DIY_EFI Digest Wednesday, March 24 1999 Volume 04 : Number 191 In this issue: Re: O2 Sensor Tweaking...and MAF Enlarging... Re: Injector Math Re: valve overlap Re: "Negative Overlap" or more commonly known as Pressure Balance cams Re: O2 Sensor Tweaking...and MAF Enlarging... Re: Rochester Fuel injection system diy flow bench Re: valve overlap Chrysler CCD Re: diy flow bench Re: Rochester Fuel injection system Bad O2s Re: valve overlap Re: diy flow bench Re: FI fuel line Re: Brake by wire List Topics... Re: MPH Diacom reading Re: Injector Math Re: Injector Math Re: Chrysler CCD Re: diy flow bench Re: diy flow bench Re: List Topics... Re: diy flow bench DIY-EFI References Re: diy flow bench Re: diy flow bench See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Tue, 23 Mar 1999 16:32:54 -0600 (CST) From: Roger Heflin Subject: Re: O2 Sensor Tweaking...and MAF Enlarging... On Wed, 24 Mar 1999, Richard Wakeling wrote: > Hi Larry, > > One of the many maps or tables used by the PCM is called the Air/fuel > ratio table. Diacom sees this as the commanded air/fuel ratio. > When set to 14.7 A/F (stociometric) BLM comes into play but when set to > 12.5 A/F for heavy or full power condition BLM calculations are ignored > and BLM will be seen as 128 meaning that we are not in closed loop and > we are sitting some where on our A/F table which is not 14.7. During > this condition no additional fuel is added by the BLM and this means > that we can adjust our full power A/F and no that it will not be leaned > off as you thought it might. > > Cheers Richard. (Love thoes Delco's) > > They won't learn anymore in open loop but some of the computer do use the BLM's. I found the code in mine that detects WOT, and if the BLM is less than 128 it sets it to 128, above 128 it leaves it. The strategy seems to be leave the engine as rich as seems correct, and don't dare go lean. So some of the adjust will be taken out by the BLMS. I went through the actual assembly code, and matched what I think the code is doing with what diacom reports it is doing, and everything seems to match. I also made some substantial changes on how the integrators/BLMS interact. Before when the BLMS were being changed, the integrators were not being adjusted, and with the VE tables being off this causes things to oscillate over 30-60seconds before getting the mixture right, I added code so that when the BLM is raised the integratros are lowered by 2, and if the BLM is lowered the integrator is raised by 2 to maintain the same fuel mixture. This resulted in the mixture being right much faster. The fuel usage code was pretty clear in that 2 int steps are equal to 1 blm step. I also adjusted my BLMS to be 128 at wot, I wanted full control of the fuel and to be able to get consistant fuel from run to run. I also remember others running the buick turbo V6's saying that on that car it used the BLM, and did not set it to 128 if it was lean, my car is later than the buick V6's so I would figure it was a fix to keep GM from having to replace as many engines from going lean at WOT and burning pistons. Roger 93 Z28 ------------------------------ Date: Tue, 23 Mar 1999 18:03:24 -0800 From: "Walter Sherwin" Subject: Re: Injector Math >Negative overlap cams are what you might expect. The intake valve opens >after the exhaust valve closes. This design greatly reduces the mid range >torque of an engine in exchange for fewer concerns with EFI tuning. The >really high output atmo engines have variable valve timing to greatly >increase overlap at mid rpm. During idle and high rpm overlap is reduced. >At idle, high overlap causes great reversion and poor emissions. At high >rpm, exhaust backpressure limits the effectiveness of overlap. Also at high >rpm reducing overlap retards the inlet valve closing which helps cylinder >fill. Thank-you Gary! One question though. I kinda figured that the "negative overlap" cam title referred to reduced overlap, during the period which both the intake and exhaust valves would be simultaneously off their seats, near TDC. Did the "n.o." cams go to the extreme of actual "zero", or "negative", seat-seat overlap? Or, just significantly reduced overlap versus their naturally aspirated counterparts? Thanks; Walt. ------------------------------ Date: Tue, 23 Mar 1999 18:24:54 -0800 From: "Walter Sherwin" Subject: Re: valve overlap >I'm not sure about 'negative' overlap, but I'll assume they are referring to >less overlap. Thank-you Jim! That's exactly what I was wondering to myself, whether there actually were cams with zero, or negative, seat-seat overlap timing. I am a HUGE fan of Crane's HIR series (Hydraulic Inverted Flank Roller) camshafts, with speed density EFI. They have much "reduced" overlap, and achieve much of the aforementioned potential, but don't actually utilize true "zero" or "negative" overlap numbers. I love reading the list stuff, and pondering the possibilities! Walt. ------------------------------ Date: Tue, 23 Mar 1999 18:33:18 -0800 From: "Walter Sherwin" Subject: Re: "Negative Overlap" or more commonly known as Pressure Balance cams Subject: "Negative Overlap" or more commonly known as Pressure Balance cams >The concept is quite simple and Dave Vizard in his book about Chevy Cams >covers it extensively. Like all his books - more fact and theory than brand >specific. Thanks! ------------------------------ Date: Wed, 24 Mar 1999 09:46:00 +1000 From: Matt Boland Subject: Re: O2 Sensor Tweaking...and MAF Enlarging... Kurek, Larry wrote: > Guys: > > There is a major debate going on the F-body lists concerning HP gains from > "porting" the stock MAF. I am arguing that the HP gains being shown on the > dyno (7-10hp), are the result of lean out since the MAF is now out of > calibration and NOT due to the increased airflow. I think the stock MAF > flows around 650-700CFM, which on a NA 350 is MORE than adequate. Also, what > I am arguing, and has been proven by a few list members, is that this gain > is short term, since the PCM will 'relearn" the correct fuel trim values > from the O2 feedback, and adjust the mixture accordingly. So, any leanout > effect will be compensated for by additional fuel and you will be back to > zero gain. One list member has argued that any effect of this learning will > not be applied at WOT since the computer is not in learn mode. Doesn't the > PCM just use the last value in the BLM to adjust WOT fuel? Don't you need to > force this BLM cell to 128 (with custom programming) when going WOT to > negate any learning effect? > > Finally, and this is my major question to this list. Has anyone ever > considered, or actually built, a voltage adder/subtracter for "massaging" of > the O2 signal? From what I can tell, this is the ONLY way to seriously > impact fuel curves (short of reprogramming) over the long term AND at WOT. > I'm sure you could build something that takes an input voltage and adds or > subtracts, say 0-100mv, and send this signal to the PCM. A nice dial setup > (adjustable pot) could vary the range (I would assume a +/- 100mv range > would work), and have the ability to synchronize two inputs (for a > left/right O2 setup) with the one dial. Doable? If so, how? comments? > > TTYL! > > Larry You could use an opamp configured as a voltage adder for each side. You could use a pot to derive your +/- 100mv and simply feed it to the adder along with the O2 sensors signal. - -- Matt Boland m.boland@xxx.au CSIRO Division of Exploration and Mining Phone: +61 7 3212-4482 PO Box 883 Kenmore Fax: +61 7 3212-4455 QLD 4069 Australia ------------------------------ Date: Tue, 23 Mar 1999 18:44:16 EST From: ECMnut@xxx.com Subject: Re: Rochester Fuel injection system > If you call a Pontiac a big block, yes, never on a BBC, either 348/409 or > 396/427. Sorry about that.. The thread appeared to be about Rochester FI.. I intended to share some info.... Not make a counterpoint.... Anyone looking for parts for the old RFI may want to try early Pontiac sources, in addition to the more obvious Chevs.. My apologies for any any muddy water or ruffled feathers. MV ------------------------------ Date: Wed, 24 Mar 1999 09:56:26 +1000 From: Matt Boland Subject: diy flow bench Does anybody know if anybody has built a diy flowbench ? I had an idea that you could use an electric motor with an air pump on it and measure the current drawn by the motor. You could use it uncalibrated in just a good, better mode or maybe you could calibrate it by flowing known items. It would be easy to hook up a PC and have a proffesional looking display. The bench part would be easy to build and you could mount the motor/pump underneath. Any thoughts? - -- Matt Boland m.boland@xxx.au CSIRO Division of Exploration and Mining Phone: +61 7 3212-4482 PO Box 883 Kenmore Fax: +61 7 3212-4455 QLD 4069 Australia ------------------------------ Date: Tue, 23 Mar 1999 18:54:22 -0800 From: "Walter Sherwin" Subject: Re: valve overlap >I believe you also want to use the less overlap cam's on a N2O engine, >for similar reasons. For my car there is a 224/236-112 cam, and a >224/236-114 cam, the 114 cam is for blown/N2O applications, and the >112 cam is for NA engines. I am running the 114 cam because I want to >run N20 someday. I believe the stock cam in my car was somewhere >around 202/205-117 so it has even more separation. > > Roger > 93 LT1 Z28 (350) Thanks Roger! Yup, agreed, N2O and supercharging need much the same, whilst turbocharging is somewhat different. Wider LSA spreads apart the IVO and EVC timing points. Assuming split overlap, the resulting "retarded" EVC helps to crutch a weak exhaust port and aids in the exhausting of the additional N2O/supercharge exhaust mass. If only valves could be opened instantaneously! Imagine opening/closing valves with electronic solenoids, and computer control. Infinitely adjustable/variable timing curves for the entire RPM spectrum! Walt. ------------------------------ Date: Wed, 24 Mar 1999 00:41:13 +0200 From: Niinikoski Juha Subject: Chrysler CCD I have 92 Chrysler voyager 3.3. Today started to learn Chrysler CCD bus. For research purposes I got partly dead ECM and EATX boxes. They are not exactly what I have in my setup but still they are CCD boxes. I searched topics about Chrysler CCD but found very few. Does anyone know anything more about this Chrysler implementation ? I opened the boxes and found Chrysler numbered IC's. CPU's are recognizable. EATX have SC424007 labeled CPU and ECM SC424004. Does anyone have more information what these are ? Juha Niinikoski http://www.geocities.com/MotorCity/Factory/6113/ ------------------------------ Date: Tue, 23 Mar 1999 19:36:00 -0500 From: "Bruce Plecan" Subject: Re: diy flow bench - -----Original Message----- From: Matt Boland To: diy_efi@xxx.edu> Date: Tuesday, March 23, 1999 7:23 PM Subject: diy flow bench Popular Hot Rodding had 2 articles about doing that several years ago, add a MAF sensor, and you got a state of the art bench Bruce >Does anybody know if anybody has built a diy flowbench ? I had an idea >that you could use an electric motor with an air pump on it and measure >the current drawn by the motor. You could use it uncalibrated in just a >good, better mode or maybe you could calibrate it by flowing known >items. It would be easy to hook up a PC and have a proffesional looking >display. The bench part would be easy to build and you could mount the >motor/pump underneath. Any thoughts? > >-- > >Matt Boland m.boland@xxx.au >CSIRO Division of Exploration and Mining Phone: +61 7 3212-4482 >PO Box 883 Kenmore Fax: +61 7 3212-4455 >QLD 4069 Australia > > > ------------------------------ Date: Tue, 23 Mar 1999 19:29:40 -0500 From: Shannen Durphey Subject: Re: Rochester Fuel injection system Sorry, you're out of luck. According to my 63 vette manual, those symptoms don't exist. Actually, if you'd like some pages scanned, will try to accomodate. There are 55 in all, so there will be several files. I have no idea how similar 68 units are to 63. Shannen Jemison Richard wrote: > > Does anyone have any trouble shooting information, web sites, etc for a > Rochester Fuel Injection System? Also, does anyone remember the RFI ever > being offered on the big block? This is in a '68 Vette and the symptoms are > crappy idle and blubbering - any change in settings causes stalling during > gear changes. > > Anything will help. Thanks > > Rick > jemisonr@xxx.com ------------------------------ Date: Tue, 23 Mar 1999 19:51:10 -0500 From: "Bruce Plecan" Subject: Bad O2s Anyone hear about any problems with the GM 25312184 O2 Sensors?.. It's the four wire, I just got a new one and the heater ground goes only to the shell. Infinite ohms, heater power to heater ground wire. Bruce ------------------------------ Date: Tue, 23 Mar 1999 20:05:54 -0500 From: "Jim Yeagley" Subject: Re: valve overlap Yes, you're right! I should have said "a tighter or smaller lobe seperation angle." Thanks! Jim Yeagley 1996 Dodge Indy Ram See it and many others at: www.indyram.org 1975 Pontiac Grandville Brougham Conv. (in baskets) webmaster@xxx.org jimyeagley@xxx.net >I'm curious (not being picky). Going by the apparent meaning of the phrase >'lobe separation', wouldn't greater lobe separation mean less overlap? > >Basic is good. Basic answer please. > >Gwyn Reedy >Brandon, Florida >mailto:mgr@xxx.com > > With a normally aspirated (unblown) engine, more valve >> overlap, or a larger lobe seperation angle, aids mid to upper rpm hp by >> allowing the outward flowing exhaust gasses to create a sort of vacuum in >> the combustion chamber when the piston is around tdc and both valves are >> open, where this vacuum starts to 'pull' the intake charge in before the >> downward moving piston begins to draw. At lower rpms, it creates >> that lopey idle we all know and love, but robs low end torque. > > ------------------------------ Date: Tue, 23 Mar 1999 21:01:29 -0500 From: Shannen Durphey Subject: Re: diy flow bench I'll bet this guy has a pretty good idea of what it takes. http://www.htrd.com/kem/flowbench/ I found the link in the archives. Shannen Matt Boland wrote: > > Does anybody know if anybody has built a diy flowbench ? I had an idea > that you could use an electric motor with an air pump on it and measure > the current drawn by the motor. You could use it uncalibrated in just a > good, better mode or maybe you could calibrate it by flowing known > items. It would be easy to hook up a PC and have a proffesional looking > display. The bench part would be easy to build and you could mount the > motor/pump underneath. Any thoughts? > > -- > > Matt Boland m.boland@xxx.au > CSIRO Division of Exploration and Mining Phone: +61 7 3212-4482 > PO Box 883 Kenmore Fax: +61 7 3212-4455 > QLD 4069 Australia ------------------------------ Date: Tue, 23 Mar 1999 21:25:52 -0500 From: Todd Israels Subject: Re: FI fuel line At 03:15 PM 3/20/99 -0800, you wrote: >I'm getting ready to run my fuel line for my engine transplant project and >need to change over the stock low pressure carb. lines to high pressure >lines designed for fuel injection. Was planning to get steel line and form >fittings and all but my local speed shop now has high pressure rubber hose >designed for FI systems. It apparently has a high strength braided liner >molded into the rubber that is real strong. Using this hose with the clamps >made for it sure would be easier than bending and forming steel lines. >Anybody elso use this or have advice? I can't see any disadvantages so >far?? > >Mike Pilkenton > Did the rubber line thing on an old beater (82 Ford Granada wagon that you had to stratigicaly place your feet in the rain or get wet). The repair lasted 4 months but after the Fords final off road bashing I noted that the lines had noticabley worn at the clamps and other attachment points. I would not consider this a permanent solution. The ACCEL cataloge has Saganaw to AN adapters but seem $$, luckely you want need a large number of these. Just to make hose from fuel filter to fule rail. From fuel filter to pump use setup from stock GM vehical. For return pressure is not great can use old carb line. ------------------------------ Date: Tue, 23 Mar 1999 21:32:17 -0500 From: Todd Israels Subject: Re: Brake by wire At 12:07 PM 3/23/99 +0000, you wrote: >We are a group of final year automotive students from Sheffield Hallam >University, England, and are currently researching the theory of a brake >by wire system for use in passenger vehicles, as part of a project. This >system can be retrofitted to any vehicle currently employing a hydraulic >braking system, and does not require ABS to be a prerequisite, however >this can be introduced by means of operating software modifications. We >would be grateful if anyone with relevant information could contact us, >any help would be greatly appreciated. Thankyou. Rob Devlin, Stephen Fry >and Andy Somerville. > > > Wow interesting Idea brings to mind all kinds of scary failure and redundency considerations in the design. Do You have a web site on the project? Keep us up to date with your progress. Todd Israels ------------------------------ Date: Tue, 23 Mar 1999 21:44:06 -0800 From: rr Subject: List Topics... I'd like to have the list cover anything that is EFI related, which of course panhard bars are not part of. If that thread had died early, with just a few posts, not much of a big deal. But it went on too long. Others have also, remember the Pontiac Tempest rear clutch/transaxle thread? That one last a month? It just ate bandwidth. I found the intake stuff to be OK. Why, because it's EFI related. I read it and archived it, I think that it may come in handy down the road. Who kmows when I might be building a dual TBI manifold. When reading this stuff, sometimes it's late at night, and having to slog through a lot on non-related posts become a problem. The eye's aren't working too well, and, well, efi related posts sometimes get deleted before being read. With fewer non-related postings, the borderline postings become much more tolerable. I also would like the list to grow... Thanks for listening, BobR. - -- ------------------------------ Date: Tue, 23 Mar 1999 21:45:42 -0800 From: rr Subject: Re: MPH Diacom reading Have you checked that the VSS is working? BobR. Carmine wrote: >Does anyone know why the MPH reading from C3 ECM is always 0 MPH? > >Carmine > ------------------------------ Date: Tue, 23 Mar 1999 21:00:36 -0600 From: Tom Sharpe Subject: Re: Injector Math - --------------016DB66858818F30D32CAF40 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Bruce Plecan wrote: > > > -----Original Message----- > From: Walter Sherwin > To: diy_efi@xxx.edu > > Subject: Re: Injector Math Competetion Cams used to do one > ofs.Crane will, but be sure to get the wallet out, and they > just might stonewall ya.For a SBC might try Carl Summers, > list member.Bruce > > > You forgot Lunati, they are good to work with and they have > a set of mix and match profiles. pick the intake lobe you > like, the exhaust lobe and the centerline and they'll grind > it cheap. > > tom S > > > - --------------016DB66858818F30D32CAF40 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit  

Bruce Plecan wrote:

  
-----Original Message-----
From: Walter Sherwin <To: >
Subject: Re: Injector Math Competetion Cams used to do one ofs.Crane will, but be sure to get the wallet out, and they just might stonewall ya.For a SBC might try Carl Summers, list member.Bruce
 

You forgot Lunati, they are good to work with and they have a set of mix and match profiles. pick the intake lobe you like, the exhaust lobe and the centerline and they'll grind it cheap.

tom S
 
 

- --------------016DB66858818F30D32CAF40-- ------------------------------ Date: Tue, 23 Mar 1999 21:12:58 -0600 From: Tom Sharpe Subject: Re: Injector Math Walter Sherwin wrote: > >Negative overlap cams > This design greatly reduces the mid range > >torque of an engine in exchange for fewer concerns with EFI tuning. > > Thank-you Gary! One question though. I kinda figured that the "negative > overlap" cam title referred to reduced overlap, during the period which both > the intake and exhaust valves would be simultaneously off their seats, near > TDC. Did the "n.o." cams go to the extreme of actual "zero", or > "negative", seat-seat overlap? Or, just significantly reduced overlap > versus their naturally aspirated counterparts? IMHO you really need to look at degrees open (duration and location) at .020 and .050 for the intake and exhaust. roller hydraulic lifters changed all of the rules of thumb I'm used too as they only have very small clearance ramps. Traditional performance cams have wide centerlines (to close exhaust later and help idle) and extra duration on the exhaust to make up for a poor exhaust port/system. They run better advanced as the above changes make the intake lobe retarded relative to a std cam profile. The intake closing point has the most effect on torque (peak). Spreading the CL and adding exhaust duration really just opens the exhaust earlier. Roundy round SBCs usually use lots of lift/duration and narrow centerlines (lots of overlap). Just make them rich enough and they will idle (fail em. tests) but boy will they make torque - and RPM. Pick the intake lobe that gives you the required RPM range and HP/torque, then pick the exhaust lobe & CL (exhaust close) that will get you past the sniffers. Just my .02 Tom S ------------------------------ Date: Tue, 23 Mar 1999 19:26:47 -0800 (PST) From: Jim Davies Subject: Re: Chrysler CCD On Wed, 24 Mar 1999, Niinikoski Juha wrote: > I searched topics about Chrysler CCD but found very few. Does anyone know > anything more about this Chrysler implementation ? > > I opened the boxes and found Chrysler numbered IC's. CPU's are recognizable. > EATX have SC424007 labeled CPU and ECM SC424004. Does anyone have more > information what these are ? > Chrysler patented a chip to control the bus, IIRC. Try a search at the IBM patent site or the PTO. ------------------------------ Date: Tue, 23 Mar 1999 20:31:07 -0700 From: bearbvd@xxx.net (Greg Hermann) Subject: Re: diy flow bench >Does anybody know if anybody has built a diy flowbench ? I had an idea >that you could use an electric motor with an air pump on it and measure >the current drawn by the motor. You could use it uncalibrated in just a >good, better mode or maybe you could calibrate it by flowing known >items. It would be easy to hook up a PC and have a proffesional looking >display. The bench part would be easy to build and you could mount the >motor/pump underneath. Any thoughts? > A shop vac, a box and a manometer should get you close. an ammeter on the vac would add a little more info on what is going on. A bolt to push on a rocker arm, and a dial indicator to measure valve opening, and you can get truly useful data--like where the "knee" in a port's flow is with increasing valve lift--so you can make informed decisions as to how much valve lift is enough. Regards, Greg >-- > >Matt Boland m.boland@xxx.au >CSIRO Division of Exploration and Mining Phone: +61 7 3212-4482 >PO Box 883 Kenmore Fax: +61 7 3212-4455 >QLD 4069 Australia ------------------------------ Date: Tue, 23 Mar 1999 23:21:09 -0500 From: "Bruce Plecan" Subject: Re: diy flow bench - -----Original Message----- From: Shannen Durphey To: diy_efi@xxx.edu> Date: Tuesday, March 23, 1999 9:37 PM Subject: Re: diy flow bench He also, references the PHR articles. As a second thought: get an old MAF, and matching ecm, hack the diagnostics, so that it doesn' use any default values, and hook a diacom to it. Instant accurate gram/second flow rates. Then if your real good you could set the MAP filtering rates. Since your just doing one port the "smaller" the better (ie jus an old 4 cylinder). Makes me want to build one now, well maybe after I finish the ecm bench LOL. Bruce >I'll bet this guy has a pretty good idea of what it takes. >http://www.htrd.com/kem/flowbench/ > >I found the link in the archives. >Shannen > >Matt Boland wrote: >> Does anybody know if anybody has built a diy flowbench ? I had an idea >> that you could use an electric motor with an air pump on it and measure >> the current drawn by the motor. You could use it uncalibrated in just a >> good, better mode or maybe you could calibrate it by flowing known >> items. It would be easy to hook up a PC and have a proffesional looking >> display. The bench part would be easy to build and you could mount the >> motor/pump underneath. Any thoughts? ------------------------------ Date: Tue, 23 Mar 1999 20:30:17 -0800 (PST) From: Orin Eman Subject: Re: List Topics... This sums it up well. Please keep the off topic threads short. It helps to preface the subject of an off topic post with 'OT' to give members a chance of deleting such messages without having to open them. Other administrivia. Please don't post binaries or other attachments. Majordomo doesn't usually let them thru and they end up in a special folder at my ISP... it can be a while before I get around to looking at them. And when I do, I always ask that the attachment be uploaded to the ftp site and a note posted to the list saying where the file is. And finally, try to set your mailer for plain text only. HTML email is practically unreadable to me and some others. Plain text with a html attachment containing the same text is a waste of bandwidth IMO. Orin, list admin. > I'd like to have the list cover anything that is EFI related, > which of course panhard bars are not part of. If that thread > had died early, with just a few posts, not much of a big deal. > But it went on too long. Others have also, remember the Pontiac > Tempest rear clutch/transaxle thread? That one last a month? It > just ate bandwidth. > I found the intake stuff to be OK. Why, because it's EFI related. > I read it and archived it, I think that it may come in handy down > the road. Who kmows when I might be building a dual TBI manifold. > When reading this stuff, sometimes it's late at night, and > having to slog through a lot on non-related posts become > a problem. The eye's aren't working too well, and, well, > efi related posts sometimes get deleted before being read. ------------------------------ Date: Wed, 24 Mar 1999 14:49:07 +1000 From: Matt Boland Subject: Re: diy flow bench Shannen Durphey wrote: > I'll bet this guy has a pretty good idea of what it takes. > http://www.htrd.com/kem/flowbench/ > > I found the link in the archives. > Shannen > Thanks, that's a good start. Anybody out there who has the Popular Hotrod Articles on a diy flowbench? Apparently it's October and November 1993. I think it might be a little hard to track em' down here in Oz but I'll try. Man!!! I can just taste the cast iron dust now!!!!!!!! - -- Matt Boland m.boland@xxx.au CSIRO Division of Exploration and Mining Phone: +61 7 3212-4482 PO Box 883 Kenmore Fax: +61 7 3212-4455 QLD 4069 Australia ------------------------------ Date: Tue, 23 Mar 1999 20:29:06 -0700 From: spence family Subject: DIY-EFI References "GM Fuel Injection Diagnosis" GM training publication 16009.10-6 (cost $25)is a good reference for GM EFI information. This is a GM factory training manual and is available to the public. Order from: MSX International 1425 Pacific Dr. Auburn Hills, MI 48326 Phone (800) 393-4831 Fax (248)377-1510 The book was updated in 1998 so it covers the latest systems as well as early TBI. This book has lots of "Good Stuff" and is specific to GM. Includes sensor calibrations, specific engine information, theory of operations, DIS systems, and actual numbers!. 200 pages of stuff! Would be very helpful for DIY EFI's, or just understanding the way GM does it. They will send you a catalog for free! There are many other interesting titles. They have both training manuals and instructor's guides for each title.. I got the manual... Tony Spence Electrical Engineer New Mexico State University Just interested in a deeper understanding of GM fuel injection and have a thirst for information. found the diy_efi page very interesting. thanks ------------------------------ Date: Wed, 24 Mar 1999 17:18:04 +1100 From: George Gorman Subject: Re: diy flow bench To do it with the minimum of electronics- I would use an AC blower. The air would flow through the fan, the port on the bench, through a sharp edged circular orifice in the line, and through a variable flow restriction. (some sort of valve for varying the overall head- A speed control on the fan or a blow off valve will solve the same problem) Explanation- The fan provides the head. Put a manometer across the flow bench. This tells you when you have got to your desired pressure drop.(10'' or whatever) You adjust this with your variable air flow restriction. Put a manometer (a plastic tube full of water?)across the sharp edged orifice. A mech eng textbook will give you the empirical relationship between head loss and volume flow rate for a sharp edged orifice of diameter D, say. This is quite accurate - much better than measuring dodgy variables like motor current. the procedure then is - move poppet valve to new setting start motor play with restriction until desired head across flow bench measure head across orifice and use this to calculate airflow, using textbook relationship. At 09:56 24/03/99 +1000, you wrote: >Does anybody know if anybody has built a diy flowbench ? I had an idea >that you could use an electric motor with an air pump on it and measure >the current drawn by the motor. You could use it uncalibrated in just a >good, better mode or maybe you could calibrate it by flowing known >items. It would be easy to hook up a PC and have a proffesional looking >display. The bench part would be easy to build and you could mount the >motor/pump underneath. Any thoughts? > >-- > >Matt Boland m.boland@xxx.au >CSIRO Division of Exploration and Mining Phone: +61 7 3212-4482 >PO Box 883 Kenmore Fax: +61 7 3212-4455 >QLD 4069 Australia > > > > > George Patrick Gorman Mechanical Engineer Australian Arrow P/L Ph (03) 9785 0853 Fax (03) 9775 0477 65 Lathams Rd, Carrum Downs Victoria, Australia 3201 george_gorman@xxx.au ------------------------------ Date: Wed, 24 Mar 1999 03:32:28 -0500 From: Shannen Durphey Subject: Re: diy flow bench Smokey Yunich talked about the MAF conversion in an issue of circle track around 92. 'Course Smokey being a perfectionist figured it would take more time than it's worth to calibrate it, but thought it would be technically possible. Don't think he looked at the ECM aspect of things. Now that's a guy with an original DIY flow bench. Shannen Bruce Plecan wrote: > > -----Original Message----- > From: Shannen Durphey > To: diy_efi@xxx.edu> > Date: Tuesday, March 23, 1999 9:37 PM > Subject: Re: diy flow bench > > He also, references the PHR articles. > As a second thought: > get an old MAF, and matching ecm, hack the diagnostics, so that it doesn' > use any default values, and hook a diacom to it. Instant accurate > gram/second flow rates. > Then if your real good you could set the MAP filtering rates. > Since your just doing one port the "smaller" the better (ie jus an old 4 > cylinder). > Makes me want to build one now, well maybe after I finish the ecm bench LOL. > Bruce > > >I'll bet this guy has a pretty good idea of what it takes. > >http://www.htrd.com/kem/flowbench/ > > > >I found the link in the archives. > >Shannen > > > >Matt Boland wrote: > >> Does anybody know if anybody has built a diy flowbench ? I had an idea > >> that you could use an electric motor with an air pump on it and measure > >> the current drawn by the motor. You could use it uncalibrated in just a > >> good, better mode or maybe you could calibrate it by flowing known > >> items. It would be easy to hook up a PC and have a proffesional looking > >> display. The bench part would be easy to build and you could mount the > >> motor/pump underneath. Any thoughts? ------------------------------ End of DIY_EFI Digest V4 #191 ***************************** 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".