DIY_EFI Digest Tuesday, May 11 1999 Volume 04 : Number 275 In this issue: RPM independence Re: CFM Continued... Re: RPM independence Re: RPM independence Re: CFM Continued... knock sensor Re: CFM Continued... Did anyone see the employment ad at Callaway ? Re: Did anyone see the employment ad at Callaway ? Hobbs pressure switches RE: L-jetronic mods Re: knock sensor O2 sensor trick Re: CFM Continued... Re: knock sensor Re: CFM Continued... Re: CFM Continued... RE: RPM independence Re: CFM Continued... Re: alternative engines, WARPED Re: Did anyone see the employment ad at Callaway ? Re: RPM independence Re: alternative engines, WARPED Re: Did anyone see the employment ad at Callaway ? Re: CFM Continued... Re: Espen's Reed Valves Re: Did anyone see the employment ad at Callaway ? Re: Espen's Reed Valves Re: Looking for a 1-psi Hobbes switch Reed Valves See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Wed, 12 May 1999 12:01:03 -0700 From: "Howard Wilkinson" Subject: RPM independence I have given more than a little thought to the possibility of an EFI system that operated completely independently of engine RPM. The idea being that as the injectors are batch fired anyway, the timing is irrelevant so long as the injectors fire at engine RPM or more. Such a system could be almost entirely MAF based. The injectors would begin at a very short pulse width, and simply increase pulse rate up to a set pulse rate where width would be increased thereafter. Such a system could be operated based on mathematical formulae rather than on look up tables. A simple equation based on ECT could modify the result for cold operation, and a TPS modifier would give accelerator pump effect. Map should not be necessary as air density should directly effect MAF output. An O2 loop would handle minor dicrepancies. A lot of the complexity of the common EFI systems comes from the desire to fire the injectors once per revolution. Because of RPM dependence, the MAP, MAF, & TPS outputs are meaningful only in the context of RPM. Total fuel delivery per unit time is only directly related to MAF.... It is not closely related to RPM, Throttle Position, or Vacuum individually as it is to MAF. The MAF tells us how much fuel we must deliver per unit time, but the system must then work out the pulse rate based on RPM, and pulse width for that rate to achieve the desired delivery per unit time. If we know that x amount of fuel is delivered at Y pulse width per pulse, then it becomes a simple matter to determine how many pulses per unit time are required to deliver that amount of fuel. At some point pulse rate reaches a max practical limit, and at that point pulse rate can become constant, and pulse width may be modified above that point to control fuel delivery. The fewer factors you are changing the simple the program becomes. Perhaps this is a simple minded vew of the process, but then I'm a simple minded sort of guy.... I am of the "KISS" school of thought. H.W. ------------------------------ Date: Mon, 10 May 1999 15:20:23 -0400 From: "David A. Cooley" Subject: Re: CFM Continued... > > And you can't flood an EFI. > Actually, you can! Been there, Done that! ------------------------------ Date: Mon, 10 May 1999 15:25:54 -0400 From: "Bruce Plecan" Subject: Re: RPM independence One thing I've been musing over is something similiar. But way over driving the injectors as a function of rpm. That way I could use say two ecms one for timing (a v-8, as a v-8, on a v-8) Then one for fuel at say the injector firing rate of a 6 cylinder. Bruce > I have given more than a little thought to the possibility of an EFI > system that operated completely independently of engine RPM. The idea > being that as the injectors are batch fired anyway, the timing is > irrelevant so long as the injectors fire at engine RPM or more. > Such a system could be almost entirely MAF based. The injectors > would begin at a very short pulse width, and simply increase pulse > rate up to a set pulse rate where width would be increased thereafter. > Such a system could be operated based on mathematical formulae rather > than on look up tables. A simple equation based on ECT could modify > the result for cold operation, and a TPS modifier would give > accelerator pump effect. Map should not be necessary as air density > should directly effect MAF output. An O2 loop would handle minor > dicrepancies. > A lot of the complexity of the common EFI systems comes from the > desire to fire the injectors once per revolution. Because of RPM > dependence, the MAP, MAF, & TPS outputs are meaningful only in the > context of RPM. Total fuel delivery per unit time is only directly > related to MAF.... It is not closely related to RPM, Throttle > Position, or Vacuum individually as it is to MAF. The MAF tells us > how much fuel we must deliver per unit time, but the system must then > work out the pulse rate based on RPM, and pulse width for that rate to > achieve the desired delivery per unit time. > If we know that x amount of fuel is delivered at Y pulse width per > pulse, then it becomes a simple matter to determine how many pulses > per unit time are required to deliver that amount of fuel. At some > point pulse rate reaches a max practical limit, and at that point > pulse rate can become constant, and pulse width may be modified above > that point to control fuel delivery. The fewer factors you are > changing the simple the program becomes. > Perhaps this is a simple minded vew of the process, but then I'm a > simple minded sort of guy.... I am of the "KISS" school of thought. > H.W. ------------------------------ Date: Mon, 10 May 1999 16:06:15 EDT From: A70Duster@xxx.com Subject: Re: RPM independence Been there, done that. Very difficult for idle control. Too much fuel at idle because the injector duration is shorter that the injector ON/OFF transition period. Maybe at low MAF numbers (idle, low rpm cruse) increase the period of the injector to get decent idle fuel injection control. See ya, Mike ------------------------------ Date: Mon, 10 May 1999 16:08:22 -0400 From: "Gary Derian" Subject: Re: CFM Continued... A single runner flows for only 1/3 to 1/4 of an engine cycle. Gary Derian > 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 16:38:38 -0700 From: Brian Lewis Subject: knock sensor Hello Everyone, I am thinking of adding a knock detection circuit to an engine management system that I am developing. What type of signal conditioning do I need to add a GM style sensor? What type of output does this sensor produce and how do I determine if detonation has occured? Are there any resources on this somewhere? Thanks in advance. Brian Lewis ------------------------------ Date: Mon, 10 May 1999 14:04:26 -0700 (PDT) From: Squash Subject: Re: CFM Continued... - --- "David A. Cooley" wrote: > > > > And you can't flood an EFI. > > > > Actually, you can! > Been there, Done that! I meant by means of the float bowls. Fuel slosh. Bogging. With EFI, you can fill your cylinders up with gas if that's what u wanna do! Andy _________________________________________________________ Do You Yahoo!? Get your free @xxx.com ------------------------------ Date: Mon, 10 May 1999 14:22:46 -0700 From: Eric Aos Subject: Did anyone see the employment ad at Callaway ? Software Engineer-Engine Management A hands on software engineer to develop the special sections of the GM/Delphi engine control unit for the Y car platform. Working on a consultant basis, relatively simple adjustments to such parameters as rev limits, torque thresholds, and display functions. Opening is immediate. ------------------------------ Date: Mon, 10 May 1999 17:31:11 -0400 From: "Bruce Plecan" Subject: Re: Did anyone see the employment ad at Callaway ? Subject: Did anyone see the employment ad at Callaway ? Yep, they been looking since X-mas Grumpy > Software Engineer-Engine Management > > A hands on software engineer to develop the special sections of the > GM/Delphi engine control unit for the Y car platform. Working on a > consultant basis, relatively simple adjustments to such parameters as > rev limits, torque thresholds, and display functions. Opening is > immediate. > ------------------------------ Date: Mon, 10 May 1999 17:35:55 -0400 From: James Seabolt Subject: Hobbs pressure switches Someone wrote: > 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. You can get these switches at NAPA. The two pole switches sell for $14. The three pole (Closed/normally open/normally closed) sells for more. The two pressure switches that Hobbs makes I know of are rated 3 to 10 pounds (two pole) and the other one is (.1 to 24 PSI) three pole. The later is the most versitile. - ---------------------------------------------------------- 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 17:51:58 -0400 From: James Seabolt Subject: RE: L-jetronic mods "James Montebello" wrote: >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. I can tell you everything they did to it. They ran 6 pounds of boost and a really small turbo. Installed four sets of boost switches: #1) added 1700 ohms resistance at 1PSI to the coolant temperature circuit #2) added an additional 500 ohms at 5PSI #3) closed the contacts in the TPS at 1 pound (which dumps even more fuel) #4) overboost switch which did something at 9 pounds Installed INOX head gasket which has stainless steel inserts instead of copper. Despite being a little thicker I think this only dropped the C/R from 8.1:1 to 7.9:1 not much. Next thing they did was alter the advance curve from 28 degrees total advance to 10 degrees total advance. All they did was install a fixed clip in place of one of the springs. This really effect horsepower. That's it. The end result was an extra 18 horses! Just 18 horses at 6 pounds of boost. In theory 7 pounds equals 50% more power so the car should have went from 102 to at least 140. Some owners complained that when the boost switches kicked in, this dumped way to much fuel into the motor at once. Also the retarded timing caused the cast iron exhaust manifolds to warp. No oil cooler either. The Warner ISI turbo had a life expectantcy of no more than 20,000 miles. This is a good example of how not to design a turbo system. I think there was roughly 800 conversions done, most of which were converted back to original. - ---------------------------------------------------------- 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 16:52:00 -0500 (CDT) From: Roger Heflin Subject: Re: knock sensor On Mon, 10 May 1999, Brian Lewis wrote: > Hello Everyone, > > I am thinking of adding a knock detection circuit to an engine management > system that I am developing. What type of signal conditioning do I need to > add a GM style sensor? What type of output does this sensor produce and how > do I determine if detonation has occured? Are there any resources on this > somewhere? Thanks in advance. > > Brian Lewis > I believe the GM sensor is basically a pizeo (sp?) microphone. There is a circuit in the ECM (it is a removable chip/module on 94+ vehicles or is in the chip carrier on pre-94 vehicle (f-bodies, unknown about other models)). I believe the circuit in the ECM is some sort of filter, it is my belief that a better knock sensor could be made with a more exoitic detection algorithm (DSP). It is also my belief that other stuff could be detected with this more exoitic setup (misfires? listen for the iginition and yell if it is not there). I believe the GM filter is a notch filter, and if the energy in the band gets above a certain amount it sends an output high which signals knock. The knock module in the block is a mic though. All of the "interesting" knock circuitry is in the ECM as a removable module or in the chip carrier in the ECM. Roger ------------------------------ Date: Mon, 10 May 1999 17:53:31 -0400 From: James Seabolt Subject: O2 sensor trick Been running my car all day long with the O2 sensor disabled under boost. It has been around 86F today and not narry a sign of pinging! No water injection either! The real test will be this summer when it get's upto 95F. - ---------------------------------------------------------- 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 16:53:56 -0500 (CDT) From: Roger Heflin Subject: Re: CFM Continued... On Mon, 10 May 1999, Squash wrote: > --- "David A. Cooley" wrote: > > > > > > And you can't flood an EFI. > > > > > > > Actually, you can! > > Been there, Done that! > > I meant by means of the float bowls. Fuel slosh. > Bogging. With EFI, you can fill your cylinders up > with gas if that's what u wanna do! > > Andy I think with the EFI setups you can get quite a bit of fuel sitting in the intake and causing flooding. GM has a clear flood mode, you floor the pedal and it cuts the injectors off until you let up. Roger ------------------------------ Date: Mon, 10 May 1999 16:55:16 -0500 From: steve ravet Subject: Re: knock sensor GM ECMs use a basic piezoelectric knock sensor. It's a microphone. It goes to what's called ESC, which does some sort of filtering that varies by application. Output of the ESC module is an on/off signal to the ECM that knock is occurring. On C3 style ECMs the ESC circuitry is a separate module, about 2" x 2" x .5". On P4 style ECMs it's on the module that also holds the EPROM. In general, some vary. Bruce did some work characterizing the response of ESC modules. If you're using a GM engine you can probably get an ESC module for it from the junkyard along with a sensor and be done with it. Lots of knock sensor info in the archives also. - --steve Brian Lewis wrote: > > Hello Everyone, > > I am thinking of adding a knock detection circuit to an engine management > system that I am developing. What type of signal conditioning do I need to > add a GM style sensor? What type of output does this sensor produce and how > do I determine if detonation has occured? Are there any resources on this > somewhere? Thanks in advance. > > Brian Lewis ------------------------------ Date: Mon, 10 May 1999 16:19:54 -0600 From: bearbvd@xxx.net (Greg Hermann) 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... > The Hemi runner may well flow 300 cfm at one of the two standard test pressures--this simply means that it will flow all the air that the engine wants at a far lower pressure drop than the standard test pressure. Say you Hemi is turning 6500 rpm, is the stock 426 cubes, and is good for 94% volumetric efficiency at 6500 rpm (optimistic, but a Hemi might do this well). OK--426/8 = 53.25 x .5 x 6500 / 1728 = 100.15 cfm of air flow to each cylinder. (Call it 100 cfm.) (But realize that this is an AVERAGE flow rate. It is higher when the valve is at maximum lift, and lower at partial valve lift, and non-existent when the valve is closed. Say the cam is such that the valve is off the seat to a significant degree 33% of the time (240 degrees of duration at .050" valve lift). Each intake runner flowed 300 cfm at a test pressure drop of 25" of H2O . (with a CONSTANT test flow rate, and probably at a valve lift of .650".) Well--first of all--the fact that the valve is only open 33% of the time means that the flow through the valve would have to average 300 cfm DURING THE TIME THAT THE VALVE IS OFF ITS SEAT, in order to achieve the AVERAGE 100 cfm flow calculated above. Next--things get more complicated--one would really need to integrate the area under the valve lift curve and the pressure drop in the port at various valve lifts, and so on, in order to figure out exactly how much air was flowing in the port at different parts of the valve lift curve, and at what pressure drop, in order for the engine to draw in the amount of air it consumes. It IS important to remember that the net effect of pressure drop as air flows through the inlet tract of an engine is less dense air filling the cylinders. Which translates into less oxygen to burn fuel, and therefore less power as the pressure drops increase. The flow bench numbers are hardly an exact indication of what goes on in real world flow inside an engine, but hopefully, the example above will illustrate why the standard flow bench test pressures for heads (either 25 or 28" of H2O, depending on who is doing the testing) are fairly realistic--that is to say--in the ballpark for the flow velocities which occur at maximum valve lift in a real engine. Regards, Greg ------------------------------ Date: Mon, 10 May 1999 18:37:57 -0400 From: "David A. Cooley" Subject: Re: CFM Continued... At 02:04 PM 5/10/99 -0700, you wrote: >--- "David A. Cooley" wrote: >> > >> > And you can't flood an EFI. >> > >> >> Actually, you can! >> Been there, Done that! > >I meant by means of the float bowls. Fuel slosh. >Bogging. With EFI, you can fill your cylinders up >with gas if that's what u wanna do! Ah.. Been there and done that too! It's a bear when you forgot to put the needle valve and seat back in and try to start the car! =========================================================== David Cooley N5XMT Internet: N5XMT@xxx.net Packet: N5XMT@xxx. Member #7068 Sponges grow in the ocean... Wonder how deep it would be if they didn't?! =========================================================== ------------------------------ Date: Mon, 10 May 1999 16:54:39 -0700 From: "James Montebello" Subject: RE: RPM independence > I have given more than a little thought to the possibility of an EFI > system that operated completely independently of engine RPM. The idea > being that as the injectors are batch fired anyway, the timing is > irrelevant so long as the injectors fire at engine RPM or more. > Such a system could be almost entirely MAF based. This is, essentially, what CIS (aka K-Jetronic) does. Airflow is the ONLY parameter used to adjust fuel flow rate, except for cold running and WOT operation. Engine speed isn't a factor at all. Designing an EFI system to emulate this is straightforward. However, if you plan on controlling ignition as well as fuel, you're going to need crank position and speed, anyway, so using it as part of the fuel delivery strategy doesn't add any more complexity. It also opens up a few new avenues of overcoming common problems. A MAF (or MAP or CIS) system is sensitive to reversion when high-lift, long-overlap cams are used. With given exhaust and intake systems, reversion will only take place at certain engine speed ranges, so it can be compensated for if the engine speed is known. More data is almost always better than less. The frequently forgotten other half of the KISS principle is: keep it simple, but not TOO simple. james montebello ------------------------------ Date: Mon, 10 May 1999 20:17:39 -0700 From: "Walter Sherwin" Subject: Re: CFM Continued... >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. Neat! Where was this published? Walt. ------------------------------ Date: Mon, 10 May 1999 20:17:28 -0400 From: Shannen Durphey Subject: Re: alternative engines, WARPED Todd....!! wrote: > > 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!! No one has yet determined an absolute answer for those questions. What's to say your idea of nothing is the last word? Well, this post is my last word on this. > > Are we deep yet? > > Back to FI....Am about to rebuild a VACUUM 750 Holley, any tips? > > LATER! > > Todd....!! Dig a deep hole, insert the Holley, re install dirt. Is that deep enough? Shannen ------------------------------ Date: Mon, 10 May 1999 20:50:03 -0400 From: Shannen Durphey Subject: Re: Did anyone see the employment ad at Callaway ? Eric Aos wrote: > > Software Engineer-Engine Management > > A hands on software engineer to develop the special sections of the > GM/Delphi engine control unit for the Y car platform. Working on a > consultant basis, relatively simple adjustments to such parameters as > rev limits, torque thresholds, and display functions. Opening is > immediate. Maybe subcontract the job to DIY_EFI.. Shannen ------------------------------ Date: Wed, 12 May 1999 19:22:53 -0700 From: "Howard Wilkinson" Subject: Re: RPM independence Mike: I beg your pardon here, but I was not able to translate this into something that fit into the framework of what I was talking about.... Ultra short duration was not contemplated. > > Too much fuel at >idle because the injector duration is shorter that the injector ON/OFF >transition period. > My thinking was to set injector duration more or less to what was required at idle, and increasing pulse rate with RPM... extreme short pulse duration would serve no purpose that I can see. Would you mind elaborating on this a little bit please? H.W. ------------------------------ Date: Mon, 10 May 1999 20:55:47 -0600 From: bearbvd@xxx.net (Greg Hermann) Subject: Re: alternative engines, WARPED >Todd....!! wrote: > >> >> 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!! > >No one has yet determined an absolute answer for those questions. >What's to say your idea of nothing is the last word? Well, this post >is my last word on this. > >> >> Are we deep yet? >> >> Back to FI....Am about to rebuild a VACUUM 750 Holley, any tips? >> >> LATER! >> >> Todd....!! > >Dig a deep hole, insert the Holley, re install dirt. >Is that deep enough? >Shannen But--I LIKE 3310's!! Greg ------------------------------ Date: Mon, 10 May 1999 20:58:58 -0600 From: bearbvd@xxx.net (Greg Hermann) Subject: Re: Did anyone see the employment ad at Callaway ? >Eric Aos wrote: >> >> Software Engineer-Engine Management >> >> A hands on software engineer to develop the special sections of the >> GM/Delphi engine control unit for the Y car platform. Working on a >> consultant basis, relatively simple adjustments to such parameters as >> rev limits, torque thresholds, and display functions. Opening is >> immediate. > >Maybe subcontract the job to DIY_EFI.. >Shannen Bruce musta raised Grumpy's pay some--kinda surprised he's still in Arcanum, otherwise! Greg ------------------------------ Date: Mon, 10 May 1999 20:08:18 -0700 (PDT) From: Squash Subject: Re: CFM Continued... The article is in the may 1999 issue of "Car Craft" magazine. You should buy it! 502EFI ended up with 591HP and 532lb/ft 502 with 850 holley on the same intake got 542HP and 524 lb/ft And that is across the RPM range, not just at the peak! Even with mismatched intake ports (peanut, rectangle, oval) the EFI made more HP and torque. But compared to the holley 850 and a dual-plane intake, they only managed to get less than 10 hp and 10 lb/ft of torque. So don't think that any EFI will blow away a carb under all circumstances! Andy - --- Walter Sherwin wrote: > >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. > > > > > Neat! Where was this published? > > Walt. > > _________________________________________________________ Do You Yahoo!? Free instant messaging and more at http://messenger.yahoo.com ------------------------------ Date: Mon, 10 May 1999 20:54:00 -0500 From: dave.williams@xxx.us (Dave Williams) 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. The owner of Boyesen, the major motorcycle reed valve aftermarket manufacturer, gave a talk on uses of reed valves in racing engines at the last Superflow conference in Colorado. ------------------------------ Date: Mon, 10 May 1999 23:21:52 -0400 From: "Bruce Plecan" Subject: Re: Did anyone see the employment ad at Callaway ? Ya might get him away from the steam threshers, but not the Pullers Doc Software Engineer-Engine Management > >> A hands on software engineer to develop the special sections of the > >> GM/Delphi engine control unit for the Y car platform. Working on a > >> consultant basis, relatively simple adjustments to such parameters as > >> rev limits, torque thresholds, and display functions. Opening is > >> immediate. > >Maybe subcontract the job to DIY_EFI.. > >Shannen > Bruce musta raised Grumpy's pay some--kinda surprised he's still in > Arcanum, otherwise! > Greg ------------------------------ Date: Mon, 10 May 1999 23:51:18 -0400 From: "Bruce Plecan" Subject: Re: Espen's Reed Valves And, > > -> 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. > > The owner of Boyesen, the major motorcycle reed valve aftermarket > manufacturer, gave a talk on uses of reed valves in racing engines at > the last Superflow conference in Colorado. > > ------------------------------ Date: Mon, 10 May 1999 00:30:08 -0600 From: "Programmer" Subject: Re: Looking for a 1-psi Hobbes switch Why don't you just use a MAP sensor from a turbo app ?? Lyndon IP TECH LWester@xxx.com - -----Original Message----- From: Ed To: diy_efi@xxx.edu> Date: Saturday, May 08, 1999 8:26 PM Subject: Looking for a 1-psi Hobbes switch >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. > >-Ed ------------------------------ Date: Tue, 11 May 1999 09:45:19 +0200 From: "Espen Hilde" Subject: Reed Valves > The owner of Boyesen, the major motorcycle reed valve aftermarket > manufacturer, gave a talk on uses of reed valves in racing engines at > the last Superflow conference in Colorado. What did he say? ------------------------------ End of DIY_EFI Digest V4 #275 ***************************** 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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