DIY_EFI Digest Tuesday, 3 September 1996 Volume 01 : Number 257 In this issue: FI sizes/Alcohol questions Re: DIY_EFI Digest V1 #256 Re: Knock sensors Ancient History Spare parts for Roto Master turbo Re: Knock sensors Re: DIY_EFI Digest V1 #256 Re: Ancient History Re: DIY_EFI Digest V1 #256 Re: Ancient History Re: Ancient History Re: L28E Injector size ?? Re: Ancient History, and Djet and cams See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Thor Johnson Date: Mon, 2 Sep 1996 11:05:47 -0400 (EDT) Subject: FI sizes/Alcohol questions Could someone mail me a list of Injector part#'s/sizes ? All we havve around here are Western Auto people who can't look up a part unless you tell them the make/model of car or a part #. I am trying to outfit our Formula SAE car for alcohol (~6:1, right), now I just need to find the correct size injectors. Do I have to get a special fuel pump for alcohol (b/c of lubricity), or can I use a gas model (longevity not a factor here). TIA, Thor Johnson johnsont@xxx.edu http://falcon.mercer.peachnet.edu/~johnsont Have you seen the WarpMap lately? http://falcon.mercer.peachnet.edu/~johnsont/warpmap ------------------------------ From: talltom Date: Mon, 2 Sep 1996 09:36:08 -0700 (PDT) Subject: Re: DIY_EFI Digest V1 #256 >I know this is an "E"FI list, but since my interest stems from >aviation/reliability, I'd like to know all I can about the mechanical FI >systems also. Is it still used widely in automotive. Are pieces >available to build a system commercially? Sources (besides car parts >depts, of course)? Finally, is the assumption that the mechanical >systems are more reliable, a "reliable" assumption? Neophyte questions >from a neophyte. > >Garfield Well most europeeon cars used them from in the early 70's thru mid-late 80's. Can't say about the availability of commercial parts, but can tell you that you'd better be able to find a distributor head/air cone combo that can approximate your supply needs else you have to do redesign that's not worthwhile. There may be aviation systems similar out there, but I'd bet price is ridicoulous. I don't think mechanical systems are more reliable in the whole picture. They need proper care and maintenance and are very unforgiving to abuse. Bad fuel, setting unused, and wear on finely machined parts all will do them in. With proper use and maintenance they are dependable though. Just higher in maintenance. Naturally aspirated I'd rather have a carburetor, as I don't like high maintenance anything. I still believe that the efi concept is the best, just getting one to work in configurations other than stock, or in the case of some even stock.(Bosch d-jetronic brain-$1400, Cadillac $800) The way I understand it I'm one of probably 12 people on the face of the earth with a bosch d-jetronic that doesn't work!(everything I own that's electronic has something wrong with it) ------------------------------ From: talltom Date: Mon, 2 Sep 1996 09:36:12 -0700 (PDT) Subject: Re: Knock sensors Have to say that I've seen "Dr. Jacobs" advertise so much stuff that sounded flakey, I'd personally have to ride in the before and after and watch the proceedure to believe it. 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 vary widely. In fact one day it decided to run harder than it had previous and fried the tires hitting second. The result being the rear end stepped out to the left and the car climbed the curb to teh demise of the right front corner. My question is what kind of expieriences have others had with knock retard systems? I'd think that by now this would have been refined some. >Sounds like BS from the Doctor. >No decent system is going to retard 6deg at the first instance of knock. > >I agree with Todd, the J&S is a good system. >No time for messin with knobs while pushing the envelope in a >fast car. > >Fred > >>In his 1992 book, Dr.(?) Jacobs claims that knock sensors jump the >>timing back six degrees, and it takes some time to recover to optimum. >>Meanwhile, an acceleration, like to pass a car, is over with. He says >>a dashboard-mounted timing control, which he happens to sell, gives >>better results. Comments? > ------------------------------ From: "Robert J. Harris" Date: Mon, 2 Sep 1996 10:06:26 -0700 Subject: Ancient History Am new to this mailing list, but have been thinking about this for years. Several years ago I drove a 1966 Chevelle with a 350 V-8 that had neck-snapping acceleration and excellent all-around drivablity. Belonged to a young machinist I took an aluminum head in to have a crack welded on. Asked his secret - and was amazed. Seems he took an older, off the shelf Hilborn mechanical fuel injection, modified it slightly and put it on the engine. Hold the objections, rumors and myths till I finish. He drilled the heads so that the untimed variable flow injector sprayed directly on the intake valve from the back side of the valve pocket. What was lacking in mechanical sophistication was made up in simple physics. 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. Gasoline and air, when mixed has an broad range of combustion, from a 12 to one mixture for power to a 19 to one mixture for economy. The secret is how well it is vaporized and atomized prior to combustion. >From a vaporization point of view, gasoline has components that boil (vaporize) at temperatures from room temp to about 540 degrees F. Smokey once built and patented an engine that heated the intake mixture to this point and made amazing power and efficiency for NASCAR engines. The fuel - -puddling on an intake valve has its temp raised several hundred degrees - without heating the incoming air charge. More fuel vaporized probably than even the most modern injectors achieve - by merely dumping it on the hottest spot in the intake system. Plus fuel vaporizing had to cool the valve - so even less heat added to the air mass - meaning a denser fuel air charge to the cylinder. Next, from an atomization point of view, the unvaporized gasoline components and fresh fuel were injected at the point where there is the maximum turbulence and violence in the air flow - the seat of the intake valve. Cold dry air to the port, fuel in at the valve seat itself - no drop out problems period. Not mechanically possible to mix it much finer. With simple tuning and good physics, this crude system worked very well indeed. The extremely high quality fuel-air charge made up for much of the mixture variations that this simple system had and made a very responsive, decent fuel economy street engine. No moral to this story, just food for thought. On my DIY conversion I am thinking about, I plan to put my injectors in the valve pocket if at all possible for all of the above. Only thing better would be to steal a diesel injector and squirt the fuel directly into the chamber against both intake and exhaust. ------------------------------ From: Niels Ezerman Date: Mon, 02 Sep 1996 19:58:54 +0200 Subject: Spare parts for Roto Master turbo Hello all, I know this is not the right topic for this group, but i hope it ok this time, i think maybe some of you could help. For a friend with a Fiat X1/9 race car we are searching the following items: For the Roto Master turbo, type TU4S we need: Shaft, spare # 408337-2 Center house, spare # 430027-57 And a repair kit. If the above is not available, then for the type S4: Shaft, spare # 104011 Do you know a address, phone, fax or anything we would be very pleased. Thanks, Niels Ezerman Silkeborg, Denmark. nez@xxx.dk [http://www.cybernet.dk/users/nez/] ------------------------------ From: Todd Knighton Date: Mon, 02 Sep 1996 11:01:45 +0000 Subject: Re: Knock sensors 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 talltom wrote: > > Have to say that I've seen "Dr. Jacobs" advertise so much stuff that sounded > flakey, I'd personally have to ride in the before and after and watch the > proceedure to believe it. > > 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 > vary widely. In fact one day it decided to run harder than it had previous > and fried the tires hitting second. The result being the rear end stepped > out to the left and the car climbed the curb to teh demise of the right > front corner. > My question is what kind of expieriences have others had with knock > retard systems? I'd think that by now this would have been refined some. > > ------------------------------ From: rickydik@xxx.com (RD Rick) Date: Mon, 2 Sep 1996 12:06:45 -0700 Subject: Re: DIY_EFI Digest V1 #256 talltom wrote: >... The way I understand it I'm one of probably 12 people on the face >of the earth with a bosch d-jetronic that doesn't work!(everything I >own that's electronic has something wrong with it) I may be able to help you, Tom. I have a Djet tester, 17 years of driving Djet 914's, lots of spares, psuedo-schematics, oscilloscope, etc., and a distributor machine to do dynamic things. What is the nature of your problem? RD ------------------------------ From: rickydik@xxx.com (RD Rick) Date: Mon, 2 Sep 1996 12:23:53 -0700 Subject: Re: Ancient History RJ Harris wrote on diy_efi: >Am new to this mailing list, but have been thinking about this for years. >Several years ago I drove a 1966 Chevelle with a 350 V-8 that had>neck-snapping acceleration and excellent all-around drivablity. Belonged to>a young machinist I took an aluminum head in to have a crack welded on. >Asked his secret - and was amazed. > >Seems he took an older, off the shelf Hilborn mechanical fuel injection,>modified it slightly and put it on the engine. Hold the objections, rumors>and myths till I finish. > >He drilled the heads so that the untimed variable flow injector sprayed>directly on the intake valve from the back side of the valve pocket. What>was lacking in mechanical sophistication was made up in simple physics. > >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. > >Gasoline and air, when mixed has an broad range of combustion, from a 12 to>one mixture for power to a 19 to one mixture for economy. The secret is how>well it is vaporized and atomized prior to combustion. > >From a vaporization point of view, gasoline has components that boil >(vaporize) at temperatures from room temp to about 540 degrees F. Smokey>once built and patented an engine that heated the intake mixture to this>point and made amazing power and efficiency for NASCAR engines. The fuel>-puddling on an intake valve has its temp raised several hundred degrees ->without heating the incoming air charge. More fuel vaporized probably than>even the most modern injectors achieve - by merely dumping it on the>hottest spot in the intake system. Plus fuel vaporizing had to cool the>valve - so even less heat added to the air mass - meaning a denser fuel air>charge to the cylinder. > >Next, from an atomization point of view, the unvaporized gasoline >components and fresh fuel were injected at the point where there is the>maximum turbulence and violence in the air flow - the seat of the intake>valve. Cold dry air to the port, fuel in at the valve seat itself - no>drop out problems period. Not mechanically possible to mix it much finer. > >With simple tuning and good physics, this crude system worked very well>indeed. The extremely high quality fuel-air charge made up for much of the>mixture variations that this simple system had and made a very responsive,>decent fuel economy street engine. > >No moral to this story, just food for thought. On my DIY conversion I am>thinking about, I plan to put my injectors in the valve pocket if at all>possible for all of the above. Only thing better would be to steal a>diesel injector and squirt the fuel directly into the chamber against both>intake and exhaust. Very good information there; thanks. 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. People on the 914fans lists have been debating the injector timing question, so your post is being forwarded there. Hope you don't mind. RD ------------------------------ From: "Tony Bryant" Date: Tue, 3 Sep 1996 08:25:44 +1200 Subject: Re: DIY_EFI Digest V1 #256 > >I know this is an "E"FI list, but since my interest stems from > >aviation/reliability, I'd like to know all I can about the mechanical FI > >systems also. Is it still used widely in automotive. Are pieces > >available to build a system commercially? Sources (besides car parts > >depts, of course)? Finally, is the assumption that the mechanical > >systems are more reliable, a "reliable" assumption? Neophyte questions > >from a neophyte. > > How about the real mechanical FI systems? Like off a '69 Mercedes coupe. No I'm not talking about K-Jet, I talking something that looks like a diesel fuel pump/distributor. I've only seen it in a workshop manual. Anybody with any experience with these, care to comment? *********************************************************** * "Insanity is the only sane response to an insane world" * * >> bryantt@xxx.nz << * *********************************************************** ------------------------------ From: "Tony Bryant" Date: Tue, 3 Sep 1996 08:53:10 +1200 Subject: Re: Ancient History > > > >With simple tuning and good physics, this crude system worked very > well>indeed. The extremely high quality fuel-air charge made up for > much of the>mixture variations that this simple system had and made a > very responsive,>decent fuel economy street engine. > > > >No moral to this story, just food for thought. On my DIY conversion I > am>thinking about, I plan to put my injectors in the valve pocket if at > all>possible for all of the above. Only thing better would be to steal > a>diesel injector and squirt the fuel directly into the chamber against > both>intake and exhaust. > > Very good information there; thanks. > > 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. > > People on the 914fans lists have been debating the injector timing > question, so your post is being forwarded there. Hope you don't mind. > > RD > What I want to know, is what happens when you have radical cam timing? This nice puddle of fuel on the inlet valve gets blown back up the inlet duct when the valve opens? Makes nice flames, if you don't run an air cleaner :-) But this surely can't make for repeatable fuel volume supplied to the cylinder? comments? *********************************************************** * There'll be no more misery * I came, I saw, I left * * When the world's our rotisserie * > bryantt@xxx.nz < * *********************************************************** ------------------------------ From: "Robert J. Harris" Date: Mon, 2 Sep 1996 16:38:08 -0700 Subject: Re: Ancient History Remember the Reichstag - ---------- > From: Tony Bryant > To: diy_efi@xxx.edu > Cc: 914@xxx.com > Subject: Re: Ancient History > Date: Monday, September 02, 1996 1:53 PM > > > > 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. > > > > People on the 914fans lists have been debating the injector timing > > question, so your post is being forwarded there. Hope you don't mind. > > > > RD > > > > What I want to know, is what happens when you have radical > cam timing? This nice puddle of fuel on the inlet valve > gets blown back up the inlet duct when the valve opens? > Makes nice flames, if you don't run an air cleaner :-) > But this surely can't make for repeatable fuel volume supplied > to the cylinder? > > comments? > > *********************************************************** > * There'll be no more misery * I came, I saw, I left * > * When the world's our rotisserie * > bryantt@xxx.nz < * > *********************************************************** Prior to cheap timing electronics, untimed fuel injection was the normal way. Timing is merely the thinnest icing on the cake. Alcohol fueled indy car engines screamed for hours at high RPM and dirt track sprint cars make 700+ horsepower from 400 ci engines on alcohol using Hilborn type units. Modern AA fuel dragsters make pushing 4000 horsepower with nitro fuel using Hilborn type units. World land speed records are routinely set at Bonneville Salt Flats with these primitive systems. Weber carbed formula racing and even street engines made incredible horse power per cubic inch without the benefit of timing. In every case - the higher the quality the mixture - the higher the performance. Untimed fuel injection's have reliably repeatably routinely made enormous amounts of power, with from mild to wild cam timing, with fuels varying from gasoline to liquid dynamite. Made it with the consistency needed to win races in virtually every category imaginable. This is not theory, this is proven fact that you can see every race day. The basic modification he made was move the location of the injector to what appears to be the optimum point. On every engine - a small portion of exhaust gas is pulsed into the intake manifold the amount depending on cam timing, load, and engine RPM. This is then sucked back into the cylinder diluting the charge. For you old timers, this is why you must richen a carb when putting headers on an engine - because the reversion pulse is damped - leaving less flow thru the carb (the first pulse backwards - followed by the normal forward pulse.) Untimed fuel systems have a fuel air mixture that is pushed backwards up the manifold (reverted) before being sucked back in. As this is very hot gas with no oxygen present (e.g. no flame!!) and lots of CO2, and this hot gas is quenched by contact with relatively cold (far below ignition temperature) matter in the intake tract - cold mixture cold intake valve, cold head, all that happens thru almost all ranges of performance is charge dilution and therefore less than theoretical power is developed. Aside - a very rich fuel mixture such as present when fuel is "puddled" on the valve is not combustible. A lean - i.e. minimally vaporized mixture such as from a mistuned carb or timed injector is explosive!! What timed fuel injection in conjunction with proper cam timing does is allow this reversion pulse to go up and come back out the exhaust port before adding fuel to the incoming air. Properly done, no air pump is needed for the cat converter as the reverted air pulse shoves oxygen out the exhaust. The chamber gets a full, dense properly mixed charge and makes better power, fuel efficiency and lower emissions. In all endeavors we tend to forget what has worked and is working in our efforts to achieve the new. We get enamored with new technology and scorn the old. We should instead - understand the baseline from where we want to go and use that to our advantage. Use only from the new what is needed to solve the unsolvable with the old - progress - not perfection. ------------------------------ From: MaxBoost@xxx.com Date: Mon, 2 Sep 1996 22:38:31 -0400 Subject: Re: L28E Injector size ?? The injector flow rate for the 280ZX non-turbo is 185 cc/min and is very common. The turbo flows 259 cc/min. Max. ------------------------------ From: rickydik@xxx.com (RD Rick) Date: Mon, 2 Sep 1996 22:42:18 -0700 Subject: Re: Ancient History, and Djet and cams 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. Correcting myself here: fuel squirts at beginning of intake stroke on two cyl, and beginning of exhaust stroke on the other two. Note: injector duration at Op Temp, WOT, 6,000 rpm, is 8.3 ms, while the valve is open only 5 ms. Bryantt piped up from down under: >What I want to know, is what happens when you have radical >cam timing? This nice puddle of fuel on the inlet valve >gets blown back up the inlet duct when the valve opens? >Makes nice flames, if you don't run an air cleaner :-) >But this surely can't make for repeatable fuel volume supplied >to the cylinder? >comments? My '73 914 just happens to have a high lift cam with a lot of overlap. It won't idle decent below about 2000 rpm. To pass a smog check, I set the lifters out to .030", and then it idles fine. Clatters like hell. I've never had backfires with it. An additional problem is the low vacuum, about 12", below 2000 with that engine. The Djet responds to low vacuum by squirting more fuel, which makes it richer until it dies. I have found a fix for the ECU to alter the fuel curve, but haven't tried it in the car yet. RD ------------------------------ End of DIY_EFI Digest V1 #257 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. 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