DIY_EFI Digest Thursday, 5 September 1996 Volume 01 : Number 260 In this issue: Re: Ancient History Re: J&S Knock Sensor Costs Re: Really long water injection post, $0.04 worth tall drivers Re: water injection & detonation supression Re: hi compressions: wasDIY_EFI Digest V1 #258 Knock sensor spectrum? Re: Ancient History Re: Ancient History Re: J&S Knock Sensor Costs RE: d disease RE: Ancient History Re[2]: Knock sensors Re: Ancient History Re: Manifold/throttle bodys-ED:-) Re: Knock sensor spectrum? Re: Bosch to Hitachi, Ancient history various long post(trying to catch up) Re: DIY_EFI Digest V1 #259 Re: Manifold/throttle bodys-ED:-) Re: Manifold/throttle bodys-ED:-) Re: Really long water injection post, $0 Subject: Re: Knock sensors Re: DIY_EFI Digest V1 #259 Autronic SMC data logging Fuel on the intake valves Re: hi compressions: wasDIY_EFI Digest V1 #258 Ford TFI Distributor re: Ancient History Re: Ancient History Re: Knock sensor spectrum? Re: various long post(trying to catch up) Re: Re Propane injectors Re: Re Propane injectors See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: dave.williams@xxx.us (Dave Williams) Date: Tue, 03 Sep 1996 19:14:00 +0000 Subject: Re: Ancient History - -> I'm interested to learn more about when should I inject fuel for best - -> power and when - -> should I do so for best efficiency. It seems that a Hillborn system - -> just dumps fuel and fuel guaranteeing full combustion but at the - -> expense of efficiency. Once you go to full throttle the injector pulsewidth should approach 100%; basically the injector is on all the time. At idle and low RPM the injector timing makes a small difference, but it's mostly an emissions thing. Lots of quite efficient cars simply batch left bank, right bank, and to hell with trying to time it. ------------------------------ From: pfontana@xxx.it (fontana pasquale) Date: Wed, 4 Sep 96 11:57:09 +0200 Subject: Re: J&S Knock Sensor Costs Hello Todd where i can get it??? Give-me an e-mail with all you it's possible about this . Thanks PASQUALE *** ** \||/ * * ('') >talltom wrote: > >> Yeah, from what I've heard about that J&S stuff it sounds pretty neat. Kind >> of afraid to ask price, but I did make note of the address, and someday when >> in pain will inquire. >> > > About $325.00 with monitor, I think. \Costs less than a set of pistons >and rings! > >Todd > > ------------------------------ From: Dirk Wright Date: Wed, 4 Sep 1996 07:41:08 -0400 (EDT) Subject: Re: Really long water injection post, $0.04 worth On Tue, 3 Sep 1996, Edward C. Hernandez wrote: > >...an article involving water injection to reduce detonation. My >question is: What happened to this wonderful idea? I saw an ad toward >the back of the magazine in which Edelbrock that was selling their >Vari-Injection > > I've been running my Vari-Jection unit for 6 years without problems. Does Edelbrock still sell these? How much do they run? **************************************************************************** Dirk Wright wright@xxx.gov "I speak for myself and not my employer." 1974 Porsche 914 2.0 "A real hifi glows in the dark and has horns." 1965 Goodman House **************************************************************************** ------------------------------ From: Dirk Wright Date: Wed, 4 Sep 1996 07:55:39 -0400 (EDT) Subject: tall drivers On Tue, 3 Sep 1996, talltom wrote: > > >The Djet in 4 cyl engines has just two injector circuits. I'm 6' and > >fit the 914, but my 6' 4" son hates it. You would need a bubble > >canopy. :) > > I suspect the reason your son hates it has to do more with his age than his > size. Am I right? Is this a teenager? > I'm 6'3" and I fit into my 914 just fine. Of course, a 928 is even more comfy, but that's another story.... **************************************************************************** Dirk Wright wright@xxx.gov "I speak for myself and not my employer." 1974 Porsche 914 2.0 "A real hifi glows in the dark and has horns." 1965 Goodman House **************************************************************************** ------------------------------ From: Dirk Wright Date: Wed, 4 Sep 1996 07:58:23 -0400 (EDT) Subject: Re: water injection & detonation supression On Tue, 3 Sep 1996, George M. Dailey wrote: > Gentlemen, OEMs use exhaust gas to supress detonation, right? Exhaust gas > recirculation systems to be exact, EGR. This seams superior to water > injection. Is it? > I thought EGR was strickly for reduced exhaust emmisions? I would think that the hot exhaust gas would heat up the intake such that it would increase the likelihood of detonation. Water injection would cool the intake air, making it denser. Of course, for real density, these's nothing like nitrous! **************************************************************************** Dirk Wright wright@xxx.gov "I speak for myself and not my employer." 1974 Porsche 914 2.0 "A real hifi glows in the dark and has horns." 1965 Goodman House **************************************************************************** ------------------------------ From: Dirk Wright Date: Wed, 4 Sep 1996 08:11:43 -0400 (EDT) Subject: Re: hi compressions: wasDIY_EFI Digest V1 #258 On Tue, 3 Sep 1996, RD Rick wrote: > > I have read that the big reason for four valves is to get the spark > right in the center. > That's as I understand it. Comments? According to Mr. Mackerle, of "Air Cooled Motor Engines:" "More advantages are offered by the use of a hemispherical combustion chamber with inclined valves. The exhaist valve of such a layout can be efficiently cooled on the whole of its circumference. The maximum flow area is about 32% at the inlet valve and 22.3% at the exhaust valve. Small changes can still be made by altering the respective sizes of the valves and by construction details. The conditions prevailing with aluminum alloy heads, in which inserted valve seats are used of necessity, are probably less favorable. "By the use of a "pent roof" four-valve cylinder head layout, the flow area at the exhaust valve seats may also be increased to about 32% of the piston crown area. The coefficient of flow through the ports is however less favorable than in the forgoing case (hemispherical combustion chamber), for flow is restricted by the close proximity of two valves and on the outer side also by the vertical wall." Hope this helps **************************************************************************** Dirk Wright wright@xxx.gov "I speak for myself and not my employer." 1974 Porsche 914 2.0 "A real hifi glows in the dark and has horns." 1965 Goodman House **************************************************************************** ------------------------------ From: walter.kaufmann@xxx.ch (Walter Kaufmann) Date: Wed, 4 Sep 1996 16:05:27 +0200 Subject: Knock sensor spectrum? Can anyone tell me more about the frequency sprectrum from the knock sensor? How does it looks like? Does it look so at every case of knocking? (high speed, bad fuel and so) or is it different? How different or what spectrum? How to interpret this signal? Frequency, intensity or what? Electronic work like filters? Many thanks Walter ------------------------------ From: Todd Knighton Date: Wed, 04 Sep 1996 08:05:47 +0000 Subject: Re: Ancient History > >carbs don't use manifold vacuum to meter fuel. All they use is the > >depression created by airflow through a metering venturi. > > How about SU carbys? Dont the pistons get sucked up according to > manifold vacuum? > They also use a velocity across a variable venturi to create it's own depression (hence vacuum) though not directly the manifold vacuum. Todd Knighton Protomotive Engineering ------------------------------ From: Todd Knighton Date: Wed, 04 Sep 1996 08:20:14 +0000 Subject: Re: Ancient History > > Once you go to full throttle the injector pulsewidth should approach > 100%; basically the injector is on all the time. At idle and low RPM > the injector timing makes a small difference, but it's mostly an > emissions thing. Lots of quite efficient cars simply batch left bank, > right bank, and to hell with trying to time it. > If you run the injectors beyond 80% dwell, they become erratic and the flow rates go to hell. Stay below 80% and you'll make your engine much happier. Also, if you're running above 80%, you can burn your driver circuitry out prematurely. As well as, at idle and low rpm, small changes in injector timing make a hell of a lot more difference than at high rpm. It's the percentage thing. for example Idle timing 1.5ms change timing .5ms that's a 30% change Full throttle timing 10ms change timing .5ms that's only a 5% change Low numbers are much more critical. Even worse are high rpms, light throttle. At 6000 rpm's there's only 10ms from TDC to TDC, and if you're looking for 8 bit resolution you're alread into the 1.25ms per step, go 10 bit resolution and you're looking at 9 microsecond resolution. Where at 600 rpm's you've got 100ms from TDC to TDC and ten times the time to work with. Todd Knighton Protomotive Engineering ------------------------------ From: Todd Knighton Date: Wed, 04 Sep 1996 08:23:05 +0000 Subject: Re: J&S Knock Sensor Costs Had you followed the DIY list, I've posted it about 4 times, but here it is again. J&S Electronics (714) 534-6975 13925 parway Drive Garden Grove, CA 92643 fontana pasquale wrote: > > Hello Todd > where i can get it??? > > Give-me an e-mail with all you it's possible about this . > > Thanks > > PASQUALE > *** > ** \||/ > * * ('') > > >talltom wrote: > > > >> Yeah, from what I've heard about that J&S stuff it sounds pretty neat. Kind > >> of afraid to ask price, but I did make note of the address, and someday when > >> in pain will inquire. > >> > > > > About $325.00 with monitor, I think. \Costs less than a set of pistons > >and rings! > > > >Todd > > > > ------------------------------ From: Mark Pitts Date: Wed, 4 Sep 1996 13:48:37 +-200 Subject: RE: d disease Durrr me dunno either, what is DIGIFANT? Mark - ---------- From: RD Rick[SMTP:rickydik@xxx.com] Sent: Wednesday, September 04, 1996 12:14 AM To: diy_efi@xxx.edu Subject: Re: d disease I wrote: >>The Djet and Ljet EFI in the aircooled opposed VW and Porsche 914 >>engines sprays directly at the intake valve from three inches away. >>With the Djet, the fuel is squirted in at the beginning of the intake >>stroke two of the cyls, and at the beginning of the power stroke on the >>other two cyls, so its operation is compromised... >If it's any help Mercedes applications I believe inject just before or slightly >after intake valve opening. > Here I'm really going to screw myself, but here goes. It would seem to me that >one could use a mercedes brain on a four cylinder and set the points up so that>the sequence you want is accomplished. > All I ask for the idea is enough of the mercedes brains to keep me supplied>before you guys grab them all up.:-) Hey. super idea! Will the Merc dist. fit in the VW hole? I promise you the second V8 ECU I find. >Just for those who aren't thoroughly neaseated yet, maybe I should mention>the fact that we haven't checked into DIGIFANT yet! :-> What's Digifant? RD ------------------------------ From: Mark Pitts Date: Wed, 4 Sep 1996 13:42:58 +-200 Subject: RE: Ancient History In that case, how did the early wick carbs work? Mark - ---------- From: RABBITT_Andrew@xxx.au] Sent: Wednesday, September 04, 1996 11:32 AM To: diy_efi@xxx.edu Subject: re: Ancient History >> Liquid fuel does not burn - period. It must be vaporized before it >>burns. All forms of carboration - including fuel injection - atomize >>the fuel hoping enough vapor will be formed to start combustion so >>that the heat and violence of combustion will finish the job. Power >>and fuel efficiency are directly related to how well that is done. >Um, sorry. Gasoline vapor explodes, it does not burn. Liqiud gasoline >burns.... You definitely DO want to minimise the vapourisation of fuel until the inlet valves are closed. When fuel vapourises its density drops by a couple of orders of magnitude, displacing air and reducing your effective Volumetric efficiency. All the applications that Robert J. Harris quoted in his original post were high-speed, high power applications, and sequential fuelling is not going to give you anything here. What sequential injection does give is better low speed, part load combustion stability leading to better real-world driveability. ------------------------------ From: Terry Sare Date: 4 Sep 96 10:33 CDT Subject: Re[2]: Knock sensors The TI web page has a app note on building a DSP based knock detection system. The web page is www.ti.com and to get to the app notes you have to request a password. The app note is spra039.pdf and has the formulas etc. No code though. TS Remember the Reichstag - ---------- > From: Todd Knighton > To: diy_efi@xxx.edu > Subject: Re: Knock sensors > Date: Monday, September 02, 1996 4:01 AM > > Tom, > My first question is, how tall are you really?!? ha, ha. > > I've found that if I run the ignition timing too close to the limit on > the dyno that the knock sensors hit, the runs will be very > inconsistent. But if the engine is set up properly, and the knock > sensors never need to do any thing then the engine performs well and > consistently. > Knock sensors are for worst case scenario's. Bad gas, carbon buildup, > impropper octane, exceedingly high temperatures. I've never found a > system that works well enough to let it run on the sensors. > We use the knock sensors with the monitor from J&S to tune the engine > till there is no more knock showing, not to leave it run on it. A > properly calibrated engine should never see knock anyway! > > Todd Knighton > Protomotive Engineering > > > > > I did a Corvette with a turbo on it and used a old buick spark retard > > system, and while it worked, I wasn't really very happy with it. It would > > retard 3 degrees for every clatter it didn't like, and hold it for 20-60 > > seconds. The problem was that it was inconsistent, back to back runs would Dumb Idea forming - maybe. By knock sensor, I assume we mean the knock caused by the fuel air mixture igniting prior to the timed spark - generally at medium load and rpm. Since this occurs before the timed spark, nothing you can do to the timed spark directly affects the knock. Retarding the spark lowers power thereby lowering the temp/pressure part of the equation - eliminates knock. Why not use the sensor to directly change a parameter that controls knock - temperature? Instead of retarding timing and losing power - why not richen mixture? More fuel - more evaporative cooling - lower temp - rat noww Richening mixture small amount has no negative effect on power. Early turbos (pre EFI and intercoolers) often ran as high as 40% rich to cool the charge to keep from detonating. Simple algorithm - already have feedback loop for O2 sensor. Step bang the correction a fixed ammout richer. O2 sensor corrects back over time. No more knock, no power loss, far less critical to tune, no need to f with ignition timing and if it false alarms - worst effect is lowered fuel mileage. Just a thought for what its worth ------------------------------ From: SnoMo1@xxx.com Date: Wed, 4 Sep 1996 11:53:18 -0400 Subject: Re: Ancient History Gentlemen, I have been on this list for some time now, and have found your discussions informative, and interesting. This latest thread (discussions of gas milage from a big block) has finally prompted me to ask a question. Why is it a 3500 lb big block car can get 12mpg when on the other end of the weight (and size) spectrum, my parents have a 14,000 +lb motorhome powered by a 454 chevy (tbi), with ovedrive, 5.13 ? gears, 20" wheels (rim dia) , and the areodynamics of a house, and still get 10-11mpg on the highway. And, when pulling a towed 3700lb vehicle (Brono II 4x4) they still get 8-10mpg. This has been documented over 10's of thousands of miles. And yet, if I buy a full size truck with 4-wheel drive and a 5.0 to 5.8 litre V-8, I can only excpect 16mpg? Do you think that possibly many vehicles are being over-geared? I recently changed the gears on my 2.8 L ford ranger from 3.73 to 4.11 and actually saw a slight increase in mileage. I think this was cause by always having the foot to the floor. Now, the engine revs higher, but I notice the pedal isn't constantly kissing the carpet. And, by the way I did take into account the odometer error after changing the gears (plural, 4-wheel drive makes changing gears a pain!). Just thinking outloud again, Mark ------------------------------ From: "Edward C. Hernandez" Date: Wed, 04 Sep 1996 12:42:22 -0400 Subject: Re: Manifold/throttle bodys-ED:-) talltom wrote: > > Hey Ed, if you're the manifold guru for Ford, how come the > manufacturers haven't gone to throttle bodies for each cylinder like > on some of the vettes? Guru?! Your words, not mine, but thanks. I was unaware of any Corvettes with actual port throttles, though I believe the LT-5 had what we call runner controls. Those can deactivate one runner of a dual runner design, they don't actual control engine speed like a true throttle. >...it can't cost very much when they're already using port inj. Heck > it might even be cheaper, being as the current > massive aluminum castings could be eliminated in place of plastic > plumbing. It does cost very much. True throttles have to seat accurately in their bores, and the shaft CANNOT bind under any conditions. Thus, special care must be taken when manufacturing the bores, whether they be plastic or aluminum. Most Al throttle bodies are die cast(cheap) and then their bores are machined. Without going into a lot of manufacturing detail, a cost effective plastic throttle body must be made a certain way to avoid this machining operation, and thus far, that way is incompatible with how most plastic intakes are made today. Even if you hurdle that one, you still need, for a V8, 8 separate plates, 16 screws(or welds), anywhere from 2 or 4 or even 8 shafts, accompnied by 4 or 8 or 16 sealed bearings, cables(or motors)....It will never be as cheap as one throttle body. BUT, I like port throttles(ala Euro spec BMW M3) from a performance standpoint since they make for excellent throttle response while letting the designer get as wild as he wants with the intake tracting. - -- Ed Hernandez Ford Motor Company ehernan3@xxx.com ------------------------------ From: pfontana@xxx.it (FONTANA PASQUALE) Date: Wed, 4 Sep 96 19:00:09 +0200 Subject: Re: Knock sensor spectrum? Hello Walter You can have more informations about this problem by the application note: 17. ENGINE KNOCK DETECTION USING TMS320C25 AND TMS320C30 DSPS APPLICATION REPORT spra039.pdf (329 KBytes) You must register as TI-ME and after you can download this . I hope is help you. * * * \| | |/ Pasquale * (nigth &day) ( ' ' ) * * >Can anyone tell me more about the frequency sprectrum from the knock sensor? > >How does it looks like? > >Does it look so at every case of knocking? (high speed, bad fuel and so) or is >it different? How different or what spectrum? > >How to interpret this signal? Frequency, intensity or what? > >Electronic work like filters? > >Many thanks >Walter > > > > ------------------------------ From: Todd King Date: Wed, 04 Sep 96 10:26:00 PDT Subject: Re: Bosch to Hitachi, Ancient history <<< From: "Terry McLane 312.630.0533" Date: Tue, 3 Sep 1996 15:02:05 CDT Subject: Bosch to Hitachi MAF The voltage figures I quoted were only for purposes of example, but it should only be necessary to measure the air flow up to the engine's peak volumetric efficiency. This should cooincide with peak torque >>> A good way to do this would be to put both sensors in series; set up a 6811 w/ onboard A/D to sample the output of both sensors during some WOT pulls. Then you have a conversion map to go by. Then to convert you could use the 6811 to sample the new sensor, refer to the conversion map, then output the converted value to a D/A and LPF. Sounds harder than it really is. Of course a nice, easy inverting op amp would be the way to go if the new sensor output lends itself to that, as Tom Cloud has indicated. But the other way is more fun :-) My GM MAF uses a frequency output, about 30 Hz to 150 Hz. <<< From: Arnaldo Echevarria Date: Tue, 3 Sep 1996 19:43:15 -0400 Subject: Re: Ancient History ... guy with a 455 got 20MPG(??!) in one of the real street eliminators. Yeah right! ..or did you see the buick turbo v-6 that got 48mpg and ran low 13's in the 1/4 mile?) Yeah, he had problems that day and was only able to get 13's out of it. My Turbo Regal gets about 17 city, 24 hwy. The 48 mpg was real but was done with a special, lean cruise mode chip. I have this type chip in my car right now and will be driving it to Vancouver, BC (from Portland) to race there at the end of the month; I'll report my mpg from the trip. 'Course with the ported iron heads I'm installing this month I plan to get real bad strip mpg, especially when those new 50 lb/hr injectors get thirsty with all that intercooled air being blown past 'em :-) I'll run the stock cam for now (195 deg dur. @xxx. I'm hoping for about 11.50 at near 120 mph for starters but we'll see. I'll be gathering lots of good EFI data so hopefully we can learn something... Todd Todd_King@xxx.com ------------------------------ From: "Edward C. Hernandez" Date: Wed, 04 Sep 1996 13:51:15 -0400 Subject: various long post(trying to catch up) > Gentlemen, OEMs use exhaust gas to supress detonation, right? NO, we use it for NOx control because it reduce peak combustion temperatures(reducing NOx formation). It has a side effect of reducing burn rates(because it significantly dilutes the mixture), which means you need more spark advanvce when EGR is on. Problem is, EGR heats up the inlet air, shortening the fuse. Water can do this without heating up the air(arguably, cooling it) and without diluting the mixture to the same extent. I'm having second thoughts about water's effect on burn rates now... >I have read that the big reason for four valves is to get the spark >right in the center. Flame front has much shorter distance to travel, >meaning higher compression without detonation. You could probably get >the same effect with four spark plugs per cyl. Yes for all three sentences. There has been research on the last. Edelbrock Vari-Jection is no longer offered. One possible source for spec sheets on sensors would be a certain kind of service manual from the dealership. I've seen exerpts from such a manual that we used to diagnose faulty sensors a few years back. Can't a imagine a dealership without one of these manuals. If they won't sell you one, maybe you can convince them to give you an outdated one. Short term knocking is okay, but the longer or more severe it is, the greater chances of scuffing bores and breaking ring lands and losing crush in the rods bearings. Personally, I try never to knock. I don't always succeed, but I wince when I hear it. dn, is there a FAQ for some of this stuff? I don't know if you have a site or just a digest. I can't get over the firewall here. I would consider writing a FAQ or two for your site so the same questions don't get asked over and over. Ed Hernandez Ford Motor Company ehernan3@xxx.com ------------------------------ From: talltom Date: Wed, 4 Sep 1996 11:44:39 -0700 (PDT) Subject: Re: DIY_EFI Digest V1 #259 >From: rickydik@xxx.com (RD Rick) >Date: Tue, 3 Sep 1996 15:07:32 -0700 > >Is your 1200 idle with a 4 holer, or a V8? > >RD 4 >------------------------------ > >From: rickydik@xxx.com (RD Rick) >Date: Tue, 3 Sep 1996 15:13:32 -0700 >Subject: Re: d disease >> Here I'm really going to screw myself, but here goes. It would seem >to me that >one could use a mercedes brain on a four cylinder and set >the points up so that>the sequence you want is accomplished. >> All I ask for the idea is enough of the mercedes brains to keep me >supplied>before you guys grab them all up.:-) > >Hey. super idea! Will the Merc dist. fit in the VW hole? >I promise you the second V8 ECU I find. I see we have our priorities estblished!:-) >>Just for those who aren't thoroughly neaseated yet, maybe I should >mention>the fact that we haven't checked into DIGIFANT yet! :-> > >What's Digifant? > >RD Just another vw fuel system that was for all intents and purposes was propietary and short lived. I believe it was used on late 60's early 70's squarebeeks. The name was repulsive enough to keep me from ever learning about it. ------------------------------ From: Dirk Wright Date: Wed, 4 Sep 1996 15:40:05 -0400 (EDT) Subject: Re: Manifold/throttle bodys-ED:-) On Wed, 4 Sep 1996, Edward C. Hernandez wrote: BUT, I like port throttles(ala Euro spec BMW M3) from a > performance standpoint since they make for excellent throttle response > while letting the designer get as wild as he wants with the intake > tracting. I remember my old alfa with the spica mechanical injection had one throttle per cylinder. pretty cool. **************************************************************************** Dirk Wright wright@xxx.gov "I speak for myself and not my employer." 1974 Porsche 914 2.0 "A real hifi glows in the dark and has horns." 1965 Goodman House **************************************************************************** ------------------------------ From: Chuck Tomlinson Date: Wed, 04 Sep 1996 16:30:32 -0400 Subject: Re: Manifold/throttle bodys-ED:-) >Hey Ed, if you're the manifold guru for Ford, how come the manufacturers >haven't gone to throttle bodies for each cylinder like on some of the >vettes? I know the vettes are two intake per cyl. but the advantages >are many with one valve also, and it can't cost very much when they're >already using port inj. Heck it might even be cheaper, being as the current >massive aluminum castings could be eliminated in place of plastic plumbing. >??????????????? I'm not Ed, but... ZR-1s were the only Vettes with throttle plates in the intake runners, and they only controlled 8 of the 16 runners. I think these secondary throttles were 2-state i.e. either fully open or fully closed. Otherwise, the ZR-1 engine has a regular two-butterfly throttle body on the front of the plenum. In general, it would seem that balancing airflow (cylinder-to-cylinder) through many individual throttles would be a more complex and expensive proposition than having one throttle and a plenum. I thought some BMWs have individual throttles (M-engines?), but I don't know what the real benefits are. Cadillac Northstars already use plastic manifolds with single butterfly throttles, as will the "Gen III" small block Chevrolet in the '97 Vette. - -- Chuck Tomlinson ------------------------------ From: "Woodd, Michael" Date: Thu, 5 Sep 1996 07:50:00 +1200 Subject: Re: Really long water injection post, $0 Ed says... >I disagree. The best analogy I can think of is an old fashioned bomb >fuse burning its way to a big black bomb. Think of the bomb as the knock >limit. If it goes off, you've ignited the end gas as explained above: it >explodes al at once. The fuse represents the parameters that control the >knock limit(pressure, temperature and TIME). Your goal is to burn the >mixture completely before the fuse reaches the bomb. Anything you do to >increase pressure or temperature shortens the fuse, and the converse is >true. Time is defintely a variable, which means that the knock limit is >related to burn rate. Therefore, another approach is to outrun the fuse, >which fast burn combustion chambers can do. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Explain yourself. And where *have* you been??.... Mike Woodd (wooddm@xxx.nz) ------------------------------ From: "Woodd, Michael" Date: Thu, 5 Sep 1996 08:15:00 +1200 Subject: Subject: Re: Knock sensors Bob says... >Why not use the sensor to directly change a parameter that >controls knock - temperature? I think it has already been said here, and I think the general idea was that you can't reduce the temperatures enough by just adding more fuel, unless you add a whole hell of a lot. Thats what brought up the water injection thing, I think What about injecting water upon knock sensed (for non-turbo cars)? How far can you increase spark advance and continue adding more water before something happens (like the engine hydraulics...)? Mike Woodd (wooddm@xxx.nz) ------------------------------ From: Daniel Ridge Date: Wed, 4 Sep 1996 17:36:59 -0400 (EDT) Subject: Re: DIY_EFI Digest V1 #259 > >What's Digifant? > > > >RD > > Just another vw fuel system that was for all intents and purposes was > propietary and short lived. I believe it was used on late 60's early > 70's squarebeeks. The name was repulsive enough to keep me from ever > learning about it. The Vanagon kept Digifant and four-speed transmissions and the leading edge of automotive technology for many years (snicker). How could it not be a Bosch system, though? I know little about it, but it was my understanding that Digifant bridged the gap between LJet and Motronic (ie integrated spark but dumber brain) What is it really? - -Dan ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\___/~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Daniel Ridge | USRA CESDIS Research Minion, Beowulf Project | Code 930.5 email: newt@xxx. W274 tel: 301-286-3062 | Goddard Space Flight Center fax: 301-286-1777 | Greenbelt, MD. 20771 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\_|_/~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ http://cesdis.gsfc.nasa.gov/people/newt ------------------------------ From: Doug Robson Date: Thu, 05 Sep 1996 06:00:52 +1100 Subject: Autronic SMC data logging Hi All , Fred Have re installed injection to race car with smaller throttle bodies Off to dyno next week to see if we avoid last times problems ( 50 mm bodies versus these 45's ). Also the Data Logging prototype is working well but ill need input as to how to design front end and what people might want to montitor and how it should be displayed. Also someone here asked me about it and I apologise for losing his name. please ask again. Look forward to hearing from y'all regards - -- |===============================================================| | When I die, | | I want to go in my sleep, like my grandfather, | | not screaming like the passengers in his car. | |---------------------------------------------------------------| | Doug Robson mailto:doug@xxx.au | | mailto:Doug.Robson@xxx.com | | Sydney, Australia http://www.cia.com.au/doug | |---------------------------------------------------------------| | Club Car Racing Register of NSW | Thank God | | 1992/93 Under 2 litre State Champion | for | | http://www.cia.com.au/doug/ccrrnsw.html | Gravity | |===============================================================| ------------------------------ From: Thomas Burns Date: Wed, 04 Sep 1996 17:34:39 -0500 Subject: Fuel on the intake valves I was reading in this month's Chevy High Performance mag. about the new LS1 motor being placed in the new Corvette. They mentioned that the injectors have been repositioned and the intake has a small section cutout along the top of the port allowing the fuel to squirt more directly on or towards the intake valve. I thought this was interesting, especially considering we were just talking about the Hilburn systems. Coincidence???? - -Tom ------------------------------ From: "John Faubion" Date: Wed, 4 Sep 1996 17:32:48 -0500 Subject: Re: hi compressions: wasDIY_EFI Digest V1 #258 > I have read that the big reason for four valves is to get the spark > right in the center. Flame front has much shorter distance to travel, > meaning higher compression without detonation. You could probably get > the same effect with four spark plugs per cyl. BTW, I believe Actually the big reason for multivalve chambers is more area is exposed around the valve to flow fuel. Two small valves have much more flow capacity than 1 large valve but is more expensive that manufacture. > detonation is what happens after spark but the mix explodes before the > flame can travel far enough to get the whole mix burning. Pre-ignition > is another phenomenon in which hot parts or diesel effect ignite the > mix before spark. > That's as I understand it. Comments? True. John Faubion jfaubion@xxx.net ------------------------------ From: Mark Eidson Date: Wed, 4 Sep 1996 16:27:22 -0700 Subject: Ford TFI Distributor I have been observing for a couple of weeks now and have verified some of my own theories and learned a lot of new stuff. My first attempt at EFI is installing a Holley Pro-Jection 4DI on a 302 '70 Mustang. It has a medium performance hydraulic roller cam, 9.5:1 compression, 351 cast iron exhaust manifolds and a 3.50: axle ratio. In order to use the Spark Control feature a "Ford non-signature TFI distributor" is required. My questions for the group are: What model Fords use this type of distributor, i.e., where do I find one? Does the distributor have vacuum advance and mechanical advance? Are one or both of these functions controlled by the ECU? me *************************************************************************** * Mark Eidson Voice: (602)752-6513 * * Staff Design Engineer Fax: (602)752-6000 * * Manager System Integration and * * Verification E-Mail: mark.eidson@xxx.com * * VLSI Technology, Inc. * * 8375 South River Parkway * * M/S 265 * * Tempe, Arizona 85284 * *************************************************************************** ------------------------------ From: RABBITT_Andrew@xxx.au Date: Thu, 5 Sep 1996 08:57:26 est Subject: re: Ancient History >In that case, how did the early wick carbs work? Never seen one! I would guess that since they're not around now, they didn't (work, that is!) ------------------------------ From: Sandy Date: Wed, 4 Sep 1996 18:39:24 -0700 Subject: Re: Ancient History > Once you go to full throttle the injector pulsewidth should approach >100%; basically the injector is on all the time. At idle and low RPM I'm not sure how close to 100% is good, I have the idea that is should be less then that as that can lead to injector and driver overheating. ------------------------------ From: Sandy Date: Wed, 4 Sep 1996 18:45:45 -0700 Subject: Re: Knock sensor spectrum? At 07:00 PM 9/4/96 +0200, you wrote: >Hello Walter > >You can have more informations about this problem by the application note: > >17. ENGINE KNOCK DETECTION USING TMS320C25 AND TMS320C30 DSPS >APPLICATION REPORT > > spra039.pdf (329 KBytes) > Can this be put on one of the FTP sites or Web pages? Sandy ------------------------------ From: Darrell Norquay Date: Wed, 4 Sep 1996 19:46:15 -0700 (PDT) Subject: Re: various long post(trying to catch up) At 01:51 PM 9/4/96 -0400, Ed H. wrote: >dn, is there a FAQ for some of this stuff? I don't know if you have a >site or just a digest. I can't get over the firewall here. I would >consider writing a FAQ or two for your site so the same questions don't >get asked over and over. I don't have a site or a digest, I think ya got me confused with somebody else. There is an affiliated site here at the University of Calgary which has some of the DIY_EFI stuff on it. Doing up some FAQ's is a hell of an idea, though. I'd be willing to throw in a little time to get this stuff organized. One of the list members was keeping up a source listing for EFI parts and books, etc., but I havent heard of anything new lately. I don't remember where it was posted, either. Yo, Johnny, ya got some place we can put this stuff? regards dn dnorquay@xxx.com ------------------------------ From: pantera@xxx.com (David Doddek) Date: Wed, 4 Sep 1996 22:34:24 -0500 Subject: Re: Re Propane injectors Craig wrote: >Is there such a thing as an electronically controlled diesel injector? >(aka instead of the usual mechanical fuel pump distributor thing..) > Yes: But diesel injection needs around 25,000 psi of fuel pressure, so the injector is a plunger piston pump that is operated off a lobe of the cam shaft (twice as wide as the one that opens the valves). The electric solenoid is a bypass port that when ON blocks the outlet of the injector 'pump' and forces it into the cylinder. When OFF the flow returns to the fuel tank. 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: Craig Pugsley Date: Thu, 5 Sep 1996 14:17:02 +1000 (EST) Subject: Re: Re Propane injectors > >Is there such a thing as an electronically controlled diesel injector? > >(aka instead of the usual mechanical fuel pump distributor thing..) > > > Yes: > > But diesel injection needs around 25,000 psi of fuel pressure, so the > injector is a plunger piston pump that is operated off a lobe of the cam > shaft (twice as wide as the one that opens the valves). The electric > solenoid is a bypass port that when ON blocks the outlet of the injector > 'pump' and forces it into the cylinder. When OFF the flow returns to the > fuel tank. Aaah, I see why "EFI diesels" are only recently appearing. Do they really use 25000 PSI?? I thought it would only be a few hundred PSI. Craig. ------------------------------ End of DIY_EFI Digest V1 #260 ***************************** 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".