DIY_EFI Digest Wednesday, August 11 1999 Volume 04 : Number 462 In this issue: Re:: ALDL Connectors Re: Turbo header design Re: DIY_EFI Digest V4 #461 Injector firing points Bosch AMM (MAF) adjustment screw See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Tue, 10 Aug 1999 16:26:35 +0000 From: xxalexx@xxx.com Subject: Re:: ALDL Connectors > I have 16 pin connectors, and looking for new sources. > Alex > http://www.obd-2.com > and a welcome back to CSH-HQ > > > Subject: ALDL Connectors > > > > Been posted in the DIY archives. Both 12+16. Try OBD for the 16 in search > > Bruce > > > > > > Date: Sat, 7 Aug 1999 19:58:45 EDT > > >From: Mikepoore@xxx.com > > >Subject: Looking for ALDL connectors > > > > > >Does anyone know where I can find 12 pin and 16 pin GM ALDL connectors? I am > > >looking for the male ends. I've got my interface working, but I would like to > > >connect and disconnect it a little easier than pin by pin. > > > > > >Mike Poore > > > > ------------------------------ Date: Tue, 10 Aug 1999 16:56:01 -0600 From: "Kevin Yachimec" Subject: Re: Turbo header design I missed the part of this post that stated the intended use of the vehicle in question, so the following information may not apply. If the header/manifold is for a street turbo application there is no measurable gain by using a tuned the length header unless you using a pulse type turbine and housing designed for receiving exhaust pulses. Most turbos you find on production vehicles have the best results if the manifold smoothes out all the pulses into a constant flow with heat lost being minimized. I have a promotional paper from Allied Signal outlining manifold design for their turbos. It covers both their new pulse type turbos (like the ones you see on all those 10 second Honda's with equal length headers) and their standard turbos, if I can find it I'll post it 'incoming'. >Greg Hermann wrote: > > > FOR THIS PARTICULAR V-8> (IT HAS A 90 degree crank) > > Firing order > > 1 8 4 3 6 5 7 2 > > With this firing order, take every other cylinder in the firing order if > you want 180 degree (crank rotation) spaced pulses into a pair of 4 into 1 > collectors: > > 1, 4, 6, & 7 go into one collector (two end cylinders from one bank, and > the two center cylinders from the other bank. > > 8, 3, 5, & 2 go into the other collector. (the two end cylinders on the > other side, and the two middles from the first side. > > If you want PROPERLY done tri-wyes, go 1/2 way around the firing order, so > that the pulses in the pairs of tubes which combine at the first wye are > spaced evenly, 360 (crank) degrees apart: > > 1 & 6; 8 &5; 4 & 7; 3 & 2. As you can see, each pair takes one tube from > each bank of the motor. > > Then, at the second wye, pair 1-6 with 4-7 and pair 8-5 with 3-2 so as to > get evenly spaced pulses at the second wye in each header. > > If you wanna go with REALLY long tri-wye branches, (surprising how > fantastically good this is for street, high torque, & 4x4 type apps.) start > out with a regular set of 4 into one headers (of the smallest tube size you > can find), cut them off a bit before the collectors, and do the snaking > back and forth under the bell housing/tranny to get the correct first wye > pairings. The second branches want to be the same length as the first ones, > but there are no crossovers if you plan ahead. After the four second > branches combine into two (tertiary) pipes, you want a length of pipe of > length equal to all the first and second branches. At the end of that pipe, > you need a gap (no diameter change of offset in the pipe) in the pipe about > 3/4 inch long. Put an empty plenum chamber around that gap. The volume of > the plenum needs to be maybe double the internal volume of the last > (single) length of pipe feeding it. Just run a full size tail pipe and low > restriction muffler behind the plenum (Not much vehicle length left after > this, anyway!) > The headers will effectively see the plenum as an open ended (to > atmosphere) pipe. DO NOT omit the plenum, it is worth quite a bit of HP and > response! > For street stuff, usually, primary tubes 1 trade size SMALLER than the size > which can be swedged square to fit into a flange and match the port > properly work out to be the correct size. (If a 1-7/8" tube can be squared > at one end and fitted into a flange so that the inside of that tube matches > the port shape, then run the primary tubes with 1-3/4 " tubing.) You want > the internal AREA of your primary tubes to be about equal to the > cros-sectional AREA of the exhaust port. The above is what usually works > out right. (Especially if the engine designer did his homework!) The extra > work involved in getting down to the smaller tube size is why most off the > shelf headers use too big a tube size! Figure the length of the primary > tubes so that each of their internal volumes is about 140% of the > displacement of an individual cylinder. (For instance, for a 350 cid V-8, > using 1-3/4" tubes (which are about 1-5/8" inside diameter in 16 gauge > tube, this would mean you want (at least) 24 inch long primary tubes.) (And > if you are using lighter than 16 gauge tubing, don't bother!) > If the primaries are 1-3/4", then 2" is usually about right for the > secondaries, and 2-1/4" for the next ones. (A quarter inch increase in tube > size at each successive wye is usually about right. > > 1-3/4" diameter primary tube size was only an example. It is prolly BIG for > a street 350, 1-5/8" or 1-1/2" is more likely to be right (but with more > tube length so as to get to the same internal tube volume!) > > If you build a set of tri-wyes this way, they will sound and run like > nothing else! The throttle response will be astounding! But it is a ROYAL > pain in the #@$% to do it! > > All my experience says that the biggest gain from headers is from giving as > much of the exhaust gas as possible somewhere to go freely during the > "blowdown" part of the exhaust stroke--before the piston starts back up > significantly. Yes, it's nice to have a low pressure pulse in the exhaust > port at overlap, and that pulse helps to scavenge clearance gasses if you > have it there at the right time, but the longer you can keep the blowdown > stage flow sonic, the less work the engine will have to waste pumping > exhaust gas out of its cylinders, and the more sonic energy there will be > available for creation of a scavenging pulse! > > Regards, Greg > Kevin Yachimec Cybertech Automation Inc. (780)483-6222 Ext. 118 keviny@xxx.ca ------------------------------ Date: Tue, 10 Aug 1999 22:23:38 EDT From: ARoss10661@xxx.com Subject: Re: DIY_EFI Digest V4 #461 In a message dated 8/10/99 2:29:46 PM Central Daylight Time, DIY_EFI-Digest-Owner@xxx.edu writes: << From: JMACKENZ@xxx.com Subject: PC based engine management system Hi, I'm new to the digest and have joined because I've set myself a long term project to design and build a road legal drag car (ie nothing too stupid or expensive) for which the engine is fully managed from a laptop computer. I'm doing this mainly as a challenge for fun and will share all my results / code etc when I have anything worthwhile. I've never attempted anything like this before and any cars which I have built previously have always used carbs rather than EFI but I will put the effort in to make sure I succeed. My knowledge of the workings of common engine management systems is very limited and this is the first area which I need to learn about. Does anyone have a good document or website which describes basics / details of the engine management system including the fuel maps? I'm also looking for a description of the what is sensed from the engine (ie airflow / MAP / oil / water temperature / crank position etc) and what effect this has on the fuel delivery volume / timing and the ignition timing? Also I need to figure out or buy an input / output device for the laptop (PCMCIA / Parallel / RS232 ?) which will allow me to sample all the inputs and output to fuel injectors etc. Any advice on this would be most appreciated! What I'm looking to achieve initially is to have an engine (very probably a Rover V8 from a 1984 Rovertec Vitesse) for which the fuel delivery is managed via a hardware interface to a laptop which runs custom written software. I would then like to add in the ignition timing then a supercharger or Janspeed twin turbo setup (or both). Eventually my goal would be to include servo throttle control and other stuff to basically allow the car to drag a 1/4 mile based on an optimised program without any driver intervention except for steering! I know this is a huge never-ending project but it'll keep me entertained for a long while and it'll be worth it in the long term. I know I'll destroy numerous engine parts. I'm lucky that I have a lot of technical support and enthusiasm from friends. I'm aware that the first year will be spent in the garage but this is no different to most of my projects! In addition to standard tools, the equipment I have (or have access to) includes the following; Emmisions meter Numerous volt / current etc meters Digital oscilloscope EEPROM programmer My background - I'm a degree qualified Electronic / Mechanical engineer with a great interest in cars. I work in IBM as a senior WW test engineer for Thinkpad (Laptops) manufacturing which means that I can program in C / Turbo Pascal and Rexx and have a pretty good understanding of computers. Working in IBM also gives me access to the skills required for ciircuit design etc which I'm a bit rusty on myself. I will be working closely with a friend who has a lot of experience with building strange cars and engines but he also has little knowledge of EFI systems. If anyone can offer me any initial (and hopefully ongoing) help and support then I would be most appreciative. I am a complete novice in this field just now but I'm a fast learner if I get the help I need. Best Regards James MacKenzie ------------------------------ >> James, This sounds like a fantastic project let me know if I can be of help (similar interests lesser credentials) Al ------------------------------ Date: Wed, 11 Aug 1999 14:58:14 +1200 From: "Nicholas Parker" Subject: Injector firing points This is a multi-part message in MIME format. - ------=_NextPart_000_000F_01BEE409.EFF80500 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi, I've sort of jumped the gun here. I have already written the guts of an open loop sequential fuel = injection and ignition unit in assembler for an 80c552 (8051 variant), = uses map , rpm , coolant temp so far. I've only tested it with a scope = on a bench (along with pulse inputs and a MAP sensor..) Now I have an Infineon (Siemens) developement kit for the 167 mpu (16 = bit, all features and instructions you can possibly imagine + a big = errata sheet ahem....) and I'm starting to code an ecu in C because, = shit its easy to do floating point maths! and plus the 167 is so fast = you can write in C and not be hugely clever (Microsofts motto ?) like = when you're using an 8051 based slug..not that you need it. My = application is sequention injection in a 4 cyl, my question is; When do = injectors fire ? What I think I know: The injector in question should fire after the appropriate inlet = valve(s) are open, and subtract from this position, the time required = for the injector to open etc..problem is I have heard that injectors = stay on from 6- 8 ms. How can this be ? At 7500rpm, you've got only 4ms / 180degs of crank = rotation ? 8ms sounds too much, even when I imagine the momentum of the intake air stopping 'itself' it = coming out the intake valve when the piston is beginning to compress the = mixture...? Anyone know a very ugly approx for injector pulse width, based on = cylinder size, inj flow rate, and manifold pressure...If I wasn't lazy = I'd make and rig up a 'logger' to my car.... Also do most factory cars (say 4 cyl for this question) have a = distribtor sensor that gives a pulse for each cyclinder when its say 50 = degs before tdc , so that only a delay 0- 50 degs (for example) is = required to generate all possible igntion firing points ? (This is what = I implemented in my 80c552 system). I have got such a distributor off of a friend, but unfortunately, no info as to its angle = relative to cam/crank. Thanks, Nick Parker. - ------=_NextPart_000_000F_01BEE409.EFF80500 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi,
 
I've sort of jumped the gun here.
I have already written the guts of an open loop = sequential=20 fuel injection  and ignition unit in assembler for an 80c552 = (8051=20 variant), uses map , rpm , coolant temp so = far.  I've only tested it with a scope on a bench
(along with pulse inputs and a MAP = sensor..)
 
Now I have an Infineon (Siemens) developement kit = for the 167=20 mpu (16 bit, all features and instructions you can possibly imagine + a = big=20 errata sheet ahem....) and I'm starting to code an ecu in C=20 because, shit its easy to do floating point maths! and plus the 167 is = so fast=20 you can write in C and not be hugely clever (Microsofts motto ?) like = when=20 you're using an 8051 based slug..not that you need it.  = My application is sequention injection in a 4=20 cyl, my question is;  When do = injectors fire=20 ?  What I think I know:
 
The  injector in question = should fire after the=20 appropriate inlet valve(s) are open, and subtract from this position, = the time=20 required for the injector to open etc..problem is = I have=20 heard that injectors stay on from 6- 8 ms.
How can this be ?  At 7500rpm, you've got only = 4ms /=20 180degs of crank rotation ? 8ms sounds too much,
even when I imagine the momentum of the intake air = stopping=20 'itself' it coming out the intake valve when the piston is beginning to = compress=20 the mixture...?
 
Anyone know a very ugly approx for injector pulse = width, based=20 on cylinder size, inj flow rate, and manifold pressure...If I wasn't = lazy I'd=20 make and rig up a 'logger' to my car....
 
Also do most factory cars (say 4 cyl for this = question) have a=20 distribtor sensor that gives a pulse for each cyclinder when its say 50 = degs=20 before tdc , so that only a delay 0- 50 degs (for example) is = required to=20 generate all possible igntion firing points ?  (This is what I = implemented=20 in my 80c552 system).    I have got such a
distributor off of a friend, but unfortunately, no = info as to=20 its angle relative to cam/crank.
 
 
Thanks,
Nick Parker.
- ------=_NextPart_000_000F_01BEE409.EFF80500-- ------------------------------ Date: Wed, 11 Aug 1999 00:00:29 -0400 From: bjanesi@xxx.com Subject: Bosch AMM (MAF) adjustment screw I am investigating the replacment of my stock VAF meter (Merkur XR4Ti) with a Bosch AMM, as used in many (Saab, Volvo, MB) LH-Jetronic equipped cars. And yes, I do know about the Pro-M MAF replacement (that would be too easy). As you may know, there is an adjustment screw on the Air Mass Meter, used for fine tuning of the idle mixture. My question... What specifically is being adjusted here? I always assumed it was the base voltage output from the hot-wire. However, I've recently been told (by someone who seemed to know what they were talking about), that this is an entirely separate circuit which adjusts the injector pulse width at idle (only). Anyone have some definitive data on this? If it is a separate circuit, that makes this a more challenging project since this function would not be supported in the Ford EEC-IV found in the Merkur. Specifically, I have an AMM from a Volvo 230FT motor (2.3L Turbo); Bosch p/n 0 280 212 007. If anyone happens to have the schematic for this, that would be real helpful. Thanks, Brad Anesi '88 Merkur XR4Ti 5-speed '91 Alfa Project 164Q 5-speed ___________________________________________________________________ Get the Internet just the way you want it. Free software, free e-mail, and free Internet access for a month! Try Juno Web: http://dl.www.juno.com/dynoget/tagj. ------------------------------ End of DIY_EFI Digest V4 #462 ***************************** 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".