DIY_EFI Digest Monday, May 10 1999 Volume 04 : Number 274 In this issue: Re: Looking for a 1-psi Hobbes switch Re: Looking for a 1-psi Hobbes switch Re: Espen's Reed Valves Re: 730edit program Re: absurd pressures figures was: atomization enhancement Re: L-jetronic mods Re: L-jetronic mods Re: Espen's Reed Valves Re: 730 on a 406 small block RE: Hessitation in Late Model Subarus RE: Looking for a 1-psi Hobbes switch Re: CFM Continued... Re: CFM Continued... Re: alternative engines Re: alternative engines, WARPED 5th injector Re: Hessitation in Late Model Subarus Re: 5th injector Re: CFM Continued... RE: L-jetronic mods See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Mon, 10 May 1999 07:04:58 -0400 From: Scott Knight Subject: Re: Looking for a 1-psi Hobbes switch > Actually, on one Ford I have worked on, the oil pressure gauge was connected > to a standard idiot light switch. The gauge reads half when the switch is > closed and zero when the switch is open. Replacing the switch with a sender > made the gauge not work at all. This was on a 87 T-bird with digital dash. > I think Ford does this on other models as well. Must some of those engineers defected over to GM to work on the B-car a few years ago, because that is the way all the LT1's are. Gauge reads over 2/3 when running and zero when shut off. The way to change it over to a true pressure sending unit is to remove an inline resistor and add one to ground in the signal circuit (at least on the GM). Oh yeah, the stock switch is about 5 psi also :^(. Later dates. - -- Scott Knight mailto:sknight@xxx.com http://www.mich.com/~sknight IRC:SS396man '95 Black Impala SS '94 Ducati 900SS CR ------------------------------ Date: Mon, 10 May 1999 08:23:23 -0400 (EDT) From: Pat Ford Subject: Re: Looking for a 1-psi Hobbes switch Previously, you (DemonTSi@xxx.com) wrote: another alternative is the diaphram used in washing machines they work in inches of water ( put a restrictor to prevent backfire from poping it) > In a message dated 5/8/99 5:54:18 PM Pacific Daylight Time, > EdDSP@xxx.com writes: > > << Here's what I'm doing. I'd like to mount a switch on an intake manifold > that'll work once there is positive pressure (boost). Such a switch > exist? A part # would be most appreciated too. >> and the washer machine one is adjustible > > The lowest psi activated switch I've ever seen was a 3psi unit...that goes > for like 125 bucks! You can get an adjustable hobbs one (sold for use with > nos systems) that activates at 5psi for like under 10 bucks. Then you can use > a regulator or other restrictor inline and adjust it to show the switch the > psi you need. > > Van - -- Pat Ford email: pford@xxx.com QNX Software Systems, Ltd. WWW: http://www.qnx.com (613) 591-0931 (voice) mail: 175 Terrence Matthews (613) 591-3579 (fax) Kanata, Ontario, Canada K2M 1W8 ------------------------------ Date: Mon, 10 May 1999 09:16:54 -0400 From: "Bruce Plecan" Subject: Re: Espen's Reed Valves Please don't confuse operating rpm of the engine with the effective range of the reeds. The Yamhahaha, I mention was a 10,500 shift point engine. But, at any engine speed over about 2,000 rpm you could see the stand off in the intake tract meaning the reeds had "blown" open. Yes reeds can "vibrate" at high frequencies (just look at a clarinet), but that doesn't mean that as a check valve they will actually perform that way. Grumpy > Crank case pre compression on a two stroke wouldn't work very well if the > reeds stayed open. > The key to performance at high RPMs is low weight, high stiffness and the > proper shape. To get performance at low RPMs also, Boyesen's multi stage > reeds can be used. > Remember that 2000RPM is only 33Hz. Locking open at that frequency sounds > improbable. 20,000RPM, sound more like it. > Composite reeds, often using graphite, work well into the 9000's on > outboards. The problem with composite reeds is that they don't last very > long, however, the failure is not very dramatic. Metallic reeds, on the other > hand, while long lasting, will tear an engine to pieces if they break at an > inopportune moment. > Maximizing reed cage area is important since larger reeds will give better flow. > Now, anyone for a homegrown EFI system for 2-stroke outboard ? > Regards, > John Hornkvist ------------------------------ Date: Mon, 10 May 1999 06:28:04 -0700 (PDT) From: Squash Subject: Re: 730edit program I have the first 10 or so switches (or call them tables if you want) and the main VE and the upper and regular spark tables. The user interface is crude at this point, but my goal is to edit bins, not look fancy. Andy - --- The Punisher wrote: > How is the 730 edit program coming along? > The gm eprom editor that My friend is writing me > will be a couple of months > away, The program wont take long but he just cannot > spare the time yet. What > tables and switches do you have incorporated into > yours so far ? > Hope it turns out good, because the other stuff I > have seen so far is less > than impressive IMHO. > > > > _______________________________________________________________ > Get Free Email and Do More On The Web. Visit > http://www.msn.com > _________________________________________________________ Do You Yahoo!? Get your free @xxx.com ------------------------------ Date: Mon, 10 May 1999 08:27:38 -0500 From: Matt S Bower Subject: Re: absurd pressures figures was: atomization enhancement Jennifer and Brock Fraser wrote: > > The Cummins ISB and ISC engines (at least most of their applications) use > Bosch VP44 pumps, which is basically a warmed over version of the good ole > rotary pump, but will full electronic authority over timing and delivery. > They are headed for common rail. You have to understand that emissions regs > drive these changes, and Tier 2 isn't being phased in for "off-road" until > 2002 for the most popular of rated power ranges. VP44's still use poppet > valves, and are NOT particularly high pressure systems (1000-1100 BAR), > although they do a better job than something like a Stanadyne or Lucas > rotary pump. Stanadyne or Lucas rotary pumps, as I mentioned before, are > only good for about 600-700 BAR. We fondly call these "drip pumps" or even > "gravity injection". Possibly this will help illustrate the frame of > reference. > > -Brock The ISC is Cummins CAPS fuel system. As well as the ISD or ISL (same engine) Which is the bored and stroked ISC, same block etc. Diffenece only in that the fuel control is done by injectors on the pump with an extra effect of using injector plungers to increase fuel pressure for low rpm. Very much different from the VP44 but uses the same principals of operation. Good Post! ------------------------------ Date: Mon, 10 May 1999 09:38:36 -0400 From: "Bruce Plecan" Subject: Re: L-jetronic mods While lots of folks laugh at Fiats, they happen to be very well designed, for what they are intended to be. Anyway: My suggestion is go to a junk yard and snag a 1227749, and just start with that. The Bosch while nice is going to get rare, and the Air Door will jam from a back fire (just a matter of time, IMHO). The 1227749 is what is used in the GM syclones, and uses a 2 bar calibration, MAP sensor, so you don't run out of "table space". There is a $15 prom editor at the syty home page.. By using the Sunbird chip it's for 4 cylinder to begin with. Can be wired for P+H, or Saturated injectors. Other than checking to see if the TPS is a 0-5v signal, and VSS compatability, might be easier then where your headed.. I'm not in favor of hammering the calibration from NA to 7 PSI, Doc > Hello. I'm new to the list (sort of), so forgive me this subject has been > covered before. > I installed a custom turbo system on my 1980 Fiat Spider. Building the > system was a task itself but getting the engine to resist detontation has > been an uphill battle. If detonation is as destructive as what everybody > describes, then my engine would have been toast months ago because my > engine has shown no ill effects. So far anyway. > I had been running a few band-aid solutions such as water/alcohol > injection, timing retard, etc. but these are getting old. My real problem > is fuel enrichment. > Here's some specs: > 2 liter/twin cam/hemi design > C/R: 8.1:1 (factory), current unknown, head was resurfaced during the last > rebuild. > Bosch L-jetronic fuel injection system w/lambda sensor > Turbo: Rayjay 301 > Boost: 7 pounds > gasoline : 93 octane (of course) > Fuel enrichement device, rising rate fuel pressure regulator and a 2nd cold > start valve mounted upstream triggered at around 2 pounds. > With these specifications, this engine should handle 7 pounds of boost with > no problems. That is with proper fuel enrichment, but I can't figure out > how to get more fuel into the engine. > The most frustrating thing is, the potentional is there, I just don't know > how to unlock it. > The other day, I was able to trick the computer into dumping more fuel into > the motor than it could handle, to the point the car was smothering and > belching black smoke out out the exhaust at 7 pounds. The engine seemed to > handle the extra amount of fuel until the contacts in the throttle position > switch closed and dumped too much fuel. > I did this by installing a set of boost switches which adds resistance > (about 2000 ohms) between the computer and coolant temperature sensor. This > doesn't work on my car because I've got a rising rate fuel pressure regulator. > My latest experiment was to splice a Hobbs pressure switch between the > oxygen sensor and computer. As soon as I hit boost (.1 pounds) the control > loop is disrupted. > Today the temperature was near 80F and the car seemed to do OK. > Can someone tell me this: > I was under the impression that when the engine is under wide open > throttle, the throttle position switch breaks the control loop. Is this > correct? > Or no matter what, the engine is still in the control loop? > My theory is that any attempts to get more fuel into the engine are being > overiden by the oxygen sensor even under wide open throttle, but by > breaking the control loop, now I can get more fuel into the engine. > Seems like my latest attempt has worked by I would still be more > comfortable knowing that I am getting the most fuel I can get into my motor > without causing the car to choke. > > Here's a rundown of my current setup: > > 1) rising rate fuel pressure regulator > 2) 2nd cold start valve mounted upstream before the throttle body triggered > at around 2 pounds. > 3) Oxygen sensor to computer broken at .1 pounds > > I would like to do away with the 2nd cold start valve and use the injectors > as my sole source for fuel because I know they have the potential when the > fuel pressure is stepped up. > > Also I want to point out that during the experiment where I got too much > fuel into the engine was done with the 2nd cold start valve disconnected. > > What could I do to increase the pulse rate of the injectors? My attempt to > create my own boost switch didn't work. I tried rigging up another pressure > switch with several rated resistors (600-1000 ohms) in parallel but the CPU > didn't like this. > > Also is there anything to my latest experiment by breaking the circuit > between the oxygen sensor and computer under boost? > > If you guys need anymore details, just email me. > > This fuel injection system has been around for 25 years so I am sure there > is someone on here that knows how to trick this system. > > Should I just have the injectors remapped to flow more fuel and run a lower > fuel pressure so the engine won't run rich at idle and cruise? > > Great Scott! I'm running out of options here. Someone help me! > > Thanks. > > > ---------------------------------------------------------- > > James Seabolt -----> mailto:jseabolt@xxx.net > Webpage: http://users.intermediatn.net/jseabolt/ > ICQ # : 7344463 > > United States > > 1980 FIAT 2000 TURBO Spider injected (John Deere aspirated) > 1981 FIAT 2000 Spider (Rest in Pieces) > 1981 FIAT X 1/9 (Injected) > 1994 JEEP Wrangler (2.5l ) > 1976 Chevrolet Pickup (454 Big block/7.3 liter) > > ---------------------------------------------------------- > ------------------------------ Date: Mon, 10 May 1999 09:01:57 -0500 From: DC Smith Subject: Re: L-jetronic mods James, I ran a non-intercooled turbo Buick for years. (didn't see a intercooler listed) Knock city on a hot day at under 10 lbs of boost with 93 octane in the tank. It wasn't because the car was lean, it was because of the temp of the charge entering the motor. Are you sure it needs more fuel? Do you have a scan tool that'll give you some O2 numbers? Maybe a EGT meter? I can't help you with tweaking the Bosch injection, (maybe bigger injectors?) but there are a few things all turbo motors need to be able to crank it up. Also, if there is any oil getting burned at all, it will knock down the octane kick of your fuel considerably. Just a few ideas. Take care Major snipage to follow.. :) James Seabolt wrote: > > Hello. I'm new to the list (sort of), so forgive me this subject has been > covered before. > > I installed a custom turbo system on my 1980 Fiat Spider. Building the > system was a task itself but getting the engine to resist detontation has > been an uphill battle. If detonation is as destructive as what everybody > describes, then my engine would have been toast months ago because my > engine has shown no ill effects. So far anyway. *********************************************************************** Dan Smith 84 Regal 12.13@112 GSCA# 1459 St.Charles, Missouri mailto:dcsmith@xxx.net http://www.tetranet.net/users/morepoweral *********************************************************************** ------------------------------ Date: Wed, 12 May 1999 07:17:15 -0700 From: "Howard Wilkinson" Subject: Re: Espen's Reed Valves John wrote: >>>>>>>>>> major snip <<<<<<<<<< >Now, anyone for a homegrown EFI system for 2-stroke outboard ? > >Regards, >John Hornkvist > I'm interested..... let's hear about it ;-) H.W. ------------------------------ Date: Mon, 10 May 1999 10:27:56 -0400 From: "Bruce Plecan" Subject: Re: 730 on a 406 small block Well, there's a basic problem here: Firing four P+H injectors. The only gm ecm that does that is the 1227749. You can do the Series Parralel (?) injector wiring but injector low speed response is lacking, ie less than (from memory) 2.0 msec. (to run a 730) A 749 will see a 730 memcal, thou no TCC (not that it matters here), I've run an astrovan v-8 conversion with a 749/730, but never did finish the cal or indepth testing. This uses non "standard" pinouts to work, and really is getting deep for a heavy duty drivetrain, like ya got. It might just be easier referring to M Pitts postings about the injector drivers he used and go that route, with an external driver board for whatever ecm you use. While the 730 is no doubt a nice box, the firing strategy is for Batch. The 747 is for TBI, also, much easier to work with table wise. The 747 doesn't have IAT compensation, but for your combo you'll probably be shutting alot of stuff off anyway. Also, no radiator fan control. I'm at a total loss about how a tunnel ram will work. That might be a huge source of signal dampening for the MAP, and can be any of two ways, fine, or, too self dampening. You might want to go thru the archives some, and read some about fuel pressure regulators, and what I did with two, ref TBIs. Grumpy > >Weight of car?, Auto/Manual tranny?, Final Drive Gearing?. > >Your running two. of the 4-barrel units?. > >Or two 2 barrel units. > >You want to start with the TBI, and then go port??. > 3250 lbs aprox with driver, turbo400 trans with 2500-3000 stall converter. > 3.73 gears. dual 670cfm 2 barrel holley projections with 80 pound injectors. > I already have all the TBI stuff (and it looks good on the tunnel ram too), > but later I plan to weld up a new plenum top for the tunnel ram and go port. ------------------------------ Date: Mon, 10 May 1999 10:10:49 -0500 From: Don.F.Broadus@xxx.com Subject: RE: Hessitation in Late Model Subarus Please send any info to Don F. Broadus@xxx.com thank you for your time and research. > -----Original Message----- > From: G. Scott Ponton [SMTP:gscottp@xxx.com] > Sent: Sunday, May 09, 1999 10:44 AM > To: diy_efi@xxx.edu > Subject: Re: Hessitation in Late Model Subarus > > Don, > > The system should be fairly easy for you to impliment. The problem I > had > was fitting an HEI behind a Tripower intake. With the rear carb so far > back > there wasn't room for an HEI distributor. So I had to manufacture my own > and mount the rest of the HEI circiutry to a heat sink mounted elsewhere. > Unless the rest on the list are willing to read all of this I think it > may be better if we took the discussion "off list" and save the bandwidth. > > Scott ------------------------------ Date: Mon, 10 May 1999 10:38:14 -0500 From: Don.F.Broadus@xxx.com Subject: RE: Looking for a 1-psi Hobbes switch Ford had 3 Hobbs switches mounted on the fender of the 4 cyl. turbo mustang check at your local U-Pull-it . Don > -----Original Message----- > From: Pat Ford [SMTP:pford@xxx.com] > Sent: Monday, May 10, 1999 7:23 AM > To: diy_efi@xxx.edu > Subject: Re: Looking for a 1-psi Hobbes switch > > Previously, you (DemonTSi@xxx.com) wrote: > > another alternative is the diaphram used in washing machines they work in > inches of water ( put a restrictor to prevent backfire from poping it) > > > In a message dated 5/8/99 5:54:18 PM Pacific Daylight Time, > > EdDSP@xxx.com writes: > > > > << Here's what I'm doing. I'd like to mount a switch on an intake > manifold > > that'll work once there is positive pressure (boost). Such a switch > > exist? A part # would be most appreciated too. >> > > and the washer machine one is adjustible > > > > > The lowest psi activated switch I've ever seen was a 3psi unit...that > goes > > for like 125 bucks! You can get an adjustable hobbs one (sold for use > with > > nos systems) that activates at 5psi for like under 10 bucks. Then you > can use > > a regulator or other restrictor inline and adjust it to show the switch > the > > psi you need. > > > > Van > > > -- > Pat Ford email: pford@xxx.com > QNX Software Systems, Ltd. WWW: http://www.qnx.com > (613) 591-0931 (voice) mail: 175 Terrence Matthews > (613) 591-3579 (fax) Kanata, Ontario, Canada K2M 1W8 ------------------------------ Date: Mon, 10 May 1999 11:08:37 -0700 From: "Todd....!!" Subject: Re: CFM Continued... Fred, You're probably aware that a 30+% loss can be attained by using a stock or aftermarket WET (Made for Carburetor) intake for a fuel injection application (No turbo's involved) With this in mind, I believe a gain of 10-30% in power and gas mileage attained by switching from carb to FI would be negated by the lack of efficiency due to this phenomenon... what are ya'll's thoughts about this? This is kindof worrying me and is also beginning to make me double think my twin turbo FI 440/451 project... Thanks! Todd....!! - ---------- Frederic Breitwieser wrote: > > > a stock 350 ci engine. I’m looking for an EFI intake system for my twin > > turbo 434 ci engine. > > Aaaaah. > > > The guy putting the turbos together said that the stock TPI is a good choice > > because it will give me something really important for a fun to drive street > > car, great throttle response and low end torque. > > This is true, because the runners are smoothly curved, and long. Typically > longer runners give you more low-end torque, however at higher RPMs your engine > will wease to death. Several manufacturers have come up with variable length > runners... the one that sits in my mind is the new Ford Taurus... long runners > for low end grunt, and shorter parallel runners for higher RPMs. > > Instead of a 2500/3000rpm spool up range you could size for smaller turbos and > have them spool up faster, thus taking even more advantage of the longer > runners... but then your high end will suffer from runner length as before, but > even more from grossly undersized turbos. but, it will take off the line quite > nicely. > > I'm doing this with my Dodge truck actually... 383 cid stroked to 431, two small > turbos, then a max RPM of 4000 RPM. Great for towing, not top speed. Its a > 6000lb truck anyway :) > > You might get more performance by using a much larger throttle body, and doing > some runner port work. > > > with 15 lbs of boost it seems to me that the stock TPI is still small for a > > 434 performance engine, or will the boost really make up the difference for > > the small tubes? > > I believe the velocity would be too great for your engine... but I am not an > expert in this area. For my dodge engine, I've already drilled out the > manifold, welded in injector bungs, and going to use the TPI GM setup to manage > the dodge motor, and instead of the GM TPI manifold, I'm just using the dodge > intake with all the GM "stuff" attached. You might consider that approach for > your engine... chose a carb manifold that suits your needs and application, then > mill into it some injector bungs. Its a fair amount of work, but in the end I > believe its worth it. > > -- > > Frederic Breitwieser > > Xephic Technology > "Leadership in IT" > Bridgeport, CT 06606 > > Web: http://www.xephic.dynip.com > Voice: (203) 372-2707 > Fax: (603) 372-1147 ------------------------------ Date: Mon, 10 May 1999 11:15:19 -0700 From: "Todd....!!" Subject: Re: CFM Continued... With what you say in mind, then WHY does a STOCK 426 Hemi SONGLE intake runner flow about 300 cfm each, from the factory?? Just wonderin... I have heard that you want your cfm to be about 30% MORE than what is theoretically required, due to our nonprefect world operating environment and all... Thanks for your formula's and input in this subject, it's enlightening... Todd....!! - --------- Greg Hermann wrote: > > >Thanks to Ken, Todd & Gary for your answers regarding CFM. Perhaps I didnít > >ask the question correctly. A stock TPI runs out of flow about 4800 rpm on > >a stock 350 ci engine. Iím looking for an EFI intake system for my twin > >turbo 434 ci engine. > > > >The guy putting the turbos together said that the stock TPI is a good choice > >because it will give me something really important for a fun to drive street > >car, great throttle response and low end torque. > > > > How fast are you planning to turn the engine? Say for a 434, 5400 will be it? > > Then, the engine will be trying to breathe in 434 x 5400 x 0.5 x 1/1728 , > or 678 cfm at the highest speed you will be turning it. The runners to each > cylinder will be wanting to flow 1/8 of this much, or about 85 cfm each. > > The trick is to size everything in the flow path so that you do not have > excessive pressure drop at any one point in the path at the amount of flow > the engine wants to draw in. What the guy talking to you is missing is that > with a pressurized intake--the pressure drop in the runners is proportional > to the density of the air flowing through them! > > Of course--you will also have proportionally more pressure you can afford > to lose with the turbo motor, So whatever will work well with the same size > and speed range NA motor is pretty close for a turbo motor. Going maybe a > fuzz BIGGER than what you would use for a similar size/speed NA motor will > tend to lower backpressure from the turbo on the motor, and lower EGT's > some. > > Going any smaller than what you would run on an NA 434 would hurt > performance some, and durability more. > > Flow on the inlet side of the turbos will be the amount of air the engine > breathes times the manifold density ratio--a LOT more cfm. Everything on > the inlet side of the turbos should be sized accordingly, and also to have > VERY low pressure losses at this design flow The amount of back pressure > which the turbo(s) will put on the engine to make a given amount of boost > is EXTREMELY sensitive to losses in the inlet tract to the turbos!. > > Regards, Greg ------------------------------ Date: Mon, 10 May 1999 11:43:34 -0700 From: "Todd....!!" Subject: Re: alternative engines Well Gary, I agree kindof... I believe that when we ever get our transporter technology perfected, we'll just be able to transport the EXACT correct air/fuel mixture straight to the combustion chamber without the need for any intake runners or anything like that!! As well as extract the exhaust from teh combustion chamber in the same manner!! WHALAA, almost perfect combustion every time! LATER! Todd....!! - ---------- Gary Derian wrote: > > You have to stop thinking in a 3 dimensional Newtonian space and think in a > 4 dimensional space-time continuum. Fortunately, EFI operates in 3D space > for now, in a few years, the electronics will take advantage of quantum > effects. > > Gary Derian > > > Thanks for that insight Mike! > > > > However, I must ask: > > > > You mention that the Sun warps space... > > > > If Space is a LACK of everything, thus meaning that it is truly NOTHING, > > then how can NOTHING be WARPED?? > > > > Please explain? > > > > Thanks! > > > > Todd....!! > > ------------------------------ Date: Mon, 10 May 1999 11:53:16 -0700 From: "Todd....!!" Subject: Re: alternative engines, WARPED The ONLY reason 'space' 'exists' is because we SAY it exists, there is no other determining factor except that. Theoretical Space is just that space, NO MASS. Space as a location/region known as OUTER space, sure, it can and does contain mass, however, within these masses, within each molecule of these masses and between the eletrons and protons and neutrons there is still SPACE, SURe the electrons, protons, and neutrons are made up of even smaller particles, and between these particles there is still even MORE SPACE.... If you look at a molecule of say, hydrogen, and look at the 'SPACE' IN BETWEEN the electrons and the center where the proton and neutron are located, there is nothing there!! Just like in OUTER SPACE there is 'nothing' in between the moon and the Earths atmosphere except a few objects such as space trash and satellites!! Are we deep yet? Back to FI....Am about to rebuild a VACUUM 750 Holley, any tips? LATER! Todd....!! A70Duster@xxx.com wrote: > > In a message dated 5/7/1999 10:46:08 AM Mountain Daylight Time, > gderian@xxx.com writes: > > << > Thanks for that insight Mike! > > > > However, I must ask: > > > > You mention that the Sun warps space... > > > > If Space is a LACK of everything, thus meaning that it is truly NOTHING, > > then how can NOTHING be WARPED?? > > > > Please explain? > > > > Thanks! > > > > Todd....!! > > >> > > Oh God, U had to ask. Space, like a vacuum and where satellites cruse in > orbit, is where something can exist. Even space is quantized. Very, very, > very many packets of space exist together to create the visible universe that > we live in. Anything with mass distorts the "uniform" close proximity > packing of space packets. > > So space is something. It's massless, energyless and momentumless. But it > is a region where mass, energy and momentum can exist. > > The are MANY questions on regions where normal space does not exist (i.e., > Black holes, beyond our universe for example). > > Now returning to EFI...... ------------------------------ Date: Mon, 10 May 1999 13:42:48 -0400 From: James Seabolt Subject: 5th injector One more thing I could add to my dilema. Since there is no way to adjust the fuel flow of my second cold start valve other than when the fuel pressure increases (despite that it's still not spraying enough fuel at 7 pounds of boost), I have been thinking of replacing it with an actual fuel injector from the same system. Then controlling the pulse rate using a 555 timer IC and a potentiomter. Then I can control the pulse rate from the dash. I think 555 is right, it's been awhile since my college days. The injectors used in the Bosch L-jetronic system should operate at 4 volts. I think. I don't know of any voltage regulators that would step down the voltage to 4 volts. I suppose I could use a regulator that steps the voltage down to 5 volts and install a resistor to bring it down an extra volt. Has anyone ever built a system like this using the above components? I've seen 5th injector units in books but don't know where to purchase one. Micro Dynamics makes them, but I don't think they are sold in the United States. But I would rather build my own system. After all that's what this mailing list is about. Building your own stuff rather than going out and buying them. - ---------------------------------------------------------- James Seabolt -----> mailto:jseabolt@xxx.net Webpage: http://users.intermediatn.net/jseabolt/ ICQ # : 7344463 United States 1980 FIAT 2000 TURBO Spider injected (John Deere aspirated) 1981 FIAT 2000 Spider (Rest in Pieces) 1981 FIAT X 1/9 (Injected) 1994 JEEP Wrangler (2.5l ) 1976 Chevrolet Pickup (454 Big block/7.3 liter) - ---------------------------------------------------------- ------------------------------ Date: Mon, 10 May 1999 10:51:37 -0700 From: GARY Subject: Re: Hessitation in Late Model Subarus Thank you everyone for all your input on Knock Sensor and associated engine hesitation problems. I am still fiddling around with mine and have taken on a partner, via email, with the same problem with and interest in Subarus. I am digesting all of what has been suggested and am doing a small amount of experimentation. My partner found a web site that has a guy named Mike Chaney who is a GM knock sensor hacker. I have emailed him and invited him to join this group. He has a formula for desensitizing the knock sensor, and his web site offers a real cool little program that tells you what resistor values to use for any given resistance of knock sensor according to what percentage of dampening you wish for. He adds a resistor in series with the KS and parallels the KS with new resistor, with another resistor to maintain a circuit resistance equivalent to stock. His instructions show that for a ten percent decrease in signal strength, you ad a resistor in series with your KS of a value that is 10 percent of the resistance of the knock sensor. What do you think of that? here is his website url: http://www.charm.net/~mchaney/f-tech.htm While I like the idea of the two resistors, one for dampening generated signal and one for maintaining overall circuit original resistance, I question how he came up with his formula for the percentage of dampening. I have emailed him and inquired. As for my wish to manipulate the ignition timing (not knock sensor related here), I am still searching. Superchips has been of no help but looked promising at first! They report that no IconRace product is available for my car. They told me that they should be able to chip it, but have not seen one. I think they are wrong as my EPROM type of ECU resembles what they refer to as "previously unchippable." Thanks again everyone and I'm all ears once again. - -- GARY mailto:hobiegary@xxx.net ------------------------------ Date: Mon, 10 May 1999 13:54:30 -0400 From: "David A. Cooley" Subject: Re: 5th injector > > Since there is no way to adjust the fuel flow of my second cold start valve > other than when the fuel pressure increases (despite that it's still not > spraying enough fuel at 7 pounds of boost), I have been thinking of > replacing it with an actual fuel injector from the same system. > > Then controlling the pulse rate using a 555 timer IC and a potentiomter. > Then I can control the pulse rate from the dash. > > I think 555 is right, it's been awhile since my college days. > > The injectors used in the Bosch L-jetronic system should operate at 4 > volts. I think. I don't know of any voltage regulators that would step down > the voltage to 4 volts. I suppose I could use a regulator that steps the > voltage down to 5 volts and install a resistor to bring it down an extra volt. Why would the injector be run at 4 volts? I've only seen BOSCH and other injectors that were made for 12 volts. The ECM usually just grounds one side to turn it on and the other side goes to 12 volts when the key is on. Best bet is have it pulse at a specific rate, but adjust the Pulse width as boost increases. ------------------------------ Date: Mon, 10 May 1999 11:23:12 -0700 (PDT) From: Squash Subject: Re: CFM Continued... >-- "Todd....!!" wrote: > > With this in mind, I believe a gain of 10-30% in > power and gas mileage > attained by switching from carb to FI would be > negated by the lack of > efficiency due to this phenomenon... You will gain tunability, throttle response, and depending on how your engine is built, you can "tame" it a bit. And you can't flood an EFI. I just read an article where a 502GM engine had a single-plane intake with a 4bbl 1000cfm TB on it and injectors mounted in the ports. They installed and tweaked a 750cfm (or was it 850cfm?) holley carb on that intake and compared it to the EFI. The EFI won in HP and torque, not to mention starting and all the other givens. Andy _________________________________________________________ Do You Yahoo!? Get your free @xxx.com ------------------------------ Date: Mon, 10 May 1999 11:41:53 -0700 From: "James Montebello" Subject: RE: L-jetronic mods Around '80 - '81, the Fiat Spider was sold with a turbo in this country. It was, as I recall, an option added by the US importer, not a factory item. The same L-Jet was used, albeit recalibrated. I'd try and scare up some data on this conversion. I'd guess that the conversion parts couldn't have been all that expensive or exotic, given the origin, nor could I imagine extensive modifications were done to the L-Jet to get it to work. james montebello > -----Original Message----- > From: owner-diy_efi@xxx.edu > [mailto:owner-diy_efi@xxx.edu]On Behalf Of > James Seabolt > Sent: Sunday, May 09, 1999 10:24 PM > To: diy_efi@xxx.edu > Subject: L-jetronic mods > > > Hello. I'm new to the list (sort of), so forgive me this > subject has been > covered before. > > I installed a custom turbo system on my 1980 Fiat Spider. Building the > system was a task itself but getting the engine to resist > detontation has > been an uphill battle. If detonation is as destructive as > what everybody > describes, then my engine would have been toast months ago because my > engine has shown no ill effects. So far anyway. > > I had been running a few band-aid solutions such as water/alcohol > injection, timing retard, etc. but these are getting old. My > real problem > is fuel enrichment. > > Here's some specs: > > 2 liter/twin cam/hemi design > C/R: 8.1:1 (factory), current unknown, head was resurfaced > during the last > rebuild. > Bosch L-jetronic fuel injection system w/lambda sensor > Turbo: Rayjay 301 > Boost: 7 pounds > gasoline : 93 octane (of course) > > Fuel enrichement device, rising rate fuel pressure regulator > and a 2nd cold > start valve mounted upstream triggered at around 2 pounds. > > With these specifications, this engine should handle 7 pounds > of boost with > no problems. That is with proper fuel enrichment, but I can't > figure out > how to get more fuel into the engine. > > The most frustrating thing is, the potentional is there, I > just don't know > how to unlock it. > > The other day, I was able to trick the computer into dumping > more fuel into > the motor than it could handle, to the point the car was > smothering and > belching black smoke out out the exhaust at 7 pounds. The > engine seemed to > handle the extra amount of fuel until the contacts in the > throttle position > switch closed and dumped too much fuel. > > I did this by installing a set of boost switches which adds resistance > (about 2000 ohms) between the computer and coolant > temperature sensor. This > doesn't work on my car because I've got a rising rate fuel > pressure regulator. > > My latest experiment was to splice a Hobbs pressure switch between the > oxygen sensor and computer. As soon as I hit boost (.1 > pounds) the control > loop is disrupted. > > Today the temperature was near 80F and the car seemed to do OK. > > Can someone tell me this: > > I was under the impression that when the engine is under wide open > throttle, the throttle position switch breaks the control > loop. Is this > correct? > > Or no matter what, the engine is still in the control loop? > > My theory is that any attempts to get more fuel into the > engine are being > overiden by the oxygen sensor even under wide open throttle, but by > breaking the control loop, now I can get more fuel into the engine. > > Seems like my latest attempt has worked by I would still be more > comfortable knowing that I am getting the most fuel I can get > into my motor > without causing the car to choke. > > Here's a rundown of my current setup: > > 1) rising rate fuel pressure regulator > 2) 2nd cold start valve mounted upstream before the throttle > body triggered > at around 2 pounds. > 3) Oxygen sensor to computer broken at .1 pounds > > I would like to do away with the 2nd cold start valve and use > the injectors > as my sole source for fuel because I know they have the > potential when the > fuel pressure is stepped up. > > Also I want to point out that during the experiment where I > got too much > fuel into the engine was done with the 2nd cold start valve > disconnected. > > What could I do to increase the pulse rate of the injectors? > My attempt to > create my own boost switch didn't work. I tried rigging up > another pressure > switch with several rated resistors (600-1000 ohms) in > parallel but the CPU > didn't like this. > > Also is there anything to my latest experiment by breaking the circuit > between the oxygen sensor and computer under boost? > > If you guys need anymore details, just email me. > > This fuel injection system has been around for 25 years so I > am sure there > is someone on here that knows how to trick this system. > > Should I just have the injectors remapped to flow more fuel > and run a lower > fuel pressure so the engine won't run rich at idle and cruise? > > Great Scott! I'm running out of options here. Someone help me! > > Thanks. > > > ---------------------------------------------------------- > > James Seabolt -----> mailto:jseabolt@xxx.net > Webpage: http://users.intermediatn.net/jseabolt/ > ICQ # : 7344463 > > United States > > 1980 FIAT 2000 TURBO Spider injected (John Deere aspirated) > 1981 FIAT 2000 Spider (Rest in Pieces) > 1981 FIAT X 1/9 (Injected) > 1994 JEEP Wrangler (2.5l ) > 1976 Chevrolet Pickup (454 Big block/7.3 liter) > > ---------------------------------------------------------- > > ------------------------------ End of DIY_EFI Digest V4 #274 ***************************** 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".