DIY_EFI Digest Tuesday, 16 July 1996 Volume 01 : Number 199 In this issue: Report on failed mail Re: oil control RE: EFI--Bosch Motronic Re[2]: oil control RE: EFI--Bosch Motronic Re: oil control Re: oil control Re: RE: EFI See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: nmail-daemon@xxx.com Date: Mon, 15 Jul 96 05:45:27 EDT Subject: Report on failed mail Errors were detected when processing your mail message which was entered at 12-JUL-1996 05:33 From: US4RMC::"diy_efi@xxx.edu" To: DIY_EFI-Digest@xxx.edu Subj: DIY_EFI Digest V1 #196 - ---------------- The following error message was returned whilst sending to address SPESHR::M_MCDONALD %MAIL-E-OPENOUT, error opening !AS as output -RMS-E-CRE, ACP file create failed -SYSTEM-F-EXDISKQUOTA, disk quota exceeded This is a soft error, but the retry period has expired. No more attempts to send to this address will be made. - ---------------- The text of your failed mail message follows: DIY_EFI Digest Friday, 12 July 1996 Volume 01 : Number 196 In this issue: Non-Electronic Materials Suppliers RE: Bosch ECU Schematics Non-Electronic Materials Suppliers re: Re: cypress FPGA tools Re: Non-Electronic Materials Suppliers ALDL Communications... Re: Bosch Motronic AFM Spring Tension - Further Comments Re: Bosch Motronic AFM Spring Tension - Further Comments RE: GM mass airflow sensor Re: ALDL Communications... Re: GM Mass Airflow Sensor RE: EFI See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. - ---------------------------------------------------------------------- From: ljp2@xxx. Plebani) Date: Thu, 11 Jul 1996 08:51:52 EDT Subject: Non-Electronic Materials Suppliers As part of my efi project I need to fabricate a manifold for my 427 ci FE block Ford. In order to evaluate design alternatives, I would like to be aware of the availability and price of potential components. Could someone suggest suppliers for injectors, fuel rails, throttle bodies, Weber throttle bodies (with injector boss), pumps, regulators, etc. Lou Plebani ljp2@xxx.edu - ------------------------------ From: "Orin Harding" Date: Thu, 11 Jul 96 08:54:55 UT Subject: RE: Bosch ECU Schematics I don't know if this will be what you're looking for, but there is a company in the UK that makes what they call an "implant" for the BOSCH Motronic. This allows complete user programming of the Motronic ECU. The company is: General Engine Management Systems Limited Unit A1/D, Thorpe Techno Park Crabtree Road, Egham, Surrey, TW2 8RN, England Phone: +44 (0) 784 470525 Fax: +44 (0) 784 470527 Contact name: Richard Armitage Hope this helps Orin Primary e-mail address: orin@xxx.com Secondary e-mail address: NAMGBR@xxx.net Check our WEB site: www.deltacp.com Phone/Fax: (910) 854-3232 Mobil Phone: (910) 601-8418 - - ---------- From: owner-diy_efi@xxx.edu on behalf of John Dammeyer Sent: Thursday, July 11, 1996 7:33 AM To: diy_efi@xxx.edu Subject: Re: Bosch ECU Schematics At 06:09 PM 10/07/1996 -0400, you wrote: >At 02:31 PM 6/11/96 +0000, you wrote: >>I am looking for Bosch ECU Schematics for the following cars: >> >>BMW 530i, 1978 >>Datsun 280Z, 1975-1978 >>Datsun/Nissan 280ZX, 1979-1983 (incl. turbo). >> >>If anyone has any schematics for the ECUs for these cars, any or all >>of them, in any format, please let me know. Also, if anyone knows of >>any good source of information on these systems, I'd love to see it. >> As I understand it the Bosch uses the CAN bus for communications. Your first step in reverse engineering or even monitoring the system would be to determine which two wires make up RT+ and RT-. Then attach a suitable CAN card monitor and eavesdrop. Coupled with logging other real time info such as engine RPM there is a likelyhood that you would be able to determine which messages say what. But.... other than reporting some sort of status or replacing completely a particular module I'm not sure what you'd do with it. 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: Flavio.Corradini@xxx.it Date: Thu, 11 Jul 96 16:34:28 +0200 Subject: Non-Electronic Materials Suppliers - - --openmail-part-007fa628-00000001 Content-Type: text/plain; charset=US-ASCII; name="Message" Content-Transfer-Encoding: 7bit > As part of my efi project I need to fabricate a manifold for my 427 ci FE > block Ford. In order to evaluate design alternatives, I would like to be > aware of the availability and price of potential components. Could someone > suggest suppliers for injectors, fuel rails, throttle bodies, Weber throttle > bodies (with injector boss), pumps, regulators, etc. > > Lou Plebani > ljp2@xxx.edu > - - --openmail-part-007fa628-00000001 Content-Type: text/plain; charset=US-ASCII; name="MMWW" Content-Transfer-Encoding: 7bit After Market EFI Systems: Magneti Marelli - Weber UK 42-46 Somers Road - Rugby Warwickshire CV22 7DH - Great Britain Tel. 44-1788/532302 - Fax 1788/532307 OEM EFI Systems: Magneti Marelli - Weber USA 37483 Interchange Drive Farmington Hills, MI 48335 - USA Tel. 1-810/4715513 - Fax 810/4715530 - - --openmail-part-007fa628-00000001 Content-Type: text/plain; charset=US-ASCII; name=".signature" Content-Transfer-Encoding: 7bit +--------------------------------------------------------------+ | Magneti Marelli S.p.A. Flavio Corradini | | Engine Control Division EMail: corradini@xxx.it | | Via Timavo, 33 Tel.: +39 51 6157.835/6157.011 | | I-40134 Bologna (ITALY) Fax.: +39 51 6157.782/6157.020 | +--------------------------------------------------------------+ - - --openmail-part-007fa628-00000001 Content-Type: text/plain; charset=US-ASCII; name=".snote" Content-Transfer-Encoding: 7bit +--------------------------------------------------------------+ | The views expressed here are not necessarily those of my firm| +--------------------------------------------------------------+ - - --openmail-part-007fa628-00000001-- - ------------------------------ From: SRavet@xxx.com Date: Thu, 11 Jul 96 9:53:39 CDT Subject: re: Re: cypress FPGA tools Darrell Norquay Wrote: | | Don't you mean Warp2? Warp4 is the full enchilada, timing simulator and | all, and it sells for US$5000! I know, 'cause I just took a Cypress VHDL | seminar last week, and got a copy of Warp2, along with a CD full of | libraries, Warp2 for several platforms including the MAC and Sun, the VHDL | text, and a 1 day intensive VHDL course for CDN$99. Yes, WARP 2 is the package I was referring to. Warp 2 is the full enchilada for CPLD devices. Cypress CPLD parts have a very simple timing model, so the simulator is included. For FPGAs, you do need the more expensive package, which also includes schematic capture, etc. | | >The download cable/software wasn't available at the time, although it | >should be now. I need to call back and see. The download cable/software | >works with all of the Cypress "ISR" chips (in system reprogrammable). | | The guys at the seminar gave me the impression that they haven't released | their ISP devices yet, due out in August, I think. They didn't mention the | download cable + software. Warp2 just generates JEDEC files which you need | a pricey device programmer to use. I'm pretty sure they offerred me some samples of the ISP devices, but maybe not. Once they are available, if they aren't already, you won't need the pricey programmer. That's what makes this deal so attractive. For $200 ($99 for WARP 2, and $99 for the download software/cable) you can program your own CPLDs in VHDL. Cypress is pretty generous with samples, also. Steve Ravet sravet@xxx.com Baby you're a genius when it comes to cooking up some chili sauce... - ------------------------------ From: Sandy Date: Thu, 11 Jul 1996 08:23:29 -0700 Subject: Re: Non-Electronic Materials Suppliers MSD Fuel systems in Texas has a bunch of stuff. Also you may want to find TURBO magazine (not all places have it) but they always have a bunch of adds for Injectors, and things like that. At 08:51 AM 7/11/96 EDT, you wrote: >As part of my efi project I need to fabricate a manifold for my 427 ci FE >block Ford. In order to evaluate design alternatives, I would like to be >aware of the availability and price of potential components. Could someone >suggest suppliers for injectors, fuel rails, throttle bodies, Weber throttle >bodies (with injector boss), pumps, regulators, etc. > > Lou Plebani > ljp2@xxx.edu > - ------------------------------ From: Donald Whisnant Date: Thu, 11 Jul 1996 15:00:13 -0400 Subject: ALDL Communications... A while back, several of you guys were hooking up your ALDL serial connectors to your pc's ... I believe I even received a copy of the software to change the pc serial port to something near 8192 baud... What I was wondering (since I'm planning to try to hook mine up this weekend and do some reading) is what the signal levels are on the aldl serial line ... Is it 0 to 12v or is it 0 to 5v?? And, is it inverted?? I was thinking about using either MAX203 or MAX233 RS-232 signal level converters, but they are designed for 0-5 with standard non-inverted inputs ... If it is inverted or is 0-12 instead of 0-5, I'll need to put a transistor or two on the front of the MAX chip to change it's level and/or polarity... Either way is no big deal and I'm hoping someone can answer this so that I won't have to drag the oscilloscope outside to check it... Thanks .... Donald Whisnant dewhisna@xxx.com - ------------------------------ From: Todd Knighton Date: Thu, 11 Jul 1996 13:07:21 -0700 Subject: Re: Bosch Motronic AFM Spring Tension - Further Comments Brad Anesi wrote: > > Herewith the opinion of Don (ex-Alfa, now Fiat R&D): > > 9. Significant changes cannot be made by DIY, nor without a dyno. Not so, key driveability issues can and always will be attacked by in car testing. No dyno I've found yet can tell me how the thing will lurch along in traffic. > 11. There are other ways of increasing fuel delivery such as raising rail > pressure, larger nozzles, with larger AFM. But the intake runners and > valves have to be sized accordingly. But why, when the maps are so readily available? > 12. Our experiences with DIY modified EFI systems do not yield > measurable differences. We've taken 911 Carrera's from 214 hp Normally aspirated to 250+hp normally aspirated and all the way to 765 Hp turbocharged, I tend to think that's measureable!! > > Conclusion: for DIY, it seems more cost effective to use carburetors and > a modern ignition system, leaving original EFI system intact for use later > at resale. This boy must be "SATAN", telling people on the DIY EFI list that Fuel injection should only be used later for resale and that carburetors are the only way to go. What a Schmuck. I'll put the OE EFI stuff up against carburetors any day. Todd Knighton Protomotive Engineering. - ------------------------------ From: matthew@xxx.com (Matthew Wallis) Date: Thu, 11 Jul 96 17:28:11 EDT Subject: Re: Bosch Motronic AFM Spring Tension - Further Comments > > > 12. Our experiences with DIY modified EFI systems do not yield > > measurable differences. Todd, Can you give some more details on this change. > > We've taken 911 Carrera's from 214 hp Normally aspirated to > 250+hp normally aspirated and all the way to 765 Hp turbocharged, I tend > to think that's measureable!! > > > > Conclusion: for DIY, it seems more cost effective to use carburetors and > > a modern ignition system, leaving original EFI system intact for use later > > at resale. - ------------------------------ From: john spears Date: Thu, 11 Jul 96 18:54 EST Subject: RE: GM mass airflow sensor I've seen several questions/comments about the output of GM MAF sensors. I ran an airflow vs. frequency output today on the LT1 MAF that is used on the high output aluminum head version (F and Y car) and also on the LT4 (Y car). This is the largest diameter MAF sensor (3.5" O.D.) used on GM engines I beleive, so it would support the most HP. The flow is in grams/second and the output is in kilohertz. 5gm/sec = 2 khz (idle) 50gm/sec = 5.0khz 100gm/sec = 6.7khz 150gm/sec = 7.7khz 200gm/sec = 8.5khz 250gm/sec = 9.2khz 300gm/sec = 9.7khz 335gm/sec = 10 khz (max) I hope that's of some value. John Spears - ------------------------------ From: Gary W Harris Date: Thu, 11 Jul 96 17:24:00 PDT Subject: Re: ALDL Communications... Text item: Don, The serial data is 0--5 volt simplex, and needs to be converted to RS-232 for the PC. I use a maxim chip powered from a 9-volt battery to do this. A diode and pull-up resistor are also necessary to "wire-or" the PC TxD to the ECU's simplex data line. This works great! I have a schematic, but it's in Viewlogic format. I can snail-mail you if you send me your address. Gary Harris A while back, several of you guys were hooking up your ALDL serial connectors to your pc's ... I believe I even received a copy of the software to change the pc serial port to something near 8192 baud... What I was wondering (since I'm planning to try to hook mine up this weekend and do some reading) is what the signal levels are on the aldl serial line ... Is it 0 to 12v or is it 0 to 5v?? And, is it inverted?? I was thinking about using either MAX203 or MAX233 RS-232 signal level converters, but they are designed for 0-5 with standard non-inverted inputs ... If it is inverted or is 0-12 instead of 0-5, I'll need to put a transistor or two on the front of the MAX chip to change it's level and/or polarity... Either way is no big deal and I'm hoping someone can answer this so that I won't have to drag the oscilloscope outside to check it... Thanks .... Donald Whisnant dewhisna@xxx.com Text item: External Message Header The following mail header is for administrative use and may be ignored unless there are problems. ***IF THERE ARE PROBLEMS SAVE THESE HEADERS***. Reply-To: diy_efi@xxx.edu Precedence: bulk Sender: owner-diy_efi@xxx.edu Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii Subject: ALDL Communications... To: diy_efi@xxx.edu MIME-Version: 1.0 X-Mailer: Mozilla 2.02 (X11; I; SunOS 5.5.1 sun4m) From: Donald Whisnant Date: Thu, 11 Jul 1996 15:00:13 -0400 Message-ID: <31E54F3D.463C@xxx.com> Received: from indycar by atl.lmco.com (8.6.13/ATL 1.14) with SMTP id PAA18719; Thu, 11 Jul 1996 15:00:26 -0400 Received: from atl.lmco.com (hannibal.ATL.LMCO.COM [166.20.244.250]) by franklin .vf.lmco.com (8.7.5/8.7.3) with SMTP id PAA30143 for ; Thu, 11 Jul 1996 15:00:28 -0400 (EDT) Received: from franklin.vf.lmco.com ([166.17.5.51]) by dekalb.vf.mmc.com (8.7.5/ 8.7.3) with ESMTP id PAA05506 for ; Thu, 11 Jul 1996 15:00:28 -0400 (EDT) Received: from dekalb.vf.mmc.com by coulomb.eng.ohio-state.edu via ESMTP (940816 .SGI.8.6.9/940406.SGI) for id PAA13562; Thu, 11 Jul 1996 15:0 1:24 -0400 Received: by coulomb.eng.ohio-state.edu (940816.SGI.8.6.9/940406.SGI) id TAA13574; Thu, 11 Jul 1996 19:01:48 GMT Received: from coulomb.eng.ohio-state.edu (coulomb.eng.ohio-state.edu [128.146.9 0.150]) by ormail.intel.com (8.7.4/8.7.3) with SMTP id NAA28993 for ; Thu, 11 Jul 1996 13:52:39 -0700 (PDT) Received: from ormail.intel.com (ormail.intel.com [134.134.248.3]) by relay.jf.i ntel.com (8.7.4/8.7.3) with ESMTP id NAA24183 for ; Thu, 11 Jul 1996 13:52:39 -0700 (PDT) Return-Path: owner-diy_efi-outgoing@xxx.edu - ------------------------------ From: jimmy staton Date: Thu, 11 Jul 1996 19:31:37 -0500 Subject: Re: GM Mass Airflow Sensor jimmy staton wrote: > > RABBITT_Andrew@xxx.au wrote: > > > > >>>I'm curious if anybody has a clue as to the upper (frequency > > output) limit of the currently used GM mass-airflow sensor.<<< > > > > does 9600 Hz make any sense? > > the GM manual I have has the freq listed as 30HZ-150HZ unless that has > changed, last 1 I checked was out of an 1982 Firebird and that was > right. The GM training manual I have lists 2.8L,3.0L,3.8L as freq based type it lists the 5.0L,5.7L & Bosch as analog. - ------------------------------ From: Land Shark Date: Thu, 11 Jul 1996 18:31:53 -0600 Subject: RE: EFI FORGIVE ME ALL .. I just HAD to answer this one .. a bit late due to the holiday, but REPLY I MUST .. At 16:28 7/6/96 -0700, you wrote: >Feel free to share with the EFI DIY list. Herewith the opinion of Don >(ex-Alfa, now Fiat R&D): Ok .. well .. IMHO .. It's time for Fiat to hire me then.. >The EFI discussion is difficult: one must first know if the system is >analog or digital and to which degree of autoadaptivity is provided. >Example: Fiat uses/has used _many_ executions of Bosch Motronic alone, >many L-Jet, Monotronic, Weber-Marelli, Rochester, Hitachi.... We are talking about Bosch Motronic.. Digital Motor Electronics utilizing Multi-Point Fuel Injectors .. I have worked on Alfa, Ferrari, BMW, Porsche and VW systems .. my expertise is with mostly BMW .. others like Todd Knighton are the gurus at things like Porsches .. >1. Forget that the closed loop O2 sensor function will correct, in the >end, any minor changes upstream. It will, but that does not seem to be the >issue. We talk open loop. Fine .. >2. Spring tension makes a difference only during _transient_ movement and >will enrichen until steady state, where it has no effect. There is no >effect at WOT as you are already using the longest pulse found in the >look-up table (MAP) for that set of parameters. Umm .. Motronic does NOT look up PULSE WIDTHS .. It MEASURES air .. calculates LOAD from AIR and RPM and a constant (based upon injector size) then corrects for operation conditions (maps) to yeild injector PW .. Changing the "air" measurement DOES indeed change the AFR .. Not to argue this to death, but I've HAD cars on the 5 gas and SEEN it happen when I had to UNDO the "tweaking" that someone had done to the "spring" in the AFM .. >3. Remember, electrons are faster than air! And .. >4. The base calibration is not always based on vane position: depends on >system. On EVERY Motronic I have disassembled .. the base cal is directly correlated to the AFM or AirMass sensor Voltage output .. >5. Even open-loop, later generations use autoadaptivity, which further >permits default corrections for components operating outside their spec. >ranges, within the ROM map. I'd like to see this .. I have seen no adaption outside of closed loop functionality .. I'm ready to sign the Fiat NDA .. >6. Aside from AFM vs inputs to controller, this signal is further >corrected by rpm, load, temps, etc., always cross-checking table for >correct fuel delivery before the O2 sensor. Yup .. these are the "operating conditions" I spoke of above .. Although LOAD is in fact the BASIS for the fuel injection and not a "correction" to it .. >7. To see the effects, get a J.C. Whitney A/F checker. NO WAY! .. all that will tell you is .. RICH or LEAN .. and that is that ... U need either a UEGO setup or a BOSCH LA-2 system >8. In systems with separate ignition controllers, more benefits can be had >by changing the spark map. Why not in systems with integrated spark also .. maps are easy to tweak! >9. Significant changes cannot be made by DIY, nor without a dyno. UNTRUE .. I have brought BMW M3's from 240 to 278HP with the Torque raised from 225 to 252 lb/ft at peak .. this is VERY significant and only a bit of that tuning was EVER done on a dyno .. >10. Perceptions and stop-watch times do not always concur. No, but a state of the art DynoJet dyno never lies! >11. There are other ways of increasing fuel delivery such as raising rail >pressure, larger nozzles, with larger AFM. But the intake runners and >valves have to be sized accordingly. All KLUDGES, it is much easier to apply a complex mathematical function to the existing fuel maps .. >12. Our experiences with DIY modified EFI systems do not yield measurable >differences. Well, Fiat .. loan me a car, and I'll tune it tighter than you've ever seen one tuned .. Jim Conforti - ------------------------------ End of DIY_EFI Digest V1 #196 ***************************** 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". % ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ====== % Received: from mail11.digital.com by us4rmc.pko.dec.com (5.65/rmc-22feb94) id AA14261; Fri, 12 Jul 96 05:27:07 -040 % Received: from coulomb.eng.ohio-state.edu by mail11.digital.com (8.7.5/UNX 1.2/1.0/WV) id FAA08549; Fri, 12 Jul 1996 05:23:06 -0400 (EDT % Received: by coulomb.eng.ohio-state.edu (940816.SGI.8.6.9/940406.SGI) for diy_efi-digest-outgoing id JAA16045; Fri, 12 Jul 1996 09:00:14 GM % Received: by coulomb.eng.ohio-state.edu (940816.SGI.8.6.9/940406.SGI) for DIY_EFI-Digest-Send@xxx.edu id JAA16028; Fri, 12 Jul 1996 09:00:09 GM % Date: Fri, 12 Jul 1996 09:00:09 GMT % Message-Id: <199607120900.JAA16028@xxx.edu> % From: DIY_EFI-Digest-Owner@xxx.edu % To: DIY_EFI-Digest@xxx.edu % Subject: DIY_EFI Digest V1 #196 % Sender: owner-diy_efi-digest@xxx.edu % Precedence: bulk % Reply-To: diy_efi@xxx.edu ------------------------------ From: jfaubion@xxx.mil (jfaubion) Date: Mon, 15 Jul 96 10:41:25 cdt Subject: Re: oil control >Anybody have trouble containing oil in the turbos? I have a setup with 2 >brand-new turbos that leak oil badly into the hot section causing great >billows of blue smoke. You don't give much info on the setup or the make and model of the turbos. Are you sure it is leaking into the exhaust side? If it is a draw through setup you may be pulling the oil into the intake side. Check the plugs to be sure. >Application is SBC with high volume oil pump which delivers about 90 PSI >cold. Oil supply lines are #4AN and drains are #6AN back to top of oil pan The line sizes are good but 90 psi?!? I realize that is cold but if your running much over 60-70 psi warm you are inviting a whole rash of problems from oil foaming and over heating to starvation and poor seal life. Most of the automotive turbos run just fine with only 20-30 psi of oil pressure. >Is the oil seal a mechanical unit or does it have some sort of "packing >gland" that can be replaced? Depends on the make and model. >Could I have damaged it by excessive pressure, or could I just turn down >the pressure and hopefully solve the problem? I've never read anywhere >that too much oil (pressure) is bad for these things. It is quite possible that lowering the pressure would be sufficient. Most people don't have that much pressure. Just be careful to maintain the flow when you reduce the pressure. John ------------------------------ From: tom sparks Date: Mon, 15 Jul 1996 11:18:47 -0500 Subject: RE: EFI--Bosch Motronic Land Shark You wrote: in regard to the Bosch Motronic system. It MEASURES air .. calculates LOAD from AIR and RPM and a constant (based upon injector size) then corrects for operation conditions (maps) to yeild injector PW .. So, let me see if I've got this straight. 1. Sensory information (air volume, engine speed) is taken in by the controller 2. Computations based on known, constant, well-established relationships like gas laws and whatnot are performed to come up with a pretty good idea about fuel demand, and relates that demand figure to injector gph flow rating. Presumably this yields a duty cycle number that is used for the next step. 3. Then other sensory information (engine temp, air temp, throttle position? manifold air pressure etc.) is used to search the lookup tables for the appropriate injector PW.These lookups are created through empirical work on the dyno or on the track. -[are there computations made here too?] Am I getting this right? Please correct if not! But if I am getting it right, could someone on this list please contrast this approach with the approach Bosch takes on other systems they might make. And also The approach other manufacturers might take to the very same task. I may be wrong but I think the answers to these questions would really help out the budding DIYer and give them a global view of the process and perhaps help them to break down the process into managable portions. Feel free to tell me to put a cork in it and go read a good book. (But don't forget to suggest said book :-) Thank you and best regards, Tom sparks ------------------------------ From: jfaubion@xxx.mil (jfaubion) Date: Mon, 15 Jul 96 11:26:31 cdt Subject: Re[2]: oil control >On all the Installations I have done I use -10 return lines. Try putting a >pressure gauge on the -6 return at the turbo, if you see more than a few >pounds, go to a larger drain line. Boy, I read that wrong. I thought he was using a -8 return line! A -8 line should be plenty and the -10 even better, but a -6 is probably too small. John ------------------------------ From: Land Shark Date: Mon, 15 Jul 1996 11:29:18 -0600 Subject: RE: EFI--Bosch Motronic At 11:18 AM 7/15/96 -0500, you wrote: >Land Shark You wrote: in regard to the Bosch Motronic >system. > > > It MEASURES air .. calculates LOAD from AIR and RPM and a constant (based > upon injector size) then corrects for operation conditions (maps) > to yeild injector PW .. > > >So, let me see if I've got this straight. Close .. but forget the GAS LAWS those are for MAP sensor systems.. >1. Sensory information (air volume, engine speed) is taken in by the controller > >2. Computations based on known, constant, well-established relationships >like gas laws and whatnot are performed to come up with a pretty good idea >about fuel demand, and relates that demand figure to injector gph >flow rating. Presumably this yields a duty cycle number that is used for >the next step. Computation is done to calculate the base pulse width .. it is a theoretical pulse width for lambda=1 with the injector size and a VE of 1 figured in .. >3. Then other sensory information (engine temp, air temp, throttle position? >manifold air pressure etc.) is used to search the lookup tables for the >appropriate injector PW.These lookups are created through >empirical work on the dyno or on the track. -[are there computations made >here too?] No, the other sensory info, and the LOAD value and the RPM value calc'd above are used to find CORRECTIONS to the calculated base pulse width .. Mathematically it goes like this .. Q=f(Vafm) Tl = Q/(n*Ki) LOAD, air per cycle, expressed as a time duration of the injectors Ti = (Tl*a*b*c...)+z (where a,b,c are the multaplicative corrections to make the fueling proper, and z is the additive corr. for batt voltage effects on the linearity of the injectors) Ti is what we open the injectors for .. Time fur Injection Hope this helps... Jim ------------------------------ From: marvin2@xxx.com (Roy Browning) Date: Mon, 15 Jul 1996 18:47:56 -0700 Subject: Re: oil control You wrote: > >Hey all you turbo gurus...... > >Anybody have trouble containing oil in the turbos? I have a setup with 2 >brand-new turbos that leak oil badly into the hot section causing great >billows of blue smoke. >Application is SBC with high volume oil pump which delivers about 90 PSI >cold. Oil supply lines are #4AN and drains are #6AN back to top of oil pan >just below the block. I'm having trouble believing that BOTH units could >have been assembled improperly. Is the oil seal a mechanical unit or does >it have some sort of "packing gland" that can be replaced? Could I have >damaged it by excessive pressure, or could I just turn down the pressure and >hopefully solve the problem? I've never read anywhere that too much oil >(pressure) is bad for these things. > >Thanks in advance for any help you might provide..... > > > Bill > > The seal in the exhaust end of most turbo units consist of a single or dual piston ring type seal with a mechanical slinger to keep most of the oil away from the ring. if there is an oil leak then they must be replaced. If someone rebuilt one turbo incorrectly it is very conceivable that two or more were done so. I have had about 25% of the rebuilt turbos I have installed fail within a few hundred miles. The turbo seals are very critical and difficult to rebuild to exact tolerances. Best of luck, Roy ------------------------------ From: pantera@xxx.com (David Doddek) Date: Mon, 15 Jul 1996 22:53:39 -0500 Subject: Re: oil control Perhaps I can be of some help. I have twin turboed a 351C in the back of a Pantera and had my share of problems. The other replies are right, 90 psi is too high for both the turbos and the engine. 60 psi is a lot better. You can change your relief spring on your oil pump with one for lower pressure and still retain the high volume pump. Try a spring from a stock pump, just make sure that it is for the same length of hole in the releif passage. You may also be able to get a set of various springs from the manufacture of your pump. Another thing that can be done is add a restriction orfice in the oil lines to the turbo. About a .040" hole is usually adequate. Turbos actually do not need a lot of oil, they just NEED oil and ALL the time. The return line is the most critical. It must be LARGE. I have a 3/4" tube leading from the turbos to below the area of high heat and then a 3/4" hose directly to the TOP of th oil pan. The return lines must not be allowed to have ANY back pressure. Even high cranck case pressure may cause the turbos to leak oil. Return lines must empty above the oil level and not have any low areas that will collect oil and block off the natural flow of the return oil. The large diameter of the lines is necessary because when oil passes through a bearing with a shaft spinning at up to 100,000 rpm the oil tends to turn into something that resembles whip cream. Whip cream does not flow well in a pipe. If the pipe is too small then pressure will be built up in the turbo and get pushed out the seals. There are two types of seals in a turbo, a dynamic and passive seal. The dynamic seal is simply a disk that slings the oil away from the shaft before it gets to a section of little ridges to try and hold the oil back. There is actually no real physical pressure seal. The passive seal consists of a carbon disk that has a very close fit to a mating surface to seal out the oil. The dynamic seal is not suitable for a setup where the throttle body is upstream of the turbo. The vaccuume in the intake will draw oil out of the turbo into the intake. It will also allow gas to get into the turbo bearings and make them wear out fast. The passive carbon seal is better, but costs more. Remember, the shaft of a turbo has bearings that "float" and the shaft may move around to a small extent. They are designed to have slop in the shaft bearings. The oil takes up the gap. This is the only way that bearings can have low resistance and live at 100,000 rpm. I hope this is of some help. I had a few of these problems, and had to learn the hard way. David J. Doddek |pantera@xxx.com Owner SGD Electronics & Development Engr for Caterpillar |h 309 685-7965 Formula SAE Team Sidewinder 94-95 |w 309 578-2931 89 T-bird SC, 69 Fairlane w/SGD EFI |fx 217 428-4686 74 Pantera w/Electromotive Tec-II Twin turbos and Nitros | Hey, If you are going to go fast, go REEEAAL FAST. | ------------------------------ From: pantera@xxx.com (David Doddek) Date: Mon, 15 Jul 1996 22:53:43 -0500 Subject: Re: RE: EFI >1. How exactly would the controller calculate "load" from "air" and "rpm" >and "a constant"? i.e. what would the equation be? (please treat me as >completely ignorant, though I am not quite) > I will try to put this in simple terms without using any fancy formula. The basic theme of the mass air flow system is a device that measures the volume of air that is entering the engine. Remember that in a gasoline engine we want to have a specific ratio of fuel and air mixed together entering the engine. Usually for the ideal situation the ratio is 1 part gas to 14.6 parts of air by mass. For higher load situations a slightly richer (more fuel per air) is required for best power. Let us assume for an instant, that we have a device to measure the amount of air passing by. By measuring the temperature of the air, the device may more accurately measure the mass of the air. If we know the mass of air flowing into the engine per unit time, then we may calculate the amount of fuel needed to obtain the correct ratio of fuel and air. We cannot just squirt the fuel into the engine as we please, so we decide to inject a specified amount of fuel each revolution or portion of a revolution into the engine. To determine the amount of fuel the engine requires each injection event we can measure the RPM of the engine and know the amount of air that enters the engine in one revolution by dividing the total amount of air by the rpm. With the amount of air known to enter a cylinder per designated event, we can calculate the amount of fuel required for that amount of air. Now that we know the amount of fuel required for a 100% effecient engine, we can look up a map that tells us the REAL effeciency of the engine at a specific operating point and offset the calculated fuel. We will also need to add in amounts of fuel for choke, acceleration and what not. Now with this fuel quantity, we multiply it by the magical constant that will give a time value. This time value is the time the injector must be open in order to deliver the amount of fuel desired. Now all you have to do is determine when to inject the fuel. And that is a different story. I can also give the same basic type of description of speed density if anyone wants. David J. Doddek |pantera@xxx.com Owner SGD Electronics & Development Engr for Caterpillar |h 309 685-7965 Formula SAE Team Sidewinder 94-95 |w 309 578-2931 89 T-bird SC, 69 Fairlane w/SGD EFI |fx 217 428-4686 74 Pantera w/Electromotive Tec-II Twin turbos and Nitros | Hey, If you are going to go fast, go REEEAAL FAST. | ------------------------------ End of DIY_EFI Digest V1 #199 ***************************** 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".