actual code it WILL HANG. Been there done that. Todd Knighton Protomotive Engineering ------------------------------ From: "John Faubion" Date: Wed, 28 Aug 1996 19:45:33 -0500 Subject: Re: Re[2]: real time dyno? > > >2) You do not want to suck away 200 HP, only enough to cause an > > >RPM drop. Yes, at higher torque, you need to suck away more torque > > >to get a reliable RPM drop. > > > > I was told a few days ago that if you applied a known load to an engine you > > could calculate engine torque using the known load and the amount of rpm > > drop. Got any ideas on what the formula would be? > > Ah! So that's were that question came from! This is the first I've > heard of such a method. Considering that you mentioned it here first, how about a bit of explanation? John Faubion jfaubion@xxx.net ------------------------------ End of DIY_EFI Digest V1 #251 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. 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