DIY_EFI Digest Wednesday, 27 August 1997 Volume 02 : Number 291 In this issue: Re: cranking ignition injection timing SS Header parts. Re: injection timing Re: injection timing Re: injection timing Re: injection timing More Coil-on-Plug Re: For REALLY good injection, check this out, plus a bit Re: For REALLY good injection, check this out Re: SS Header parts. Re: More Coil-on-Plug Re: Ignition timing Re: Ignition timing Re: Converting CFM to Lbs/min Re: More Coil-on-Plug Re: O2 sensor buffering/interfacing Re: injection timing See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Todd King Date: Tue, 26 Aug 97 13:35:00 PDT Subject: Re: cranking ignition <<< Does anyone know how the ignition timing is done on distributorless ignition systems when cranking the engine? How is the ignition timed when the crank is not turning over at constant revs >>> Well on the GN's there is an EST module "bypass" mode for starting; the timing is fixed at some hardwired value until the rpm exceeds 400 or so, where the timing duties are then handed over to the ECM. The crank sensor works with a cam position sensor to determine phase. Crank rpm is never totally "constant", nor does it need to be. <<< Superchips: I'm worried when they say on their web site, "We can make a chip for any car in a couple of hours." >>> You are right to be wary here; I hear that these fine folks were the proprieters of a real chip "scam" that came to light several years ago; something about selling a power chip for a Nissan turbo that was totally stock with a Stuperchips decal on it. The only power increase came from a cheapo boost bleeder valve sold with it. Todd tking@xxx.com ------------------------------ From: "Dave J. Andruczyk" Date: Tue, 26 Aug 1997 16:57:13 -0400 (EDT) Subject: injection timing How come a Bosch CIS ( continuous injection ( mechanical)) on a Porsche 924 ( or any audi /VW for that matter of the late 70's ) tends to have a MUCH smoother idle than many newer sequential efi systems. ?? The spray is always sprayed constantly, at the intake valve, and to mee that would cause puddling, and rough idle, but ironically runs smoother and better than most efi systems. My car with a stock ( but soon to be modified CIS (K-Jetronic)) is capable of idling STEADILY at under 300 RPM. A stab at the gas peadle gives immmediate response. ( nearly impossible to stall it even at the low idle when just jabbing at the accelerator.) Anyone ever consider adding a feedback system to CIS other than KE-jetronic's (frequency valve ) ??? (trick is to modulate "control pressure", (formerly from the warm up regulator, why not put in a variable valve to control pressure in the circuit to give closed loop fuel delivery ? Just some thoughts for chewing.. Dave ------------------------------ From: "David W. Taylor" Date: Tue, 26 Aug 1997 14:04:48 -0700 Subject: SS Header parts. You can buy pipe pieces called "Weld-L's" from hydraulic shops. Heavy wall tubing pieces bent into 45,90,180 degree bends. They come in stainless if desired. I havn't used them yet but A guy at one of the turbo engineering outfits recomended them to me for building a custom exhaust to feed a turbo. The mild steel are so cheap I was planning on prototyping in mild then building the permanant unit in stainless. BTW they are CAST not tubing. SO they are fairly beefy. - -- David Taylor Portland Oregon-My opinions are mine ,, and nobody elses. Off-Ph(503) 613-8132 mailto:dwtaylor@xxx.com ------------------------------ From: Orin Eman Date: Tue, 26 Aug 1997 15:35:19 -0700 (PDT) Subject: Re: injection timing > Anyone ever consider adding a feedback system to CIS other than > KE-jetronic's (frequency valve ) ??? (trick is to modulate "control > pressure", (formerly from the warm up regulator, why not put in a > variable valve to control pressure in the circuit to give closed loop > fuel delivery ? Only the earlier K-Lambda systems used the frequency valves. The later CIS systems used a a differential pressure regulator which was essentially a valve as you describe. As far as I remember, the later systems didn't have the warmup/control pressure regulator and it was all electronically controlled thru the differential pressure regulator. The differential pressure regulator regulated the pressure difference between the upper and lower chambers in the CIS metering head. The pressure difference depends on the current thru the regulator - you would set it for a certain current at idle. Sounds pretty much what you are describing! Orin. ------------------------------ From: Stephen Dubovsky Date: Tue, 26 Aug 1997 19:11:06 -0400 Subject: Re: injection timing At 04:57 PM 8/26/97 -0400, you wrote: > >How come a Bosch CIS ( continuous injection ( mechanical)) on a Porsche >924 ( or any audi /VW for that matter of the late 70's ) tends to have a >MUCH smoother idle than many newer sequential efi systems. ?? The spray >is always sprayed constantly, at the intake valve, and to mee that would >cause puddling, and rough idle, but ironically runs smoother and better >than most efi systems. My car with a stock ( but soon to be modified CIS >(K-Jetronic)) is capable of idling STEADILY at under 300 RPM. A stab at >the gas peadle gives immmediate response. ( nearly impossible to stall it >even at the low idle when just jabbing at the accelerator.) > >Anyone ever consider adding a feedback system to CIS other than >KE-jetronic's (frequency valve ) ??? (trick is to modulate "control >pressure", (formerly from the warm up regulator, why not put in a >variable valve to control pressure in the circuit to give closed loop >fuel delivery ? > > >Just some thoughts for chewing.. > >Dave > > Actually the CIS (K-jetronic) is closed loop. The system pressure is set up to run rich (good for WOT) and leans the system out to stoic by letting some air 'leak' around the metering flap (or is this the 'freq valve' you refer to in the KE-jetronic?) Anyway, the only real difference in leaning the mixture and lowering the fuel pressure is that you could probably reduce the idle speed a little bit more in the fuel-P system. My 83 3.0L 911 (last year w/ CIS) used to idle at 800-1000 rpm, but now w/ a K&N air filt idles at 1500. Something about improved flow;) BTW, it still idles at 800-1000 at startup, but runs rich until the O2 sensor heats and puts the system in closed loop;) I SHOULD go in and set the idle speed better by adjusting the flap or throttle body, but what's wrong w/ running a little rich at startup;) (BTW, I also have the air-intake pop off valve to keep the rare backfire on VERY cold mornings from blowing up my airbox). Just a few, but sometimes worthless, thoughts... Stephen Dubovsky ------------------------------ From: sheridan@xxx.com (Brad Sheridan) Date: Tue, 26 Aug 1997 16:40:11 +0100 Subject: Re: injection timing >How come a Bosch CIS ( continuous injection ( mechanical)) on a Porsche >924 ( or any audi /VW for that matter of the late 70's ) tends to have a >MUCH smoother idle than many newer sequential efi systems. ?? The spray >is always sprayed constantly, at the intake valve, and to mee that would >cause puddling, and rough idle, but ironically runs smoother and better >than most efi systems. My car with a stock ( but soon to be modified CIS >(K-Jetronic)) is capable of idling STEADILY at under 300 RPM. A stab at >the gas peadle gives immmediate response. ( nearly impossible to stall it >even at the low idle when just jabbing at the accelerator.) > >Anyone ever consider adding a feedback system to CIS other than >KE-jetronic's (frequency valve ) ??? (trick is to modulate "control >pressure", (formerly from the warm up regulator, why not put in a >variable valve to control pressure in the circuit to give closed loop >fuel delivery ? I think most KE-Jetronics also use the differential pressure regulator to do what I think you're looking for. I know the one on my 16V Scirocco does. By varying the current to the DPR, you can control the fuel delivery electronically. You're getting smooth idle at 300 rpm? And good off idle response? My 8V Scirocco with CIS had good response, most 16Vs that I've driven, or talked to the owners of, don't seem to have nearly as good response as the 8Vs. But I don't recall it idling down anywhere near to 300 rpm smoothly. Brad ------------------------------ From: "Dave J. Andruczyk" Date: Tue, 26 Aug 1997 19:55:02 -0400 (EDT) Subject: Re: injection timing > Only the earlier K-Lambda systems used the frequency valves. The later > CIS systems used a a differential pressure regulator which was essentially > a valve as you describe. Yes, I know, (i mis-spoke about KE vs K lambda), but why not modify the control pressure regulatro to do the control pressure modulation, by using say for example a stepper motor with a "screw shaft" ( a shaft that looks like a scre for linear drive) that is able to change the pressure on the control pressure diaphragm, thus actively controlling the mixture. ITs a hell of a lot simpler than the "electrohydraulic actuator" designed by bosch, and a hell of a lot cheaper than a 800 dollar new distributor. Just an idea for those who might want a little feedback from their older pre KE and K Lambda systems.. A stepper motor, and a driver is about 20 dollars, an electrohydraulic fuel distrib is over $800. Hell you could be cheap and use a Pot on the dash to adjust the mix. Dave ------------------------------ From: Gary Ohst Date: Tue, 26 Aug 1997 15:29:08 -0700 Subject: More Coil-on-Plug Thanks to those responding so far. Here are a few more comments. The 1997/98 GM LS1 V8, and maybe Nissan?, use a coil-near-plug system. There are individual coils at each cylinder, however, they are still connected to conventional spark plugs by a small lenght of spark plug wire. True coil-on-plug has no spark plug wires at all. The coils connect directly to the plug. The coils are smaller and use higher primary voltage to make up for the fact that they have fewer windings. The simplest implementation would be on 4-valve/cyl head with centrally located spark plugs. The coils can mount directly over the plugs. This is what Ford appears to have done on the 32-valve 4.6 liter V8. It would be more difficult on the 16-valve LS1 because the plugs still exit to the side near the exhaust manifold. The Oldsmobile Quad 4 might be good canidate. I'll have to check out a current model to see if they are using the new coil-on-plug hardware. - --Gary-- ------------------------------ From: Terry Martin Date: Tue, 26 Aug 1997 17:02:29 -0700 Subject: Re: For REALLY good injection, check this out, plus a bit Further to Robert Harris' contribution, which I do say was good, I was looking for information on "Bucky-balls", so named after Buckminster Fuller's geodesic concepts. These are goofy geodesic form heavy carbon molecules. Trying to stay on subject, and assuming DIY-EFI is the appropriate place for innovative minds trying to "go fast" with EFI, and also assuming that what is EFI'd is directly proportional to output energy, it seems the discussion of EFI fuel alternatives is appropriate here. (It's been a hell of a lot more informative than elsewhere). Sometimes, while not formally educated, individuals do come up with advanced concepts. I know at least one guy in Saskatchewan, (a stubble jumper no less), that runs a still and blends his own "gasahol" (at least from what ethanol he doesn't consume). A big cost of operating a grain farm these days, other than no-tillage farming(read heavy herbicide and fertilizer useage), is a)the beer, and b)the fuel to run various equipment. Mr. Harris already knows the problem with ethanol blended gasoline. Blending diesel is one way to "blowed up good", and gasoline powered carb'd vehicles don't respond well to ethanol blended diesel, leaving DIY-EFI. Given that ethanol costs nothing but time and the initial investment in distillation gear, which "ain't thet much of a problem" in Saskabush, a custom injected engine with the injectors designed around the fuel, or vise versa, would be a big advancement for small operators that run their own equipment. (Can you say Combine?) Anyhow, with seven 1/4's of prime land potentialy going in the crapper for taxes, (my great grandparents settled it), and there's guy's out there ploughing tonnes of barley under this year because it's selling too cheap to bother taking off, it seems to me that farming is not only to provide fuel for people. Back to Bucky-ball's & Comments? Terry ------------------------------ From: Terry Martin Date: Tue, 26 Aug 1997 15:32:54 -0700 Subject: Re: For REALLY good injection, check this out Robert Harris wrote: > > Nope. Hydrogen has high energy, but the amount of > hydrogen in a hydro-carbon is closely related to the > number of carbon atoms. Example > H H H > | | | > H - C ... C .... C -H > | | | > H H H > for paraffin's like methane, ethane, propane, butane etc and then it > gets complex. Generally speaking the amount of H is aprox 2x the > amount of carbon atoms - but this still is a very low mass compared > to the carbon mass. Happy to see you included propane as an example, given you have shown the chain for it. :-) See, I read as well as type, maybe better. Anyhow point taken. This is after all a DIY group, but it never ceases to amaze me how much competence pops out when heating things up a little. Engines aren't the only things that work on heat, brains really get boosted. Terry ------------------------------ From: Terry Martin Date: Tue, 26 Aug 1997 17:21:35 -0700 Subject: Re: SS Header parts. David W. Taylor wrote: > > You can buy pipe pieces called "Weld-L's" from hydraulic shops. > Heavy wall tubing pieces bent into 45,90,180 degree bends. An oldy but goody if you're really into DIY, get the pipe out of dumpsters at muffler shops, pack it with sand to keep it from collapsing and heat and bend away. The first time I saw this done was on a forge in a blacksmith shop. friggin amazin. The big trick is to collapse the inner wall of the curve, and stretch the outer wall as little as possible. It goes with where you apply the heat. Terry ------------------------------ From: swagaero Date: Tue, 26 Aug 1997 17:39:58 -0700 Subject: Re: More Coil-on-Plug Gary Ohst wrote: > > Thanks to those responding so far. Here are a few more comments. > > The 1997/98 GM LS1 V8, and maybe Nissan?, use a coil-near-plug system. > There are individual coils at each cylinder, however, they are still > connected to conventional spark plugs by a small lenght of spark plug > wire. > > True coil-on-plug has no spark plug wires at all. The coils connect > directly to the plug. The coils are smaller and use higher primary > voltage to make up for the fact that they have fewer windings. The > simplest implementation would be on 4-valve/cyl head with centrally > located spark plugs. The coils can mount directly over the plugs. This > is what Ford appears to have done on the 32-valve 4.6 liter V8. It > would be more difficult on the 16-valve LS1 because the plugs still exit > to the side near the exhaust manifold. > > The Oldsmobile Quad 4 might be good canidate. I'll have to check out a > current model to see if they are using the new coil-on-plug hardware. > > --Gary-- Coil on plugs are to expensive as there are not enough being produced the best coil setup is by GM for the 3800 ect ect and Saturns totally reliable. Steve - -- ----|------||------|---- --|------[]------|-- 0/ \0 www.flash.net/~swagaero ------------------------------ From: "alex nicu" Date: Tue, 26 Aug 1997 18:24:16 PDT Subject: Re: Ignition timing Hi! A good source of informations ( graphs etc ) you can find in the demo version of the Motec software . Without the motec efi box , you can simulate the running engine ( Motec include 2 or 3 ex engines ). http://www.motec.com Alex - -------------------------------------------------------------------------- http://home.onestop.net/nalex - -------------------------------------------------------------------------- ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com ------------------------------ From: swagaero Date: Tue, 26 Aug 1997 19:14:38 -0700 Subject: Re: Ignition timing Question?? Is anyone running their own sequential system on an engine at this time.?? ----|------||------|---- --|------[]------|-- 0/ \0 www.flash.net/~swagaero ------------------------------ From: Simon Quested Date: Wed, 27 Aug 1997 12:04:14 +1200 Subject: Re: Converting CFM to Lbs/min Oops :-) Yep, it's for a turbo flow map > What is the medium, air??? Cheers +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Simon Quested (E-mail questeds@xxx.nz) Computer Technician, Silicon Graphics & Windows NT Support Centre for Computing and Biometrics LINCOLN UNIVERSITY OF NEW ZEALAND Phone (64)(03) 3252811 Ext. 8087 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ http://www.lincoln.ac.nz/ccb/techs/simon/default.htm +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ When the chips are down, the cow is empty. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ------------------------------ From: James C Patterson Date: Tue, 26 Aug 1997 21:58:39 -0700 (PDT) Subject: Re: More Coil-on-Plug I recall years ago when SAAB came out with their engine management system. One of the big points was that it had a coil-on-plug setup. It may be something to check out. James Patterson james@xxx.edu ------------------------------ From: Justin Albury Date: Wed, 27 Aug 1997 16:21:09 +1000 Subject: Re: O2 sensor buffering/interfacing Tom C > I've come up with a circuit I can share -- and it should > answer another question that's been circulating also -- about > how to force a richer mixture. The circuit I've seen that was > posted a few weeks back only reduces the amplitude of the signal. > If you were to change the offset reference (is now ground), you'd > be able to keep the amplitude of the EGO swing around "stoich" > while adjusting for richer or leaner. > > If anyone is interested, I have the circuit in a GIF format > > Tom Cloud > > He laughs last thinks slowest would love a copy tom justin jalbury@xxx.au ------------------------------ From: "Robert Harris" Date: Tue, 26 Aug 1997 23:38:02 -0700 Subject: Re: injection timing Gasoline is an excellent solvent. Dissolves oil and grease from everything - including valves, rings, cylinder walls and nicely dilutes the oil - especially when the metal is cold. All that nasty oil coated metal is stripped clean and shiny - a good recommendation for running extra rich at cold idle.:) "When some one gets something for nothing - some one else gets nothing for something " If the first ingredient ain't Habanero, then the rest don't matter. Robert Harris - ---------- > From: Stephen Dubovsky > To: diy_efi@xxx.edu > Subject: Re: injection timing > Date: Tuesday, August 26, 1997 4:11 PM > > At 04:57 PM 8/26/97 -0400, you wrote: > > > >How come a Bosch CIS ( continuous injection ( mechanical)) on a Porsche > >924 ( or any audi /VW for that matter of the late 70's ) tends to have a > >MUCH smoother idle than many newer sequential efi systems. ?? The spray > >is always sprayed constantly, at the intake valve, and to mee that would > >cause puddling, and rough idle, but ironically runs smoother and better > >than most efi systems. My car with a stock ( but soon to be modified CIS > >(K-Jetronic)) is capable of idling STEADILY at under 300 RPM. A stab at > >the gas peadle gives immmediate response. ( nearly impossible to stall it > >even at the low idle when just jabbing at the accelerator.) > > > >Anyone ever consider adding a feedback system to CIS other than > >KE-jetronic's (frequency valve ) ??? (trick is to modulate "control > >pressure", (formerly from the warm up regulator, why not put in a > >variable valve to control pressure in the circuit to give closed loop > >fuel delivery ? > > > > > >Just some thoughts for chewing.. > > > >Dave > > > > > > Actually the CIS (K-jetronic) is closed loop. The system pressure is set > up to run rich (good for WOT) and leans the system out to stoic by letting > some air 'leak' around the metering flap (or is this the 'freq valve' you > refer to in the KE-jetronic?) Anyway, the only real difference in leaning > the mixture and lowering the fuel pressure is that you could probably > reduce the idle speed a little bit more in the fuel-P system. My 83 3.0L > 911 (last year w/ CIS) used to idle at 800-1000 rpm, but now w/ a K&N air > filt idles at 1500. Something about improved flow;) BTW, it still idles > at 800-1000 at startup, but runs rich until the O2 sensor heats and puts > the system in closed loop;) I SHOULD go in and set the idle speed better > by adjusting the flap or throttle body, but what's wrong w/ running a > little rich at startup;) (BTW, I also have the air-intake pop off valve to > keep the rare backfire on VERY cold mornings from blowing up my airbox). > > Just a few, but sometimes worthless, thoughts... > Stephen Dubovsky ------------------------------ End of DIY_EFI Digest V2 #291 ***************************** 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".